Anal
Anal cancers are composed predominantly of squamous carcinomas and are HPV-associated
in 90% of instances. The little attention that anal cancer has received may be
related in equal parts to the stigma surrounding this malignancy and to the rarity
of this tumor in the general population where the incidence has been estimated at 1
to 2 per 100,000. 49 The profile of anal cancer among the public was raised considerably when the
Hollywood and stage actress Farrah Fawcett went public with her personal struggles
after she had been diagnosed with invasive anal cancer and underwent surgery,
radiation therapy, and also sought non-traditional treatments for this
condition.
In the United States, the incidence of anal cancer is more common in women than men
with a rate of 1.8 compared to 1.1, respectively, per 100,000. 50 In WLWHA, the incidence of invasive anal cancer is approximately 15- to
60-fold greater than the general population. 51 Risk factors for anal infection with HPV include cigarette smoking, presence
of anal warts, and cervical HPV infection.
Survival from anal cancer significantly improves when it is diagnosed at an early
stage; yet, most are diagnosed at an advanced stage when symptoms of pain, pruritus,
or bleeding supervene. 49 An important argument for anal cancer screening in PLWHA, in addition to its
increased incidence and mortality in the HIV-infected population, is the biological
similarity between the cervix and the anus. Both anatomical sites include a
transition zone and squamous epithelium with the propensity for HPV infection. 52 High-resolution anoscopy (HRA) is similar to cervical colposcopy, allowing
for visualization of dysplastic lesions and the identification of suspicious lesions
to biopsy. 53
Screening for anal cancer is currently based on cytological detection of HPV-induced
abnormalities, followed by histological confirmation and treatment of the precursor
lesion, high-grade anal intraepithelial neoplasia (AIN). 53 Although similarities exist between cervical and anal cancer screening,
outcome research into anal cancer screening is lacking. 54 The various techniques which are used to screen for anal cancer include
digital anal rectal exam (DARE), anal Papinicolaou (Pap) test, and HRA. Anal
cytology is a fair predictor of AIN with a sensitivity ranging from 61% to 93% in
various studies. 8 HRA followed by biopsy are used as an adjunct for AIN diagnosis. Yet, there
is a poor correlation between the cytological and histological grade of AIN.
Cytology underestimates dysplasia grade compared with the corresponding biopsy.
There are no randomized studies to establish the reliability and validity of anal
cancer screening, or evidence of improved survival rates from anal cancer screening. 53 There also is no consensus as to who should be screened with DARE. 54 , 55 The
sensitivity, specificity, negative predictive value, and quality-of-life metrics and
costs associated with false-positive and false-negative DARE have not been
established.
An ongoing study ( NCT01946139 ) seeks to establish the best strategy for anal
dysplasia screening in women and compares three different assays (the HPV Hybrid
Capture 2 (HC2) assay; the HPV messenger ribonucleic acid (mRNA) assay (APTIMA); and
the OncoHealth HPV E6/E7 onco-protein assay) against the gold standard,
biopsy-confirmed high-grade squamous intraepithelial lesion (HSIL). The results of
this study should be available in 2018.
Additional barriers to more widespread anal cancer screening are the paucity of
medical practitioners well trained in HRA, the challenges of getting prior
authorization from Insurance carriers to pay for the procedure, and variations in
interpreting anal biopsy specimens. Ironically, the CDC has supported anal cytology
screening for PLWHA but have qualified this endorsement by emphasizing the need for
further studies to address screening and treatment programs. 56
Although no consensus guidelines exist, several financial analyses support strategies
around anal cancer screening. Researchers estimated that the biennial screening of
WLWHA would account for a 4.4-year increase in quality-adjusted life years (QALY) at
an incremental cost effectiveness ratio of US$34,763 per life gained compared to no screening. 57 Another analysis estimated that a yearly anal Pap test for HIV-infected MSM
would translate to US$16,000 per QALY gained compared to no screening. 58 A third study evaluated the feasibility and acceptability of anal screening
among HIV seropositive men. 59 The high prevalence of high-risk HPV serotypes and the frequency of
false-negative cytology suggested that HRA would have most clinical benefits as a
primary screening strategy for anal cancer in this high-risk group. The analysis was
hampered, however, by uncertainty as to how best to monitor those participants with
lower grades of AIN.
