The impact of age on the risk of ipsilateral breast tumor recurrence after breast-conserving therapy in breast cancer patients with a > 5 mm margin treated without boost irradiation

Autor: Yuka Ono, Michio Yoshimura, Kimiko Hirata, Chikako Yamauchi, Masakazu Toi, Eiji Suzuki, Masahiro Takada, Masahiro Hiraoka, Takashi Mizowaki
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Radiation Oncology, Vol 14, Iss 1, Pp 1-8 (2019)
Druh dokumentu: article
ISSN: 1748-717X
DOI: 10.1186/s13014-019-1327-8
Popis: Abstract Background The boost irradiation to the tumor bed following whole-breast irradiation (WBI) reduced the risk of ipsilateral breast tumor recurrence (IBTR). However, in Japan, almost all patients with a margin ≤5 mm receive boost irradiation to the tumor bed, but the decision to perform boost irradiation for those with a margin > 5 mm is dependent on the institution. Thus, institutional guidelines on utilizing boost irradiation for patients aged ≤40 or ≤ 50 years vary. We investigated the IBTR rate to assess the appropriate age for boost irradiation to the tumor bed with a margin > 5 mm. Methods From January 1993 to December 2010, 419 patients with early-stage breast cancer and negative margins (> 5 mm) after breast-conserving surgery received WBI without boost irradiation. The Gray test was used to compare the cumulative incidence of IBTR among patients aged ≤40, 41–50, and ≥ 51 years. Hazard ratios were estimated using the Fine and Gray models. Furthermore, as a subgroup analysis, we investigated whether IBTR depended on the use of systemic therapy, such as anthracycline or taxane regimens. Results The median follow-up time was 9.3 years. In multivariate analysis, only age predicted IBTR (p = 0.047). The 10-year IBTR rate was 15.7% in patients aged ≤40, 3.8% in those aged 41–50, and 2.0% in patients aged ≥51 years. The difference between patients aged ≤40 and 41–50 years was statistically significant (p = 0.045), whereas the difference between patients aged 41–50 and ≥ 51 years was not significant (p = 0.21). Conclusions In our institutional surgical setting, when boost irradiation is performed only for patients with a margin ≤5 mm, the IBTR rate after WBI without boost irradiation was significantly higher in patients aged ≤40 years, suggesting that boost irradiation should be used for patients in this age group.
Databáze: Directory of Open Access Journals
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