Image-guided intensity-modulated radiotherapy in patients with FIGO IIIC1 cervical cancer: efficacy, toxicity and prognosis.

To investigate the efficacy, toxicity and prognosis of image-guided intensity-modulated radiotherapy (IG-IMRT) in patients with FIGO IIIC1 cervical cancer. We retrospectively reviewed clinical records of patients with FIGO IIIC1 cervical cancer treated with definitive IG-IMRT in our institute from January 2008 to December 2017. A dose of 50.4Gy in 28 fractions was prescribed to at least 95% of PCTV, the positive pelvic lymph nodes received a dose of 56-61.6Gy in 28 fractions with simultaneous integrated boost (SIB). Weekly cone beam compute tomography (CBCT) and daily megavoltage CT (MVCT) was performed before treatment. Both 2D brachytherapy and 3D brachytherapy were allowed in our study. Weekly Cisplatin (30-40mg/m2) was the first line regimen for concurrent chemotherapy. Overall survival (OS), disease free survival (DFS), local control (LC) and local regional control (LRC) was calculated with Kaplan-Meier method. Cox proportional hazard model was used to perform univariate and multivariate analyses. A total of 502 patients were enrolled in this study. The median follow-up duration was 42.1 months (range: 2.3-137.3 months). The 3-year and 5-year estimated OS, DFS, LC, LRC were 81.7% and 75.5%, 71.4% and 68.6%, 89.9% and 89.9%, 86.1% and 84.3%, respectively. The incidences of chronic grade 3 or greater gastrointestinal and genitourinary toxicities were 2.7 % and 0.8%, respectively. Pelvic lymph nodes recurrence occurred in 21 patients (4.2%). Advanced T stage was identified as adverse factor for OS and LC. More positive lymph nodes (≥2) were associated with worse OS, DFS and LRC. The cycles of concurrent chemotherapy significantly affected OS, DFS and LRC. For patients with FIGO IIIC1 cervical cancer, IG-IMRT was well tolerated with excellent survivals. T stage and number of positive lymph nodes significantly influenced the survivals indicating the heterogeneity of stage IIIC1 cervical cancer patients. Adequate cycles of chemotherapy (≥4 cycles) was of great value for this group of patients.