A National Institute of Health (NIH) funded study will shed more light on this
important area. The Anal Cancer High-Grade Squamous Intraepithelial Lesion Research
Outcome (ANCHOR) Study is a Phase III randomized clinical trial for PLWHA of age
35 years and older and who have high-grade AIN not previously treated. 60 One-half of the study volunteers will have their high-grade AIN treated and
the other half will be monitored every 6 months but not receive treatment unless
they develop invasive anal cancer. The primary outcome is the time from
randomization to anal cancer diagnosis. Secondary end points include incidence of
adverse events subsequent to treatment and quality of life. Treatment options
include imiquimod, topical fluorouracil, infrared coagulation, thermal ablation, and
laser therapy.
Vaccination is also an important but underutilized strategy for anal cancer
prevention with its greatest impact to be among those between the ages of 9 and
26 years. Strategies to reduce the burden of anal HPV-associated disease have been
more extensively studied in men than women because of the high incidence of anal
cancer in MSM. 8 An international study of 13,800 anogenital samples collected from women
suggests that incorporation of the nine-valent HPV vaccine among young girls and
women in 48 countries could lead to as much as an 86% reduction in anal cancer. 61
Lung
Lung cancer is the leading cause of cancer mortality for both men and women in the
United States. In PLWHA, lung cancer is also the most common non-ADM, and the
leading cause of death. 4 The number of lung cancers has doubled over the past 20 years, and the burden
is seen primarily in people over the age of 50 years, which is tied to the
cumulative risk of tobacco use and aging in this population. 11 Among WLWHA, there is a fourfold increased incidence of lung cancer compared
to the general population. The reasons for this are likely multifactorial and
include the carcinogenic effects of tobacco as well as the effects of chronic
inflammation exacerbated by repeated and frequent pulmonary infections. 12 , 13 Patients with
HIV and lung cancer tend to present at a more advanced stage of disease and more
commonly with non-small cell histology compared to HIV-negative patients. 14 They also have a worse 5-year overall survival compared to those without HIV
(9% vs 23%); those with CD4+ count greater than 200 cells/uL have a better prognosis
than those with less than 200 cells/uL. 15 In a South African study, there was no statistical sex difference between
those with and those without HIV infection. 11
Initial randomized controlled studies in lung cancer screening focused on using chest
radiography with or without sputum cytology and showed no impact on lung cancer mortality. 16 The National Lung Screening Trial (NLST) sought to compare low-dose helical
chest computerized tomography (LDCT) screening with chest radiographs. Participants
between the ages of 55 and 74 years, and with at least 30-pack-year history of
smoking, were recruited from 33 large medical centers across the United States. 17 At a median of 6.5 years of follow-up, there was a 20% relative reduction in
lung cancer mortality in the LDCT group compared with the conventional chest
radiograph group.
There are some potential benefits of screening high-risk PLWHA with LDCT, assuming
they match the profile of those participants recruited to the NLST. 18 These include shifting the diagnosis of cancer from advanced disease to an
earlier stage and with the promise of a better opportunity for cure. Although the
NLST study participants reflected well the demographics of high-risk US smokers, it
is worth emphasizing that the screening took place at major medical centers with
multidisciplinary teams reviewing radiographs. These teams were also provided
resources to ensure study participants were able to receive well-coordinated care.
Such resources may not be available in community medical centers or in US Veterans
Health Medical Centers where the use of screening LDCT has not yet been widely embraced. 19 In addition, the participants for the NLST were highly motivated and may not
reflect the profile of WLWHA or the disparity in care that such women may face.
The downside of LDCT screening includes the cumulative effect of radiation exposure
through repeated exams, surgical and medical complications associated with
diagnosis, treatment for those who prove not to have malignancy, and over-diagnosis
and over-treatment of lung cancers. 18 This may be particularly true for PLWHA with low CD4+ count, as they may be
more likely to have false-positive LDCT findings because of infections or
non-specific scarring from other opportunistic infections. In a recent study,
asymptomatic PLWHA with CD4+ count >200 cells/uL did not show a higher rate of
incidental pulmonary nodules on LDCT screening than HIV-negative controls, though
they did have more lymphadenopathy than controls. 20
In total, 224 HIV-infected (current or former smokers) underwent LDCT screening to
assess the computer tomography (CT) detection rate for lung cancer. 21 None of the pulmonary nodules detected in 48 participants at baseline were
diagnosed as cancer by study end, and only one cancer was detected in 678
patient-years. This may have been because of the young age of the screened
population. In order for such screening efforts to be most effective, the population
of WLWHA must overlap with the profile of NLST participants.
