Long-Term Outcomes of Simultaneous Integrated Boost in Node-Positive Cervical Cancer: A Single-Institution Retrospective Study

Background Nodal involvement in cervical cancer is associated with poor prognosis. Although modern radiotherapy techniques (intensity-modulated radiotherapy (IMRT)/volumetric-modulated arc therapy (VMAT)) enable safe nodal dose escalation, clinical data, particularly from Indian settings and node-positive subgroups, remain limited. This study evaluated outcomes and toxicity using a simultaneous integrated boost (SIB) to radiologically involved nodes. Methods We retrospectively analyzed 56 patients with node-positive, locally advanced cervical cancer treated between 2018 and 2023. All patients received pelvic external-beam radiotherapy (45-50 Gy) with nodal SIB (median, 55 Gy in 25 fractions), followed by intracavitary brachytherapy (24 Gy in 3 fractions or 28 Gy in 4 fractions). Weekly cisplatin was administered when feasible. Tumor and nodal responses were assessed at 3 months, and survival was estimated using Kaplan-Meier and compared with log-rank tests. Results After a median follow-up period of 35 months, complete response was observed in 46 (81.8%) and 51 (91%) patients with primary and nodal diseases, respectively. Initial failures were categorized as local in seven cases (12.5%), regional in six (10.7%), and distant in 15 (27.3%). The five-year local and regional control rates were 86% and 85%, respectively; the distant recurrence-free survival rate was 64%, and the overall survival rate was 68%. Patients with para-aortic nodal disease (IIIC2) exhibited inferior distant control compared to those with IIIC1 (median, 29 months vs. not reached; p = 0.047). Late grade ≥3 gastrointestinal and genitourinary toxicities were observed in two (3.6%) and one (1.8%) patients, respectively. Vaginal stenosis was reported in 14 (25.0%) patients, with grade 3 stenosis occurring in 2 (3.6%) patients. Conclusions Definitive chemoradiation with IMRT/VMAT using a simultaneous integrated nodal boost achieved high complete response rates, excellent pelvic control, and low rates of severe late toxicity in node-positive cervical cancer. Distant relapse remained the main pattern of failure, particularly in patients with para-aortic involvement. These findings support nodal dose escalation as a safe, practical strategy and highlight the need for systemic intensification in high-risk patients.