{"paper_id":"9757e44c-f668-449e-a8fe-5690f5ae6ae0","body_text":"-\n6\n/\n%\n\u0001\n6\n/\n*\n7\n&\n3\n4\n*\n5\n:\n1\n0\n\u0001\n#\nP\nY\n\u0001\n\u0012\n\u0012\n\u0018\n\u0013\n\u0013\n\u0012\n\u0001\n\u0011\n\u0011\n\u0001\n-\nV\nO\nE\n\f\n\u0015\n\u0017\n\u0001\n\u0015\n\u0017\n\u000e\n\u0013\n\u0013\n\u0013\n\u0001\n\u0011\n\u0011\n\u0001\n\u0011\n\u0011\nCancer risk after hospital discharge diagnosis of benign ovarian cysts and\nendometriosis.\nBorgfeldt, Christer; Andolf, Ellika\nPublished in:\nActa Obstetricia et Gynecologica Scandinavica\nDOI:\n10.1111/j.0001-6349.2004.00305.x\n2004\nLink to publication\nCitation for published version (APA):\nBorgfeldt, C., & Andolf, E. (2004). Cancer risk after hospital discharge diagnosis of benign ovarian cysts and\nendometriosis. Acta Obstetricia et Gynecologica Scandinavica, 83(4), 395-400. https://doi.org/10.1111/j.0001-\n6349.2004.00305.x\nTotal number of authors:\n2\nGeneral rights\nUnless other specific re-use rights are stated the following general rights apply:\nCopyright and moral rights for the publications made accessible in the public portal are retained by the authors\nand/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the\nlegal requirements associated with these rights.\n • Users may download and print one copy of any publication from the public portal for the purpose of private study\nor research.\n • You may not further distribute the material or use it for any profit-making activity or commercial gain\n • You may freely distribute the URL identifying the publication in the public portal\nRead more about Creative commons licenses: https://creativecommons.org/licenses/\nTake down policy\nIf you believe that this document breaches copyright please contact us providing details, and we will remove\naccess to the work immediately and investigate your claim.\n\nDownload date: 23. Jun. 2026\n\nORIGINAL ARTICLE\nCancer risk after hospital discharge\ndiagnosis of benign ovarian cysts and\nendometriosis\nCHRISTER BORGFELDT1 AND ELLIKA ANDOLF2\nFrom the 1Department of Obstetrics and Gynecology, University Hospital, Lund, and the 2Division of Obstetrics and\nGynecology, Karolinska Institutet, Danderyd Hospital, Stockholm, Sweden\nActa Obstet Gynecol Scand 2004; 83: 395–400. # Acta Obstet Gynecol Scand 83 2004\nBackground. The aim was to evaluate whether patients with benign ovarian cysts, func-\ntional ovarian cysts, or endometriosis have an increased risk of developing gynecologic\ncancer.\nMethods. The Swedish Hospital Discharge Register was used to identify a cohort of\nwomen discharged from hospital with the diagnoses of ovarian cyst ( n ¼ 42 217), func-\ntional ovarian cyst (n ¼ 17 998), or endometriosis (n ¼ 28 163). To each case, three controls\nwere matched. The National Swedish Cancer Register matched all incident cancers\ndiagnosed among cases and controls. From the Fertility Register, the date of birth of\nchildren born to the cases and controls were obtained.\nResults. Women with endometriosis had an increased risk for ovarian cancer (OR 1.34;\n95% CI 1.03–1.75), but no association was found between ovarian cysts or functional\ncysts and ovarian malignancy, including all ages. Young women (15–29 years old) dis-\ncharged from hospital for ovarian cysts and functional cysts showed an increased risk of\ndeveloping ovarian cancer later in life (OR 2.2; 95 % CI 1.3–3.9 and OR 1.8; 95% CI 1.5–\n2.0), as well as women with ovarian cysts who had undergone ovarian cyst resection or\nunilateral oophorectomy (OR 8.8; 95% CI 5.2–15). The risk of developing ovarian cancer\nwas inversely related to parity. Mean age at diagnosis was significantly lower in all three\nstudy groups.\nConclusion. In this study women with endometriosis and young women who had under-\ngone surgery with removal of an ovarian cyst had an increased risk of developing ovarian\ncancer.