A case-control study of male breast cancer

A case-control study was conducted in Los Angeles County, CA, of 75 male breast cancer cases aged 20-74 yr at diagnosis to investigate the role of a number of suspected risk factors. The study involved both interviews and laboratory measurements. Factors under study included fertility and marital history, obesity, alcohol and cigarette consumption, use of drugs known or suspected of causing gynecomastia, family history of breast cancer, history of radiation exposure to the upper body, sex chromatin analysis, serum levels of prolactin, testosterone, estrone, estradiol and sex-hormone-binding globulin, as well as urinary levels of estrone, estradiol, and estriol. Two patients versus no controls tested positive for sex chromatin and were excluded from further analyses. The only statistically significant risk factor identified was greater weight of the cases at age 30; a man who weighed 80 or more kg at age 30 had twice the risk of breast cancer of a man weighing less than 60 kg at that age. Serum estrone levels were positively, and sex-hormone-binding globulin levels were negatively, related to body weight, and we interpret the greater weight of the cases as suggesting that the underlying risk factor is an increased exposure to bioavailable estrogen. None of the differences observed between cases and controls for either the serum or urinary hormone levels was, however, statistically significant and there did not appear to be any large absolute excess of estrogens or deficit of testosterone in the cases. This apparent contradiction may be explained by the fact that there was little difference in weight between the cases and controls at the time of sampling.     

A case-control study of breast cancer in Taiwan--a low-incidence area.

To investigate risk factors for breast cancer in Taiwan, a low-incidence area, a case-control study was conducted. This comprised 244 subjects with diagnosed and pathologically confirmed breast cancer (age range 20-80 years) and 450 female ophthalmology outpatients as controls. Univariate and multiple logistic regression analysis suggests that breast cancer in Taiwan is aetiologically similar to breast cancer in high to moderate-incidence areas. A family history of breast cancer appears to be the most important factor contributing to the risk of breast cancer (odds ratio = 4.69). The effect of reproductive hormones (represented by the years of history of menses in premenopausal women, odds ratio = 3.35; or the age at menarche in post-menopausal women, odds ratio = 2.67) plays a significant role in tumorigenesis. Breast feeding appears to be a particularly important protective factor in Taiwanese women (odds ratio = 0.57).     

Diet and breast cancer in Shanghai and Tianjin, China.

Various aspects of adult diet have been linked to breast cancer development. These include intake of fat (risk factor), and intake of fibre, soy protein and vitamins A, C and E (protective factors). Results of previous studies have been inconsistent. We examined the possible associations between breast cancer and various indices of nutrient and food intake in two Chinese populations who are at relatively low risk for breast cancer (one-fifth the rate in US white women). Two case-control studies of breast cancer were conducted in the cities of Shanghai and Tianjin, China. In Shanghai, 534 women aged 20-69 years with histologically confirmed breast cancer were recruited, whereas in Tianjin 300 women aged 20-55 years with histologically confirmed breast cancer were interviewed. All controls were community controls who were individually matched to the cases by sex and age (case-control ratio = 1:1). All interviews were conducted in person. Findings from the two studies were similar, although the diets in Shanghai and Tianjin were different in many respects. Cases and controls were similar in their consumption of soy protein, measured either in absolute levels or as percentages of total protein. Overall, all components of dietary fat (saturated fat, monounsaturated fat, polyunsaturated fat) showed a modest, non-significant association with breast cancer after adjustment for energy intake and other non-dietary risk factors for breast cancer. Intake of crude fibre, carotene and vitamin C, on the other hand, exhibited strong, statistically significant inverse associations with breast cancer risk. The last three indices were highly correlated, rendering it impossible to disentangle their individual effects; they were closely associated with intake of green vegetables in the two study populations. Vitamin E intake was unrelated to breast cancer risk in Shanghai and Tianjin. In the multivariate logistic regression model which included all non-dietary risk factors for breast cancer and energy intake, Shanghai women in the lowest tertile of crude fibre intake and highest tertile of fat intake had a 2.9-fold increased risk for breast cancer relative to those in the highest tertile of crude fibre intake and lowest tertile of fat intake. The comparable relative risk in Tianjin women was 2.4. Our data indicate a strong protective effect against breast cancer development with intake of foods rich in fibre, vitamin C and carotene. Our results are also compatible with dietary fat having a modest, positive effect on breast cancer risk within the range of exposure experienced by women in China.(ABSTRACT TRUNCATED AT 250 WORDS)     

A case-control study of lactation and cancer of the breast.

