Radiotherapy dose escalation on pelvic lymph node control in patients with cervical cancer

Data supporting dose escalation for node-positive cervical cancer are currently limited to small retrospective studies. The goal of this study was to assess whether radiation dose was associated with lymph node control or gastrointestinal toxicity in patients with node-positive cervical cancer.

A total of 390 patients with carcinoma of the uterine cervix were treated between October 1997 and October 2017. Patients included in our analysis were those with squamous cell carcinoma or adenocarcinoma who were node-positive, treated definitively, and with at least one follow-up visit and post-treatment imaging scan. We excluded those without follow-up and those treated with palliative intent. All patients were treated with external beam radiation to pelvic±para-aortic fields with concurrent weekly cisplatin. All lymph nodes present at the time of treatment were stratified by size as <2 cm or ≥2 cm. Acute and late gastrointestinal toxicity were recorded for all patients.

A total of 77 patients with 206 lymph nodes were identified. Median stage at presentation was FIGO IIB. Thirteen patients underwent definitive surgical resection followed by adjuvant radiation, of which 12 were treated to doses ≤5040 (range 2700-5940) cGy. Sixty-four patients were treated with definitive chemoradiation, of which 42 (66%) received ≤5040 (range 4500-5040) cGy and 22 (34%) received >5040 (range 5300-6640) cGy. Patients with pre-chemoradiation lymph nodes ≥2 cm had inferior lymph node control compared with patients with pre-chemoradiation lymph node <2 cm at 12 months (77% vs 100%, p=0.002). Radiation dose >5040 cGy was not significantly associated with improved lymph node control compared with ≤5040 cGy when analyzing all patients (12 months, 100% vs 89%, p=0.112). In patients with pre-chemoradiation lymph nodes ≥2 cm, radiation dose >5040 cGy was associated with improved lymph node control (12 months, 100% vs 60%, p=0.020). Acute grade ≥2 gastrointestinal toxicity was not associated with radiation dose >5040 cGy (20% vs 13%, p=0.424). Two patients developed grade ≥2 late gastrointestinal toxicity, both of whom were treated to ≤5040 cGy.

This series supports the role of dose escalation for patients with lymph nodes ≥2 cm. Dose escalation is associated with improved control in patients with larger lymph nodes, and is not associated with greater gastrointestinal toxicity.