Objective To investigate the outcomes of observation-alone versus adjuvant radiotherapy for patients with lymph node negative FIGO 2018 stage IB cervical carcinoma following radical hysterectomy with negative prognostic factors.

Methods The National Cancer Database was accessed and patients with no history of another tumor, diagnosed with intermediate risk (defined as tumor size 2–4 cm with lymph-vascular invasion or tumor size >4 cm) pathological stage IB squamous, adenosquamous carcinoma or adenocarcinoma of the cervix between January 2010 and December 2015 who underwent radical hysterectomy with lymphadenectomy and had negative tumor margins were identified. Overall survival was assessed following generation of Kaplan–Meier curves and compared with the log-rank test. A Cox model was constructed to control for a priori selected confounders known to be associated with overall survival.

Results A total of 765 patients were identified and adjuvant external beam radiotherapy was administered to 378 patients (49.4%). There was no difference in overall survival between patients who did and did not receive adjuvant radiotherapy, P=0.44: 4-year overall survival rates were 88.4% and 87.1% respectively. After controlling for patient age, histology, and surgical approach, the administration of adjuvant radiotherapy was not associated with better survival (HR 0.86, 95% CI 0.54 to 1.38). For patients who received adjuvant radiotherapy, there was no survival difference between those who did (n=219) and did not (n=159) receive concurrent chemotherapy, P=0.36: 4-year overall survival rates were 89.8% and 86.3%, respectively.

Conclusion In a large cohort of patients with lymph node negative, margin negative, stage IB cervical carcinoma, with negative prognostic factors, the administration of adjuvant external beam radiation therapy was not associated with a survival benefit compared with observation alone.