Risk factors relevant to cystic breast disease: a case-control study

Risk Factors for Benign Breast Disease and their Relation with Breast Cancer Risk. Pooled Information from Epidemiologic Studies

Information from published case-control studies on benign breast disease was pooled using standard statistical methods to obtain single, overall risk estimates. This analysis showed that higher socio-economic status (pooled relative risk, RR = 1.24, 95% confidence interval, CI = 1.13-1.37), later menopause (pooled RR = 1.87, 95%, CI = 1.67-2.11) and late age at first birth (pooled RR = 1.30, 95%, CI = 1.13-1.50) were associated with an increased risk of benign breast disease, whereas an apparent protection was given by greater body mass index (pooled RR = 0.58, 95%, CI = 0.50-0.67) and the use of oral contraceptives (pooled RR = 0.75, 95%, CI = 0.67-0.83). The role of these factors did not appear to be materially different in the various histopathologic categories considered, although available information allowed only a general distinction between breast dysplasia (fibrocystic disease) and benign tumors, chiefly fibroadenoma. In conclusion, the general evidence from published studies indicates that benign breast lumps appear to share a number of important risk factors with breast cancer.

Benign breast disease among first-degree relatives of young breast cancer patients

Benign breast disease is associated with increased risk of breast cancer. To further clarify whether there is a genetic link between benign and malignant breast lesions, the authors identified 14,648 first-degree female relatives of 8,807 patients in whom breast cancer was diagnosed at <50 years of age by using Danish nationwide cancer and population registers. Hospital register data were used to follow the relatives for occurrence of benign breast disease from 1977 to 2003 and to calculate rates of benign breast disease in the general population of Danish women for comparison. Risk for relatives was increased for benign breast diseases (observed/expected ratio = 1.54, 95% confidence interval: 1.42, 1.66), particularly for relatives aged <40 years. Higher risks were observed after breast cancer had been diagnosed in the family; however, an increased risk for relatives aged <50 years (observed/expected ratio = 1.24, 95% confidence interval: 1.02, 1.51) was present before breast cancer was diagnosed in the family. Enhanced surveillance of close relatives of breast cancer patients seems to be an important factor to address when investigating the association between benign breast disease and familial breast cancer. A genetic link between benign breast disease and breast cancer was indicated by our data but needs to be confirmed in future studies.

Family history of breast cancer, age and benign breast disease

A major risk factor for breast cancer is having a first-degree family history of the disease. Benign breast disease (BBD), particularly atypical hyperplasia, is also associated with an increased risk of breast cancer. However, the relationship between family history of breast cancer and BBD is unclear. From 1989 through 1997, 80,995 participants in the Nurses' Health Study II were followed; 16,849 reported a first diagnosis of BBD. Pathology slides were reviewed for 1,465 women who reported having a tissue biopsy, and these were classified as nonproliferative BBD, proliferative BBD without atypia or atypical hyperplasia. Women with a family history of breast cancer were more likely to report a physician diagnosis of BBD [rate ratio (RR) = 1.38, 95% confidence interval (CI) 1.29-1.46]. The magnitude of this association declined with age from RR = 1.96 (95% CI 1.55-2.47) at 25-29 years to RR = 1.20 (95% CI 0.95-1.52) at age 45-50 years. Among women with proliferative disease, those with a family history of breast cancer were almost 3 times as likely to have atypia (prevalence odds ratio = 2.72, 95% CI 1.23-5.89) than those with no family history. In conclusion, women with a family history of breast cancer appear to be at increased risk of being diagnosed with BBD, in particular the high-risk types of BBD associated with a greatly increased risk of breast cancer. This link adds weight to the belief that BBD with atypia is a precursor or marker lesion for breast cancer.

Molecular epidemiologic studies of polycyclic aromatic hydrocarbon-DNA adducts and breast cancer

We review our studies on the role of polycyclic aromatic hydrocarbon (PAH)-DNA adducts in breast cancer. Additionally we report on analyses of the reliability of the scoring procedures used with immunohistochemical assay for PAH-DNA adducts and of potential bias arising from the use of benign breast disease (BBD) controls. We conducted a case-control study utilizing two control groups: BBD controls who donated tissue and blood samples, and healthy controls who donated blood samples. In comparisons of tumor tissue from cases and benign tissue from BBD controls, increasing adduct levels were significantly associated with case-control status [odds ratio (OR) = 2.40, 95% confidence interval (CI) 1.18-4.92], whereas in comparisons of nontumor tissue from cases and benign tissue from BBD controls the association was nonsignificant (OR = 1.97, 95% CI 0.94-4.17). We also show among cases, but not among BBD controls, that the GSTM1 null genotype is associated with increased adduct levels in breast tissue. Our reliability study found the scoring procedures used with the immunohistochemical assay to have high reliability, 0.93 in nontumor, 0.82 in tumor, and 0.74 in benign tissues. However, we found that the technician significantly contributed to the total variability of a series of data. Finally, we did not find a consistent bias to the null associated with the use of BBD controls; however, BBD controls may overestimate the prevalence of family history of breast cancer compared to that of healthy controls (18% vs.14%). We hypothesize that the higher prevalence results from a referral bias and discuss how this may influence our results.

A case control study of factors associated with macroscopic breast cysts

Women who have a breast cyst aspirated are at increased risk of developing breast cancer. We present an age-matched case control study comparing the reproductive characteristics of 352 women who had a breast cyst aspirated with a control group of 352 contemporaneous clinically normal women. Women with breast cysts were more likely to be nulliparous [odds ratio (OR) = 2.28, 95% confidence interval (CI) = 1.34-3.88] or have a late age at first live birth (chi 2 trend = 5.6, P less than 0.025), and a late menopause (chi 2 trend = 4.3, P less than 0.05). They were less likely to have ever used the oral contraceptive pill (OR = 0.38, 95% CI = 0.26-0.55) or to have used the pill for a short duration (chi 2 trend = 16.8, P less than 0.001), and were less likely to have had a hysterectomy (OR = 0.58, 95% CI = 0.36-0.93). They were more likely to wear a small bra (chi 2 trend = 18.6, P less than 0.001) and bra cup (chi 2 trend = 5.6, P less than 0.025). Nulliparity, late age at first live birth and late menopause are factors common to breast cancer risk.