Prognostic value of tumor parameters measured by MRI in cervical cancer patients receiving CCRT.

Abstract

e17027 Background: This study aimed to evaluate the response of solid tumors after the completion of external beam radiotherapy (EBRT) and investigate the prognostic value of tumor parameters such as tumor volume and size (TV & TS) and tumor volume reduction rate (TVRR) early during the treatment in local advanced cervical cancer patients. Methods: We retrospectively reviewed 310 Chinese patients with locally advanced cervical cancer. They were all received concurrent chemoradiotherapy (CCRT) during the treatment based on intensity modulated radiotherapy (IMRT). Clinical data at the time of diagnosis, including FIGO stage, TV and TS were measured by pelvic magnetic resonance imaging (MRI) before and after EBRT were available. Information about distant metastasis, relapse and date of death was also collected, with a follow-up until Aug 2018. Youden index was used to identify the optimal cut-off point of continuous tumor parameters and divide patients into subgroups. Prognostic factors (age, FIGO stage, RT dose, pre-RT TS and TV, mid-RT TS and TV, TVRR) were using the log-rank test and Cox regression models to analyze the association between predictors and time-to-event outcomes. Results: The median follow-up time was 50 months. In univariate analysis, the FIGO stage, TVRR, TV and TS were associated with overall survival rate. Interestingly, the group of higher TVRR showed a better OS, PFS and LRFS than the group of lower TVRR ( P <0.05). Moreover, the groups of lower TV and TS showed better OS, PFS and LRFS than the higher groups, respectively. In the OS-related multivariate analysis, the mid-RT TV remained statistically significant after adjustment for age and FIGO stage ( P < 0.05). In the PFS-related multivariate analysis, the tumor volume reduction rate (TVRR) remained statistically significant after adjustment for age, FIGO stage, TS, and TV ( P <0.05). In addition, in the LRFS-related multivariate analysis, TVRR also remained statistically significant after adjustment for age, FIGO stage, TS, and TV ( P <0.05). Conclusions: Our results confirmed that tumor parameters including TS, TV and TVRR, measured before the completion of CCRT, are valuable prognostic factors in patients with locally advanced cervical cancer.