Management and prognosis of cervical cancer patients treated with definitive radiation therapy who have partial metabolic response on post-therapy positron emission tomography

To describe the management and outcomes of cervical cancer patients initially treated with radiation who had partial metabolic response (PMR) on three-month post-radiation 18F-fluorodeoxyglucose positron emissions tomography (FDG-PET). Cervical cancer patients treated with radiation between 1997 and 2013 who had PMR on initial post-therapy FDG-PET were identified from a prospectively maintained database. Descriptive statistics were used to summarize patient demographics, tumor characteristics, surveillance methods, and treatment modalities. Kaplan-Meier methods were used to estimate progression-free (PFS) and overall survival (OS) for patients who underwent cervical biopsy prior to additional therapies and for patients who were managed with chemotherapy, radiation, surgery or no intervention. PMR was identified in 81/542 (15%) women on initial post-radiation PET. Thirty women underwent cervical biopsy, of whom 14 (47%) had persistent cancer. Nine underwent treatment, (three surgery, five chemotherapy alone and one chemotherapy and radiation) but all died of disease; PFS and OS were similar whether women had surgery, chemoradiation therapy, or no treatment. A second surveillance FDG-PET had PPV and NPV of 91% and 75% for progression, respectively, and identified the 19% percent of patients with persistent disease outside of the cervix. Cervical biopsy had a higher PPV (100%) and lower NPV (62.5%) for progression. At the end of the study period, 46 (57%) patients were dead of disease, including all 8 patients (100%) with para-aortic or supraclavicular involvement. If PMR is identified on three-month FDG-PET following completion of radiation for cervical cancer, repeat FDG-PET and/or biopsy are indicated to detect persistence and assist in counseling. PMR predicts poor outcomes, particularly for those with positive cervical biopsies and lymphatic involvement. •Partial metabolic response on initial restaging FDG-PET presents a diagnostic and prognostic challenge.•Initial restaging FDG-PET has a false positive rate of 53%, necessitating biopsy for patients desiring early salvage therapy.•Serial FDG-PET scans are diagnostically valuable, with markedly improved predictive values compared to a single scan.•Optimal treatment of PMR is uncertain, with surgical salvage conferring the highest possibility of cure.