We have examined the relation of lactation, by total duration, with breast cancer risk among pre- and post-menopausal women. In a hospital-based case-control study conducted in Athens (1989-91), involving 820 patients with confirmed breast cancer and 795 orthopaedic patient controls and 753 hospital visitor controls, logistic regression was used to analyse the data controlling for demographic, nutritional and reproductive factors, including parity and age at any birth. Among post-menopausal women, there was no association between breastfeeding and breast cancer risk, but among premenopausal women those who has breastfed for > or = 24 months had an odds ratio of 0.50 (95% confidence interval 0.23-1.41). A reduction of the odds ration was also evident among premenopausal women who had breastfed between 12 and 23 months (odds ratio 0.70; 95% confidence interval 0.34-1.60). In conjunction with several other recent reports these results support the hypothesis that breastfeeding of prolonged duration may reduce the risk of breast cancer among premenopausal women but not among post-menopausal women. The biology underlying this different effect remains unknown, and the practical implication of the finding is a marginal importance.     

A case-control study of hair dye use and breast cancer.

A case-control study of the relationship between hair dye use and breast cancer included 129 breast cancer patients and 193 control women drawn from the records of a multiphasic screening clinic. Information was obtained by telephone interview on a number of risk factors for breast cancer and on variables pertaining to hair dye use: chronologic time, duration, frequency, type, and color. From this, quantitative measures of cumulative hair dye use at various intervals prior to breast cancer (or an equivalent for controls) were obtained. A multivariate risk factor score was used to control for confounding variables. The adjusted relative risks for breast cancer versus hair dye use were greater than unity but were not generally significant. However, integral measures of hair dye use (No. of yr times frequency per yr) were significantly related to breast cancer when confounding variables were controlled. The association between hair dye use and breast cancer was greatest among women over 50 years of age and among those at lower natural risk for breast cancer. An analysis of temporal patterns showed that breast cancer was related mainly to hair dye use 10 or more years before cancer diagnosis. Because of the retrospective nature of the hair dye data and the small sample size, these results require further validation.     

A population-based case-control study of endometrial cancer in Shanghai, China

A case-control study of 268 patients with endometrial cancer and 268 population controls was conducted during 1988-1990 in Shanghai, China, to evaluate etiologic factors in a population whose risk had not been substantially altered by the use of exogenous estrogens. In spite of this, the major risk factors resembled those found in other studies. The risk of endometrial cancer was significantly elevated among nulligravidas (OR = 5.4, 95% CI = 2.0-14.6) and decreased with number of pregnancies (p less than 0.01). Late age at menopause was associated with increased risk, while early age at menarche was unrelated. Use of oral contraceptives for more than 2 years was associated with a reduction in endometrial cancer risk (OR = 0.4, 95% CI = 0.1-1.2), while short-term use of oral contraceptives and other methods of contraception were unrelated. Obesity was a strong predictor of risk, with women in the highest quartile of weight having 2.5 times the risk of those in the lowest quartile. In contrast to many other studies, cigarette smokers were at elevated risk (OR = 1.7, 95% CI = 0.9-3.0). Risk was also elevated among women reporting a history of gall-bladder disease, polycystic ovaries, menstrual symptoms, and non-estrogen hormone use.     

A case-control study of diet and breast cancer in Argentina

A case-control study of breast cancer was carried out in La Plata, Argentina, where the incidence of the disease is comparable to the highest rates recorded worldwide. One hundred and fifty incident cases were identified through major hospitals. For each case, a hospital control, matched by age and hospital, and a neighbourhood control, matched by residential area and age, were also chosen. Cases and controls were interviewed to obtain information on past diet, as well as demographic and socio-economic characteristics, reproductive and menstrual history and other potential breast-cancer risk factors. The dietary information was obtained from questions on the consumption of specific food items and information on portion sizes from an earlier study was used to estimate intake of calories and selected nutrients. There was a substantial excess energy intake among cases as compared to both control groups, which was present across all 3 major macronutrients which contribute to total calories. Among the food groups, the consumption of eggs was a risk factor for breast cancer, and whole-milk products and green leafy vegetables were protective. After adjusting for the calorie difference in multivariate statistical analyses of nutrients, fibre and beta-carotene consumption were weakly protective. The results are discussed with reference to possible methodological difficulties and previous studies of diet and breast cancer.     

