Audit of local recurrence following breast conservation surgery with 5-mm target margin and hypofractionated 40-Gray breast radiotherapy for invasive breast cancer.
BACKGROUND
The risk of ipsilateral breast tumour recurrence (IBTR) following breast conservation surgery (BCS) for invasive breast cancer (IBC) and radiotherapy is dependent on patient-, tumour- and treatment-related variables. In the Cambridge Breast Unit, breast conserving surgery has been performed with a target radial margin of 5 mm for IBC, in combination with 40-Gy hypofractionated (15 fractions) breast radiotherapy, since 1999.


METHODS
An audit was performed of cases treated between 1999 and 2004. A total of 563 patients underwent BCS for invasive breast cancer with 90.4% receiving radiotherapy (RT) and 60.4% of patients receiving boost RT (3 fractions of 3-Gy).


RESULTS
After a median follow-up of 58 months, five of the 563 (0.9%) patients developed IBTR. The 5-year actuarial IBTR rate was 1.1%. In terms of distant disease recurrence (DDR), 29 of the 563 (5.2%) had DDR during follow-up, giving a 5-year actuarial DDR rate of 5.4%. The 5-year breast cancer specific survival was 95%, with the poorer NPI groups having worse breast cancer specific survival (Log-rank, P<0.0001). More importantly, patients with IBTR had a shorter breast cancer-specific survival than those who were IBTR-free (Log-rank, P<0.0001).


CONCLUSIONS
Our treatment regimen, combining BCS with a 5-mm target margin and hypofractionated 40-Gy RT, results in an extremely low rate of IBTR, and compares favourably with the target IBTR rate of <5% defined by the Association of Breast Surgeons (ABS) at BASO guidelines.
Liau
Siong-Seng
SS
Cambridge Breast Unit, Addenbrooke's Hospital, Cambridge, UK.
Cariati
Massimiliano
M
Noble
David
D
Wilson
Charles
C
Wishart
Gordon C
GC
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery*; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental / Q000379:methods* / Q000592:standards; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D016896:Treatment Outcome