Search

Fractures in postmenopausal women may serve as a surrogate measure of bone density, reflecting long-term lower estrogen levels, and lower estrogen levels appear to be inversely associated with breast and endometrial cancer. Breast cancer cases aged 50-79 years (n = 5,559) and endometrial cancer cases aged 40-79 years (n = 739) were enrolled in a US case-control study in 1992-1994 to evaluate the relation between fractures and risk of breast and endometrial cancer. Controls for the breast cancer analysis (n = 5,829) and the endometrial cancer analysis (n = 2,334) were randomly selected from population lists (driver's license and Medicare files). Information on fracture history and other risk factors was obtained by telephone interview. Compared with women without a fracture in the past 5 years, the odds ratios for women with a history of fracture were 0.80 (95% confidence interval (CI): 0.68, 0.94) for breast cancer and 0.59 (95% CI: 0.40, 0.89) for endometrial cancer. Height loss (> or =2.5 cm) and recent fracture history were associated with the lowest risk of breast cancer (odds ratio = 0.62, 95% CI: 0.46, 0.83) and endometrial cancer (odds ratio = 0.15, 95% CI: 0.05, 0.43). These data suggest that the endogenous hormonal factors associated with increased fracture risk are also related to decreased breast cancer risk and, more strongly, to endometrial cancer risk.

As more women obtain screening mammograms regularly and at younger ages, the diagnosis of breast carcinoma in situ becomes more frequent. To examine whether risk factors for carcinoma in situ correspond with risk factors for invasive breast cancer, we analyzed data from a population-based case-control study conducted in 1988-1990. We identified newly diagnosed cases of carcinoma in situ (n = 301) and invasive breast cancer (n = 3789) in women 18-74 years of age from Wisconsin's statewide tumor registry. Cases and population controls (n = 3999) completed structured telephone interviews. Overall, associations with risk of carcinoma in situ in relation to many reproductive life-style risk factors were similar to those associated with risk of invasive disease. Women who reported a family history of breast cancer had a 2-fold elevated risk of carcinoma in situ (odds ratio, 2.67; 95% confidence interval, 2.00-3.57). Personal history of benign biopsied breast disease also increased risk of carcinoma in situ (odds ratio, 2.19; 95% confidence interval, 1.62-2.95). Subgroup analysis suggested that high vitamin A intake and high alcohol intake may be associated with risk of ductal but not lobular carcinoma in situ. These data support the presence of common risk factors between in situ and invasive breast cancer.

Objective: Although many studies have shown that higher weight increases the risk of postmenopausal breast cancer, some aspects of this association are unclear. In order to examine the risk associated with different patterns of weight change, we analyzed data from a large case-control study of postmenopausal breast cancer., Methods: Participants included women aged 50 79 years (n = 5031) who are newly diagnosed with invasive breast cancer in Massachusetts, New Hampshire, and Wisconsin. Similarly-aged population controls (n = 5255) were selected at random from driver's license files and Medicare beneficiary lists. Height, weight, and information on other breast cancer risk factors were ascertained by structured telephone interviews from 1992 to 1995, and logistic regression was used to estimate multivariable-adjusted odds ratios (OR) and 95% confidence intervals (CI)., Results: Women in the top quintile groups for height at age 20, recent weight, and recent body mass index had significantly increased risks of breast cancer. Among women who reached their highest adult weight at younger ages (<45 years), increasing weight loss since that age was associated with a reduced risk of postmenopausal breast cancer (OR 0.90, CI 0.84 0.98, per 5 kg). However, weight loss among women whose highest weight occurred after age 45 was not associated with risk (OR 1.00, CI 0.95 1.05, per 5 kg). Weight gain since the lowest adult weight increased risk by 8% for each 5 kg of gain (OR 1.08, CI 1.06-1. 11). Temporary weight cycling (weight loss followed by weight gain) was not associated with increased risk., Conclusions: Weight gain clearly increased risk of postmenopausal breast cancer. These data lend further support to efforts aimed at helping women avoid weight gain as they age.

The relation between body size and breast cancer remains uncertain, particularly with regard to differences between pre- and postmenopausal women. The authors examined whether height, weight, body mass index, and weight change were associated with breast cancer risk among pre- and postmenopausal women. This population-based case-control study included women aged 20-74 years (n = 6,548) who were diagnosed with invasive breast cancer during 1988-1991 in Maine, Massachusetts, New Hampshire, and Wisconsin. Similarly aged control women (n = 9,057) were selected at random from driver's license files and Health Care Financing Administration files. Height, weight, and information on other breast cancer risk factors were ascertained by telephone interview, and logistic regression was used to estimate multivariate-adjusted odds ratios and 95% confidence intervals. Among premenopausal women, the adjusted odds ratio for the upper quintile group of height relative to the lowest was 1.36 (95% confidence interval (CI) 1.05-1.76). The heaviest premenopausal women had a lower risk (odds ratio (OR) = 0.87, 95% CI 0.70-1.10). Among postmenopausal women, the adjusted odds ratios were higher for the upper quintile categories of both height (OR = 1.27, 95% CI 1.11-1.45) and weight (OR = 1.57, 95% CI 1.37-1.79). Weight gain since ages 18 and 35 years was associated with increased postmenopausal breast cancer risk, and risk was lower in women who had lost weight. These findings suggest that programs to avoid weight gain merit study as a means to reduce risk of postmenopausal breast cancer.

