Advanced cervical cancer and neoadjuvant treatment: predictive role of 18F-FDG PET/CT for treatment response

Objectives To evaluate the predictive role of 18F-FDG PET/CT in predicting response to neoadjuvant treatment in patients with advanced cervical cancer (CC).

Methods This study retrospectively included 13 women with CC who underwent to 18F-FDG PET/CT before and after neoadjuvant treatment (chemotherapy n=10; chemoradiotherapy n=3). Baseline and post-treatment PET-derived parameters (maximum standardized uptake value-SUVmax and metabolic tumour volume with a threshold of 60-MTV60) of the primary tumors have been performed to assess treatment response and predictive value. Two-tailed t-test was used to assess the differences between PET parameters.

Results The median age at the time of baseline 18F-FDG PET/CT was 52 years (range: 36-91); the median time interval between baseline and post neoadjuvant treatment scans was 3.6 months (range: 1.8-7.9). Comparing baseline and post-treatment scans, 7/13 patients showed response to therapy and 6/13 patients had stable disease or progressive disease. The mean and median SUVmax of the primary tumour were 16.9 and 12.7 (range 3.7-35.5) and 11.3 and 7.5 (range 2.8-4.1) for the baseline and post-treatment scan, respectively. The mean percentage change in SUVmax between baseline and post treatment scan was 44.8% (range: 5.9 - 79.4%) and -2.8% (range: -102.7 - 74.1%) in responders and non-responders, respectively. Interestingly, baseline mean and median SUVmax of the primary tumor were higher (21.5 and 19.2; range: 3.7-35.5) in non-responders or progression after treatment compared to responders (13.0 and 11.7; range: 8.3-25.3). The mean and median MTV60 of the primary tumor were 11.5 and 7.16 (range 1.8-56.5) and 6.4 and 3.1 (range 0.8-34.8) for the baseline and post-treatment scan, respectively. The average percentage change in MTV60 between baseline and post treatment scan was 39.3% (range: -85.9 - 98.6%) and -75.7% (range: -454.5- 91.0%) in responders and non-responders, respectively. Strikingly, baseline mean and median MTV60 of the primary tumor were lower (6.8 and 4.8; range: 1.8-15.2) in non-responders or progression after neoadjuvant treatment compared responders to treatment (15.7 and 8.9; range: 5.2-56.5), although not reaching statistical significance.

Conclusions Although these study included only a small cohort of patients with advanced CC, the strong differences between SUVmax, MTV60 and their variation between baseline and post-treatment scans in responders and non-responders may be relevant for patients’ treatment decision-making.