男性和女性乳腺癌对照研究

目的研究男性乳腺癌（MBC）的临床特点和可能影响预后的因素。方法回顾1996年1月至2008年1月住院治疗且经病理证实的17例MBC病例，并以同期102例女性乳腺癌患者作对照分析。结果MBC占同期住院治疗的乳腺癌的1．15％（17／1473）。男性组患者的就诊年龄较大、发现肿块至就诊时间较长，就诊时局部皮肤改变及腋窝淋巴结肿大的发生率高于女性组（均P〈0．05），校正了肿瘤分期及腋窝淋巴结状况因素，两组总体5年肿瘤相关生存率差异无统计学意义（P〉0．05）。结论该组MBC患者与女性乳腺癌预后相近，性别不一定是影响MBC的预后因素。     

Risk factors for breast cancer: A case-control study of screen-detected breast cancer in Miyagi Prefecture, Japan

We examined the associations between reproductive factors and the risk of breast cancer on the basis of information from a total of 201,363 breast cancer screening program participants in Miyagi Prefecture, Japan, during 1987-1991. A case-control study method was applied on analysis. Data on 204 breast cancer cases identified and 810 screening year-, age- and screening area-matched normal controls were extracted. After adjustment for potential confounders, a trend of decreasing risk of breast cancer with increasing number of parity was observed (p for trend=0.03). Among parous women, lactation for the last child decreased the risk of breast cancer (odds ratio (OR) = 0.61, 95% confidence interval (95% CI) 0.39–0.94). These findings were consistent with those in clinical breast cancer reported previously. When cases were divided into two age groups, younger ( 49 y.o.) and older (50 y.o. ), family history of breast cancer among mother and sisters (OR=3.51, 95% CI 1.05–11.80), and lactation for the last child (OR=0.46, 95% CI 0.25–0.84) were associated with younger age breast cancer, whereas number of parity was associated with older age breast cancer (p for trend=0.03). The results by age group suggest that different mechanisms may exist in breast cancer developing at early and late onsets.     

Food and botanical groupings and risk of breast cancer: a case-control study in Shanghai, China.

Breast cancer incidence rates more than double in Chinese women as they migrate from China to Hong Kong to the United States, suggesting that environmental factors contribute to the international variation in breast cancer incidence. Several dietary factors, which differ between the United States and the Chinese population, including intake of soy, meat, and fruits and vegetables, have been suggested to affect breast cancer risk. This report describes results from a case-control study of diet and risk of breast cancer nested in a randomized trial of breast self exam in Shanghai, China. Participating breast cancer cases (n = 378) and frequency age-matched controls (n = 1,070) completed a comprehensive food frequency questionnaire and a risk factor questionnaire. After adjustment for age, total energy intake, and total years of breast-feeding, women in the highest quartile of fruit and vegetable intake (> or =3.8 servings/d) were significantly less likely to have breast cancer (odds ratio, 0.48; 95% confidence interval, 0.29-0.78) as compared with women in the lowest quartile of intake (< or =2.3 servings/d). Egg consumption was also significantly inversely associated with risk of breast cancer (odds ratio for > or =6.0 eggs/wk versus < or =2.0 eggs/wk is 0.56; 95% confidence interval, 0.35-0.91). There was no difference in soy consumption between cases and controls. None of the associations with a single botanical family explained the strong inverse relationship between fruits and vegetables and breast cancer risk. These results provide additional evidence in support of the important role of fruits and vegetables in breast cancer prevention.     

Relationship between breast cancer and colorectal adenomatous polyps. A case-control study.

Although there is a known reciprocal association between breast and colorectal cancer in women, few studies have investigated whether a similar association exists between breast cancer and colorectal adenomatous polyps, known to be precursor lesions for colon cancer. A case-control study was conducted on patients in three colonoscopy practices in New York to determine possible risk factors for adenomatous polyps. Among women studied, there were 128 patients with incident adenomatous polyps and 284 control subjects who underwent colonoscopy and had no colorectal neoplasia. No significant association between the incidence of an adenomatous polyp in the colon or rectum and a history of breast cancer was found (odds ratio, 0.71; 95% confidence interval, 0.34 to 1.64). If shared risk factors for breast and colorectal cancer are the reasons for the concurrence of these two malignant lesions, these results suggest that these factors act at the level of promoting adenomatous polyps of the colon and rectum into colorectal cancer.     

女性乳腺癌发病危险因素的病例-对照研究

目的 通过病例-对照研究探索女性乳腺癌的危险因素,为制定乳腺癌预防措施提供科学依据.方法 选取1148例初诊的乳腺癌患者作为病例组,根据年龄和月经史按1:2频数匹配健康对照2229例,收集两组的人口学特征资料和体重指数(BMI)、治疗前雌二醇(E2)检测结果,采用单因素和多因素Logistic分析乳腺癌的危险因素.结果 病例组绝经患者占40.59%,对照组绝经者占39.08%.单因素分析中,妊娠、生育、流产、哺乳次数多,初潮年龄晚者,罹患乳腺癌风险降低(P<0.05);BMI越高,罹患乳腺癌的风险越高(P<0.05);而E2水平与罹患乳腺癌风险无关(P>0.05).非条件Logistic多元回归分析显示,初潮年龄、妊娠次数、生育次数均为保护因素.结论 女性乳腺癌发病与月经、生育史有关.妊娠或生育均为乳腺癌的保护因素,初潮年龄越早,罹患乳腺癌的风险越高.     

