Case-control study of occupational exposures and male breast cancer

Risk factors for male breast cancer

Male breast cancer (MBC) presents problems with identification of high-risk groups. Risk factors include hepatic dysfunction, high ambient working temperature, exposure to exhaust fumes and obesity, but none identify a group with a high absolute number of MBC cases. The two significant cohorts are BRCA2 mutation carriers and individuals with Klinefelter's syndrome (KS), responsible for up to 15% of cases. Since >90% of male tumours are ER+ve, endocrine intervention is logical with the likely agent being tamoxifen. In terms of an acceptable endocrine agent, compliance studies. Compliance studies indicate that men do not tolerate tamoxifen well because of side-effects. Although certain groups with an increased risk of MBC can be identified, the absolute number of cases is small so, at present, a meaningful prevention study is not an option.

Association of occupational heat exposure and colorectal cancer in the MCC-Spain study

OBJECTIVE

Heat exposure and heat stress/strain is a concern for many workers. There is increasing interest in potential chronic health effects of occupational heat exposure, including cancer risk. We examined potential associations of occupational heat exposure and colorectal cancer (CRC) risk in a large Spanish multi-case--control study.

METHODS

We analyzed data on 1198 histologically confirmed CRC cases and 2690 frequency-matched controls. The Spanish job-exposure matrix, MatEmEsp, was used to assign heat exposure estimates to the lifetime occupations of participants. Three exposure indices were assessed: ever versus never exposed, cumulative exposure and duration (years). We estimated odds ratios (OR) and 95% confidence intervals (CI) using unconditional logistic regression adjusting for potential confounders.

RESULTS

Overall, there was no association of ever, compared with never, occupational heat exposure and CRC (OR 1.09, 95% CI 0.92-1.29). There were also no associations observed according to categories of cumulative exposure or duration, and there was no evidence for a trend. There was no clear association of ever occupational heat exposure and CRC in analysis conducted among either men or women when analyzed separately. Positive associations were observed among women in the highest categories of cumulative exposure (OR 1.81, 95% CI 1.09-3.03) and duration (OR 2.89, 95% CI 1.50-5.59) as well as some evidence for a trend (P<0.05).

CONCLUSION

Overall, this study provides no clear evidence for an association between occupational heat exposure and CRC.

Occupational heat exposure and prostate cancer risk: A pooled analysis of case-control studies

BACKGROUND

Heat exposures occur in many occupations. Heat has been linked to key carcinogenic processes, however, evidence for associations with cancer risk is sparse. We examined potential associations between occupational heat exposure and prostate cancer risk in a multi-country study.

METHODS

We analysed a large, pooled dataset of 3142 histologically confirmed prostate cancer cases and 3512 frequency-matched controls from three countries: Canada, France, and Spain. Three exposure indices: ever exposure, lifetime cumulative exposure and duration of exposure, were developed using the Finnish Job-Exposure Matrix, FINJEM, applied to the lifetime occupational history of participants. We estimated odds ratios (ORs) and 95% confidence intervals (CIs), using conditional logistic regression models stratified by 5-year age groups and study, adjusting for potential confounders. Potential interactions with exposure to other occupational agents were also explored.

RESULTS

Overall, we found no association for ever occupational heat exposure (OR 0.97; 95% CI 0.87, 1.09), nor in the highest categories of lifetime cumulative exposure (OR 1.04; 95% CI 0.89, 1.23) or duration (OR 1.03; 95% CI 0.88, 1.22). When using only the Spanish case-control study and a Spanish Job Exposure Matrix (JEM), some weakly elevated ORs were observed.

CONCLUSIONS

Findings from this study provide no clear evidence for an association between occupational heat exposure and prostate cancer risk.

Male Breast Cancer: An Updated Review of Epidemiology, Clinicopathology, and Treatment

Male breast cancer (MaBC) is a rare clinical entity, which makes up approximately 1% of all breast cancers. However, the incidence of MaBC has been steadily increasing over the past few decades. The risk factors for MaBC include age, black race, family history of breast cancer, genetic mutations, liver cirrhosis, and testicular abnormalities. The majority of patients with MaBC present with painless lumps, and about half of the patients have at least one lymph node involved at the time of diagnosis. The treatment of MaBC models that of female breast cancer (FeBC), but this is mainly due to lack of prospective studies for MaBC patients. The treatment modality includes surgery, adjuvant radiation, endocrine therapy, and chemotherapy. However, there are some distinct features of MaBC, both clinically and molecularly, that may warrant a different clinical approach. Ongoing multinational effort is required, to conduct clinical trials for MaBC, or the inclusion of MaBC patients in FeBC trials, to help clinicians improve care for MaBC patients.