\nKey words: epidemiology; ovarian cancer; ovarian neoplasm\nSubmitted 28 January, 2003\nAccepted 5 May, 2003\nOvarian cancer is the sixth most frequent cancer\namong Swedish women and the fourth leading\ncause of death in cancer among women aged\n45–64 years (1). As a result of unspecific and\nmostly mild symptoms, two-thirds of the patients\nare already in an advanced stage of the disease\n(FigO stages III and IV) at the time of diagnosis,\nfacing a poor prognosis (2). The life-time risk for\novarian cancer in Swedish women is 1.5%, which\nis comparable to that of the rest of the Western\nindustrial world. Thus, one woman out of 70 will\ndevelop the disease (3). The life-time risk ranges\nfrom 0.6% in women without a family history of\novarian cancer, at least three term pregnancies,\nand a minimum of 4 years of oral contraceptive\nuse, to 3.4 % in nulliparous women not having\nused oral contraceptives. Even though the major-\nity of ovarian cancers are sporadic, the greatest\nrisk factor is a family history of the disease (4).\nThe significance of benign ovarian cysts and\ntheir relation to ovarian cancer is unclear. Pri-\nmary ovarian cancer is supposed to arise from the\n# Acta Obstet Gynecol Scand 83 (2004)\nActa Obstet Gynecol Scand 2004: 83: 395- -400 Copyright # Acta Obstet Gynecol Scand 2004\nPrinted in Denmark. All rights reserved\nActa Obstetricia et\nGynecologica Scandinavica\n\nmesothelial surface cells of the ovary or its inclu-\nsion cysts. It has been shown that a higher rate of\nsurgery for ovarian cysts is not associated with an\nearlier diagnosis of ovarian cancer (5,6). Further-\nmore, abnormal morphological changes have\nbeen found in macroscopically normal ovaries in\nasymptomatic women undergoing surgery for\nhereditary reasons (7). On the other hand, weak\nepidemiological data suggest a malignant poten-\ntial in certain benign ovarian tumors (8). Endo-\nmetriosis and endometriomas have been found to\nbe associated with an increased risk of developing\novarian cancer (9). Also, dysplasia and transition\nfrom benign to malignant epithelium have been\nfound in ovarian cystadenocarcinomas (10–12),\nindicating that ovarian cysts may be precursors of\novarian cancer.\nAnother question is whether women having\nhad a benign or functional cyst have an altered\nrisk of developing ovarian cancer. The aim of this\ncase–control study was to evaluate whether\npatients with benign ovarian cysts, functional\novarian cysts, or endometriosis have an increased\nrisk of developing gynecologic cancer, especially\novarian cancer.\nMaterials and methods\nData from The Swedish Hospital Discharge Registry (The\nNational Board of Health and Welfare) were used to identify\na cohort of women born in Sweden before 1970. All were\ndischarged from hospital during the period 1969–96 with the\ndiagnoses of ovarian cyst, functional ovarian cyst, or endo-\nmetriosis. The unique personal identification number,\nassigned to each resident in Sweden, was used. The Swedish\nHospital Discharge Registry started in 1969. At that time it\ncovered 60% of the Swedish population, in 1978 75 %, and\nin 1983 85 %. Since 1987, all patients discharged from\nhospitals in Sweden are included. The register contains\ninformation about surgical procedures and up to eight dis-\ncharge diagnoses, coded according to the International\nClassification of Diseases (ICD-8 1969–86 and ICD-9\n1987–96). The diagnostic codes used in the present study\nwere ovarian cyst, including benign or unknown ovarian\ntumor (220.0–9 benign tumor in ovary; 620.2 unspecified\ncyst in ovary; 235.99, 236.2 unknown ovarian tumor), func-\ntional ovarian cyst/Corpus luteum (615.2 and 620.0–1), and\nendometriosis (625.3 and 617.0–9). To each case three\ncontrols, with the same date of birth, were matched using\nthe Swedish Population Register, Statistics Sweden, which\nincludes all persons living in Sweden. Codes from The\nSwedish Hospital Discharge Registry for surgical procedures\nand dates of operations were linked to the cases and con-\ntrols. Data from the National Swedish Cancer Register,\nfounded in 1958, matched all incident cancers diagnosed\namong cases and controls up to December 31, 1997. The\nCancer Registry has coded malignant neoplasms according\nto the ICD-7 classification during the entire period of the\nstudy. The Fertility Register, also kept by Statistics Sweden,\ncontains information on all children born to Swedish\nwomen. From the Fertility Registry, the dates of birth of\nchildren born to the cases and controls were obtained.