Occupational exposures and male breast cancer: A nested case-control study in the Nordic countries

A Rare Case of Remittent Male Invasive Ductal Carcinoma With New Metastasis After Incomplete Adjuvant Therapy

Breast cancer is a rare disease in men with many barriers to effective management such as limited research and treatment modalities. While the current standard of care utilizes mastectomy and axillary dissection with chemotherapy, clinicians must follow the female-staged breast cancer protocol, as there is no established regimen for men. In this case presentation, we report a 43-year-old male with a prior history of ER-positive invasive ductal carcinoma (IDC) who presented with a recurrent breast lesion. The patient had previously undergone left breast mastectomy with sentinel node biopsy with negative margins. The patient declined adjuvant chemotherapy and tamoxifen therapy after the initial dissection. Three years after the primary dissection, the patient presents with a breast lesion and metastasis to bilateral axillary lymph nodes, lungs, and spine. The diagnosis was supported by a right axillary biopsy which revealed an ER-positive and PR-positive lesion. We want to shed light on the importance of complete and thorough treatment of primary IDC in men while highlighting the implications of incomplete treatment. We hope that this clinical case will serve as a guide for physicians in promoting adjuvant treatments after primary tumor removal in male IDC.

Lifetime Exposure to Welding Fumes and Risk of Some Rare Cancers

We investigated the association between exposure to welding fumes and the risk of biliary tract, male breast, bone, and thymus cancer, as well as cancer of the small intestine, eye melanoma, and mycosis fungoides, among men in a European, multicenter case-control study. From 1995-1997, 644 cases and 1,959 control subjects from 7 countries were studied with respect to information on welding and potential confounders. We linked the welding histories of the participants with a measurement-based exposure matrix to calculate lifetime exposure to welding fumes. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models, conditional on country and 5-year age groups, and adjusted for education and relevant confounders. Regular welding was associated with an increased risk of cancer of the small intestine (OR = 2.30, 95% CI: 1.17, 4.50). Lifetime exposure to welding fumes above the median of exposed controls was associated with an increased risk of cancer of the small intestine (OR = 2.00, 95% CI: 1.07, 3.72) and male breast (OR = 2.07, 95% CI: 1.14, 3.77), and some elevation in risk was apparent for bone cancer (OR = 1.92, 95% CI: 0.85, 4.34) with increasing lifetime exposure to welding fumes. Welding fumes could contribute to an increased risk of some rare cancers.

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.

Male breast cancer: an update

Male breast cancer (MBC) is rare, accounting for less than 1% of all breast cancer but the incidence has increased worldwide. Risk factors include increased longevity, obesity, testicular diseases and tumours, and germline mutations of BRCA2. BRCA2 carriers have 80 times the risk of the general population. Men generally present with breast cancer at an older age compared with women. Histologically, MBC is often of grade 2, hormone receptor positive, HER2 negative, and no special type carcinoma although in situ and invasive papillary carcinomas are common. Reporting and staging are similar to female breast cancer. Metastatic lesions to the male breast do occur and should be differentiated from primary carcinomas. Until recently, MBC was thought to be similar to the usual ER positive post-menopausal female counterpart. However, advances in MBC research and trials have highlighted significant differences between the two. This review provides an up to date overview of the biology, genetics, and histology of MBC with comparison to female breast cancers and differential diagnosis from histological mimics.

Occupational exposure to specific organic solvents and risk of subtypes of breast cancer in a large population of Danish women, 1964-2016

OBJECTIVE

To explore associations between occupational exposure to four specific organic solvents, respectively, and female breast cancer, including subtypes.

METHODS

Using the Danish Cancer Registry, we identified 38 375 women under age 70 years with primary breast cancer. Five randomly selected breast-cancer-free controls per case matched on year of birth were retrieved from the Danish Civil Registration System . A nationwide pension fund was used to retrieve full employment history, and exposure to 1,1,1-trichloroethane, trichloroethylene (TCE), benzene and toluene was assessed using a job exposure matrix. ORs were estimated using conditional logistic regression with adjustment for reproductive factors and socioeconomic status.

RESULTS

Overall results indicated no noteworthy associations between the specific organic solvents and breast cancer before and after age 50 years, except for a small increased risk after age 50 in women exposed to TCE (OR=1.15, 95% CI: 0.97-1.36). After age 50 years, exposure to TCE was associated with a small increased risk in women with over 20 years of latency (OR=1.26, 95% CI: 1.02-1.56). Further, an increased risk of oestrogen receptor positive (ER+) tumours was also observed (OR=1.21, 95% CI: 1.01-1.47), and high cumulative exposure and longer latency also increased the risk of this subtype.

CONCLUSION

This study provides limited evidence supporting the association between occupational exposure to each of the four organic solvents and breast cancer. The risk of ER+ breast tumours after age 50 years may be increased in women with TCE exposure, and this possible association therefore needs further attention in future studies.