Occupational exposure to organic solvents and breast cancer risk: a systematic review and meta-analysis

Breast cancer is the most common cancer worldwide. Recent studies suggest that organic solvent exposure could be closely related to breast cancer, although the evidence remains controversial. Thus, we evaluated existing epidemiological evidence for the association between occupational solvent exposure and breast cancer. PubMed, Embase, and Cochrane Library were searched to identify published case-control and cohort studies that addressed occupational exposure to organic solvents and breast cancer, up to April, 2021. Meta-analyses using random-effects models were conducted to obtain the pooled odds ratios (OR) and 95% confidence intervals (CI) on the incidence of breast cancer in relation to occupational exposure. The pooled OR of breast cancer among workers exposed to organic solvents overall was 1.18 (95%CI, 1.11 ~ 1.25; I² = 76.3%; 24 studies), compared to those with no exposure. After stratification by menopause and study location, it was revealed that the association between occupational exposure to organic solvents and the risk of breast cancer in postmenopausal women (OR, 1.35; 95% CI, 1.09 ~ 1.67; I² = 73.4%; 7 studies) was significant, and there was also a clear association in workers in Europe (OR, 1.21; 95% CI, 1.12 ~ 1.32; I² = 82.9%; 13 studies). We observed a significant association between occupational exposure to organic solvents and breast cancer in both cohort and case-control studies.

Occupational Heat Exposure and Breast Cancer Risk in the MCC-Spain Study

BACKGROUND

Mechanisms linking occupational heat exposure with chronic diseases have been proposed. However, evidence on occupational heat exposure and cancer risk is limited.

METHODS

We evaluated occupational heat exposure and female breast cancer risk in a large Spanish case-control study. We enrolled 1,738 breast cancer cases and 1,910 frequency-matched population controls. A Spanish job-exposure matrix, MatEmEsp, was used to assign estimates of the proportion of workers exposed (P ≥ 25% for at least 1 year) and work time with heat stress (wet bulb globe temperature ISO 7243) for each occupation. We used three exposure indices: ever versus never exposed, lifetime cumulative exposure, and duration of exposure (years). We estimated ORs and 95% confidence intervals (CI), applying a lag period of 5 years and adjusting for potential confounders.

RESULTS

Ever occupational heat exposure was associated with a moderate but statistically significant higher risk of breast cancer (OR 1.22; 95% CI, 1.01-1.46), with significant trends across categories of lifetime cumulative exposure and duration (P _trend = 0.01 and 0.03, respectively). Stronger associations were found for hormone receptor-positive disease (OR ever exposure = 1.38; 95% CI, 1.12-1.67). We found no confounding effects from multiple other common occupational exposures; however, results attenuated with adjustment for occupational detergent exposure.

CONCLUSIONS

This study provides some evidence of an association between occupational heat exposure and female breast cancer risk.

IMPACT

Our results contribute substantially to the scientific literature. Further investigations are needed considering multiple occupational exposures.

Breast cancer risk by occupation and industry in women and men: Results from the Occupational Disease Surveillance System (ODSS)

BACKGROUND

The recently established Occupational Disease Surveillance System (ODSS) was used to examine breast cancer risk in women and men by occupation and industry.

METHODS

Ontario workers in the ODSS cohort (1983-2016) were followed up for breast cancer diagnosis through the Ontario Cancer Registry. Cox-proportional hazard models were used to calculate age-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

A total of 17 865 and 492 cases were identified in working women (W) and men (M), respectively. Elevated risks were observed in management (W: HR = 1.54, 95% CI = 1.40-1.70; M: HR = 2.79, 95% CI = 1.44-5.39), administrative/clerical (W: HR = 1.16, 95% CI = 1.11-1.21; M: HR = 1.45, 95% CI = 1.06-1.99), and teaching (W: HR = 1.54, 95% CI = 1.44-1.63; M: HR = 3.00, 95% CI = 1.49-6.03). Other elevated risks were observed in nursing/health, social sciences, and janitor/cleaning services for both genders.

CONCLUSIONS

Common occupational associations in both genders warrant investigation into job-related risk factors, such as sedentary behavior, shift work, ionizing radiation, and chemical exposures.

The Epidemiology of Male Breast Cancer

Male breast cancer is a rare disease, accounting for only 1% of breast cancer diagnoses in the USA. The current literature suggests that genetic factors including BRCA2 mutations, family history, age, androgen/estrogen imbalance, and environmental exposures may predispose to male breast cancer. In this manuscript, we will review known and possible risk factors for male breast cancer, as well as describe the clinical patterns of the disease.

