Complete metabolic response after definitive radiation therapy for cervical cancer: patterns and factors predicting for recurrence.

Purpose: The purpose of this study was to determine the patterns of failure in patients diagnosed with cervical cancer treated with definitive radiotherapy and who subsequently had complete metabolic response (CMR) seen on early post-therapy (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. Additionally, we sought to determine what factors predict disease recurrence in this patient population.

Methods And Materials: We reviewed the records of 155 patients diagnosed with cervical cancer from stages IB1 to IVA who were treated with definitive chemoradiation therapy between 2003 and 2011 and had a FDG-PET at 10-16 weeks following completion of therapy. One hundred and twelve (72.0%) had CMR on follow-up FDG-PET and comprised the patients in this study.

Results: The median age of patients with CMR was 51 years and the median tumor size 4.9 cm. Median follow up was 15 months. Of the 112 patients, 11 (9.8%) had a recurrence and six (5.4%) had isolated local recurrences, and five (4.5%) had distant recurrence. Median time to recurrence was 9 months. Three-year actuarial disease-free survival and overall survival rates were 78.9% and 88.0% respectively. On Cox regression multivariate analysis, tumor size was predictive of increased risk of local recurrence in these patients with CMR with p<0.025. Age, stage, histology and nodal positivity were not significant for predicting local, distant or any recurrence.

Conclusion: Patients treated with concurrent chemoradiation had a CMR which demonstrated good clinical outcomes in terms of local control. There were equal numbers of patients suffering local and distant recurrences. In patients with a CMR, only tumor size was an independent predictor for local recurrence.