Weekly Image Guidance in Patients with Cervical Cancer Treated with Intensity-Modulated Radiation Therapy: Results of a Large Cohort Study

Background: Image guidance is recommended for patients undergoing intensity-modulated radiation therapy (IMRT) for cervical cancer. In this study, we evaluated the feasibility of a weekly image guidance pattern and analyzed the long-term outcomes in a large cohort of patients. Methods The study enrolled patients with stage IB-IVA cervical cancer who received definitive radiotherapy or concurrent chemoradiotherapy. IMRT was delivered at a dose of 50.4 Gy in 28 fractions, with weekly cone-beam computed tomography (CBCT). Physicians advised patients on rectum and bladder preparation to help them prepare on non-imaging guidance days. When significant tumor regression was observed, a second computed tomography simulation and re-planning were performed. Results The median follow-up periods were 63.4 months. The incidence rates of loco-regional and distant failure were 9.9% and 13.6%. The 5-year overall survival (OS), disease-free survival (DFS), loco-regional relapse-free survival (LRFS), and distant metastasis-free survival (DMFS) rates were 80.1%, 72.9%, 78.3%, and 74.8%, respectively. The 5-year OS, DFS, LRFS, and DMFS rates were statistically significant for patients with different stages. For patients with and without positive regional lymph nodes, the 5-year OS, DFS, LRFS, and DMFS rates were 64.5% and 86.0%, 56.8% and 78.8%, 62.7% and 84.3%, and 58.8% and 81.0%, respectively. Multivariate analysis showed that age, histology, tumor size, cancer stage, pretreatment squamous cell carcinoma antigen level, and para-aortic metastatic lymph nodes were independent prognostic factors of OS. Fifty-six (4.0%) patients experienced grade 3–4 chronic toxicities. Conclusions IMRT with weekly CBCT is an acceptable image guidance strategy in countries with limited medical resources.