Percentage Dense Area Stronger Than Absolute Dense Area as Mammography Risk Factor for Breast Cancer
In a meta-analysis reported in the Journal of the National Cancer Institute, Pettersson et al found that percentage dense area on breast mammography is a stronger predictor of breast cancer than absolute dense area. An inverse association of absolute nondense area and risk was also observed.
The meta-analysis included 13 case-control studies providing results from logistic regression analyses for associations between 1–standard deviation increments in mammographic density phenotypes and breast cancer risk.
Premenopausal Women
Among 1,776 premenopausal case patients and 2,834 premenopausal control subjects, summary odds ratios (OR) for a 1–standard deviation increase after adjustment for age, body mass index (BMI), and parity were 1.52 (95% confidence interval [CI] = 1.39–1.66) for percentage dense area, 1.37 (95% CI = 1.29–1.47) for absolute dense area, and 0.78 (95% CI = 0.71–0.86) for absolute nondense area. The results for nondense area were similar after further adjustment for absolute dense area (OR = 0.82, 95% CI = 0.71–0.94). In the fully adjusted model, there was significant heterogeneity (P = .02) among studies for absolute nondense area.
Postmenopausal Women
Among 6,643 postmenopausal case patients and 11,187 postmenopausal control subjects, summary odds ratios for a 1 standard deviation increase after adjustment for age, BMI, and parity were 1.53 (95% CI = 1.44–1.64) for percentage dense area, 1.38 (95% CI = 1.31–1.44) for absolute dense area, and 0.79 (95% CI = 0.73-0.85) for absolute nondense area. Again, the results for nondense area were similar after further adjustment for absolute dense area (OR = 0.85, 95% CI = 0.75-0.96). In the fully adjusted model, there was significant heterogeneity (P < .001) among studies for absolute nondense area.
The investigators concluded, “The results suggest that percentage dense area is a stronger breast cancer risk factor than absolute dense area. Absolute nondense area was inversely associated with breast cancer risk, but it is unclear whether the association is independent of absolute dense area.”
Andreas Pettersson, MD, PhD, of Harvard School of Public Health, and Rulla M. Tamimi, ScD, of Brigham and Women’s Hospital and Harvard Medical School, are the corresponding authors for the Journal of the National Cancer Institute article.
The study was supported by the National Cancer Institute, National Institutes of Health, Marit and Hans Rausing’s Initiative Against Breast Cancer, Department of Defense Breast Cancer Research Program, Office of the Congressionally Directed Medical Research Programs, Agency for Science, Technology and Research, Swedish Cancer Society, National Cancer Institute of Canada, and others. The study authors reported no potential conflicts of interest.
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