Introduction Male (BC) is rare, accounting for approximately 1% of all BC and about 1% of cancers occurring in men worldwide [ 1 – 3 ]. Although uncommon, it’s incidence has shown a gradual increase over recent decades, with global estimates indicating an approximate 26% rise [ 4 ]. In high-income countries such as the United States,thousands new cases are diagnosed annually, whereas in Sub-Saharan Africa (SSA), the proportional burden appears higher, with some reports suggesting an incidence of up to 15% [ 1 ].
The observed regional variation has been linked to multiple factors, including awareness, early detection, and improved diagnostic access are critical interventions for both men and women [ 5 ].. In Tanzania, male BC represents about 6% of all breast cancer cases [ 6 ]. Similar to other SSA countries, late presentation, limited awareness, sociocultural beliefs, and the scarcity of specialized oncology services contribute to delayed diagnosis and poorer survival outcomes compared to high-income settings [ 7 ].
Importantly, survival data specific to men with breast cancer in Tanzania remain scarce, limiting evidence-based planning of services for this population. Many patients first seek care from traditional healers, leading to prolonged symptom duration before medical evaluation. Consequently, advanced disease (stage III–IV) at presentation is common [ 8 , 9 ].
Despite sharing similarities with female BC, male differ in several important aspects. Men are typically diagnosed 5–10 years later than women, and they exhibit distinct hormonal and genetic profiles, including a higher likelihood of oestrogen receptor positivity and increased prevalence of BRCA2 mutations [ 10 ]. The small volume of male breast tissue also facilitates earlier extension into surrounding structures, accelerating disease progression [ 3 ].
Histologically, invasive ductal carcinoma predominates, whereas lobular carcinoma is relatively rare due to the absence of breast lobules in men [ 3 ]. Although treatment recommendations for men are largely extrapolated from female BC guidelines, growing evidence suggests biological and clinical differences warranting dedicated research [ 11 ]. In low-resource settings, limited access to timely diagnostic services, radiotherapy, hormonal therapy, and multidisciplinary care further complicates management and may negatively influence survival [ 12 ].
Therefore, the primary objective of this study was to estimate two-year overall survival among men diagnosed with breast cancer at KCMC. Secondary objectives were to describe clinicopathological characteristics and to identify patient-, tumors-, and health-system–related predictors of survival. We hypothesized that advanced stage at diagnosis, older age, and delays in diagnostic and therapeutic processes would be associated with poorer survival [ 13 , 14 ].
Materials and methods Study design and setting This was a retrospective hospital-based cohort study conducted at KCMC, a tertiary referral and teaching hospital in Northern Tanzania. KCMC provides comprehensive cancer care services, including diagnostic imaging, pathology, surgery, and systemic therapy. Radiotherapy services are not available on-site and require referral to external centres, which may introduce treatment delays.
Study population The study included all male patients with histologically confirmed primary BC treated at KCMC between January 2016 and December 2022. Data for this study were collected from August 19, 2024 to October 30, 2024. Patients with secondary breast cancer were excluded.
Follow-up information was obtained from the hospital’s cancer registry and patient records. Histopathological review Given the rarity of invasive lobular carcinoma in males, all cases initially diagnosed as invasive lobular carcinoma underwent an independent histopathological review by a board-certified senior anatomical pathologist (co-author) with extensive experience in breast pathology. The original hematoxylin and eosin (H&E) slides were re-examined to verify the diagnosis based on established histomorphological criteria.
The diagnoses were confirmed following this independent expert review before inclusion in the final analysis. Variables and definitions The primary outcome variable was two-year OS , defined as the time from diagnosis to death from any cause or last documented follow-up within the two-year period. Cause-specific mortality data were not consistently available; therefore, all-cause mortality was used, which may overestimate cancer-related deaths, particularly in older patients.
Independent variables included: sociodemographic factors, clinical characteristics, pathological features, and treatment-related variables. Diagnostic delay was defined as waiting more than two weeks for histopathological results, and treatment delay was defined as surgery performed more than six weeks after diagnosis. Data collection and management Data were collected using a structured extraction tool designed for this study.
Patient records, pathology reports, and the electronic hospital management system (EHMS) were reviewed. All information was coded and anonymized to maintain confidentiality prior to analysis. Missing data, particularly for nodal status and molecular subtype, were documented and reported descriptively.
Statistical analysis Data were analysed using SPSS version 25. Kaplan–Meier methods estimated two-year overall survival, and log-rank tests compared survival distributions. Variables were included in multivariable Cox regression based on clinical relevance and statistical significance in univariate analysis (p < 0.05).
Adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) were reported. Proportional hazards assumptions were assessed graphically and found to be acceptable.Missing data were handled using multiple imputation by chained equations (MICE) under the assumption that data were Missing at Random (MAR). Ethical considerations Ethical approval for this study was granted by the KCMC University Research Ethics Committee on 13 th , August, 2024, (Ref.
No. PG 34/2024). The consent to participate in this study was waived by the ethics committee of our institution.