A case-control study of breast cancer and alcohol consumption habits

A population-based case-control study was conducted to investigate the contribution of alcohol consumption during the early adult years (ages 18-35 years) and later adult years (older than age 35) to breast cancer risk. Alcohol consumption histories were obtained by questionnaire from 277 breast cancer cases, 372 population controls, and 433 controls with cancer of sites other than breast. Alcohol exposure during both age periods was significantly greater for breast cancer cases, but risks, estimated by maximum likelihood odds ratios, were highest for alcohol consumption frequency during the early adult period. Age-adjusted odds ratios and 95% confidence intervals (CI) for breast cancer risk and early age drinking (10 versus 0 drinks/week) were 2.2 (95% CI = 1.34, 3.5), relative to the population controls and 2.0 (95% CI = 1.3, 3.1) relative to the cancer controls. Based on later-age drinking of ten versus zero drinks/week, odds ratios were 1.8 (95% CI = 1.3, 2.6) and 1.6 (95% CI = 1.2, 2.2) relative to the population and cancer controls, respectively. The risk estimates were not altered by introduction of the following covariates into the analyses: mother with breast cancer, family status, education, body mass index, smoking, supplemental hormone use, and diet.     

A case-control study of oral contraceptive use and breast cancer

Among 989 cases of breast cancer and 9,890 controls selected from a cohort of married, female registered nurses aged 30-55 years, the relative risk (RR) of breast cancer for women who had ever used oral contraceptives (OC) compared with those who had never used them was 1.0, with 95% confidence limits 0.9-1.2. Among OC users, there was no consistent pattern of excess risk with increasing duration; in fact, the few women who had used OC longest (greater than 10 yr) had a slightly lower risk than never-users. Moreover, there was no association between OC use and breast cancer among women with a positive history of breast cancer in the mother or sister or with OC use before their first pregnancy. The only subgroup of women among whom any adverse effect was apparent was current OC users aged 50-55 years (two onsets expected vs. seven observed). This finding is consistent with earlier reports of an increased risk of breast cancer among older OC users; however, it is also likely to reflect, at least to some extent, the play of chance, since at ages 45-49 and in each younger age group fewer cases than expected were observed among current OC users.     

Organochlorines and breast cancer: a case-control study in Brazil.

Breast cancer is an important cause of morbidity and mortality in Brazil. Some studies have analyzed the potential role of organochlorine compounds in breast cancer etiology. These chemical compounds have been widely used in agriculture and in vector-control programs in Brazil. A case-control study was carried out in the main cancer hospital of the Instituto Nacional de Cancer in Rio de Janeiro to investigate exposure to organochlorinated pesticides as a risk factor for breast cancer. We investigated 177 cases of invasive breast cancer at the hospital, between May 1995 and July 1996, and 350 controls selected among female visitors at the same hospital. In addition to information obtained from interviews, blood samples were taken, to analyze residual amounts of organochlorine by gas chromatography using an electron capture detector. [1,1-Dichloro-2, 2-bis(p-chlorophenyl)ethylene] (DDE) was determined in sera of 457 women from a total of 493 participants who had serum samples available. Residues of hexachlorobenzene were found in 11 women only. No statistically significant association was found between breast cancer risk and serum level of DDE or history of exposure to pesticides. Serum levels of DDE (ng/ml) were similar in patients (median = 3.1, mean = 5.1) and controls (median = 3.1, mean = 4.8) (p = 0.93). The age-adjusted odds ratio of breast cancer for women in the upper quintile compared with those in the lowest quintile was 0.90 (95% confidence interval 0.47-1.73). When adjusted for other variables, the risk remained not statistically significant (upper quintile odds ratio = 0.79, 95% confidence interval 0.39-1.60). In our hands, exposure to organochlorinated pesticides measured by history or serum analysis was thus not a risk factor for breast cancer.     

