Young women with triple-negative and luminal-type breast cancer were more likely to respond to neoadjuvant chemotherapy than were older women with these cancers, and improved outcomes were observed for young women with luminal-A–like tumors who achieved a pathologic complete response (pCR) versus those who did not. The study suggests that neoadjuvant chemotherapy is beneficial for young women with triple-negative and luminal-type breast cancer, even those with favorable biological features that include hormone receptor positivity (HR+) and human epidermal growth factor 2–negative (HER2–) disease.
“Breast cancer is less common in women age 35 or younger, and some data suggest that these younger patients have a worse prognosis. This is not only because they tend to have more aggressive breast cancers, but because tumors that arise in younger women appear to have different biological features,” stated Sibylle Loibl, MD, PhD, associate professor at the University of Frankfurt, Germany.
The meta-analysis that Loibl and colleagues reported at the CTRC-AACR San Antonio Breast Cancer Symposium included a total of 8949 women from 8 German studies. All women had operable or locally advanced nonmetastatic breast cancer and received neoadjuvant chemotherapy. Among these women, 704 were aged 35 years or younger. pCR and disease-free survival (DFS) were compared for the younger patients (aged ≤35 years) versus women aged 36 to 50 years and women aged 51 years or older.
A greater percentage of younger women had triple-negative breast cancer (32% for younger women, about 25% for those aged 26-50 years, and 21% for those aged 51 years and older). Compared with older women, a smaller percentage of younger women had luminal-A–type breast cancer (27% vs 21%, respectively).
pCR was significantly higher in younger women compared with older women: 23.6% versus 17.5% of women in the 36- to 50-year-old age group and 13.5% of those aged 51 years and older (P <.001); this difference in pCR was confined to triple-negative and luminal-like breast cancer (HR+/HER2–). More in-depth analysis showed that this difference was restricted to women with triple-negative breast cancer: the pCR rate was 45% for younger patients versus 31% for older patients (P <.001). For all patients, regardless of subtype of breast cancer, DFS and local recurrence-free survival were significantly worse for the very young patients (aged ≤35 years) compared with middle-aged patients (aged 36-50 years; P = .031 and P = .018, respectively). No difference in DFS according to age was observed among patients who achieved pCR. However, DFS was significantly worse among women who failed to achieve pCR.
Tumor biology appeared to be impor-tant in predicting pCR and survival in younger women. Age but not pCR predicted DFS in women with luminal-A–type cancer. However, the worst DFS rate was seen among those women with luminal-A–type breast cancer who were younger than age 35 years and did not achieve pCR. The most favorable DFS was observed among younger women who did achieve pCR.
Loibl said the investigators were surprised to find that younger women with luminal-type cancer (HR+ and HER2–) who achieved pCR had improved survival compared with patients with nonpathologic CR. “This is not seen in other age groups, indicating that breast cancer in the young women is chemosensitive, even when it is a luminal-type breast cancer,” she stated.
Loibl S, Jackisch C, Gade S, et al. Neoadjuvant chemotherapy in the very young 35 years of age or younger. Presented at: 2012 CTRC-AACR San Antonio Breast Cancer Symposium; December 4-8, 2012; San Antonio, TX.