Permission to access patient records was obtained from relevant hospital authorities. Although the authors had access to information that could identify individual participants during or after data collection, however, all data presented in this study were handled confidentially and used solely for research purposes. Results Sociodemographic characteristics Among 55 patients with histologically confirmed male breast cancer treated at KCMC between January 2016 and December 2022, the mean age at diagnosis was 62.2 years (SD ± 14.3), with the majority aged 50–70 years (54.6%).
Most patients were married (92.7%), predominantly self-employed (70.9%), and over half resided in rural areas (54.6%). Regarding social and clinical risk characteristics, 34.6% reported a history of smoking and 43.6% alcohol use. More than half of patients paid for healthcare out-of-pocket (58.2%), while 41.8% had health insurance coverage.
(Refer to Table 1 ) 10.1371/journal.pone.0361615.t001 Table 1 Sociodemographic characteristics of male breast cancer patients (N = 55). Characteristic Category N % Age (years) <50 10 18.2 50–70 30 54.6 >70 15 27.2 Mean ± SD 62.2 ± 14.3 Marital status Single 3 5.5 Married 51 92.7 Divorced 1 1.8 Education level Primary/None 19 34.5 Secondary 20 36.4 Higher 16 29.1 Employment Employed 11 20.0 Self-employed 39 70.9 Unemployed 5 9.1 Residence Rural 30 54.5 Urban 25 45.5 Smoking history No 36 65.5 Yes 19 34.5 Alcohol use No 31 56.4 Yes 24 43.6 Health insurance Insured 23 41.8 Cash payment 32 58.2 Clinical characteristics Among the 55 patients, 67.27% presented with symptoms lasting more than six months before diagnosis, indicating delayed presentation. Most patients had unilateral breast involvement, with the left breast slightly more affected (52.7%).
A family history of breast or ovarian cancer was reported in 14.6% of cases, while 47.3% had comorbidities, mainly hypertension and diabetes mellitus. Regarding tumour characteristics, 45.5% had positive lymph node involvement, although nodal status was undocumented in 40% of cases. Most patients presented with advanced disease, with 30.9% diagnosed at stage III and 21.8% at stage IV, while distant metastasis was present in 21.8% of patients.
(Refer to Table 2 ) 10.1371/journal.pone.0361615.t002 Table 2 Clinical characteristics at diagnosis (N = 55). Characteristic Category n % Concurrent malignancy No 54 98.2 Yes (prostate) 1 1.8 Family history of BC/OC No 47 85.5 Yes 8 14.5 BMI Underweight 9 16.4 Normal 19 34.5 Overweight 20 36.4 Obese 7 12.7 Symptom duration ≤6 months 18 32.7 >6 months 37 67.3 Breast side Left 29 52.7 Right 26 47.3 Laterality Unilateral 55 100 Comorbidities None 29 52.7 ≥1 comorbidity 26 47.3 Regional nodes Negative 8 14.5 Positive 22 45.5 Not documented 25 40.0 TNM stage I 10 18.2 II 16 29.1 III 17 30.9 IV 12 21.8 Distant metastasis No 43 78.2 Yes 12 21.8 Pathological characteristics The predominant histological type was invasive ductal carcinoma (85.5%), followed by invasive lobular carcinoma (14.5%). Most patients (81.8%) received their diagnostic results within two weeks.
Tumour grading showed that Grade 3 tumours were most common (34.6%), followed by Grade 2 (27.3%). Luminal B was the most frequently identified molecular subtype (23.6%), although molecular classification was unavailable for 45.5% of patients. (Refer to Table 3 ).
10.1371/journal.pone.0361615.t003 Table 3 Pathological characteristics (N = 55). Characteristic Category n % Histological type Invasive ductal carcinoma 47 85.5 Invasive lobular carcinoma 8 14.5 Time to pathology report ≤2 weeks 45 81.8 >2 weeks 10 18.2 Nottingham grade Grade I 8 14.6 Grade II 15 27.3 Grade III 19 34.5 Unknown 13 23.6 Molecular subtype Luminal A 8 14.6 Luminal B 13 23.6 HER2-positive 5 9.1 Triple negative 4 7.3 Unknown 25 45.4 Treatment modalities Among the 55 male breast cancer patients, 60% underwent surgery, mainly modified radical mastectomy (84.9%). Chemotherapy was administered to 47.3%, with most receiving adjuvant therapy (65.4%), while delays in initiation beyond 12 weeks occurred among 58.8% of those receiving adjuvant chemotherapy.
Radiotherapy was rarely utilized (18.5%), and all cases received it as adjuvant treatment. Hormonotherapy was received by 30.9% of patients, with the majority initiated promptly after indication. ( Table 4 ) 10.1371/journal.pone.0361615.t004 Table 4 Treatment modalities and timelines (N = 55).