\nWomen having changed their personal identification number\nwere excluded ( n ¼ 122). The cases were then given a file\nnumber and the controls a corresponding control number\nin order to unidentify the database. This database was used\nin the statistical analyses. In order to avoid misclassification\nof benign cysts or undiagnosed malignancy at the time\nof hospital discharge, 1 year was allowed to elapse before\nany diagnosis of malignancy was accepted in the studied\npopulation.\nFor statistical analysis the Mantel-Haenszel procedure\nwas applied for the determination of odds ratio (OR) and\nthe 95 % confidence intervals (CI) after stratifications as\nspecified (13).\nResults\nRisk of developing gynecologic cancer\nThere was no change in the risk of developing\novarian cancer having had an ovarian cyst or\nfunctional ovarian cyst, while women with endo-\nmetriosis had an increased risk for ovarian malig-\nnancy (Table I). It was not possible to determine\nprecisely the ovarian status on the basis of the\noperation code for hysterectomy. Therefore,\nwomen who had undergone hysterectomy with\nor without oophorectomy were excluded, but\nthere were only minor changes in the results\nafter the exclusion of these women. No change\nin breast cancer risk was found. A decreased risk\nof developing endometrial cancer was found in\nwomen with ovarian cysts and endometriosis.\nWomen with endometriosis also had a decreased\nrisk for cervical cancer. Women with endometri-\nosis showed an even more pronounced risk of\ndeveloping ovarian cancer more than 10 years\nafter diagnosis (OR 1.46, 95 % CI 1.01–2.11).\nThere was no change in total cancer risk (all\ntypes of invasive malignancies) after having had\nan ovarian cyst, OR 0.99 (95% CI 0.85–1.14) or a\nfunctional ovarian cyst, OR 0.90 (95 % CI 0.69–\n1.19), whereas women with endometriosis had an\nincreased overall risk for malignancy, OR 1.15\n(95% CI 1.00–1.32).\nRisk of developing ovarian cancer related to\nprevious ovarian surgery\nWhen analyzing women having undergone ovar-\nian cyst resection and/or unilateral oophorect-\nomy separately, the risk for subsequent ovarian\ncancer was almost nine-fold higher, OR 8.8 (95%\nCI 5.2–14.8), as opposed to those who were not\ntreated surgically, OR 0.48 (95 % CI 0.35–0.66).\nAmong women who later developed ovarian can-\ncer ( n ¼ 367), nine women had been registered\nwith the surgical code for bilateral oophorectomy\nat least 1 year before the cancer diagnosis (cases\nn ¼ 2 and controls n ¼ 7). This may be because of\nmisclassification (using code for bilateral instead\nof the code for unilateral oophorectomy) or the\n396 C. Borgfeldt and E. Andolf\n# Acta Obstet Gynecol Scand 83 (2004)\n\nfact that the ovarian cancer had started as a\nperitoneal cancer.\nRisk of developing ovarian cancer in relation to\nage of previous ovarian cyst\nThe youngest age group (10–29 years old) with an\novarian cyst or a functional cyst, treated or not\ntreated, showed an increased risk of developing\novarian cancer (Table II). A decreased risk for\novarian cancer was observed in women aged\nolder than 50 years discharged from hospitals\nwith the diagnosis of ovarian cyst. Young\nwomen with endometriosis showed an even\nhigher increased risk of developing ovarian can-\ncer compared with the total age group.\nRisk of developing ovarian cancer in relation to\nnumber of children\nThere was almost no difference in risk figures\naccording to the number of children born after\nthe diagnosis, whereas the number of children\nbefore diagnosis of ovarian cyst, functional cyst\nor endometriosis was of importance (Table III).\nThe ovarian cancer risk was significantly\nincreased in nulliparous with functional cysts or\nendometriosis. In women with an ovarian cyst\ndiagnosis, the cancer risk also decreased with\nparity. The overall tendency was decreasing ovar-\nian cancer risk with increasing number of chil-\ndren born in all three studied groups.