Occupational exposure to magnetic fields and breast cancer among Canadian men

Occupational magnetic field (MF) exposure has been suggested as a risk factor for breast cancer in both men and women. Due to the rarity of this disease in men, most epidemiologic studies investigating this relationship have been limited by small sample sizes. Herein, associations of several measures of occupational MF exposure with breast cancer in men were investigated using data from the population-based case-control component of the Canadian National Enhanced Cancer Surveillance System. Lifetime job histories were provided by 115 cases and 570 controls. Average MF exposure of individual jobs was classified into three categories (<0.3, 0.3 to <0.6, or ≥0.6 μT) through expert blinded review of participant's lifetime occupational histories. The impact of highest average and cumulative MF exposure, as well as exposure duration and specific exposure-time windows, on cancer risk was examined using logistic regression. The proportion of cases (25%) with a highest average exposure of ≥0.3 μT was higher than among controls (22%). We found an elevated risk of breast cancer in men who were exposed to ≥0.6 μT (odds ratio [OR] = 1.80, 95% CI = 0.82-3.95) when compared to those with exposures <0.3 μT. Those exposed to occupational MF fields for at least 30 years had a nearly threefold increase in risk of breast cancer (OR = 2.77, 95% CI = 0.98-7.82) when compared to those with background levels of exposure. Findings for the other time-related MF variables were inconsistent. Our analysis, in one of the largest case-control studies of breast cancer in men conducted to date, provides limited support for the hypothesis that exposure to MF increases the risk breast cancer in men.

Male Breast Cancer

Male breast cancer (MBC) is a rare disease, accounting for less than 1% of all breast cancer diagnoses worldwide. Although breast carcinomas share certain characteristics in both genders, there are notable differences. Most studies on men with breast cancer are very small. Thus, most data on male breast cancer are derived from studies on females. However, when a number of these small studies are grouped together, we can learn more from them. This review emphasizes the incidence, etiology, clinical features, diagnosis, treatment, pathology, survival, and prognostic factors related to MBC.

Working environment and myeloproliferative neoplasm: A population-based case-control study following a cluster investigation

BACKGROUND

Occupational exposures, including those to polycyclic aromatic hydrocarbons (PAH), are suspected risk factors for myeloproliferative neoplasms (MPN).

METHODS

We investigated occupational exposures and MPN risk (54 cases and 472 controls) in a population-based case-control study in three rural Pennsylvania counties. Occupational histories, coded to SIC/SOC 1980, were linked to a previously created PAH job-exposure matrix. Odds ratios for industry (17 categories), occupation (26 categories), and PAH exposure were adjusted using logistic regression.

RESULTS

No industries or occupations were strongly or consistently associated with increased MPN risk. Analysis of employment duration found that being employed for 5 or more years in transportation, communications, and other public utilities was associated with MPN risk. There was no indication of an association with cumulative PAH exposure.

CONCLUSIONS

These few associations did not appear to have a common exposure. This exploratory study does not support the hypothesis that occupational exposure, including PAH, are strong risk factors for MPNs.

Hormone Therapy for Breast Cancer in Men

Breast cancer in men is rare, but its incidence is increasing, in keeping with the aging population. The majority of breast cancers in men are estrogen receptor positive. There is a paucity of clinical trials to inform practice, and much has been extrapolated from breast cancer in women. Hormone therapy represents the mainstay of adjuvant and palliative therapy but may have contraindications or poor tolerability. We review the evidence for choice of hormone therapy in both the adjuvant and palliative setting in breast cancer in men.

An update on male breast cancer and future directions for research and treatment

Male breast cancer is a rare disease for which treatment has been based on the evidence available from female breast cancer. The new genomic tools can better characterize the biology of breast cancer. It is hoping that these will help to clarify possible differences of breast cancer behaviour in male patients, which will have a major impact on treatment strategies and on the conduct of clinical trials in this setting. In this review we will summarize available information on epidemiology, risk factors for breast cancer in men, the new insights of the biology of this disease, current recommendations for treatment and insights for future research.

Male breast cancer: risk factors, biology, diagnosis, treatment, and survivorship

BACKGROUND

The causes, optimal treatments, and medical/psychosocial sequelae of breast cancer in men are poorly understood.

DESIGN

A systematic review of the English language literature was conducted to identify studies relevant to male breast cancer between 1987 and 2012 and including at least 20 patients. Searches were carried out on PubMed using the title terms 'male breast cancer' or 'male breast carcinoma'.

RESULTS

Relevant published data regarding risk factors, biological characteristics, presentation and prognosis, appropriate evaluation and treatment, and survivorship issues in male breast cancer patients are presented. BRCA2 mutations, age, conditions that alter the estrogen/androgen ratio, and radiation are proven risk factors. Disease biology is distinct in men, but diagnostic approaches and treatments for men are generally extrapolated from those in women due to inadequate research in men. Survivorship issues in men may include sexual and hormonal side-effects of endocrine therapies as well as unique psychosocial impacts of the disease.