Rare cancers of unknown etiology: lessons learned from a European multi-center case-control study

Rare cancers together constitute one fourth of cancers. As some rare cancers are caused by occupational exposures, a systematic search for further associations might contribute to future prevention. We undertook a European, multi-center case–control study of occupational risks for cancers of small intestine, bone sarcoma, uveal melanoma, mycosis fungoides, thymus, male biliary tract and breast. Incident cases aged 35–69 years and sex-and age-matched population/colon cancer controls were interviewed, including a complete list of jobs. Associations between occupational exposure and cancer were assessed with unconditional logistic regression controlled for sex, age, country, and known confounders, and reported as odds ratios (OR) with 95% confidence intervals (CI). Interviewed were 1053 cases, 2062 population, and 1084 colon cancer controls. Male biliary tract cancer was associated with exposure to oils with polychlorinated biphenyls; OR 2.8 (95% CI 1.3–5.9); male breast cancer with exposure to trichloroethylene; OR 1.9 (95% CI 1.1–3.3); bone sarcoma with job as a carpenter/joiner; OR 4.3 (95% CI 1.7–10.5); and uveal melanoma with job as a welder/sheet metal worker; OR 1.95 (95% CI 1.08–3.52); and cook; OR 2.4 (95% CI 1.4–4.3). A confirmatory study of printers enhanced suspicion of 1,2-dichloropropane as a risk for biliary tract cancer. Results contributed to evidence for classification of welding and 1,2-dichloropronane as human carcinogens. However, despite efforts across nine countries, for some cancer sites only about 100 cases were interviewed. The Rare Cancer Study illustrated both the strengths and limitations of explorative studies for identification of etiological leads.

Trends of female and male breast cancer incidence at the global, regional, and national levels, 1990-2017

PURPOSE

Breast cancer is a major public health concern worldwide and shows significant heterogeneity between male and female. Knowing the global incidence landscape in both sexes is critical for the breast cancer prevention and the reduction in disease burden.

METHODS

We retrieved the incidence data of breast cancer in both sexes from the Global Burden of Disease 2017 database. Average annual percentage change was used to quantify the temporal trends of breast cancer incidence.

RESULTS

Between 1990 and 2017, the number of newly diagnosed female breast cancer (FBC) cases increased from 870.2 thousand to 1937.6 thousand, with the age-standardized incidence rate (ASR) significantly increased from 39.2/100,000 to 45.9/100,000. A total of 166 countries experienced a significant increase in FBC-ASR. The most pronounced increase was mainly found in developing countries. The decrease was mostly detected in several developed countries, such as the USA and the UK. Male breast cancer (MBC) is a rare carcinoma and has no evident cluster across the world. Worldwide, the number of newly diagnosed MBC cases increased from 8.5 thousand in 1990 to 23.1 thousand in 2017, with the ASR significantly increased from 0.46/100,000 to 0.61/100,000. A total of 123 countries showed a significant increasing trend in MBC-ASR.

CONCLUSIONS

Breast cancer incidence rates are increasing in most countries in both sexes, although the epidemiological features were not completely shared between FBC and MBC. More emphases should be placed on breast cancer primary prevention and the prevention strategies might need to be tailored for both FBC and MBC.

Incidence of male breast cancer in Scotland over a twenty-five-year period (1992-2017)

Male breast cancer (MBC) accounts for around 1% of all breast cancers diagnosed. There are inconsistent reports on the incidence of MBC which some propose may be rising. Here, for the first time, the incidence of MBC in Scotland over 25 years from 1992 to 2017 was examined through interrogating the Information Services Division Scotland database. Results showed MBC incidence rose with age, peaking in the 65-70 and 75-79 age groups. Both the total number and the age-adjusted incidence of MBC increased in Scotland since 1992. This rising trend was most clear in the North of Scotland. Interestingly a higher MBC incidence in some rural areas was also observed. Our findings emphasise the need for a better understanding of MBC risk factors so that improved prevention policies can be applied for patient benefit.

Male breast cancer: a neglected disease

Male breast cancer (MBC) is rare, tending to afflict sedentary men, with adolescent obesity being a risk factor. Men fare worse compared with matched females with breast cancer. The preponderance of ER+ve disease affects the molecular profile: most cases have luminal A tumors. Through male ignorance and risk-taking, delay is frequent and this lacuna needs addressing with health education. The major gene mutation responsible for MBC is BRCA2. Five single nucleotide polymorphisms (SNPs) are significantly and uniquely associated with MBC risk with two located in the 8q24.21 regions. Mastectomy is being gradually replaced by nipple-preserving surgery and radiotherapy but this trend could be expedited with neoadjuvant endocrine therapy. Significant advances will occur only after expansion of collaborative groups and this is a matter of pressing importance.