Posted: Tuesday, June 25, 2024
Young breast cancer survivors without a germline pathogenic variant may be at low risk of developing a second primary breast cancer in the 10 years following diagnosis, according to research published in JAMA Oncology. Citing prior data indicating that women diagnosed with primary breast cancer at age 40 or younger are at higher risk of developing a second primary breast cancer than those who are older at diagnosis, Ann H. Partridge, MD, MPH, of the Dana-Farber Cancer Institute, Boston, and colleagues noted their results support the use of germline genetic testing to inform treatment decision-making and follow-up care among this population.
“As many women consider bilateral mastectomy in the setting of ipsilateral breast cancer, our results, particularly the finding of a low risk of contralateral breast cancer among noncarriers of pathogenic variants, provide new risk estimates to inform surgical decision-making,” the investigators stated. “Low observed rates of ipsilateral second primary breast cancer may also inform decisions to undergo unilateral mastectomy among women at low risk of local recurrence.”
A total of 685 women diagnosed with stage 0 to III breast cancer at age 40 or younger who underwent lumpectomy or unilateral mastectomy as primary surgery were included in the prospective study. Over a median follow-up of 10 years, 2.5% of participants developed a second primary breast cancer, two of whom had cancer in the ipsilateral breast after lumpectomy. Among 577 participants who underwent genetic testing, the 10-year risk of second primary breast cancer was found to be 2.2% for women who did not carry a pathogenic variant and 8.9% for those who did.
“While informative, the evidence from this study is not meant as the primary source for surgical decision-making, which should always consider the evolving literature as well as individual patient needs and risk factor profiles,” the researchers added. “It will be important to continue examining rates of second primary breast cancer among these young patients as they get further from primary diagnosis.”
Disclosure: For full disclosures of the study authors, visit jamanetwork.com.