CONCLUSION

Further research is needed to address gaps in knowledge pertaining to care of male breast cancer patients and survivors.

Invasive ductal breast carcinoma underneath a lipoma in a male patient

Male breast cancer is a rare malignancy and accounts for less than one percent of all cancers in men. The authors describe the case of a 76-year-old Caucasian man with invasive ductal breast carcinoma who presented with a common lipoma. This paper reviews the current literature on epidemiology, risk factors, etiology, different types of breast cancer, clinical presentation, imaging, diagnostic workup, and treatment.

Occupation and occupational exposure to endocrine disrupting chemicals in male breast cancer: a case-control study in Europe

OBJECTIVES

Male breast cancer is a rare disease of largely unknown aetiology. In addition to genetic and hormone-related risk factors, a large number of environmental chemicals are suspected of playing a role in breast cancer. The identification of occupations or occupational exposures associated with an increased incidence of breast cancer in men may help to identify mammary carcinogens in the environment.

METHODS

Occupational risk factors for male breast cancer were investigated in a multi-centre case-control study conducted in eight European countries which included 104 cases and 1901 controls. Lifetime work history was obtained during in-person interviews. Occupational exposures to endocrine disrupting chemicals (alkylphenolic compounds, phthalates, polychlorinated biphenyls and dioxins) were assessed on a case-by-case basis using expert judgement.

RESULTS

Male breast cancer incidence was particularly increased in motor vehicle mechanics (OR 2.1, 95% CI 1.0 to 4.4) with a dose-effect relationship with duration of employment. It was also increased in paper makers and painters, forestry and logging workers, health and social workers, and furniture manufacture workers. The OR for exposure to alkylphenolic compounds above the median was 3.8 (95% CI 1.5 to 9.5). This association persisted after adjustment for occupational exposures to other environmental oestrogens.

CONCLUSION

These findings suggest that some environmental chemicals are possible mammary carcinogens. Petrol, organic petroleum solvents or polycyclic aromatic hydrocarbons are suspect because of the consistent elevated risk of male breast cancer observed in motor vehicle mechanics. Endocrine disruptors such as alkylphenolic compounds may play a role in breast cancer.

A male patient from the West Indies with invasive ductal carcinoma in the right breast: a case report and literature review

BACKGROUND

Men with breast carcinoma have a poor prognosis, especially in the younger age group (30-40 years of age), because most breast enlargements in young men are dismissed as gynecomastia, resulting in an unnecessary delay in treatment.

OBJECTIVE

We describe the case of a young male patient with invasive ductal breast carcinoma.

CASE SUMMARY

In November 2005, a 30-year-old Afro-Caribbean man presented at St. Clair Medical Centre in Port of Spain, Trinidad, with a painless lump in the right breast. Diagnostic findings revealed that the patient had stage II invasive ductal carcinoma, for which he underwent a mastectomy with total axillary clearance.

CONCLUSION

Surgeons investigating unilateral breast swellings in young males should not dismiss them simply as gynecomastia, and should be wary of cancer.

Invasive Lobular Carcinoma of the Male Breast: A Rare Histology in an Uncommon Disease

SUMMARY: BACKGROUND: Breast cancer in men is an uncommon disease. Nearly all cases of male breast cancer originate in the terminal ductulolobular unit, with exceedingly rare reports of lobular carcinoma in men. Invasive lobular cancer is found in no more than 1-2% of male breast cancer cases. Most of what is known about this disease is in the form of approximately 30 case reports in the literature. CASE REPORT: We report the case of a 52-year-old man who presented at our institution with a lump in his left breast. Ultrasound-guided biopsy revealed an invasive lobular cancer. The rare histological type was confirmed by the result of the histological examination of the mastectomy specimen. The treatment was completed by dose dense chemotherapy, radiation, and endocrine therapy. CONCLUSION: Even though lobular structures are quite infrequent in the normal male, sporadic cases of invasive lobular breast cancer have been described. A short overview will be given in this case report.

Prospective evaluation of risk factors for male breast cancer

Most risk factors for male breast cancer have been derived from retrospective studies that may reflect selective recall. In the prospective National Institutes of Health-AARP Diet and Health Study, we studied 324 920 men, among whom 121 developed breast cancer. Men who reported a first-degree relative with breast cancer had an increased risk of breast cancer (relative risk [RR] = 1.92, 95% confidence interval [CI] = 1.19 to 3.09). Among the medical conditions examined, a new finding emerged regarding increased male breast cancer risk associated with a history of a bone fracture (RR = 2.20, 95% CI = 1.24 to 3.91). Obesity was positively related to risk (RR = 1.79, 95% CI = 1.10 to 2.91, for body mass indices of >or=30 vs <25 kg/m2) and physical activity inversely related, even after adjustment for body mass index. Smokers were at somewhat elevated risk, although trends with smoking characteristics were inconsistent. Alcohol consumption was not related to risk. The identified risk factors show some commonalities with female breast cancer and indicate the importance of hormonal mechanisms. Differences in risk factors may reflect unique mechanisms associated with androgens and their ratio to bioavailable estrogens.

