Weekly Image Guidance in Patients With Cervical Cancer Treated With Intensity‐Modulated Radiation Therapy: Results of a Large Cohort Study
ABSTRACT
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 nonimaging guidance days. When significant tumor regression was observed, a second computed tomography simulation and replanning 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. For patients with different stages, the 5‐year OS, DFS, LRFS, and DMFS rates were statistically significant. 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 late Grade 3/4 chronic toxicities.
Conclusions
IMRT with weekly CBCT is an acceptable image guidance strategy in countries with limited medical resources.