Clinical outcome of breast conservation therapy for breast cancer in Hong Kong: prognostic impact of ipsilateral breast tumor recurrence and 2005 St. Gallen risk categories.
OBJECTIVE
The aim of this study was to evaluate the clinical outcome of breast conservation therapy (BCT) for invasive breast cancers in our predominantly Chinese population.


METHODS
Clinical outcomes of 412 T1-2 invasive breast cancers treated by wide local excision and external radiotherapy from 1994 to 2003 were retrospectively analyzed. Only 7% lesions were first detected by mammograms. Adjuvant tamoxifen and chemotherapy were added in 74% and 45% patients, respectively.


RESULTS
The median follow-up was 5.4 years. The 5-year actuarial ipsilateral breast tumor recurrence (IBTR) rate, distant failure-free survival, cause-specific survival, and overall survival were 4%, 92%, 96%, and 98%, respectively. The 5-year distant failure-free survival for the low-risk, intermediate-risk, and high-risk categories (2005 St. Gallen) were 98%, 91%, and 80%, respectively (p = 0.0003). Cosmetic results were good to excellent in more than 90% of the assessable patients. Grade 3 histology (hazard ratio [HR], 4.461; 95% CI, 1.216-16.360; p = 0.024), age (HR, 0.915; 95% CI, 0.846-0.990; p = 0.027), and close/positive final margins (HR, 3.499; 95% CI, 1.141-10.729; p = 0.028) were significant independent risk factors for IBTR. Both St. Gallen risk categories (p = 0.003) and IBTR (HR, 5.885; 95% CI, 2.494-13.889; p < 0.0005) were independent prognostic factors for distant failure-free survival.


CONCLUSIONS
Despite the low percentage of mammographically detected lesions, the overall clinical outcome of BCT for invasive breast cancers in the Chinese population is comparable to the Western series. The 2005 St. Gallen risk category is a promising clinical tool, but further validation by large studies is warranted.
Yau
Tsz-Kok
TK
Department of Clinical Oncology, Pamela Youde Nethersole Eastern Hospital, Hong Kong, China. tkokyau@gmail.com
Soong
Inda S
IS
Chan
K
K
Chan
M
M
Cheung
P
P
Lau
H W
HW
Chang
Amy T Y
AT
Lee
Anne W M
AW
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality* / Q000628:therapy*; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D015412:Mastectomy, Segmental / Q000401:mortality*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality* / Q000517:prevention & control*; D011379:Prognosis; D018714:Radiotherapy, Adjuvant / Q000401:mortality*; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D016019:Survival Analysis; D015996:Survival Rate; D016896:Treatment Outcome