ASTRO 2020: Initial 2-Year Results of Comparison of Breast Irradiation Therapies
Posted: Tuesday, November 3, 2020
Although adjuvant breast radiotherapy with risk-adapted boost irradiation is the gold standard in primary treatment of patients with breast cancer, simultaneous integrated boost irradiation may prove to be noninferior to three-dimensional (3D) conformal radiotherapy with a consecutive boost. According to Juliane Hörner-Rieber, MD, of Heidelberg University Hospital, Germany, and colleagues, no significant differences in estimated survival rates, cosmetic assessments, or local tumor control were identified between the two treatments. The results were presented during the virtual edition of the 2020 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 19).
The phase III trial randomly assigned 502 patients with breast cancer to receive intensity-modulated radiotherapy (IMRT) with a simultaneous integrated boost (50.4 Gy/64.4 Gy in 28 fractions) or 3D conformal radiotherapy (3D-CRT) with a consecutive boost (50.4 Gy + 16 Gy in 36 fractions). All of the patients previously had breast-conserving therapy. The researchers evaluated local tumor control rates measured at 2 and 5 years and cosmetic results at 6 weeks and 2 years after radiotherapy. The relative breast retraction assessment score was used to evaluate cosmetic results via photo documentation.
After a median follow-up of about 5 years, the 2-year local tumor control rate was 99.56% with IMRT and a simultaneous integrated boost versus 99.55% with 3D-CRT and a consecutive boost (P = .487). The researchers did not find any significant differences in cosmetic results (P = .349), although the post-therapy breast retraction assessment score was significantly correlated with the initial breast retraction assessment score (P < .001) and with patient age (P = .046).
The estimated overall and progression-free survival rates for patients treated with IMRT and a simultaneous integrated boost versus 3D-CRT and a consecutive boost were also similar. Overall survival rates were 99.57% versus 99.56% (P = .148), and progression-free survival rates were 99.12% and 98.65% (P = .617), respectively.
Disclosure: For full disclosures of the study authors, visit redjournal.org.