Treatment paradigm and prognostic factor analysis of rectal squamous cell carcinoma- a retrospective study

Abstract

Background：Rectal squamous cell carcinoma（rSCC）is a rare pathological type of rectal malignant tumors. There is no consensus on the treatment paradigm of patients with rSCC. This study aims to provide a paradigm for clinical treatment via analyzing the efficacy of different treatment regimens for patients with different TNM stages. Methods：Patients diagnosed with rSCC between 2010 and 2019 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. According to the TNM staging system, Kaplan-Meier（K-M）survival analysis was used to identify the survival benefits of patients with rSCC in different treatment groups. The Cox regression method was used to identify independent prognostic risk factors. Nomograms were evaluated by Harrell's concordance index, calibration curves, DCA and K-M curve. Results：463 patients with rSCC were extracted from the SEER database. Survival analysis showed that there was no significant difference in cancer specific survival (CSS) among radiotherapy（RT）, chemoradiotherapy（CRT）and surgeryin Stage 1 (P = 0.249). In TNM Stage 2, there was significant difference in CSS among surgery, RT, and CRT (P = 0.003). In TNM Stage 3, there was significant difference in CSS between CRT, no treatment and CRT plus surgery (P < 0.001). In TNM Stage 4, there was significant difference in CSS between CRT, no treatment and CT (P = 0.041). COX regression analysis showed that Age, Marital status, N, M, CEA, PIN, Size, RT, CT, and surgery were the independent risk factors. The 1-, 3-, and 5-year C-index was 0.869,0.777,0.759, respectively. The calibration curve showed that the model had excellent calibration. The DCA curve showed that the model had excellent clinical application value. Conclusion：RT or surgery is recommended for patients with rSCC at Stage 1, and CRT is recommended for patients with rSCCat Stage 2, Stage 3, and Stage 4. Age, marital status, N, M, PIN, size, RT, CT and surgery are independent risk factors for CSS in patients with rSCC. The prediction model composed of the above independent risk factors has excellent prediction efficiency.