On the basis of NLST data and preliminary experience in screening PLWHA for lung
cancer, it is reasonable for medical providers, who have access to high-volume and
high-quality lung cancer screening and treatment centers, to discuss screening for
lung cancer in WLWHA between the ages of 55 and 80 years who have at least a
30-pack-year history of smoking, continue to smoke, or who have stopped smoking in
the past 15 years.
Our inexperience with lung cancer screening with LDCT emphasizes the importance of
robust discussions around the potential benefits, limitations, and harms associated
with lung cancer screening. Even more important is stressing the importance of
stopping smoking during clinical encounters. Tobacco smoking rates among WLWHA are
significant with rates nearly twofold to threefold higher than in the general
population. Several studies have showed that PLWHA lose more life years to smoking
than to HIV. 22 , 23 We must not
view lung cancer screening as an alternative to smoke cessation. 24
Although beyond the scope of this review, the British HIV Association has recently
published a comprehensive review of how best to address smoking cessation efforts in PLWHA. 24 Included are practical methods to choose the best strategies for an
individual patient and how to help the individual patient during the process. As the
authors strongly point out in the light of current evidence on the efficacy and
benefits of stopping smoking in PLWHA, medical care givers must make smoking
cessation a major focus in the day-to-day clinical care of PLWHA.
Breast
Although the incidence of certain cancers, particularly ADMs, are inversely
correlated with CD4+ count, these findings may not apply to WLWHA and diagnosed with
breast cancer. Retrospective case series have failed to show a clear link between
low CD4+ count and AIDS diagnosis and breast cancer. Breast cancer is the second
leading cause of death in women. 25
The epidemiology of breast cancer in WLWHA may be changing. During the modern HAART
era, the frequency of breast cancer in WLWHA is approaching that of the general
female population, where it had once been thought (paradoxically) to be much less. 26 The lower than expected breast cancer risk was linked to C-X-C chemokine
receptor type 4 (CXCR4) binding of the HIV envelope protein to neoplastic breast
cancer. Such interaction between HIV and the cancer cell was hypothesized to lead to
greater frequency of apoptosis. 27 Perhaps more significantly, women in the pre-HAART era may have had other
causes of morbidity and mortality that prevented them from being diagnosed with
breast cancer or living long enough to be diagnosed with breast cancer. 18
Certain clinical features may be different in WLWHA and diagnosed with breast cancer
compared to the general population. Specifically, they are typically identified with
breast cancer at a younger median age compared (46 vs 61 years old) to the general
female population, have a greater likelihood of multifocal breast involvement,
present with a more advanced stage at time of diagnosis, and have a possibly lesser
response to systemic chemotherapy. 26 , 28
The association between HIV, the immune reservoir, and the natural history of breast
cancer requires further study. Among 43 WLWHA, breast cancer was inversely
associated with initial stage and ranged from 100% survival for Stage I to 43%
survival for Stage III and 0% survival for those with Stage IV disease. 28 Clearly, those women diagnosed with more advanced disease or greater degrees
of immunodeficiency are less able to withstand the effects of cytotoxic chemotherapy
than those with normal CD4+ counts. Overall survival still depends strongly on stage
of breast cancer diagnosis, and those with earlier stage disease have a greater
expectation of longevity.
Breast cancer screening modalities include mammography, screening ultrasonography,
clinical and self-breast exam, breast magnetic resonance imaging, and breast
tomosynthesis. Of these, mammography is the best studied and proven method to reduce
mortality from breast cancer in those women deemed to be of average risk. 29 Harms associated with screening include over-diagnosis and subsequent
over-treatment of clinically trivial disease, radiation-associated tumors, and risk
of false-positive results resulting in recall, with or without biopsy, which may
contribute to additional anxiety. 18 An additional concern includes when false-negative results occur, which could
lead to a false sense of reassurance.
