Prognostic Value of Tumor Parameters Measured By MRI in Cervical Cancer Patients Receiving CCRT

Abstract

A range of prognostic factors had been reported to be associated with clinical outcome of cervical cancer patients. However, these parameters were measured before the start of treatment but without consideration of tumor response to RT. We believed that it might be possible to provide locally advanced cervical cancer patients an opportunity to modify and guide the treatment strategies in the midway of treatment based on the early response evaluation during RT. 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 Chinese local advanced cervical cancer patients. We retrospectively reviewed 310 Chinese patients with locally advanced cervical cancer. All recruited patients were histologically confirmed squamous cell carcinoma of the cervix and initial untreated. Then they were all received standardized concurrent chemoradiotherapy (CCRT) during the whole 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. The median follow-up time was 50 months. In univariate analysis, the group of higher TVRR showed a better OS, PFS, and LRFS than the group of lower TVRR (P＜0.05). Other tumor parameters, such as 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, FIGO stage and other tumor parameters (P＜0.05), In the PFS-related multivariate analysis, the tumor volume reduction rate (TVRR) remained statistically significant after adjustment for TS, TV, and other parameters (P＜0.05). In addition, TVRR was also independently associated with LRFS after adjustment for other parameters (P＜0.05). Our study confirmed that tumor parameters such as TS, TV, and TVRR, measured before the completion of CCRT, are valuable prognostic factors in patients with locally advanced cervical cancer.