Impact of nodal boost irradiation and MR-based brachytherapy on oncologic outcomes in node-positive cervical cancer

Abstract

This study aimed to prospectively evaluate the impact of dose-escalated irradiation of nodal metastases on clinical outcomes compared to no boost in patients with node-positive, bulky, locally advanced cervical cancer (LACC) undergoing standard chemoradiation and MRI-based brachytherapy. MethodsThis comparative study included 161 patients with node-positive LACC treated with definitive chemoradiation and MRI-based brachytherapy. The prospective Boost arm accrued 71 patients to receive nodal boost either sequentially or simultaneously to an equivalent dose of 60 Gy. The control arm comprised 90 patients treated before this protocol period with no additional nodal boost. ResultBaseline patient and tumor characteristics were similar in both groups. All patients had at least one tumor dimension >5 cm at presentation, and 31% had para-aortic node involvement. With a median follow-up of 36 months (IQR:19–50.5), the overall 3-year Local control rate was 88.8%. The 3-year Regional control (93% vs. 80%, p = 0.035) was statistically better in the Boost arm. No nodal failure was observed in nodes <3 cc and < 2 cm, even in the No-boost arm. There was no significant difference in Disease-free survival (67.6% vs. 58.9%,p = 0.454) and Overall Survival (78.9% vs. 74.4%,p = 0.87) between the two arms. Incidence of acute or late toxicities did not differ significantly with nodal boost or the boost delivery technique. ConclusionThe addition of external radiation nodal boost to standard treatment of high-volume cervical cancer has improved pelvic control with an acceptable rate of toxicities. However, high systemic failures continue to pose a challenge in improving survival outcomes.