\nMean age at ovarian cancer diagnosis\nThe mean age for ovarian cancer was signifi-\ncantly lower in the women discharged from hos-\npital for ovarian cyst (47.6 years, SEM 1.27;\nn ¼ 80) vs. the control group (54.1 years, SEM\n0.56; n ¼ 287) ( p < 0.001); for the women dis-\ncharged from hospital for functional cyst\n(40.7 years, SEM 1.70; n ¼ 31) vs. the control\ngroup (49.1 years, SEM 1.12; n ¼ 72) ( p < 0.02);\nand also for the women discharged from hospital\nwith endometriosis (49.0 years, SEM 0.91; n ¼ 90)\nvs. the control group (51.6 years, SEM 0.60;\nn ¼ 183) ( p < 0.001). Even when the youngest\nwomen below 30, respectively, 35 years of age\nwith ovarian cancer were excluded in the calcula-\ntions, the mean age for ovarian cancer was sig-\nnificantly lower in the women treated for ovarian\ncysts, functional cysts or endometriosis as\ncompared with their respective control group\n(p < 0.05 for all six comparisons).\nTable I. Odds ratio for gynecologic cancers in women with hospital discharge diagnoses, ovarian cyst, functional cyst or endometriosis\nOvarian cyst Functional cyst Endometriosis\nCancer type OR 95 % CI\nCase\nn\nControl\nn OR 95 % CI\nCase\nn\nControl\nn OR 95 % CI\nCase\nn\nControl\nn\nOvary 0.86 0.67–1.10 78 280 1.24 0.81–1.89 31 72 1.34 1.03–1.75* 81 181\nBreast 1.07 0.98–1.18 586 1680 1.00 0.85–1.18 189 569 1.10 0.98–1.23 427 71165\nEndometrium 0.66 0.51–0.86* 66 308 0.66 0.39–1.12 17 77 0.58 0.42–0.81* 39 211\nCervix 0.78 0.58–1.04 55 217 1.30 0.90–1.90 39 90 0.57 0.37–0.90* 23 120\nNo cancer 40406 124542 17461 52539 26969 81073\n*95% confidence intervals excluded 1.0\nOnly cancer diagnoses more than 1 year since the primary hospital dischargediagnoses are included.\nWomen with surgery as bilateral oophorectomy and hysterectomy with or without bilateral oophorectomy are excluded.\nStratification is performed for women’s age and the number of children born by the women before and after the primary hospital discharge diagnosis.\nTable II. Odds ratio for ovarian cancer diagnosis related to woman’s age more than 1 year since the woman’s first hospital discharge with diagnoses of ovarian\ncyst, functional cyst, and endometriosis\nOvarian cyst Functional cyst Endometriosis\nAge (years) OR CI 95 % OR CI 95 % OR CI 95 %\n10–29 2.23 1.29–3.86* 1.76 1.50–2.00* 3.52 1.56–7.95*\n30–49 0.83 0.60–1.16 0.86 0.46–1.52 1.26 0.50–3.16\n50þ 0.44 0.25–0.77* – – 0.98 0.42–2.31\n*95% confidence intervals excluded 1.0\n–: strata missing cases or controls.\nWomen with surgery as bilateral oophorectomy and hysterectomy with or without bilateral oophorectomy are excluded.\nStratification is performed for the number ofc h i l d r e nb o r nb yt h ew o m e nb e f o r ea n da f t e rthe primary hospital discharge diagnosis.\nOvarian cysts and risk of ovarian cancer 397\n# Acta Obstet Gynecol Scand 83 (2004)\n\nDiscussion\nIn this case–control study we found no association\nin the total material between the hospital discharge\ndiagnosis of an ovarian or functional cyst and later\ndevelopment of ovarian cancer. However, there\nwas a significantly increased risk for ovarian can-\ncer in young women discharged from hospital for\nan ovarian or functional ovarian cyst, especially if\nthey were childless. Endometriosis was associated\nwith an overall increased risk of developing cancer\n(all types of invasive malignancies included).\nYoung age and nulliparity increased the risk.\nWomen with unilateral oophorectomy or ovarian\ncyst resection showed an increased ovarian cancer\nrisk later as compared with those with ovarian\ncysts in whom no surgery was performed. In add-\nition, the mean ages at diagnosis of ovarian cancer\nwere significantly lower in the cases as compared\nwith the control groups.\nThere are several limitations to these data. Pri-\nmarily, one may speculate over the generalization\nof results on patients hospitalized for ovarian\ncysts/benign tumors, functional cysts, or endometri-\nosis. Women hospitalized for an adnexal lesion\nprobably had persisting and/or symptomatic\nadnexal lesions. Also, there may by an increased\nrisk for dysplasia in a long-standing cystic lesion\nespecially if epithelial cells increase in number by\nmitosis as the cyst grows. Further, in women with-\nout histopathological verification, functional cysts\nmight have been misclassified as ovarian cysts and\nvice versa. When the reliability of the registers was\ntested, the Swedish Hospital Discharge Registry\nwas found to have a misclassification rate of 