Data from a population-based case-control study were analyzed to evaluate risk of breast cancer among women according to parental age at the time of subject birth. Between 1988-91, breast cancer cases (n = 1,253) were obtained from the statewide tumor registry in Wisconsin. Concurrently, population controls (n = 1,121) were randomly selected from driver's license lists (if under age 65) and Medicare beneficiary files (if 65-74 years). Information regarding parents' ages and breast cancer risk factors was obtained by telephone interview. Relative risk estimates were very slightly elevated with increasing maternal age, although no consistent trend of increasing risk was observed (P for trend = 0.38). No association between paternal age and breast cancer risk was observed (P for trend = 0.98). Older maternal or paternal age was not associated with risk among any of the subgroups examined, except for daughters who had late age at first birth. These findings are consistent with the majority of studies that have found little or no association between parental age and breast cancer risk.

Purpose: To evaluate the effects of chemotherapy regimens on peripheral-blood stem-cell (PBSC) yields in patients with breast cancer who receive granulocyte colony-stimulating factor (G-CSF)., Patients and Methods: One hundred patients with breast cancer received cyclophosphamide 4 g/m2 for dose (CY) (n = 10), CY and etoposide 600 mg/m2 (CE) (n = 13), CE and cisplatin 105 mg/m2 (CEP) (n = 19), or CY and paclitaxel 170 mg/m2 (n = 58), followed by G-CSF. PBSC collections were initiated when the WBC count recovered to greater than 1 x 10(9)/L. A multivariate analysis was undertaken to evaluate the effects of different chemotherapy regimens and patient variables on PBSC collections as measured by the yield of CD34+ cells., Results: The medians of average daily CD34+ cell yields for patients who received paclitaxel plus CY, CE, and CEP with G-CSF were 12.9, 11.03, and 5.37 x 10(6)/kg, respectively, compared with 2.02 x 10(6)/kg in the reference group that received CY with G-CSF (P = < .0001, .002, and .09, respectively). On first-day collections, patients who received paclitaxel plus CY, CE, and CEP with G-CSF yielded medians of 11.07, 8.09, and 3.52 x 10(6) CD34+ cells/kg, respectively, compared with 0.90 x 10(6)/kg in the reference group that received CY with G-CSF (P = .0006, .02, and .09, respectively). The number of previous cycles of chemotherapy, previous radiotherapy, marrow involvement, and phase and stage of disease did not have statistically significant effects on CD34+ cell yield., Conclusion: Combination chemotherapy regimens were superior to single-agent CY for the mobilization of CD34+ cells.

We examined the association between recent oral contraceptive (OC) use and the risk of breast cancer in data from a large population-based case-control study in the United States. Cases (n = 6,751) were women less than 75 years old who had breast cancer identified from statewide tumor registries in Wisconsin, Massachusetts, Maine, and New Hampshire. Controls (n = 9,311) were selected randomly from lists of licensed drivers (if aged under 65 years) and from lists of Medicare beneficiaries (if aged 65 through 74 years). Information on OC use, reproductive experiences, and family and medical history was obtained by telephone interview. After adjustment for parity, age at first delivery, and other risk factors, women who had ever used OCs were at similar risk of breast cancer as never-users (relative risk [RR] = 1.1, 95 percent confidence interval [CI] = 1.0-1.2). Total duration of use also was not related to risk. There was a suggestion that more recent use was associated with an increased risk of breast cancer; use less than two years ago was associated with an RR of 1.3 (CI = 0.9-1.9). However, only among women aged 35 to 45 years at diagnosis was the increase in risk among recent users statistically significantly elevated (RR = 2.0, CI = 1.1-3.9). Use prior to the first pregnancy or among nulliparous women was not associated with increased risk. Among recent users of OCs, the risk associated with use was greatest among non-obese women, e.g., among women with body mass index (kg/m2) less than 20.4, RR = 1.7, CI = 1.1-2.8. While these results suggest that, in general, breast cancer risk is not increased substantially among women who have used OCs, they also are consistent with a slight increased risk among subgroups of recent users.

