The effect of delaying radiation therapy for systemic chemotherapy on local-regional control in breast cancer.
BACKGROUND
It remains controversial as to whether the administration of chemotherapy prior to radiation following the surgical treatment for localized breast cancer compromises local control.


METHODS
The outcome of 290 patients who received chemotherapy prior to breast or chest wall irradiation following curative breast cancer surgery was retrospectively analyzed to determine if delaying radiation from the time of surgery adversely affects local-regional control. The patients were divided into three groups according to the time interval from definitive surgery to the start of radiation: group 1, < 5 months; group 2, 5 to < 7 months, and group 3, 7+ months. Local-regional and distant failure events were analyzed according to the time delay from surgery to radiation.


RESULTS
The median follow-up was 6.0 years (range, 7 months to 15 years). Loco-regional failure was observed in 22 patients, 18 of which occurred within the original radiation fields. There was no significant adverse effect on local control or distant failure from delaying radiation for systemic chemotherapy. Univariate and multivariate analyses revealed that positive margins after surgery were associated with increased local recurrence.


CONCLUSIONS
Delaying radiation therapy for greater than 7 months, in order to administer chemotherapy following curative breast cancer surgery, does not compromise local control. However, positive margins were significantly associated with higher rates of local failure and even an increase in radiation boost dose was not able to fully counteract the increased risk of local failure.
Yock
Torunn I
TI
Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA. tyock@partners.org
Taghian
Alphonse G
AG
Kachnic
Lisa A
LA
Coen
John J
JJ
Assaad
S I
SI
Powell
Simon N
SN
D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy* / Q000532:radiotherapy* / Q000601:surgery; D009367:Neoplasm Staging; D011829:Radiation Dosage; D012189:Retrospective Studies; D016896:Treatment Outcome