Response to Neoadjuvant Chemotherapy and Tumor Subtype Are Strong Predictors of Locoregional Breast Cancer Recurrence
An analysis of data from 12 large clinical trials found that the cancer’s pathologic response to neoadjuvant chemotherapy and tumor subtype are strong predictors of locoregional breast cancer recurrence. According to the researchers, the study showed that these two predictors may be more informative than the tumor stage at diagnosis, which is commonly used in current practice, for evaluating locoregional breast cancer recurrence risk. The findings of this study, the largest of its kind to date, were presented yesterday at a presscast in advance of the 2014 Breast Cancer Symposium (Abstract 61).
Neoadjuvant and adjuvant chemotherapy provide equivalent survival benefits, but more women typically undergo adjuvant therapy. An important advantage of receiving chemotherapy before surgery is that it can shrink and even eradicate the tumor in the breast and axillary lymph nodes, potentially reducing the need for mastectomy, lymph node removal, and radiation therapy after surgery.
“We’re finding that receiving neoadjuvant chemotherapy is not only a good option for treating breast cancer and preventing future recurrence in other parts of the body, but it also provides important information on the risk for logocregional recurrence,” said lead study author Eleftherios Mamounas, MD, MPH, FACS, Medical Director of the Comprehensive Breast Program at the UF Health Cancer Center in Orlando, Florida, and Professor of Surgery at the University of Central Florida. “This can potentially help to better identify patients at higher risk for recurrence who may benefit from the addition of radiotherapy and those at low risk who may not need it.”
Study Details
In this study, researchers assessed locoregional recurrence rates among 11,995 women with stage I to III breast cancer who were treated with neoadjuvant chemotherapy in clinical trials conducted in the United States and Europe. After a median follow-up period of 5.4 years, the overall proportion of patients with locoregional recurrence was 8.3%.
At the time of surgery, women who did not have a pathologic complete response (defined as absence of cancer in the breast and the axillary lymph nodes) to neoadjuvant chemotherapy had an increased risk for locoregional recurrence over women who did have a pathologic complete response. Compared to women who had a pathologic complete response, those with residual disease in the breast and no cancer in the axillary lymph nodes had a 1.6 times higher risk of locoregional recurrence and those with cancer in the axillary lymph nodes had a 2.8 times higher risk of recurrence. The effect of pathologic complete response on locoregional recurrence was evident in patients treated with mastectomy and in those treated with breast-conserving surgery plus breast radiotherapy.
Locoregional recurrence rates also differed by tumor subtype. Compared to patients with hormone receptor–positive/HER2-negative and grade 1/2 tumors (5-year risk of locoregional recurrence = 4.2%), patients with all other tumor subtypes had elevated 5-year risk of locoregional recurrence: 9.2% for women with hormone receptor–positive/HER2-negative, grade 3 breast cancer; 12.2% for women with triple-negative breast cancer; 9.7% for women with hormone receptor–positive/HER2-positive breast cancer; and 14.8% for women with hormone receptor–negative/HER2-positive breast cancer.
Researchers also found that more advanced stage at diagnosis did not adversely affect rates of locoregional recurrence when pathologic complete response and tumor subtype information were taken into account.
Findings May Help Guide Decision-Making
“While more research is needed to inform new practice guidelines based on these insights, the findings provide additional information for doctors and patients to consider when trying to decide on the best locoregional treatment options after neoadjuvant chemotherapy,” stated Dr. Mamounas.
“Women with large, but not metastatic, cancer of the breast are often treated with chemotherapy before surgery,” said Amy Early, MD, FACP, Breast Cancer Symposium News Planning Team member. “This study provides new information about the use of tumor stage and the body’s pathologic response to neoadjuvant chemotherapy as predictors of recurrence, which may help guide physician and patient decisions about therapy following surgery.”
This research was supported and conducted by the CTNeoBC group. For full disclosures of the study authors, view the study abstract at abstracts.asco.org.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