Treatment Category n % Surgery No 22 40.0 Yes 33 60.0 Surgical approach (n = 33) Lumpectomy 5 15.2 Modified radical mastectomy 28 84.8 Time to surgery ≤6 weeks 21 63.6 >6 weeks 12 36.4 Chemotherapy No 29 52.7 Yes 26 47.3 Chemotherapy intent (n = 26) Adjuvant 17 65.4 Neoadjuvant 9 34.6 Time to adjuvant CT (n = 17) 4–12 weeks 7 41.2 >12 weeks 10 58.8 Radiotherapy(n = 27) No 22 81.5 Yes (adjuvant) 5 18.5 Hormonal therapy No 38 69.1 Yes 17 30.9 Two-year overall survival Overall survival was calculated from the date of histological diagnosis. During the two-year follow-up period, a total of 18 deaths were recorded, while the remaining patients were censored at last follow-up or at two years. The Kaplan–Meier estimated two-year overall survival rate was 67.3% (95% CI: 0.53–0.78) ( Fig 1 ).
10.1371/journal.pone.0361615.g001 Fig 1 Kaplan-Meier for 2-year overall survival in male breast cancer patient. Predictors of Survival In multivariable Cox regression analysis ( Table 5 ), age > 70 years and stage IV disease were independently associated with increased mortality risk ( Fig 2 , Fig 3 ). Delays in receiving histopathological results (>2 weeks) ( Fig 4 ) and delays in surgery (>6 weeks) ( Fig 5 ) remained significant predictors of poorer survival after adjustment for disease stage.
10.1371/journal.pone.0361615.t005 Table 5 Predictors of two-year overall survival (Cox regression). Variable Category Adjusted HR 95% CI p-value Age (years) <50 1.00 Reference 50–70 1.87 0.13–27.23 0.804 >70 5.02 2.50–41.16 0.009 TNM stage I 1.00 Reference II 4.08 0.47–33.15 0.074 III 5.47 0.71–48.57 0.139 IV 4.99 1.76–59.13 0.005 Radiotherapy No 1.00 Reference Yes 0.35 0.06–0.62 0.018 Hormonal therapy No 1.00 Reference Yes 0.09 0.01–0.99 0.049 Time to pathology ≤2 weeks 1.00 Reference >2 weeks 3.44 1.78–11.16 0.013 Time to surgery ≤6 weeks 1.00 Reference >6 weeks 4.15 1.07–16.11 0.027 Bold values indicate statistical significance (p < 0.05). 10.1371/journal.pone.0361615.g002 Fig 2 Kaplan-Meier survival estimates by age.
10.1371/journal.pone.0361615.g003 Fig 3 Kaplan-Meier survival estimates by TNM stage. 10.1371/journal.pone.0361615.g004 Fig 4 Kaplan-Meier survival estimates by time waiting for biopsy results. 10.1371/journal.pone.0361615.g005 Fig 5 Kaplan-Meier survival estimates by time waiting for surgery.
Receipt of radiotherapy and hormonal therapy were associated with improved survival ( Fig 6 , Fig 7 ). However, these findings should be interpreted cautiously, as patients receiving these therapies were more likely to have better performance status and access to care, introducing potential confounding by indication. 10.1371/journal.pone.0361615.g006 Fig 6 Kaplan-Meier survival estimates by radiotherapy.
10.1371/journal.pone.0361615.g007 Fig 7 Kaplan-Meier survival estimates by hormonal therapy. Discussion This study provides important insight into the clinicopathological characteristics and two-year survival of men with breast cancer treated at a tertiary referral center in Northern Tanzania. The findings confirm that male breast cancer predominantly affects older men and is frequently diagnosed at advanced stages, resulting in suboptimal survival outcomes [ 15 , 16 ].
The two-year overall survival rate of 67.3% is lower than that reported in high-income countries but comparable to other low- and middle-income settings [ 17 ]. This survival gap is likely driven by advanced stage at diagnosis, health-system delays, and limited access to radiotherapy and hormonal therapy rather than tumour biology alone. A key contribution of this study is the demonstration that diagnostic and treatment delays independently predict mortality, consistent with previous evidence linking healthcare delays to advanced stage and worse survival [ 18 – 20 ].These findings highlight the critical role of health-system performance and suggest that improving turnaround times for pathology and surgical care could yield meaningful survival gains even without advanced therapies.
Radiotherapy and hormonal therapy were associated with improved survival, although utilization was low. Given the retrospective design, these associations should not be interpreted as causal; however, they underscore the potential survival benefit of expanding access to comprehensive cancer care services. Limitations This study has several limitations, including small sample size, missing data for molecular subtyping, and limited follow-up duration.
As a single-center tertiary referral study, the findings may overrepresent advanced disease and may not be fully generalizable to all settings in Tanzania. Conclusion Male breast cancer in Northern Tanzania remains a clinically significant disease characterized by late presentation and suboptimal survival. Older age, advanced disease stage, and health-system delays are key determinants of poor outcomes.
Interventions targeting early diagnosis, timely pathology reporting, and improved access to radiotherapy and hormonal therapy are essential to improve survival among men with breast cancer in low-resource settings. Supporting information S1 Data Data set underlying the results. (XLSX)