The fact that Oncotype DX results need to be interpreted differently in men and women is not specific just to the test, but is connected to the underlying biological differences in men and women that cause breast cancer to develop and spread in sex-specific ways. It’s something these same researchers are also studying separately.
“We published another paper regarding the differences between male and female breast conditions, and in that study we showed that different biology may account for the sex differences for patients with breast cancer,” said senior author Xiao-Ou Shu, MD, PhD, MPH, Ingram Professor of Cancer Research, associate director for global health and coleader of the Cancer Epidemiology Research Program at Vanderbilt-Ingram Cancer Center, Nashville, Tennessee. “We’d like to think further whether these biology-specific tools [like Oncotype DX] also have different performance in male and female [patients]. I think that’s one of the reasons why we did this study.”
The researchers concluded that Oncotype DX is still a useful diagnostic tool in evaluating both men and women with breast cancer, but the results need to be framed in a way that will account for to the sex of the patient, rather than in a one-size-fits-all manner.
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As the study notes, in routine practice, “…RS predicts total mortality in both male and female patients with breast cancer but following distinct patterns. This finding highlights the need to develop RS categorization specifically for male patients with breast cancer.”1
The researchers also chose to focus on Oncotype DX, specifically, because it is a tool to measure outcomes that is already highly used, and thus, has a strong presence in existing databases. But Dr Wei said that it would be even more useful to have access to tumor tissue in the future.
“The reason we focused on Oncotype DX is availability — we studied from the [National Cancer Database] data,” she said. “Ideally, if we have access to tumor tissue and the sequencing data, we can understand these patterns better.”
Disclosure: One of the study authors reported a financial relationship with pharmaceutical companies. For a full list of disclosures, please refer to the original study.
References
- Wang F, Reid S, Zheng W, et al. Sex disparity observed for Oncotype DX breast recurrence score in predicting mortality among patients with early stage ER-positive breast cancer. Clin Cancer Res. 2020;26(1):101-109.
- Weiss JR, Moysich KB, Swede H. Epidemiology of male breast cancer. Cancer Epidemiol Biomarkers Prev. 2005;14(1):20-26.
- Wang F, Shu X, Meszoely I, et al. Overall mortality after diagnosis of breast cancer in men vs women [published online September 19, 2019]. JAMA Oncol. doi: 10.1001/jamaoncol.2019.2803
- Garcia M, Mulvagh SL, Bairey Merz CN, Buring JE, Manson JE. Cardiovascular disease in women. Circ Res. 2016;118(8):1273-1293.
