Trends and Age-Period-Cohort Effect on Incidence of Male Breast Cancer from 1980 to 2019 in Taiwan and the USA

Breast cancer mortality in Brazilian men: an age-period-cohort study

Introduction: Male breast cancer is a rare malignancy whose health impacts remain unknown, notably in countries like Brazil. The purpose of this article was to evaluate breast cancer mortality in Brazilian men by an age-period-cohort study. Methods: This ecological study evaluates the mortality of Brazilian men due to breast cancer using an age-period-cohort model. Data were sourced from the public, open-access Brazilian database DATASUS, available at https://datasus.saude.gov.br, covering the period from 1996 to 2021. Demographic data represent the total population of Brazilian males, while clinical data focus on patients whose cause of death was coded as 175 (ICD-9) or C50 (ICD-10). The age-period-cohort effects were analyzed following the classic model and its adaptations. The analysis was performed using R 4.4.0. Alpha® software. Results: It was noted an increasing mortality trend with aging, peaking in men over 80 years old. From 1996 to 2009, no statistically significant changes were observed in the hazard ratio (HR). However, from 2010 onward, a significant increase in HR was found, reaching a peak in 2020–2021 (HR 2.79634; 95%CI 2.37121–3.29770). A total of 34 birth cohorts (1919–2011) were analyzed. Cohorts from 1919–1964 and 1981–2011 did not show statistically significant results, while those from 1966–1979 exhibited a decreasing HR, with the lowest HR seen in the 1979 cohort (HR 0.91323; 95%CI 0.83545–0.99825). Conclusions: This study identifies a growing trend in male breast cancer mortality in Brazil, particularly after 2010, with variations across birth cohorts.

Adjuvant chemotherapy and survival in males aged 70 years or older with breast cancer: a population-based retrospective study

BACKGROUND

Male breast cancer constitutes a minority of breast cancer diagnoses, yet its incidence has been on the rise in recent decades. However, elderly male breast cancer patients have been inadequately represented in clinical trials, posing challenges in treatment decisions. This study seeks to clarify the efficacy of chemotherapy in this demographic and identify the population most likely to benefit from such intervention.

METHODS

We conducted a retrospective analysis using the Surveillance, Epidemiology, and End Results (SEER) database, encompassing a total of 1900 male breast cancer patients aged 70 years or older. Among them, 1652 were categorized in the no-chemotherapy group, while 248 were in the chemotherapy group. A multifactorial logistic regression model was employed to investigate the determinants influencing the administration of chemotherapy in elderly male breast cancer patients. Additionally, the multivariate Cox proportional hazards regression model was applied to identify factors associated with outcomes, with overall survival (OS) as the primary endpoint.

RESULTS

Multivariate logistic regression analysis revealed that grade, tumor size, and nodal status were robust predictors for elderly male breast cancer patients receiving chemotherapy. Furthermore, the multivariate analysis demonstrated that chemotherapy conferred benefits compared to the no-chemotherapy group (HR = 0.822, 95% CI: 0.682-0.991, p = 0.040). Stratified analyses indicated that individuals with N+, poorly/undifferentiated grade, and stage II/III disease could derive benefits from chemotherapy. Upon further investigation of progesterone receptor (PR) positive patients, it was found that only stage III patients experienced significant benefits from chemotherapy (HR = 0.571, 95% CI: 0.372-0.875, p = 0.010). Conversely, in PR negative patients, both stage II (HR = 0.201, 95% CI: 0.051-0.792, p = 0.022) and stage III patients (HR = 0.242, 95% CI: 0.060-0.972, p = 0.046) derived benefits from chemotherapy.

CONCLUSION

Adjuvant chemotherapy may benefit certain elderly male breast cancer patients, specifically those with positive lymph node status, poorly/undifferentiated grade, and PR-positive in stage III, as well as PR-negative expression in stage II/III. Given favorable physical tolerance, it is advisable not to hastily dismiss chemotherapy for these elderly male breast cancer patients.