Due to the better survival of patients with tumorous diseases, it is increasingly
important to predict the side effects of radiotherapy, for which the Radiation-Induced
Lymphocyte Apoptosis (RILA) method is proving to be effective in multicentric studies.
Prostate cancer is the leading cause of cancer-related deaths among men worldwide,
which is usually treated with radiotherapy. We recruited 49 patients with localized
prostate cancer and performed RILA measurements before radiotherapy. Patients were
treated with CyberKnife (35-40 Gy) or high-dose-rate brachytherapy (1 × 21 Gy). We
performed chromosome aberration test for five years and graded side effects, IPSS
and QoL questionnaire scores were recorded. We found that RILA% correlated with the
IPSS increase (p = 0.0016, r=-0.44), which was confirmed with negative binomial regression
(p = 0.0013). The negative predictive value for severe urinary side effects according
to the IPSS questionnaire was 87.9% at the lower tertile of RILA values. Chromosome
aberrations also correlated with side effects, but when we built models including
variables of baseline and treatment characteristics of the patients, RILA, and chromosome
aberrations, only RILA predicted a late increase in IPSS score (p < 0.0001, adjusted
R2 = 68%). The RILA method was shown to be predictive of urinary side effects especially
of patient-reported outcomes.
