Lower recurrence score threshold associated with mortality risk among men with breast cancer
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Oncotype DX Breast Recurrence Score appeared to be associated with mortality at a lower threshold for men with breast cancer than for their female counterparts, according to results of a retrospective study published in Clinical Cancer Research.
“Men with a mutation in breast cancer-susceptible genes, such as BRCA1 and BRCA2, are known to have a higher risk for developing breast cancer than those without a mutation,” Xiao-Ou Shu, MD, PhD, MPH, Ingram professor of cancer research and associate director for global health and co-leader of the cancer epidemiology research program at Vanderbilt-Ingram Cancer Center, told HemOnc Today. “Beyond this, little is known about risk factors for male breast cancer.”
Approximately 1% of all breast cancer cases occur among men. Because of this, diagnostic and treatment approaches are in many ways based on evidence gathered from female patients, researchers noted.
A previous study demonstrated that men with breast cancer who had higher recurrence scores, measured by the genetic assay Oncotype DX (Genomic Health), had worse crude survival outcomes than those with lower scores. However, the study did not account for independent predictive or prognostic values of recurrence score.
This study attempted to fill the knowledge gap by examining the association between recurrence score and overall mortality among men with breast cancer.
Shu and colleagues analyzed 848 men (mean age, 61.9 years; range, 26-88) and 110,898 women (mean age, 58.3 years; range, 18-90) with breast cancer included in the National Cancer Database between 2010 and 2014. They used Cox regression models to estimate overall mortality associated with recurrence score, which they evaluated continuously and by categorization using traditional (17 low risk, 18-30 intermediate risk, 31 high risk) and TAILORx (10 low risk, 11-25 intermediate risk, 26 high risk) cutoffs.
Results showed associations between recurrence score and increased risk for mortality among men until the score exceeded 21 (HR per unit of recurrence score increment = 1.13; 95% CI, 1.02-1.26), at which point the risk plateaued.
Mortality began to increase among women only when the recurrence score exceeded 23 (HR per unit of recurrence score increment = 1.02; 95% CI, 1.01-1.02).
Men with intermediate- (HR = 5.37; 95% CI, 1.79-16.11) or high-risk disease (HR = 4.28; 95% CI, 1.22-14.97) according to TAILORx cutoffs had a higher risk for mortality than those with low-risk disease, which held after adjusting for demographic, clinical characteristics and treatments aside from chemotherapy.
Fully adjusted HRs showed women in the high-risk group had a twofold (HR for TAILORx cutoffs = 2.05; 95% CI, 1.78-2.37) to 2.5-fold (HR for traditional cutoffs = 2.46; 95% CI, 2.13-2.84) higher mortality risk than those in the low-risk group. Those in the intermediate-risk group did not have higher mortality than those in the low-risk group (HR = 1.06; 95% CI, 0.96-1.18).
A lack of information on recurrence and causes of death, as well as on genetic testing, served as study limitations.
“Among routine oncology care populations with early-stage breast cancer, recurrence score is prognostic for total morality in both male and female patients, but with distinct association patterns,” Shu and colleagues wrote. “Mortality increased in much lower ranges of recurrence score for male than female patients with breast cancer. Studies are needed to develop recurrence score categorization specifically for male patients with breast cancer.” – by John DeRosier
For more information:
Xiao- Ou Shu, MD, PhD, MPH, can be reached at Vanderbilt University Medical Center, 2525 West End, Suite 600 (8390), Nashville, TN 37203-1738; email: xiao-ou.shu@vumc.org.
Disclosures: Shu reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.
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