Clinical impact of delaying initiation of radiotherapy in patients with breast cancer: stages 0, I and II, a retrospective observational study

Background: There is no consensus on how long the initiation of radiotherapy (RT) can be delayed after surgery without a negative impact on survival. Materials and methods: We conducted a retrospective study of 278 patients with stage 0-II breast cancer, all of whom were treated with surgery and RT, with those at stages I-II also receiving chemotherapy. Patients were followed-up for 5 years after diagnosis to assess disease-free and overall survival. The independent variable was the delay in the initiation of RT, assessed by two criteria: time since the last treatment, considered acceptable if <= 6 weeks, and time since surgery, considered acceptable if <= 7 months, these cut-offs being used to categorise patients into two groups according to the length of delay. Results: No statistically significant differences were observed in the probability of disease-free survival (p = 0.412) or overall survival (p = 0.890). The appearance of recurrence was 5-59 months, with an average of 38.50 (14.31). Conclusions: Delaying the initiation of RT for more than 6 weeks after last treatment does not seem to have a negative impact on disease-free or overall survival.