Breast-conserving therapy did not increase risk for local recurrence in triple-negative disease

Breast-conserving therapy did not increase risk for local recurrence in patients with triple-negative breast cancer, according to results of a prospective database review.

Researchers conducted the study to compare the outcomes of breast-conserving therapy in patients with triple-negative breast cancer vs. those with luminal A, luminal B and ERBB2 subtypes.

The analysis included 1,851 consecutive patients aged 29 to 85 years who were diagnosed with stages I to III invasive breast cancer. All patients underwent breast-conserving therapy at a single institution between Jan. 1, 2000, and May 30, 2012.

Local recurrence served as the primary outcome measure. Secondary outcomes were regional recurrence, distant recurrence and OS.

Overall, 12.6% of patients had triple-negative breast cancer, 72.4% had luminal A subtype, 11.5% had luminal B subtype and 3.5% had ERBB2-enriched subtype.

Patients with triple-negative breast cancer were more likely than those with other breast cancer subtypes to be younger at diagnosis (56 years vs. 60 years; P=.001), have larger tumors (2.1 cm vs. 1.8 cm; P<.001), have stage II vs. stage I disease (42.1% vs. 33.6%; P=.005) and have more grade 3 tumors (86.4% vs. 28.4%; P<.001).

Multivariable analysis showed triple-negative breast cancer was not associated with a significantly increased risk for local recurrence compared with luminal A subtype (HR=1.4; 95%CI, 0.6-3.3), luminal B subtype (HR=1.6; 95% CI, 0.5-5.2) and ERBB2 subtype (HR=1.1; 95% CI, 0.2-5.2).

Tumor size was the only predictor for local recurrence (HR=4.7; 95%CI, 1.6-14.3). Tumor size, grade, stage and triple-negative breast cancer subtype all were predictors for shorter OS.

“These findings are consistent with the current literature, which indicates that the triple-negative subtype is generally more aggressive, with worse prognosis overall,” the researchers wrote. “Although breast cancer patients undergoing breast-conserving therapy have long-term outcomes equivalent to those of patients treated with mastectomy, significant debate remains regarding breast conserving therapy as an appropriate treatment for triple-negative breast cancer.”