Limited-field radiation therapy in the management of early-stage breast cancer.
BACKGROUND
Several phase III trials have demonstrated equivalent long-term survival between breast conserving surgery plus radiation therapy and mastectomy in patients with early-stage breast cancer but have not provided information on the optimal volume of breast tissue requiring post-lumpectomy radiation therapy. Therefore, we examined the 5-year results of a single institution's experience with radiation therapy limited to the region of the tumor bed (i.e., limited-field radiation therapy) in selected patients treated with breast-conserving therapy and compared them with results of matched breast-conserving therapy patients who underwent whole-breast radiation therapy.


METHODS
A total of 199 patients with early-stage breast cancer were treated prospectively with breast-conserving therapy and limited-field radiation therapy using interstitial brachytherapy. To compare potential differences in local recurrence rates based on the volume of breast tissue irradiated, patients in the limited-field radiation therapy group were matched with 199 patients treated with whole-breast radiation therapy. Match criteria included tumor size, lymph-node status, patient age, margins of excision, estrogen receptor status, and use of adjuvant tamoxifen therapy. Local-regional control and disease-free and overall survival were analyzed using the Kaplan-Meier method, and the statistical significance of differences between treatment groups was calculated using the log-rank test. All statistical tests were two-sided.


RESULTS
Median follow-up for surviving patients was 65 months (range = 12-115 months). Five ipsilateral breast failures (i.e., recurrences) were observed in patients treated with limited-field radiation therapy. The cumulative incidence of local recurrence was 1% (95% confidence interval [CI] = 0% to 2.8%). On matched-pair analysis, the rate of local recurrence was not statistically significantly different between the patient groups (1% [95% CI = 0% to 2.4%] for the whole-breast radiation therapy patients versus 1% [95% CI = 0% to 2.8%] for the limited-field radiation therapy patients; P =.65).


CONCLUSIONS
Limited-field radiation therapy administered to the region of the tumor bed has comparable 5-year local control rates to whole-breast radiation therapy in selected patients.
Vicini
Frank A
FA
Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI 48072, USA. fvicini@beaumont.edu
Kestin
Larry
L
Chen
Peter
P
Benitez
Pamela
P
Goldstein
Neal S
NS
Martinez
Alvaro
A
D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000379:methods*; D001943:Breast Neoplasms / Q000473:pathology* / Q000532:radiotherapy* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007432:Intraoperative Period; D015412:Mastectomy, Segmental; D016555:Matched-Pair Analysis; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*; D009367:Neoplasm Staging; D011446:Prospective Studies; D018714:Radiotherapy, Adjuvant / Q000379:methods*; D016037:Single-Blind Method; D016019:Survival Analysis; D017211:Treatment Failure; D016896:Treatment Outcome