Impact of post‐therapy positron emission tomography on prognostic stratification and surveillance after chemoradiotherapy for cervical cancer

BACKGROUND: A study was undertaken to investigate the detection of relapse and survival outcomes in patients with cervical cancer treated with curative intent chemoradiotherapy, and evaluated with a post‐therapy 18 F‐fluorodeoxyglucose positron emission tomography (FDG‐PET) scan. METHODS: Between January 2002 and June 2007, 105 consecutive patients were prospectively enrolled into a registry study designed to assess outcomes of chemoradiotherapy. A FDG‐PET scan was performed between 3 and 12 months (median, 4.9 months) post‐treatment at clinician discretion. Tumor response was graded as complete metabolic response, partial metabolic response, or progressive metabolic disease. RESULTS: Median follow‐up was 36 months. At post‐therapy FDG‐PET, 73 (70%) patients had complete metabolic response, 10 (9%) had partial metabolic response, and 22 (21%) had progressive metabolic disease. Overall survival at 3 years was 77% in all patients, and 95% for those with complete metabolic response. On multivariate analysis, complete metabolic response ( P < .0001) and pretreatment tumor volume ( P = .041) were strong predictors for overall survival. The number of involved lymph nodes ( P < .005) and International Federation of Gynecology and Obstetrics stage ( P = .04) were predictive of relapse‐free survival. In total, 18 patients relapsed at a single site, and 13 underwent salvage, with a 3‐year survival of 67%. Patients with complete metabolic response had a distant failure rate 36‐fold less than those with partial metabolic response ( P < .0001). After complete metabolic response, only 1 patient (1.6%) relapsed without symptoms and was detected through physical examination. CONCLUSIONS: The presence of a complete metabolic response at post‐therapy FDG‐PET is a powerful predictor for survival after chemoradiation. The very low rate of recurrence in patients with a complete metabolic response justifies a conservative follow‐up approach for these patients, because relapse is usually symptomatic and not detected by routine clinical review. Cancer 2011. © 2011 American Cancer Society.