Neoadjuvant chemotherapy might be particularly critical for very young women with certain early breast cancers because of biologic differences in their tumors, according to research presented here at the 35th Annual San Antonio Breast Cancer Symposium.
"I would personally approach all young women with these cancers by suggesting neoadjuvant chemotherapy," said lead investigator Sibylle Loibl, MD, PhD, from the University of Frankfurt in Germany. "Some people think they don't need chemotherapy at all, but I think they do," she explained.
"Breast cancer in the very young woman seems to be different.... There is something behind age that drives the biology of the cancer and makes it more chemo-responsive," she noted.
In a meta-analysis of 8 trials involving 8949 patients, Dr. Loibl and her colleagues found that women younger than 35 years were more likely to achieve a pathologic complete response (pCR) after neoadjuvant chemotherapy than women 36 to 51 years (23.6% vs 17.5%) and than women older than 51 years (13.5%; P < .0001).
Additionally, those with a pCR saw benefits in both disease-free survival and local recurrence-free survival, she said.
The superior pCR rate in young women after chemotherapy was driven by better pCR in 2 types of tumors: triple-negative tumors and luminal-like tumors, she added.
Specifically, women 35 years and younger achieved higher rates of pCR in triple-negative tumors than women 36 to 51 years (45% vs 35%) and than women older than 51 years (25%; P = .004).
Similarly, women 35 years and younger achieved higher rates of pCR in luminal-like tumors than women 36 to 51 years (approximately 11% vs 8%) and than women older than 51 years (6%; P = 0.013).
She said she expects the findings will influence clinical practice.
"I think the luminal-like patients, when they're very young, will be treated more often now with chemo. For women with triple-negative tumors, it's reassuring; we can tell them you have an almost 50% chance that everything will be gone and you'll have an excellent survival," she said.
All subjects in the meta-analysis received neoadjuvant anthracycline/taxane–based chemotherapy, and some received trastuzumab.
Generally, "in younger women, we tend to be more aggressive with chemotherapy," said Carlos Arteaga, MD, PhD, associate director of clinical research and director of the breast cancer program at the Vanderbilt-Ingram Cancer Center in Nashville, Tennessee, during a meeting press conference.
"The importance of this study is that it suggests there are some biological differences that go beyond luminal B that we have to study," he said.
Dr. Loibl and Dr. Arteaga have disclosed no relevant financial relationships. Study coauthor Gunter von Minckwitz, MD, PhD, reports being a consultant/advisor for sanofi-aventis, Roche, Amgen, AstraZeneca, Boehringer, and Eisai; and conducting scientific studies/trials for Amgen, Pfizer, GSK, sanofi-aventis, Roche, Novartis, BMS, Celgene, Cephalon, Boehringer Ingelheim, and Eisai. Coauthor Carsten Denkert, MD, reports receiving grant/research support from Siemens Medical Solutions and Sividon Diagnostics; consulting for Celgene, Amgen, and Sividon; and being a shareholder in Sividon Diagnostics. Coauthor Christian Jackisch, MD, reports being on the speaker's bureau for Roche and GSK. Coauthor Michael Untch, MD, reports receiving grant/research support from and being a consultant for Bristol-Myers Squibb and Amgen.
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