7 %\n(14). The reliability of the surgical codes was\nfound to be good (15). One percent of the codes\nare missing and 5 % are erroneous. As for the\nNational Swedish Cancer Registry, approximately\n98% of the diagnoses are being morphologically\nverified (3). The missing cancer diagnoses are\nvery few when compared with the National\nDeath Certificate Register in Sweden (3). A qual-\nity study of the Fertility Register has also been\nperformed lately showing good accuracy (personal\ncommunication, Statistics Sweden). The discre-\npancy between the Fertility Register and the\nSwedish Population Register was 5–8 % in the\n1930s and 1940s, 2–4 % in the 1950s and 1960s,\nand less than 1 % since 1967. Nevertheless, the\nmissing codes and the errors in the registers\nshould be proportional in the case and control\ngroups, minimizing the importance of the errors.\nThe observation that nulliparity increases the\nrisk of ovarian cancer is in accordance with earl-\nier reports, where multiparas have a 40–60 % risk\nreduction (16–19). Infertile women, unsuccess-\nfully treated with hormones have a higher risk of\ndeveloping ovarian cancer, especially after long-\nterm use (20,21). However, women successfully\ntreated did not have an increased risk (20). The\npossible reason for this increased risk was ovar-\nian dysfunction and not the hormonal treatment.\nIn addition, another interesting hypothesis has\nbeen proposed to explain the reduced risk of\novarian cancer in parous women: namely that\npregnancy hormones or other immunological\nchanges during pregnancy may clear the ovaries\nfrom cells that have undergone malignant trans-\nformation (18).\nAs for endometriosis, our results are in accord-\nance with an earlier report based on discharge\ndiagnoses where cases were compared with the\nstandardized incidence ratio of ovarian cancer\nbut parity was not considered (9). Other reports\nhave also suggested a histological transformation\nof benign endometriosis to early epithelial\novarian cancer (22,23). There are several theories\nconcerning the development of endometriosis.\nOne theory is that endometriosis arises from\nmetaplasia of the coelomic epithelium, another\nthat endometrial cells regurgitate through\nthe fallopian tubes at menstruation and imp-\nlant on pelvic structures. Deficiency in the\nTable III. Odds ratio for ovarian cancer diagnosis from the first hospital discharge diagnoses of ovarian cyst, functional cyst, or endometriosis related to the\nnumber of children given birth to before and after diagnosis\nNumber of children Ovarian cyst Functional ovarian cyst Endometriosis\nbefore diagnosis after diagnosis OR CI 95 % OR CI 95 % OR CI 95 %\n0 0–16 1.50 0.97–2.31 2.28 1.18–4.37* 1.89 1.19–3.01*\n1–3 0–16 0.70 0.51–0.95* 1.21 0.88–1.66 1.21 0.88–1.66\n4–5 0–16 0.21 0.03–1.35 1.01 0.19–5.29 1.27 0.24–6.63\n0 0 1.43 0.87–2.32 2.47 1.15–5.30* 1.87 1.15–3.06*\n1–3 0 0.68 0.49–0.95* 1.04 0.55–1.94 1.16 0.84–1.61\n4–5 0 0.21 0.03–1.05 1.01 0.19–5.29 1.27 0.24–6.63\n*95% confidence intervals excluded 1.0.\nOnly cancer diagnoses more than 1 year since the primary hospital discharge diagnoses are included.\nGynecologic surgical procedures are not considered.\n398 C. Borgfeldt and E. Andolf\n# Acta Obstet Gynecol Scand 83 (2004)\n\nimmunological system has also been considered\nto contribute to the development of endometrio-\nsis. Local inflammatory response at the endome-\ntriotic implantations initiates proteolytic systems\nwhich are involved in carcinogenesis (24).\nChronic inflammation and/or a deficient immu-\nnological response to endometriosis may contri-\nbute to the increased risk of developing ovarian\ncancer in patients suffering from endometriosis\n(25).\nIn the present study, women with ovarian cyst\nresection or unilateral oophorectomy for benign\ncauses had a highly increased risk of later devel-\noping ovarian cancer. This may be because of\npremalignant dysplasia in the contra-lateral\novary or misclassified borderline tumors which\nmay have had unrecognized peritoneal implants.\nHisto-pathological changes have been found in\nmacroscopically normal ovaries in women oper-\nated on because of a strong family history (7,26).