Science News
from research organizations

Breast cancer adjuvant therapy benefit can wax and wane over time, study finds

Therapies completed years ago may not keep covering survivors

Date:
November 2, 2015
Source:
University of Texas Health Science Center at San Antonio
Summary:
More research of the long-term effects of adjuvant therapies for breast cancer is needed, after a study found that effects of these therapies often vary over time.
Share:
FULL STORY

After breast cancer surgery, women are prescribed adjuvant (or follow-up) therapies such as chemotherapy and endocrine drugs to reduce the risk of the cancer returning. It's been assumed that the treatment effects of these therapies remain constant over time, but a new study from the Cancer Therapy & Research Center (CTRC) at The University of Texas Health Science Center at San Antonio suggests the opposite is true.

The study, published this week in the Journal of the National Cancer Institute, looked at 19 breast cancer adjuvant therapy clinical trials of the National Surgical Adjuvant Breast and Bowel Project (NSABP). Therapies were evaluated for relative benefit, defined as the percentage by which they reduced recurrence and death among study participants.

Researchers found time-varying treatment effects of adjuvant therapies in nearly half of the trials (nine of 19). "In some trials, the benefit diminished at specific points of time after surgery," said study senior author Ismail Jatoi, M.D., Ph.D., FACS. "In other trials, there was no benefit early on, but then there was a delayed benefit that emerged more than one year after surgery."

In one clinical trial, the researchers found that a regimen provided initial benefit, but then a subsequent disadvantage, to patients, he said. Dr. Jatoi is the Dale H. Dorn Chair in Surgery in the School of Medicine at the UT Health Science Center, and serves as professor and chief of the Division of Surgical Oncology and Endocrine Surgery.

The findings may change the way oncologists talk to their patients about effects of treatments they are receiving, Dr. Jatoi said.

"We are seeing more and more long-term survivors of breast cancer who had these treatments many years ago," Dr. Jatoi said. "The question is, if these treatment effects have waned, should we consider extended adjuvant treatment regimens for the long term in some patients."

Adjuvant therapy trials should be designed and interpreted with this in mind, Dr. Jatoi said.

In 2011, Dr. Jatoi wrote a viewpoint article published in the Journal of Clinical Oncology in which he proposed that treatment effects of adjuvant therapy regimens might vary over time. He approached the NSABP, one of the nation's largest clinical trials groups, about doing a study. NSABP statisticians Hanna Bandos, Ph.D., and Jong Hyeon Jeong, Ph.D., conducted much of the work and are co-authors of the study.


Story Source:

Materials provided by University of Texas Health Science Center at San Antonio. Note: Content may be edited for style and length.


Journal Reference:

  1. Ismail Jatoi, Hanna Bandos, Jong-Hyeon Jeong, William F. Anderson, Edward H. Romond, Eleftherios P. Mamounas, Norman Wolmark. Time-Varying Effects of Breast Cancer Adjuvant Systemic Therapy. Journal of the National Cancer Institute, 2015; 108 (1): djv304 DOI: 10.1093/jnci/djv304

Cite This Page:

University of Texas Health Science Center at San Antonio. "Breast cancer adjuvant therapy benefit can wax and wane over time, study finds: Therapies completed years ago may not keep covering survivors." ScienceDaily. ScienceDaily, 2 November 2015. <www.sciencedaily.com/releases/2015/11/151102131520.htm>.
University of Texas Health Science Center at San Antonio. (2015, November 2). Breast cancer adjuvant therapy benefit can wax and wane over time, study finds: Therapies completed years ago may not keep covering survivors. ScienceDaily. Retrieved May 26, 2017 from www.sciencedaily.com/releases/2015/11/151102131520.htm
University of Texas Health Science Center at San Antonio. "Breast cancer adjuvant therapy benefit can wax and wane over time, study finds: Therapies completed years ago may not keep covering survivors." ScienceDaily. www.sciencedaily.com/releases/2015/11/151102131520.htm (accessed May 26, 2017).

RELATED STORIES