The central tenant for screening mammography is that early detection of breast cancer
prevents late-stage disease. Despite substantial increases in the number of breast
cancers that were detected in the United States from 1976 to 2008 according to an
analysis extracted from Surveillance, Epidemiology, and End Results, mammography had
a very modest impact on the rates of which women presented with advanced cancer. 30 Although it is unclear which women have been affected, the imbalance suggests
that there is substantial over-diagnosis, which may account for over 30% of newly
diagnosed breast cancers. The authors conservatively estimate that breast cancer was
over-diagnosed in 1.3 million women in the United States in the past 30 years.
Despite controversies as to what age breast cancer screening should begin, there is
widespread consensus that it should be practiced in the general female population.
Application of national guidelines to WLWHA is appropriate provided prognosis
conferred by HIV and other comorbidities are taken into account in the
decision-making process. 8 , 18 A meta-analysis of survival data of randomized control studies
from the United States, Denmark, United Kingdom, and Sweden suggests that screening
for breast cancer is most appropriate for patients with a life expectancy of greater
than 10 years. 31
The US Preventive Service Task force (USPSTF) recommends biennial screening
mammograms between ages of 50 and 74 years, and an individualized discussion for
those younger than 50-years old taking into account the harms and benefits of such screening. 32 The CDC recommends mammographic screening every 2 years for women between 50
and 74 years of age and further discussions with the patient and medical provider
regarding screening between the ages of 40 and 49 years. 33 In contrast, the American Cancer Society (ACS) recommends that women with an
average risk of breast cancer begin screening at age of 45 years, with annual
mammography from 45 to 54 years, and biannual mammography with the opportunity to
continue screening mammography as long as the women’s overall health is good and as
long as she has a life expectancy of 10 years or longer. 34 The ACS also advocates that women be given the opportunity to begin annual
screening from 40 to 44 years of age.
The differences in breast cancer screening recommendations between the USPSTF, CDC,
and the ACS are highlighted in Table 1 . Regardless of which of these guidelines medical providers
adhere to for the general female population, for WLWHA screening remains challenging
with screening rates that are only a small fraction compared to those achieved in
the general population. 35 , 36
Recommendations for breast cancer screening mammography: USPSTF, CDC, and
ACS.
USPSTF: US Preventive Services Task Force; CDC: Centers for Disease
Control and Prevention; ACS: American Cancer Society.
Ovarian
Ovarian cancers account for less than 2% of new cancer diagnoses in women. It has a
high mortality because most patients present with advanced peritoneal metastases at
time of diagnosis. 8 Among WLWHA, ovarian cancer does not seem to be associated with a greater
prevalence and is not associated with onset of AIDS diagnosis or CD4+ count. The
incidence and natural history of uterine cancer among WLWHA have not been thoroughly
studied. This is, in part, related to the paucity of reported cases. In a large
study of 85,268 WLWHA and followed for 665,987 patient-years, only 31 cases were
identified and this was less than what was expected in the general population. 26 In another study of WLWHA and encompassing the years between 2006 and 2011,
uterine cancer accounted for 4% of cancer-specific deaths. Standardized mortality
ratio of women with AIDS and uterine cancer was comparable to those without AIDS in
the same study. 78
In the general population, neither early recognition of symptoms nor annual pelvic
exam has influenced survival. Serum cancer antigen 125 (CA-125) and transvaginal
ultrasound (TVUS) have also been evaluated in several large prospective studies but
without an impact on survival, although morbidity increased in screened women
because of surgeries related to false-positive tests. 79 Efforts are underway to define best available screening strategies in
high-risk groups (e.g. parity, oral contraceptive use, tubal ligation,
endometriosis, and BRCA1/2 mutations) incorporating TVUS, CA-125, and annual
multimodal screening. 80 Cancer screenings studies thus do not appear to apply to WLWHA who do not
fall into these high-risk groups.
Summary
Experts, professional societies, and consumer groups frequently recommend different
strategies for cancer screening. Nonetheless, high-intensity screening or, in some
instances, lack of screening does not equate to a higher value of care. In order for
cancer screening to be effective, the American College of Physicians (ACP) defines
high-value care as the delivery of services providing benefits that make their harms
and costs worthwhile. Strategies designed to screen WLWHA for cancer must take into
consideration the risk of the specific cancer, patient life expectancy, and the
benefits and harms that can occur because of the cancer screening endeavor.