What makes a man a man? The lived experience of male breast cancer

Male breast cancer is a rare condition with scant research into its psychosocial impact. This phenomenologic study sought to elicit its lived experience. Following analysis of interview data, 4 key themes emerged: Living with male breast cancer, concealment as a strategy for managing the diagnosis, a contested masculinity, interacting with health services. Male breast cancer constitutes a unique lived experience for men that is unparalleled in other disease profiles. The idea of living with a feminized illness was very distressing and stigmatizing for some men. Furthermore, treatment resulted in a profound change to the concept of their embodied selves and constituted a significant change to body image and sexuality. This was reinforced in participants who experienced erectile dysfunction related to tamoxifen therapy. Sadly, some health professionals were unable to offer specific psychosocial support, and participants felt marginalized from the potential benefits of the treatment environment. However, participants adapted to the illness by reasserting and renegotiating masculinity and finding ways to accommodate life with a stigmatizing condition and an altered body image.

Male breast cancer: a review of clinical management

AIMS

Male breast cancer incidence is 1% of all breast cancers and is increasing. We aim to present an overview of male breast cancer with particular emphasis on clinical management.

METHODS

Studies were identified by an online search of literature in the MEDLINE database till June 2006 followed by an extensive review of bibliographies.

RESULTS

Increased risk factors include genetic predisposition as in BRCA2 families; testicular dysfunction due to chromosomal abnormality such as Klinefelter's syndrome or environmental factors such as chronic heat exposure and radiation. Clinical assessment with biopsy is the hallmark of diagnosis. Earlier presentations are becoming commoner but there are wide geographical differences. Surgical treatment involves simple or modified radical mastectomy along with surgical assessment of the axilla, either via sentinel node biopsy in clinically node-negative disease or axillary sampling/clearance in node-positive disease. Reconstructions for restoring body image have been recently reported. Indications for adjuvant therapies are similar to that in women. For metastatic disease, tamoxifen is still the mainstay for oestrogen receptor positive disease. For oestrogen receptor negative disease, doxorubicin based chemotherapy regimens are used. In addition, the oft neglected psychological aspects of men having a "cancer of women" are increasingly being recognised.

CONCLUSIONS

There is, thus, need for further increasing awareness among men to reduce stigma associated with presentation of symptoms related to breast. This should be in addition to stressing to clinicians the ways of earlier detection and tailor-made "gender oriented" treatment of breast cancer in men.

Male breast cancer--an andrological disease: risk factors and diagnosis

Gynaecomastia, the enlargement of the male breast, is considered as an andrological disease. To date, a review on male breast cancer (MBC) has not been published in an andrological journal. The papers underlying this review were published from authors of different institutions: Clinical Genetics, Dermatology, Gynaecology, Internal Medicine, Oncology, Pathology, Psychiatry, Radiology and Surgery. MBC accounts for approximately 1% of breast cancer patients. A total of 182 men died of breast cancer in 1999, in Germany. In the US, 1500 new cases per year occur. MBC accounts for <5% of surgically removed breast lumps. Diseases with increased oestrogen action increase the risk of MBC. Mutations of distinct genes are estimated to account for up to roughly 10% of MBC. BRCA1 and BRCA2 gene mutations are responsible for approximately 80% of the families with hereditary breast cancer. The diagnosis of MBC is not possible without histological examination. Different diagnostic procedures such as clinical diagnosis, sonography, mammography, fine-needle biopsy and core needle facilitate the decision whether a biopsy is necessary.

Epidemiology of Male Breast Cancer

Breast cancer in men is a rare disease, accounting for ∼1% of all breast cancer cases. Although the epidemiologic literature regarding female breast cancer is extensive, relatively little is known about the etiology of male breast cancer (MBC). This review is intended to summarize the existing body of evidence on genetic and epidemiologic risk factors for breast cancer in men. Overall, the epidemiology of MBC presents similarities with the epidemiology of female breast cancer. Major genetic factors associated with an increased risk of breast cancer for men include BRCA2 mutations, which are believed to account for the majority of inherited breast cancer in men, Klinefelter syndrome, and a positive family history. Suspected genetic factors include AR gene mutations, CYP17 polymorphism, Cowden syndrome, and CHEK2. Epidemiologic risk factors for MBC include disorders relating to hormonal imbalances, such as obesity, testicular disorders (e.g., cryptorchidism, mumps orchitis, and orchiectomy), and radiation exposure. Suspected epidemiologic risk factors include prostate cancer,prostate cancer treatment, gynecomastia, occupational exposures (e.g., electromagnetic fields, polycyclic aromatic hydrocarbons, and high temperatures), dietary factors (e.g., meat intake and fruit and vegetable consumption), and alcohol intake.

