Survival Rate of Radiotherapy Treatments with 3D-CRT and SBRT Techniques in Patients with Prostate Cancer CaP at the Centro Médico Nacional Siglo XXI-IMSS, Hospital de Oncologia

摘要

Introduction: Prostate Cancer (CaP) is a malignant neoplasm where one of the main treatment options is radiotherapy (RT). However, traditional RT treatment planning criteria omit radiobiological aspects for optimization. This work intends to determine the survival rate; survival values that will be taken as reference to evaluate the radiobiological optimization in a future phase. Methods: A cohort of 400 patients was taken and divided into 4 groups. Groups I and II were treated with 3D Conformal Radiotherapy (3D-CRT) technique with an absorbed dose per fraction of 1.8 Gy and 2.65 Gy with linear accelerator, while groups III and IV were treated with Stereotactic Body Radiation Therapy (SBRT) technique with an absorbed dose per fraction of 7 Gy and 7.25 Gy with Cyberknife. The biochemical failure of the treatment was determined with the Phoenix criterion, which consists of considering an increase of 2 ng/ml or more over the Prostate Specific Antigen (PSA) nadir. The follow-up period for patients is 43 months on average. Two contingency tables 2 x 2 are constructed: a) one for frequency of cure and failure, and b) other for the probability of survival. Results and discussion: From the statistical analysis of the contingency tables we obtained: an average survival rate of 92.9%, we also considered subcategories of risk (low, medium and high) and hormonal deprivation. Taking the conventional treatment and the tumor control probability as a control group, the Cochran-Mantel-Haenszel test was applied and a common odds ratio of 0.8226 was obtained, which means that the hypofractionated treatments have a higher survival rate of 17.74% than the standard fractionation treatment. Also, we have the MHC statistic value = 0.0281, df = 1 and p-value = 0.8668, then there is no significant difference for the subcategory of risk. Conclusions: An average survival rate of 92.9% was determined in cohorts of Mexican patients treated at the Centro Médico Nacional Siglo XXI, Hospital de On