In WLWHA, experience with screening for lung cancer with LDCT is small but may be
reasonable after informed shared decision-making and when access to high-quality and
high-volume lung cancer screening and treatment centers exist. Breast and colon
cancer screening should generally follow recommendations that are applied to the
general population. Gynecologic care is a priority for WLWHA and cervical cancer
screening is an important component of their routine care. Given the high burden of
HPV-associated anal cancer in PLWHA, all HIV-infected adults could be offered
screening as part of clinical care at specialized centers. Ultimately, the
NIH-sponsored ANCHOR study will determine the harms and benefits of this strategy.
WLWHA should not undergo uterine and ovarian cancer screening due to lack of
evidence of benefit coupled with increases in harm and cost. Assuming that early and
aggressive treatment is available, AASLD screening recommendations with
ultrasonography may be applied to at-risk WLWHA for HCC.
Cervical
On a global scale, invasive cervical cancer (ICC) is both the most frequent source of
new cancers in women and the cause of the most cancer-associated fatalities in women. 25 In some areas of SSA, the rates of ICC are exceedingly high and approach
168/100,000 among women who receive HAART. 62 A disproportionate number of deaths also occur in resource-limited countries
where the death rate at 17.5/100,000 is nearly threefold greater than in
industrialized countries. 8 , 25 In WLWHA, in the United States, the incidence of cervical
cancer is roughly 7 per 100,000 but is still 66% greater than the incidence seen
among non-HIV infected women. 62 In a multi-cohort North American analysis between 1996 and 2010, WLWHA had a
higher risk of ICC compared to HIV-negative women, and the risk increased inversely
to the CD4+ count. 63
Among WLWHA, ICC presents nearly 15 years earlier than in the general female
population. 64 , 65 Although several studies have suggested that ICC presents at a
more advanced stage among women infected with HIV, this has been difficult to
clearly demonstrate because in resource-limited areas, non-HIV infected women also
present with more advanced disease. 8 The increased incidence of advanced stage disease at diagnosis may be a
reflection of the limited screening of ICC among women in general and not
specifically, or solely, among WLWHA. 66
Treatment of ICC requires close collaboration between the Gynecological Surgeon,
Radiation Therapist and Oncologist. Treatment is particularly challenging in
resource-constrained countries where fear of cancer and poor infrastructure hinders
efforts at early diagnosis and treatment. 65 Interruptions in treatment and failure to deliver complete cancer care lead
to worse outcomes, and this is particularly true for WLWHA who are not engaged in
medical care and who are not receiving HAART. Although concomitant HAART may lead to
a greater likelihood of completing combined chemotherapy and radiation therapy, it
does not in itself lead to regression of high-grade cervical dysplasia. 64 , 65
Current guidelines for cervical cancer screening by the USPSTF include women between
21 and 65 years old. Grade A recommendations include a Pap test every 3 years
between 21 and 65 years old, or cytology with HPV testing every 5 years between 30
and 65 years old. 67 These recommendations do not include women with precancerous cervical
lesions, in utero exposure to diethylstilbestrol, or those with immunosuppression
including HIV infection.
For WLWHA, the CDC recommends cytology screening every 6 months after initial
diagnosis of HIV and if both tests are normal, than annual screening. 68 Guidelines from the American College of Obstetricians and Gynecologists and
the U.S. Preventive Services Task Force (USPFT) recommend that WLWHA should undergo
cervical cytology for cancer screening twice in the first year after diagnosis of
HIV infection and then annually, provided the test results are normal ( Table 3 ). 69 , 70 Two cervical
screening assessments initially are prudent for HIV-infected women, since
intraepithelial neoplasia is not uncommon and can develop rapidly in these women.
Although the importance of cervical cancer screening is better established in this
population, the vast majority of WLWHA are not receiving necessary gynecological services. 52 In an interview study which occurred over 4 years and encompassed 18 US
states, nearly a quarter of 2417 WLWHA and who were receiving care in HIV primary
clinics had not undergone ovarian and corpus uterine cancer screening over the past 1 year. 71
Cervical cancer screening summary and recommendations.
Source: American College of Obstetricians and Gynecologists and the
USPFT.
WLWHA: Women living with HIV/AIDS; HPV: human papillomavirus.