A priori hypotheses suggest that cigarette smoking could either increase or decrease breast cancer incidence. To clarify these competing hypotheses, we used data from a very large population-based breast cancer case-control study to investigate the impact of smoking on breast cancer risk. Breast cancer patients less than 75 years old were identified from statewide tumor registries in Wisconsin, Massachusetts, Maine, and New Hampshire; controls were randomly selected from driver's license lists (age less than 65) or lists of Medicare beneficiaries (age 65-74). Information on reproductive history, medical history, and personal habits including cigarette smoking was obtained by telephone interview. A total of 6,888 cases and 9,529 controls were interviewed. There was virtually no relationship between current smoking and breast cancer risk (multivariate odds ratio, 1.00; 95% confidence interval, 0.92-1.09), and former smokers had a barely increased risk (odds ratio, 1.10; 95% confidence interval, 1.01-1.19). Similar results were observed among both premenopausal and postmenopausal women. There was no suggestion that heavy or long-term smoking increased or decreased risk, nor were there indications that women who began smoking at an early age were at increased risk, as has been hypothesized. The results of this large population-based study indicate that smoking does not influence the risk of breast cancer, even among heavy smokers who began smoking at an early age.

Background: Many women attribute the development of their breast cancer to psychosocial factors such as stress and depression. Yet investigations of the relationship between breast cancer and stressful life events have had inconsistent outcomes, due in part to studies with small sample sizes and reliance on hospital-based populations., Methods: As part of a population-based, case-control study of breast cancer etiology, we evaluated the association between stressful life events and the risk of breast cancer among 258 breast cancer patients and 614 randomly selected population-based controls. Information on 11 stressful life events was collected in telephone interviews with women aged 50-79 who were participating in the ongoing study., Results: Breast cancer patients and controls experienced the same number of stressful life events in the five years prior to diagnosis or an equivalent reference date (controls), averaging 2.4 and 2.6 events, respectively. After adjustment for known breast cancer risk factors, there was no association between weighted stressful life event scores and the risk of breast cancer (odds ratio [OR] = 0.90 per unit increase; 95% confidence interval [CI], 0.78-1.05). Only one life event, death of a close friend, was significantly more often reported by controls (OR = 0.72; 95% CI, 0.52-1.00). Other life events were inconsistently and nonsignificantly associated with breast cancer risk. CONCLUSIONS. The results of this retrospective study do not suggest any important associations between stressful life events and breast cancer risk.

Objective: To evaluate the association between pregnancy terminations and risk of breast cancer., Design and Setting: Population-based case-control study in Wisconsin, Massachusetts, Maine, and New Hampshire., Study Participants: Cases were women younger than 75 years with a new diagnosis of breast cancer (n = 6888), identified from statewide tumor registries. Controls younger than 65 years (n = 9529) were randomly selected from lists of licensed drivers, or for older subjects, from lists of Medicare beneficiaries. EXPOSURES AND OUTCOMES: Breast cancer risk in relation to spontaneous or induced abortions., Results: After adjustment for parity, age at first birth, and other risk factors, pregnancy termination (induced or spontaneous) was associated with a relative risk (RR) of breast cancer of 1.12 (95% confidence interval [CI], 1.04 to 1.21), compared with the risk among women who had never had a termination. Induced terminations were associated with a RR of 1.23 (95% CI, 1.00 to 1.51), which was somewhat greater than the risk associated with spontaneous terminations (RR, 1.11; 95% CI, 1.02 to 1.20). The association with induced abortions was stronger for those performed before legalization of abortion in 1973 (RR, 1.35; 95% CI, 1.01 to 1.80) than after this time (RR, 1.12; 95% CI, 0.84 to 1.49), suggesting a bias in reporting this sensitive procedure., Conclusions: A weak positive association was observed between abortion--whether induced or spontaneous--and risk of breast cancer. The increase in risk of breast cancer was somewhat greater among women with a history of induced terminations. However, this association may be due to reporting bias and was not significantly different than the slight risk for spontaneous terminations.

Despite extensive study, concerns remain about a possible association between long-term postmenopausal hormone treatment--particularly use of combination preparations--and risk of breast cancer. The authors evaluated the use of postmenopausal hormone replacement therapy in relation to breast cancer risk in a large multicenter, population-based case-control study. Women with a new diagnosis of breast cancer were identified through statewide tumor registries in Wisconsin, Massachusetts, Maine, and New Hampshire. Controls were randomly selected from population lists in each state. For this analysis of postmenopausal women, data were available from 3,130 breast cancer cases and 3,698 controls interviewed between 1989 and 1991. Replacement hormone use was not associated with breast cancer risk in women who had ever undergone this treatment (relative risk (RR) = 1.05, 95% confidence interval (CI) 0.93-1.18). Among women who had used replacement hormones for 15 years or more, there was no clear increase in risk, although the small sample size did not preclude the possibility of a modest association (RR = 1.11, 95% CI 0.87-1.43). Risk among women using progestins in combination with estrogens was similar to that in women using estrogens alone. Risk did not vary according to type of menopause, family history of breast cancer, history of benign breast disease, or alcohol intake. These results are consistent with the majority of reports which find no overall increased risk associated with the use of replacement hormones. However, in contrast to several other studies, this study did not find long-term use to be associated with increased risk. These results also do not support a hypothesized effect of combined progestin and estrogen use on the risk of breast cancer.