A gene-environment interaction between occupation and BRCA1/BRCA2 mutations in male breast cancer?

The association of male breast cancer (MBC) with a positive breast cancer (BC) family history and with BRCA1/2 germ-line mutations points to a genetic component; a relationship with occupation has also been reported. Recently, we identified pathogenetic BRCA1/2 mutations in a population-based series of Italian MBC patients: here in, we investigated interactions between a carrier status for BRCA1/2 mutations and occupation using a case-case design and estimating case-only odds ratios (CORs). Truck-driving was the most frequent occupation (3/4 BRCA-related cases and 2/19 unrelated cases). An interaction between carrier status and working as a truck-driver emerged, when we classified MBC cases as "ever/never-held" this job title (COR 25.5; 95% Confidence Limits (CL): 1.1-1,412.5) or according to truck-driving as the "longest-held" work (COR 54.0; 95% CL: 1.6-2,997.5). The possible modifying effect on MBC risk in subjects carrying BRCA1/2 germ-line mutations of an occupation characterised by exposure to chemicals such as polycyclic aromatic hydrocarbons (PAH) that are capable of inducing DNA damage, may provide clues to the role of environmental exposures in modifying BC risk in mutation carriers in both genders.

Mortality of mental disorders in relation to potential pesticide exposure

Some studies have suggested a role of pesticide exposure in the development of neurobehavioral disorders. This case-control study examined the association between mortality from mental disorders and occupational exposure to pesticides. The study population consisted of 7756 deaths and 330,452 eligible controls identified from US death certificate files for the years 1988 through 1992. Exposure assignment was based on job title reported on the death certificates. Employment in jobs potentially involving pesticide exposure was weakly associated with the risk of death from mental disorders (odds ratio [OR] = 1.46; 95% confidence interval (95% CI) = 1.33-1.60). This association was stronger among women (OR = 2.65; 95% CI = 1.89-3.71), in particular for deaths from neurotic disorders (OR = 4.32; 95% CI = 2.44-7.64). These results must be interpreted with caution, however, because the impact of social and work-related factors other than pesticide exposure is not known.

Risk factors for male breast cancer in Canada, 1994-1998

Relatively little attention has been paid to the aetiology of male breast cancer and the current understanding of female breast cancer, primarily related to reproductive events, cannot be readily transferred to understanding the cancer in males. However, since male breast cancer occurs in the absence of factors related to childbearing and menstruation, its aetiology may provide special insights into the causes of breast cancer in women. We examined lifestyle risk factors for male breast cancer as part of a Canadian, multi-site, population-based, case-control study. Eighty-one newly diagnosed, histologically confirmed cases and 1905 male controls aged 42-74 were analysed using unconditional logistic regression. Increased risks were found for men with a mother or sister with breast cancer (adjusted odds ratio (OR) 3.65, 95% confidence interval (95% CI) 1.62-8.19). Higher physical activity levels (moderate, and strenuous recreational plus occupational) were associated with a decreased risk of male breast cancer (highest quartile, adjusted OR 0.48, 95% CI 0.26-0.91). Similarly, higher risks were associated with higher weight 2 years before interview (2.19, 95% CI 1.08-4.43), maximum weight (OR 2.66) and higher body mass index (OR 1.60). Higher vegetable consumption and coffee consumption were associated with decreased risk, whereas higher beta-carotene, vitamin E and calcium supplementation were associated with statistically significant increased risk. The small number of cases and multiple comparisons preclude strong conclusions, but our study is consistent with studies suggesting obesity and family history increase risk, and physical activity decreases risk of breast cancer.

