The Prognostic Effects of Clinicopathological Features on Rectal Cancer Patients undergoing Neoadjuvant...

To investigate the effects of clinicopathological features on disease-free survival (DFS) and overall survival (OS) in in-patients with local advanced rectal cancer (LARC) who received neoadjuvant chemoradiotherapy (nCRT).

Observational study.

Clinic of Radiation Oncology, Kayseri Training and Research Hospital and Kayseri City Hospital, Turkey, between January 2014 and June 2019.

The pre-nCRT, post-nCRT, and postoperative imaging methods of 51 patients, who were operated upon, were examined. Radiological images (CT and MRI) of the patients were reviewed using the hospital's PACS system. Pathology reports and preparations were re-evaluated, and TNM staging and the pathological tumour regression grade (pTRG) were graded according to the American Joint Committee on Cancer's (AJCC) 2018 version. For the descriptive statistics of the data, the mean, standard deviation, lowest-highest median, frequency, and ratio values were used. Cox regression (univariate-multivariate analysis) and Kaplan-Meier curves were used for survival analysis.

In the univariate model, the postoperative pathological T and N stages (ypT and ypN), pathological stage, positive lymph node count (pLN+, pathological sampling) and lymphovascular invasion (LVI) positivity had a significant effect (p <0.05) on DFS. In the multivariate reduced model, a significant independent (p <0.05) effect of the ypT and pLN+ number was observed on DFS. In the univariate model, the pathological tumour diameter after nCRT, the ypT, perineural invasion (PNI) positivity, and relapse presence had a significant effect (p <0.05) on OS. In the multivariate reduced model, a significant independent (p <0.05) effect of recurrence was observed on OS.

LVI, the ypTN stage, and the pLN+ number affected the disease-free survival, while the residual tumour diameter after nCRT, ypT stage, and PNI affected the overall survival. The predicted DFS time decreased as the ypT stage increased and the predicted OS time decreased as the recurrence increased. Key Words: Rectal cancer, Neoadjuvant chemoradiotherapy, Disease-free survival, Overall survival.