by Dennis Mann
Health Day Reporter
FRIDAY, Dec. 9, 2022 (HealthDay News) — A new genetic test may help identify which breast cancer patients can safely skip radiation after breast-conserving surgery to remove their tumor.
Swedish researchers report that patients with invasive breast cancer who scored lower in the study’s genome were just as likely to relapse whether or not they received radiation therapy after breast-conserving surgery.
Currently, people with this type of breast cancer typically have surgery to remove the cancer, followed by radiation therapy to reduce the risk of the breast cancer coming back in the same area.
“For the first time, a genetic screening test can predict which patients can ignore radiation,” said the study authors Dr. Per Karlsson. He is Professor of Oncology at Sahlgrenska Comprehensive Cancer Center and University of Gothenburg, Sweden.
More research is needed before the genetic test is ready for prime time, Karlsson said.
“We will confirm these findings in a new cohort, and we will also start a prospective trial to make sure this is correct, but it looks very promising,” he added.
In this study, researchers assessed the predictive power of POLAR (Profile of Omissions in Adjuvant Local Radiation), a 16-gene panel developed based on differences between people with and without local recurrence after breast-conserving surgery.
The study included 623 people whose cancer had not spread to lymph nodes from three trials. Their breast cancers were also estrogen receptor positive and HER2 negative. Their tumors were analyzed after surgery to see which genes were expressed.
Each person receives a POLAR score based on this analysis, and researchers then look at the benefits of radiation therapy in high and low score groups.
Key findings? People with high POLAR scores may benefit from radiation therapy, while those with lower scores may skip it, the findings show.
People with high POLAR scores who received radiation after breast-conserving surgery had a 63 percent lower risk of local recurrence compared with those who did not receive radiation. In contrast, there was no difference in recurrence rates among people with lower POLAR scores whether they received radiation therapy or not. After 10 years, 5 percent of low-scoring patients who received radiation had a local recurrence, compared with 7 percent of those who did not, the researchers found.
As long as a person can avoid radiation without risking the cancer coming back, that’s a win, Karlsson said. “There are side effects for a small percentage of people, and if in the future we can omit radiation for some patients, it will benefit quality of life,” he noted.
In addition to being time consuming, radiation can cause fatigue and skin side effects such as rashes, pain, redness and swelling.
The findings are scheduled to be presented Friday at the San Antonio Breast Cancer Symposium. Research presented at medical meetings should be considered preliminary until published in a peer-reviewed journal.
Breast cancer experts who reviewed the new research agree that doctors are entering a new era in breast cancer diagnosis and treatment.
This type of genetic analysis of breast tumors is the future, says Dr Julia Smith, a medical oncologist at NYU Langone Perlmutter Cancer Center in New York City. “We’re trying to minimize the number of treatments we give in certain subgroups, based on the molecular and genetic characteristics of the cancer.”
She said the study could help identify subgroups of people who may not need radiation.
“People with this type of breast cancer tend to do well to begin with,” Smith noted. “We need a larger cohort of women who we can follow for longer because people with this type of breast cancer usually don’t relapse until 10 to 15 years later.”
Doctors don’t want to overtreat people, agree Dr. Katherina Zabicki Calvillobreast surgeon and founder of New England Breast and Health in Wellesley, MA.
“Ignoring radiation is safe in some populations. Although well tolerated, radiation can have adverse side effects that can affect quality of life and return to work,” Calvillo explained. There may also be cost savings, she noted.
Calling the new study “interesting and important,” Dr Marisa Weiss Say the results could help tailor treatment recommendations about radiation. She is the chief medical officer and founder of Breastcancer.org in Ardmore, PA.
“The POLAR 16 genomic test seems very promising in Swedish women,” Weiss said. “Before we can confidently apply it to a different population, it is important to test its effectiveness in a more heterogeneous population within the United States.”
More information
Breastcancer.org provides more information on Genetic Analysis of Breast Cancer.
SOURCE: Per Karlsson, MD, Professor of Oncology, Sahlgrenska Comprehensive Cancer Center, University of Gothenburg, Sweden; Julia Smith, MD, Medical Oncologist, NYU Langone Perlmutter Cancer Center, New York City; Katherina Zabicki Calvillo, MD, New England Breast and Wellness, Wellesley, MA. Marisa Weiss, MD, Chief Medical Officer, Founder, Breastcancer.org, Ardmore, PA; Presentation, San Antonio Breast Cancer Symposium, December 9, 2022