\nIn ovarian cancer stage Ia, microscopic changes\nare found in up to 7% of the contra-lateral ovary\n(27), which may indicate that ovarian cancer is a\nmultifocal disease. This emphasizes the import-\nance of a thorough examination of the whole\nabdominal cavity, both at laparoscopic and\nopen surgery, for ovarian cysts and also peri-\ntoneal washing and biopsies of the peritoneum.\nWhether benign macroscopic changes, except\nendometriosis, precede ovarian cancer is unclear.\nOur finding may indicate that this is the case.\nSeveral studies have been performed to verify\nwhether an inclusion cyst in the other ovary is\nmore common in ovarian cancer patients, but\nstudies are inconclusive (5,7,26,28,29). Another\nexplanation may be that the surgical trauma itself\nstarts the process toward dysplasia and malig-\nnancy, as the removal of a cyst traumatizes the\novarian-surface epithelium. The healing process\nentails increased cell division activity and inflam-\nmation with activation of proteolytic enzymes\nsimilar to those in cancer invasion and metastases\n(24,25). In addition, inflammatory cytokines activ-\nating nitric oxide have shown to cause DNA\ndamage and inhibit DNA repair proteins (30).\nThus after ovarian surgery, as well as in endo-\nmetriosis, an inflammatory response may be the\nkey to carcinogenesis.\nCases were significantly younger when receiv-\ning the diagnosis of ovarian cancer as compared\nwith women in the control groups. In families\nwith a hereditary risk for ovarian cancer, the\nmedian age at diagnosis is significantly lower\nthan the median age of women without a history\nof familiar ovarian cancer (31). However, only\napproximately 5–10 % of all ovarian cancer is\nconsidered to be caused by inherited mutations,\nwhich is why the differences in mean age at ovar-\nian cancer diagnosis can not be fully explained by\nhereditary factors.\nIn the present study women with endometriosis\nhad a decreased risk of developing endometrial\nand cervical cancer. Treatment of endometriosis\noften includes synthetic progestin, gonadotropin-\nreleasing hormone analogs, or combined oral\ncontraceptives known to reduce the risk of endo-\nmetrial hyperplasia and cancer (32,33). The\nreduced risk of cervical cancer may be the result\nof intensified screening and treatment of pre-\nmalignant lesions of the cervix in the group of\nwomen with endometriosis, as they may have\ncontacted their gynecologist more frequently.\nIn conclusion, this hospital registry study indi-\ncates an increased risk for ovarian cancer in\nwomen suffering from endometriosis and young\nwomen treated for ovarian cysts, especially\nif the cyst is removed. This latter association\nencourages expectant monitoring in young\nwomen with asymptomatic cysts if malignancy\nis not suspected. The tentative biological explan-\nations such as the inflammatory response after\nsurgery or endometriosis-mediating carcinogen-\nesis needs to be proven.\nAcknowledgment\nThe statistical assistance of Professor Bengt Ka¨lle´n is grate-\nfully acknowledged. We also wish to acknowledge Mats\nTalba¨ck at the National Board of Health and Welfare\nand A˚ ke Jalo at Statistics Sweden for helping us to match\nthe data registers.\nFinancial support was from the Sigrid Simonssons and\nAgni Olssons Foundation.\nReferences\n1. The National Board Health Welfare Centre for Epidemiology.\nCauses of death 1997: Official Statistics of Sweden – Health and\nDiseases: Stockholm, Sweden: 2000; 3: 1–224.\n2. Pecorelli S, Benedet J, Beller U, Creasman W, Heintz A,\nPettersson F. FIGO Annual Report on the Results of Treat-\nment in Gynaecological Cancer. FIGO Annual Report on the\nResults of Treatment in Gynaecological Cancer. Oxford,\nEngland: Isis Medical Media Ltd, 2001; 6: 1–184.\n3. 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Risk of endometrial cancer\nfollowing estrogen replacement with and without progestins.\nJ Natl Cancer Inst 1999; 91: 1131–7.\nAddress for correspondence:\nChrister Borgfeldt\nDepartment of Obstetrics and Gynecology\nUniversity Hospital\nS-221 85 Lund\nSweden\ne-mail: christer.borgfeldt@gyn.lu.se\n400 C. Borgfeldt and E. Andolf\n# Acta Obstet Gynecol Scand 83 (2004)","source_license":"CC0","license_restricted":false}