PET/CT-based dose-escalated definitive radiotherapy in cervical cancer: a single-institution series

The objective was to evaluate clinical outcomes and toxicity of patients with cervical cancer treated by radiotherapy with dose escalation in involved lymph nodes based on positron emission tomography/computed tomography (PET/CT) staging.

Retrospective cohort study involving locally advanced cervical neoplasms treated with definitive radiotherapy. Volumetric modulated arc therapy (VMAT), image-guided radiotherapy (IGRT), and registration of PET/CT were employed in all. Involved lymph nodes were given higher doses simultaneously.

Between February 2012 and September 2023, there were 37 patients, with median age of 48 (range 27-91) years. Almost 70% were stages III/IVA. Two-thirds were given retroperitoneal irradiation. The mean delivered doses to primary tumor and to involved lymph nodes were, respectively, 52.5 Gy, and 62.5 Gy. The 10-year rates of overall survival, event-free survival, local-recurrence-free survival, and metastasis-free survival were, respectively, 76%, 50%, 91%, and 82%. There were 13 and 2 cases of gastrointestinal toxicity grades II and III, respectively. Grades II and III of genitourinary toxicity were seen respectively in 7 and 3 patients. On univariate analysis, age was related to local recurrence-free survival (LRFS); standard uptake values (SUV) was related to event-free survival (EFS); lymph node dose was related to overall survival (OS), and EFS; primary tumor dose was directly related to EFS, albeit inversely to the likelihood of grade > II gastrointestinal toxicity. Retroperitoneal irradiation improved LRFS, and rates of grade > II gastrointestinal toxicity. On multivariate analysis, SUV remained an independent predictor of EFS; lymph node dose was an independent predictor of OS, and age was an independent predictor of lymph node recurrence.

Dose escalation radiotherapy (RT) based on PET/CT for cervical cancer may be feasible and safe. Further robust study results are needed.