Diet and premenopausal bilateral breast cancer: A case-control study

We investigated associations between diet and premenopausal bilateral breast cancer in a familial matched case-control study. We studied 140 cases from population-based registries in Los Angeles County (California) and Connecticut, and from the major hospitals in the southern parts of the Province of Quebec. Unaffected sisters of the cases served as matched controls (222 total). Dietary intake were assessed with a food frequency questionnaire. Total fat, monounsaturated fat, polyunsaturated fat, oleic acid, and linoleic acid intake was inversely associated with premenopausal bilateral breast cancer risk. Consumption of carbohydrates (and sweetened beverages) was associated with an increased risk. We observed no associations for dietary fiber, antioxidants, or major food groupings, but we did observe inverse associations for intake of low fat dairy products and tofu. These findings suggest that monounsaturated and polyunsaturated fats, as well as soy foods, might reduce the risk of premenopausal bilateral breast cancer.     

A case-control study of reproductive variables,alcohol, and smoking in premenopausal bilateral breast cancer

Summary The transforming growth factor-s are potent growth inhibitors of normal and transformed breast epithelial cells in culture. In vivo, these peptides modulate the development of the mouse mammary gland. Tissuespecific overexpression of mature TGF-1 in transgenic mice results in mammary gland atrophy and prevention of carcinogen-induced breast tumorigenesis. However, the inhibitory effect of endogenous or exogenous TGF-s on established tumor cells is less clear. Several published circumstantial and more direct data argue that, in some cases, the tumor cell TGF-s may contribute to the maintenance and/or progression of tumor cells in an intact host by modulating their interaction with host factors. This differential role of the TGF-s on mammary cells as determined by their normal or transformed phenotype as well as the biological and clinical implications of these data are discussed.Presented at the symposium "New Approaches in the Therapy of Breast Cancer", Georgetown University Medical Center, Washington DC, October 1994, generously supported by an education grant from Bristol-Myers Squibb.     

A case-control study of breast cancer and hormonal contraception in Costa Rica

By 1981, 11% of married women in Costa Rica ages 20-49 years had used depot-medroxyprogesterone acetate (DMPA) and 58% had used oral contraceptives (OCs). Since 1977, the Costa Rican Ministry of Health has maintained a nationwide cancer registry. These circumstances provided an opportunity for a population-based, case-control study of DMPA, OCs, and breast cancer in Costa Rica. Cases were 171 women ages 25-58 years with breast cancer diagnosed between 1982 and 1984; controls were 826 women randomly chosen during a nationwide household survey. Cases and controls were interviewed with the use of a standard questionnaire covering their reproductive and contraceptive histories. Logistic regression methods were used to adjust for confounding factors. While few cases or controls had ever used DMPA, DMPA users had an elevated relative risk (RR) estimate of breast cancer of 2.6 (95% confidence limits = 1.4-4.7) compared with never users. However, no dose-response relationship was found; even the group of women who had used DMPA for less than 1 year had an elevated RR estimate (RR = 2.3; 95% confidence limits = 1.0-5.1). In contrast, OC users had no elevation in RR compared with never users (RR = 1.2; 95% confidence limits = 0.8-1.8). The results of the DMPA analysis are inconclusive. Before decisions are made on whether to continue providing this effective contraceptive method, other ongoing studies will need to confirm of refute these findings.     

Population-based case-control study of CYP11A gene polymorphism and breast cancer risk.

The CYP11A gene encodes the cholesterol side-chain cleavage enzyme (P450scc) that catalyzes the first and rate-limiting step for the biosynthesis of sex hormones. A pentanucleotide repeat [(TAAAA)n] polymorphism in the 5' of the CYP11A gene has been reported to be related to the risk of polycystic ovary syndrome, an inherited endocrine disorder characterized by hyperandrogenemia. We investigated the association of this polymorphism with breast cancer risk in a population-based case-control study conducted among Chinese women in Shanghai. Genotype assays were completed for 1015 incident breast cancer cases and 1082 community controls. Three common alleles with 4, 6, or 8 TAAAA repeats were identified in the study population. The frequency of the 8 repeat allele was more common in cases (12.6%) than controls (8.5%) (odds ratio = 1.6, 95% confidence interval = 1.3-1.9; P < 0.0001). Compared to subjects who did not carry this allele, adjusted odds ratios were 1.5 (95% confidence interval = 1.2-1.9) and 2.9 (1.3-6.7) (P for trend, <0.001), respectively, for those who carried one and two copies of this allele. This positive association was observed in both pre- and postmenopausal women and all strata defined by major breast cancer risk factors, including years of menstruation, body mass index, and waist-to-hip ratio. The results from this study indicate that the TAAAA repeat polymorphism near the promoter region of the CYP11A gene may be an important susceptibility factor for breast cancer risk.