On the rumors about the silent spring. Review of the scientific evidence linking occupational and environmental pesticide exposure to endocrine disruption health effects

Occupational exposure to some pesticides, and particularly DBCP and chlordecone, may adversely affect male fertility. However, apart from the therapeutic use of diethylstilbestrol, the threat to human reproduction posed by "endocrine disrupting" environmental contaminants has not been supported by epidemiological evidence thus far. As it concerns other endocrine effects described in experimental animals, only thyroid inhibition following occupational exposure to amitrole and mancozeb has been confirmed in humans. Cancer of the breast, endometrium, ovary, prostate, testis, and thyroid are hormone-dependent, which fostered research on the potential risk associated with occupational and environmental exposure to the so-called endocrine-disrupting pesticides. The most recent studies have ruled out the hypothesis of DDT derivatives as responsible for excess risks of cancer of the reproductive organs. Still, we cannot exclude a role for high level exposure to o,p'-DDE, particularly in post-menopausal ER+ breast cancer. On the other hand, other organochlorine pesticides and triazine herbicides require further investigation for a possible etiologic role in some hormone-dependent cancers.

Epidemiology and aetiological factors of male breast cancer: a ten years retrospective study in eastern Turkey

The aim of this study was to assess the epidemiological and aetiological factors of male breast carcinoma in eastern Turkey. For this purpose we evaluated breast carcinoma patients admitted to our regional hospital from 1990 to 2000. A total of 196 patients were admitted during that time, 11 of whom were male (5%). The average age at presentation was 60.7 +/- 7.5. Infiltrating ductal carcinoma was the most frequent histopathological type; lobular carcinoma was detected in only one of our cases. Right-sided male breast carcinoma was seen in 7 of 11 cases, left-sided in four cases. We detected gynaecomastia in two patients. Other factors were excessive alcohol consumption for 35 years in one patient, family history in one patient and exposure to electromagnetic fields (EMFs) and light at night in four patients. We demonstrated no risk factor in the other three cases. Of the patients in our study, the youngest was 45 years old--the patient with post-pubertal gynaecomastia. The overall rate of male breast carcinoma seen among people who had worked for the Turkish Institution of Electricity in eastern Turkey was 0.3%. In our study we demonstrated a close relation between exposure to EMFs and light at night and male breast carcinoma in eastern Turkey. We also supposed that not only exposure to EMFs but also the duration of the exposure could affect the risk of development of male breast carcinoma.

Male breast neoplasia in association with selective serotonin re-uptake inhibitor therapy: a report of three cases

Male breast cancer is a rare condition with very poorly understood risk factors. We report three cases of men with malignant and pre-malignant breast disease who had all been prescribed selective serotonin re-uptake inhibitors (SSRIs) for depression. Concerns about an association between this group of drugs and breast cancer in women have been previously raised and experimental evidence has suggested that these drugs could influence regulation of cellular proliferation acting through internal cellular messengers. Risk factors for the development of breast cancer are likely to be multifactorial, possibly more so in women given the complex physiological changes that occur in the female breast. Whilst the cases we report are anecdotal and other risk factors may be present, we suggest that assessment of any possible contribution that SSRI therapy may make to the development of breast neoplasia may be more easily assessed in a male population.

Breast cancer, occupation, and exposure to electromagnetic fields among Swedish men

BACKGROUND

Investigations of breast cancer among men may provide clues for environmental and occupational risk factors that may be difficult to study in women, because of confounding or effect modification from reproductive female characteristics. The objective was to estimate occupation-specific risks of male breast cancer and to assess the effect of occupational exposure to extremely low-frequency magnetic fields (ELFMF).

METHODS

Standardized incidence ratios were computed for the period 1971-1989 among Swedish men who were 25-59 years of age at start of follow-up and gainfully employed in 1970. Log-linear Poisson models were fitted to adjust for geographical area. A job exposure matrix was used to classify occupational ELFMF exposure.

RESULTS

A marked and consistent excess risk was found for machinery repairers. Increased relative risks based on few cases were also noted for librarians/archivists/curators, bank employees, non-specified clerical workers, metal processing workers, tanners/fur dressers, policemen, and custom surveillance officials. The relative risk among subjects with an estimated ELFMF exposure above the first quartile (0.12 microT) was 1.31 (95% confidence interval = 0.94-1.81), without a clear exposure-response pattern. Indications of an exposure-response relationship were found in workers with intermittent ELFMF exposure.

CONCLUSIONS

The findings give no clear evidence for an etiological role of ELFMF in the development of breast cancer in men, but suggest that large variations in exposure over the work-day may be associated with an increased risk.

Elevated risk for male breast cancer after occupational exposure to gasoline and vehicular combustion products

BACKGROUND

Automotive gasoline contains benzene, 1,3-butadiene, 1, 2-dibromoethane and 1,2-dichloroethane, and the combustion products include certain polycyclic aromatic hydrocarbons, all of which have shown mammary gland carcinogenicity in long-term bioassays. It is the aim of this paper to investigate whether men occupationally exposed to gasoline and its combustion products have an elevated risk of breast cancer.

