Postmastectomy radiation improves the outcome of patients with locally advanced breast cancer who achieve a pathologic complete response to neoadjuvant chemotherapy.
OBJECTIVE
The aim of this study was to investigate the role of postmastectomy radiation therapy in women with breast cancer who achieved a pathologic complete response (pCR) to neoadjuvant chemotherapy.


METHODS
We retrospectively identified 226 patients treated at our institution who achieved a pCR at surgery after receiving neoadjuvant chemotherapy. Of these, the 106 patients without inflammatory breast cancer who were treated with mastectomy were analyzed. The patients' clinical stages at diagnosis were I in 2%, II in 31%, IIIA in 30%, IIIB in 25%, and IIIC in 11% (American Joint Committee on Cancer 2003 system). Of the patients, 92% received anthracycline-based chemotherapy, and 38% also received a taxane. A total of 72 patients received postmastectomy radiation therapy, and 34 did not. The actuarial rates of local-regional recurrence (LRR) and survival of the two groups were compared using the log-rank test.


RESULTS
The median follow-up of surviving patients was 62 months. Use of radiation therapy did not affect the 10-year rates of LRR for patients with Stage I or II disease (the 10-year LRR rates were 0% for both groups). However, the 10-year LRR rate for patients with Stage III disease was significantly improved with radiation therapy (7.3% +/- 3.5% with vs. 33.3% +/- 15.7% without; p = 0.040). Within this cohort, use of radiation therapy was also associated with improved disease-specific and overall survival.


CONCLUSIONS
Postmastectomy radiation therapy provides a significant clinical benefit for breast cancer patients who present with clinical Stage III disease and achieve a pCR after neoadjuvant chemotherapy.
McGuire
Sean E
SE
Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Gonzalez-Angulo
Ana M
AM
Huang
Eugene H
EH
Tucker
Susan L
SL
Kau
Shu-Wan C
SW
Yu
Tse-Kuan
TK
Strom
Eric A
EA
Oh
Julia L
JL
Woodward
Wendy A
WA
Tereffe
Welela
W
Hunt
Kelly K
KK
Kuerer
Henry M
HM
Sahin
Aysegul A
AA
Hortobagyi
Gabriel N
GN
Buchholz
Thomas A
TA
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D017024:Chemotherapy, Adjuvant; D005260:Female; D006801:Humans; D008408:Mastectomy; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome
D000970:Antineoplastic Agents