The World Health Organization (WHO) have adopted an alternative model for screening
women for ICC in resource-constrained countries, “screen and treat.” This strategy
uses existing screening modalities, preferably HPV testing as first line, followed
by immediate treatments (e.g. cryotherapy) for identified cervical abnormalities. 72 However, the nexus between convenience associated with HPV testing in poorer
countries and the higher cost of such tests have not yet been examined in a
large-scale effort, and cost remains a considerable barrier for implementing these
strategies in resource-constrained countries. 73
Similar to anal cancer, ICC is a vaccine-preventable disease, but HPV vaccines remain
incompletely available for PLWHA. The Advisory Committee on Immunization Practices
(ACIP) recommends that all males and females including PLWHA between the ages of 11
and 26 years receive the nine-valent HPV vaccine. 74 , 75 The CDC now recommends 11- to
12-year-olds to receive two doses of HPV vaccine rather than the previously
recommended three doses to protect against cancers caused by HPV. The second dose
should be given 6–12 months after the first dose. 76 The American Society of Clinical Oncology has also issued updated guidelines
on HPV vaccination for the prevention of cervical cancer, which incorporates
evidence-based recommendations stratified to four levels of resource settings:
basic, limited, enhanced, and maximal ( Table 4 ). 77 These levels are designed to correspond to the financial resources of a
region as well as to the development of its health system, which include
infrastructure, personnel, and access to services.
ASCO HPV recommendations for cervical cancer prevention.
ASCO: American Society of Clinical Oncology; HPV: human
papillomavirus.
Colorectal
Globally, colorectal cancer (CRC) is the third most common cancer in men and in women
and is the leading cause of death when both genders are combined. 37 In two analyses, the prevalence of colonic adenomas in PLWHA was high
compared to the general population; however, the relative risk of CRC in PLWHA is
uncertain. 38 , 39 Conflicting information is available through various
meta-analysis and cohort studies. On one hand, a prospective cohort study in PLWHA
from 1992 to 2003 showed a greater incidence of CRC than in the general population
(standard rate ratio 2.3). 40 On the other hand, a meta-analyses and a cohort study failed to show an
elevated risk of CRC among PLWHA compared to age-matched controls. 41 , 42 In addition, a
case series involving PLWHA and with colon cancer indicated that CRC is diagnosed at
a younger age and has a more aggressive course than in the general population. 43 In contrast, a registry linkage study showed that the age of CRC was no
different in groups infected with HIV and the general population. 3
The USPSTF recommends CRC screening with intervals between screening studies
depending on the modality used for cancer detection ( Table 2 ). 44 These include high-sensitivity fecal occult blood testing (FOBT) annually,
sigmoidoscopy every 5 years with FOBT every 3 years, or colonoscopy every 10 years
in adults who are deemed at average risk for CRC beginning at age of 50 years and
continuing until age of 75 years. The CDC 45 also notes that earlier screening strategies may be needed if the person or
close relative have had colorectal polyps or CRC, inflammatory bowel disease,
familial polyposis, or Lynch syndrome.
USPSTF updated recommendation on screening for colorectal cancer.
USPSTF: US Preventive Services Task Force.
Application of USPSTF or other national CRC screening to PLWHA is reasonable,
provided prognosis conferred by HIV or other comorbidities are considered in the
decision-making process, as there is a 10-year lag to observe the mortality benefit
from screening (see Table
2 ). 44 Despite clear reasons to incorporate similar standards for PLWHA, both
genders are less likely to undergo CRC screening than the general population. Among
205 consecutive patients interviewed at outpatient clinics with either average risk
of CRC as defined by age greater than 50 years or high risk for CRC as defined by
family history of colon cancer or adenomas, those who were HIV positive were
significantly less likely to undergo CRC screening. 46 The reasons for the disparity in screening between PLWHA and the general
population are likely multifactorial and include patient and physician education
regarding CRC screening, lack of CRC screening guidelines which are specific for
PLWHA, and health care disparities faced by both men and women who are infected with
HIV and that cut across racial and economic and social divides. 47
How best to bridge this divide in CRC screening for PLWHA and the general population
is an area of active research. Successful strategies used in the general population
may be applicable to PLWHA. A 2-year randomized controlled study found that compared
to usual care, patients completed recommended screening twice as often when
electronic health record linked reminders and FOBT were sent to them. 48 Follow-up telephone calls by medical assistants and if required, nursing
assistance, each resulted in additional but smaller incremental improvements in
adherence.