METHODS

A nationwide register based case control study on male breast cancer morbidity was established among members of a pension fund, compulsory for all employees. Employment histories were reconstructed for each of 230 cases and 12,880 control subjects based on computerized records. The odds ratios, adjusted for socioeconomic status, were estimated by conditional logistic regression analysis.

RESULTS

When a lag time of at least 10 years was included, the odds ratio for breast cancer among men with over three months of employment in trades with potential exposure to gasoline and combustion products was 2.5 (95% confidence interval: 1.3-4.5). Among men younger than 40 years at the time of first employment, the odds ratio was 5.4 (2.4-11.9).

CONCLUSIONS

This study supports the hypothesis that occupational exposure to gasoline vapors and combustion products may play a role in the causation of male breast cancer. This hypothesis warrants further evaluation particularly in women.

Effect of 13 week magnetic field exposures on DMBA-initiated mammary gland carcinomas in female Sprague-Dawley rats

Several studies suggest that exposure to 50 Hz magnetic fields may promote chemically induced breast cancer in rats. Groups of 100 female Sprague-Dawley rats were initiated with four weekly 5 mg gavage doses of 7,12-dimethylbenz[a]anthracene (DMBA) starting at 50 days of age. After the first weekly DMBA administration, exposure to ambient fields (sham exposed), 50 Hz magnetic fields at either 1 or 5 G field intensity or 60 Hz fields at 1 G for 18.5 h/day, 7 days/week was initiated. Exposure continued for 13 weeks. A vehicle control group without DMBA was included. In a second study, using lower doses of DMBA, groups of 100 female Sprague-Dawley rats were initiated with four weekly doses of 2 mg of DMBA starting at 50 days of age followed, after the first weekly DMBA administration, by exposure to ambient fields (sham exposed) or 50 Hz magnetic fields at either 1 or 5 G field intensity for 18.5 h/day, 7 days/week for 13 weeks. Rats were weighed and palpated weekly for the presence of tumors. There was no effect of magnetic field exposure on body weight gains or on the time of appearance of mammary tumors in either study. At the end of 13 weeks, the animals were killed and the mammary tumors counted and measured. Mammary gland masses found grossly were examined histologically. In the first 13 week study, the mammary gland carcinoma incidences were 92, 86, 96 and 96% for the DMBA controls, 1 G, 50 Hz, 5 G, 50 Hz and 1 G, 60 Hz groups, respectively. The total numbers of carcinomas were 691, 528 (P < 0. 05, decrease), 561 and 692 for the DMBA controls, 1 G, 50 Hz, 5 G, 50 Hz and 1 G, 60 Hz groups, respectively. In study 2, the mammary gland carcinoma incidences were 43, 48 and 38% for the DMBA controls, 1 G, 50 Hz and 5 G, 50 Hz groups, respectively. The total numbers of carcinomas were 102, 90 and 79 for the DMBA controls, 1 G, 50 Hz and 5 G, 50 Hz groups, respectively. There was no effect of magnetic field exposure on tumor size either by in-life palpation or by measurement at necropsy in either study. There was no evidence that 50 or 60 Hz magnetic fields promoted breast cancer in these studies in female rats. These studies do not support the hypothesis that magnetic field exposure promotes breast cancer in this DMBA rat model.

Occupational risk factors for cancer of the central nervous system (CNS) among US women

BACKGROUND

In a recent report, we found an elevated risk of cancer of the central nervous system (CNS) in several occupations and industries, and a modest association with exposure to solvents and to contact with the public.

METHODS

To further explore the occupational risk of CNS cancer among women, we extended the analysis of the previous death certificate-based case-control study, including 12,980 female cases (ICD-9 codes 191 and 192) in 24 US states in 1984-1992 and 51,920 female controls who died from diseases other than malignancies and neurological disorders. We applied newly designed job-exposure matrices for 11 occupational hazards, previously reported as brain cancer risk factors, to the occupation and industry codes in the death certificates. We also conducted a separate analysis of 161 meningioma cases (ICD-9 codes 192.1 and 192.3), a tumor more frequent among women, particularly in the postmenopausal age group.

RESULTS

Overall, CNS cancer risk showed a 20-30% increase among women exposed to electromagnetic fields (EMF), methylene chloride, insecticides and fungicides, and contact with the public. Risk for meningioma was elevated among women exposed to lead (OR = 1.9; 95% CI 1.0, 3.9). CNS cancer did not show a clear pattern of risk increase by probability and intensity of exposure to any of the explored risk factors. Cross-classification by probability and intensity of exposure did not reveal any significant trend. Cases were too few to explore trends of meningioma by probability and intensity of exposure to lead.

CONCLUSIONS

We did not find evidence of a strong contribution of 11 occupational hazards to the etiology of CNS cancer. However, limitations of the occupational information might have reduced our ability to detect clear patterns of risk.