Gender-related prognostic significance of clinical and biological tumor features in rectal cancer patients receiving short-course preoperative radiotherapy.

Aim: To study the prognostic value of clinical and biological features of rectal cancer and potential gender differences in patients' overall survival (OS), local recurrence-free survival (RFS) and metastasis-free survival (MFS) after short-course preoperative radiotherapy (SCRT) with short or long interval between RT and surgery (break).
Background: The length of the interval between RT and surgery in SCRT is debatable and gender-related differences in patients survival are not established yet.
Materials and Methods: 126 patients received SCRT with 5 Gy dose per fraction during 5 days, followed by radical surgery after short break ≤17 days, and a long break >17 days. Pretreatment tumor proliferation (bromodeoxyuridine labeling index, BrdUrdLI and S-phase fraction) was evaluated by flow cytometry and proteins: CD34, Ki-67, GLUT-1, Ku70, BCL-2, P53 expression was studied immunohistochemically.
Results: The studied group included 84 men and 42 women. There were 33, 76, and 17 cTNM (AJCC) tumor stages I, II, III, respectively. The median follow-up time was 53.3 months (range 2-142 months). For the whole group Cox multivariate analysis revealed that tumor grade (G > 1), interval between RT and surgery >17 days, pTNM stage >1 and P53 positivity + BrdUrdLI > 7.9% were negative prognostic factors for OS. Tumor aneuploidy and MVD > 140.8 vessels/mm ² were important for RFS. pTNM stage > 1 and P53 positivity combined with BrdUrdLI > 7.9% were risk predictors for MFS. Based on tumor biological features, gender-related difference in OS, RFS, and MFS were observed. In multivariate analysis, male patients age > 62 years and break >17 days only appeared to be significant for OS.
Conclusions: In male rectal patients treated with SCRT, breaks between RT and surgery >17 days should be avoided because they negatively influence patients' survival.