Evidence-based screening modalities that have led to decreased colorectal mortality
include FOBT, sigmoidoscopy, and colonoscopy. The harms associated with screening
for CRC are due to the invasive procedures that are used initially or in the
evaluation sequence and include significant bleeding, severe abdominal pain, and
cardiovascular events and rarely, bowel perforation. 44
Hepatocellular
HIV-infected intravenous drug users (IVDU) have a heightened risk of HBV and HCV
co-infection compared to the general population and consequently are at risk for
hepatocellular cancer (HCC). Recent US data indicate that at a rate of 30 per
100,000 individuals PLWHA have a fourfold higher incidence of HCC risk than the
general population. 81 Other possible risk factors contributing to HCC in PLWHA include
immunosuppression and higher prevalence of alcoholism, non-alcoholic steatosis and diabetes. 82 The magnitude of this risk has remained relatively constant despite the
positive hepatic impacts of HAART in minimizing progression to cirrhosis.
Both HBV and HCV cause HCC, but variations in their route of transmission means that
for PLWHA and diagnosed with HCC they are more likely to have HBV, whereas as
HIV-infected IVDU with HCC are more likely to have HCV. HIV aggravates the clinical
outcome of viral-induced cirrhosis and liver-associated death; this is especially
true at low CD4+ cell counts. Among 104 HIV-infected and 484 uninfected patients,
HIV-positive patients were significantly younger than uninfected ones at HCC
diagnosis and were co-infected with HBC or HCV in the great majority of cases. 83 CD4+ cell count at diagnosis was not independently associated with survival;
but patients receiving HAART and with undetectable HIV RNA at diagnosis had a better
prognosis than untreated subjects or subjects with higher HIV viral loads. Even
though, in HIV-infected patients, HCC was diagnosed mostly at an early stage (66% at
Barcelona Clinic, Liver Cancer (BCLC), Stage A or B) and then amenable for
potentially curative approaches, the median survival time was significantly shorter
than that observed in the HIV-negative counterparts (35 vs 59 months).
The benefits associated with HCC screening interventions may include an improvement
in survival if the cancer is caught at an early phase, and although non-cirrhotic
patients might be eligible for surgical resections, most patients would require
hepatic transplants for cure. 84 The downside associated with ultrasonography as a screening test include
potential complications associated with liver biopsy if an abnormality is detected,
as well as excess exposure to radiographs and contrast dye exposure due to a need
for follow-up imaging in false-positive instances. 18
Screening guidelines from the American Association for the Study of Liver Disease
(AASLD) recommend liver ultrasonography twice yearly for those at high risk for HCC
(see Table 4 ). 84 Controversy has followed these recommendations due to a lack of randomized
controlled studies that clearly show benefit to this approach. A recent Cochrane
review concluded that there was insufficient evidence grounded by randomized
controlled trials to support routine screening liver ultrasounds and serum tumor
marker collections of HBV surface antigen positive patients for HCC. 85 The review noted the high risk of bias in many of the studies they surveyed,
including methodological flaws and incomplete long-term data ( Table 5 ).
Groups for whom HCC surveillance is recommended or in whom the risk of HCC is
increased, but in whom efficacy of surveillance has not been
demonstrated.
Source: Adapted from Bruix and Sherman. 84 Copyright©2010 John Wiley & Sons. Graphic 68371 Version
8.
HCC: hepatocellular carcinoma; NAFLD: non-alcoholic fatty liver
disease.
Among a large Chinese cohort, HCC screening of patients with HBV infection led to a
37% reduction in mortality by utilizing twice yearly liver ultrasound and serum
alpha-fetoprotein assessments. 86 Although encouraging, applying HCC screening recommendations to PLWHA and
co-infected with viral hepatitis is challenging and further studies are needed
before nuanced recommendations can be offered to this specific population. 18 A recent Cochrane review concluded that there was insufficient evidence
grounded by randomized controlled trials to support routine screening liver
ultrasounds and serum tumor marker collections of HBV surface antigen positive
patients for HCC. 85 The review noted the high risk of bias in many of the studies they surveyed,
including methodological flaws and incomplete long-term data. Complicating available
trials looking at screening for HCC is the lack of liver transplantation as a
routinely available treatment option for HCC. Emerging experience with liver
transplantation for PLWHA appears encouraging. Among Spanish patients with HIV and
HCV co-infection, liver transplantation outcomes were similar to HIV-negative
patients who underwent similar surgery. 87
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