The Impact of Timing of Adjuvant Radiotherapy on Disease free survival in neoadjuvantly-treated breast Cancer patients

Abstract

Adjuvant radiotherapy is a cornerstone in treating women with breast cancer who underwent either breast conserving surgery or mastectomy. yet, in developing countries it is difficult to start adjuvant RT to all cases as early as possible and they to be put on waiting lists. Aim of the Work: to assess the impact of delaying adjuvant radiotherapy in breast cancer patients who received neoadjuvant chemotherapy and to correlate between the radiotherapy timing and other risk factors as prognostic factors on Disease-free survival. Patients and Methods: The present study was conducted 240 women at the oncology department of Ain Shams University before 2019. Data collection for each patients' clinical data were obtained retrospectively from the patient’s medical records. The cohort was divided into two groups according to the timing of starting radiotherapy following surgery: A ≤ 8 weeks, and B > 8 weeks. Result: In Group (A) (35.8%) had a relapse event, compared to group (B) where (40.8%) had a relapse event. In those patients who had a relapse events only (8.3%) had local recurrence in Group A and the remaining 33 (27.5%) found to have distance metastasis while in Group B a total of 21 cases (17.5%) had locoregional recurrence leaving the remaining 25 (20.5%) with only distance metastasis, showing that those who received PORT within 8 weeks were associated with a statistically significant better local control (p value 0.04).Yet it failed to show control over the distance metastasis, therefore as a result it did not have a significant effect on the DFS (std error 0.7 95% CI 2.58 to 28.66, p = 0.48). Conclusion: The timing of initiation the adjuvant radiotherapy in breast cancer patients who received neoadjuvant chemotherapy does not significantly affect the 3 years Disease-free survival (DFS) yet receiving it within 8 weeks from surgery is associated with better locoregional control. Tumors larger than 5 cm (T3 and T4) and poor response to neoadjuvant chemotherapy are considered risk factors affecting DFS. Key words: Adjuvant radiotherapy, breast cancer, neoadjuvant chemotherapy, prognostic factor, disease free survival