Data from a large, multicenter, population-based case-control study were analyzed to investigate the relation between multiple birth pregnancies and subsequent breast-cancer risk in the gravidas. Women less than 75 years old who had breast cancer were identified from statewide tumor registries in Wisconsin, western Massachusetts, Maine and New Hampshire. Controls aged less than 65 years were selected randomly from lists of licensed drivers, and controls aged between 65 and 74 were selected randomly from lists of Medicare beneficiaries. Information on reproductive history and other factors was obtained by means of telephone interviews. After excluding nulliparous women, 5,880 case subjects and 8,217 controls remained for analysis. Multiple birth pregnancies occurred in 146 cases and 218 controls. Adjusted for the number of full-term pregnancies and other confounders, the odds ratio (OR) for any multiple birth pregnancy was 0.94 (95% confidence interval, 0.75 to 1.17). The null association between multiple birth pregnancies and breast cancer remained if the mother's first pregnancy or last pregnancy resulted in a multiple birth. In addition, no trend in risk emerged for age at first multiple birth or time since last multiple birth. While other investigators have suggested biological mechanisms to explain both protective and detrimental effects of multiple births and subsequent development of breast cancer, this study does not support either assertion.

Background: The evidence of an association of lactation with a reduction in the risk of breast cancer among women has been limited and inconsistent. The effect of lactation appears to be confined to premenopausal women with a history of long lactation, but most studies of this relation have been limited in statistical power. We conducted a multicenter, population-based, case-control study with a sample large enough for us to describe more precisely the association between lactation and the risk of breast cancer., Methods: Patients less than 75 years old who had breast cancer were identified from statewide tumor registries in Wisconsin, Massachusetts, Maine, and New Hampshire. Controls were randomly selected from lists of licensed drivers if the case subjects were less than 65 years old, and from lists of Medicare beneficiaries if they were 65 through 74 years old. Information on lactation, reproductive history, and family and medical history was obtained by means of telephone interviews. After the exclusion of nulliparous women, 5878 case subjects and 8216 controls remained for analysis., Results: After adjustment for parity, age at first delivery, and other risk factors for breast cancer, lactation was associated with a slight reduction in the risk of breast cancer among premenopausal women, as compared with the risk among women who were parous but had never lactated (relative risk, 0.78; 95 percent confidence interval, 0.66 to 0.91); the relative risk of breast cancer among postmenopausal women who had lactated, as compared with those who had not, was 1.04 (95 percent confidence interval, 0.95 to 1.14). With an increasing cumulative duration of lactation, there was a decreasing risk of breast cancer among premenopausal women (P for trend < 0.001) but not among postmenopausal, parous women (P for trend = 0.51). A younger age at first lactation was significantly associated with a reduction in the risk of premenopausal breast cancer (P for trend = 0.003). As compared with parous women who did not lactate, the relative risk of breast cancer among women who first lactated at less than 20 years of age and breast-fed their infants for a total of six months was 0.54 (95 percent confidence interval, 0.36 to 0.82)., Conclusions: There is a reduction in the risk of breast cancer among premenopausal women who have lactated. No reduction in the risk of breast cancer occurred among postmenopausal women with a history of lactation.

Two hundred nine female enrollees of the Group Health Cooperative of Puget Sound who developed advanced-stage breast cancer during the period 1982-1988 were interviewed about their practice of breast self-examination (BSE), use of other breast cancer screening modalities, and medical and reproductive histories. Each subject's description of how she performed the examination was scored according to her mention of up to 10 recommended BSE techniques. A random sample of 433 women without advanced-stage breast cancer from the same population was interviewed for comparison. Relative to women not practicing BSE, the risk of advanced-stage breast cancer among BSE users was 1.15 (95% confidence interval, 0.73-1.81). Frequency of BSE did not differ between women with advanced-stage breast cancer and control subjects, whether in all subjects or in subgroups defined by age, use of mammography, or frequency of clinical breast examinations. While self-described proficiency in BSE was generally low in both case and control subjects, the small percentage of women reporting more thorough self-examinations, regardless of frequency, had about a 35% decrease in the occurrence of advanced-stage breast cancer compared to women who did not perform BSE. These results suggest that, while carefully performed BSE may avoid the development of some advanced-stage breast cancers, BSE as practiced by most Seattle-area women is of little or no benefit.