Subsets of Young Patients Have Higher Pathologic Complete Response Rates


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In achieving a pathologic complete response to neoadjuvant chemotherapy, it seems that age matters, according to a study reported at the 2012 San Antonio Breast Cancer Symposium.1 Patients with breast cancer aged 35 and younger were more likely to achieve a pathologic complete response than their older counterparts. The finding was confined, however, to those with triple-negative and luminal-type tumors, German investigators reported.

“In these patients, [pathologic complete response] was associated with a good prognosis,” said Sibylle Loibl, MD, PhD, Associate Professor at the University of Frankfurt in Germany. “Breast tumors that arise in young women seem to be a special biological entity.”

The study evaluated data from eight German studies that included 8,949 women with operable or locally advanced, nonmetastatic breast cancer who were treated with neoadjuvant chemotherapy. Researchers compared pathologic complete response and disease-free survival for the subgroup of 704 women aged 35 or younger to those of older women.

Compared to the older cohort, the younger subgroup included a greater proportion of triple-negative tumors (32%) than women aged 36 to 50 (25%) or 51 years and older (21%) and a smaller proportion of luminal-A tumors. Hormone receptor–positive/HER2-negative tumors were the case for 35% of the young women, vs 48% of women aged 36 to 50 and 51% of the oldest cohort, she said.

Findings by Age and Subtype

“Age was an independent predictive factor for [pathologic complete response],” Dr. Loibl announced. Disease-free survival and local recurrence-free survival were also age-related, though no significant differences were observed in overall survival.

The pathologic complete response rate rate was 23.8% for the very young women, vs 17.5% for women aged 36 to 50 and 13.5% for those aged 51 and older (P < .001). Further analysis revealed that this difference was confined to tumors that were triple-negative and hormone receptor–positive/HER2-negative.

Compared to women aged 36 to 50 years, disease-free survival was significantly worse for women ≤ 35 (HR = 0.83; P =.031) as was local recurrence-free survival (HR = 0.74; P = .018).

“However, women aged 35 and younger with hormone receptor–positive/HER2-negative tumors who achieved a [pathologic complete response] had a better disease-free survival than younger women who did not achieve a [pathologic complete response],” Dr. Loibl noted.

Altogether, according to age there was no difference in disease-free survival when the patients achieved a pathologic complete response, but patients without a pathologic complete response had significantly worse disease-free survival if they were 35 or younger, she summed up.

“In the neoadjuvant setting, [pathologic complete response] matters,” Dr. Loibl emphasized. “The results of not achieving a [pathologic complete response] are striking. The very young have a 25% increased risk for relapse over their older counterparts, the risk for local recurrences is 33% higher, and there is a trend for worse overall survival as well.”

Importantly, patients with triple-negative disease who achieved a pathologic complete response had “excellent survival” irrespective of their age, she added.

“In contrast to other analyses, very young women with hormone receptor–positive/HER2-negative tumors benefited from a [pathologic complete response] in this study,” she said. “There is a benefit long-term with a [pathologic complete response], even in this biologically good subgroup. This young subset, therefore, where [pathologic complete response] really matters, should be considered for neoadjuvant chemotherapy,” she maintained. ■

Disclosure: Dr. Loible reported no potential conflicts of interest.

Reference

1. Loibl S, Jackisch C, Gade S, et al: Neoadjuvant chemotherapy in the very young, 35 years of age or younger. 2012 San Antonio Breast Cancer Symposium. Abstract S3-1. Presented December 6, 2012.


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