ABSTRACT
Aim: This study was performed to: (i) determine the association of breast cancer with dense breasts, and (ii) determine the breast cancer association with early onset of menarche, nulliparity, late age at first childbirth, not breast-feeding, and family history of breast cancer. Methods: This was a retrospective hospital-based case-control study. The 231 cases were women diagnosed with breast cancer on histology during the study period from July 1998 to April 2005. The 231 controls were age-matched and randomly selected women who did not have breast cancer but had mammography performed during the same time interval. Tabar classification was used to classify the mammographic parenchymal pattern of the 462 samples. The same radiologist analysed the parenchymal pattern based on the craniocaudal and mediolateral oblique views. Statistical analysis was done using the SPSS package. Results: Majority of women with breast cancer (55%) had dense breasts (29% Type IB, 19% Type IC, 4% Type IV, 3% Type V). Majority of controls (58%) had dense breasts (22% Type IB, 26% Type IC, 6% Type IV, 4% Type V). The majority of women with breast cancer had menarche at 12 years or older (93%), were parous (89%), had the first childbirth before 35 years old (91%), had breast-fed (67%), and did not have family history of breast cancer (84%). For controls, the majority had menarche at 12 years or older (88%) were parous (87%), had the first childbirth before 35 years old (98%), had breast-fed (66%), and did not have family history of breast cancer (85%). All factors explored, including breast density, were not significantly associated with breast cancer. The odds ratio for breast cancer among those with dense breast compared to those with non-dense breast is 0.8 (95% CI=0.6, 1.2). Conclusion: This study found no association between breast cancer and dense breasts (p=0.398). There was also no association between breast cancer with early onset of menarche (p=0.174), nulliparity (p=0.448), older age at first childbirth (p=0.065), not breast-feeding (p=0.716) and family history of breast cancer (p=0.665).
