This study is a retrospective cohort analysis including all women with breast cancer treated with radiotherapy at the CHU de Bogodogo between October 1, 2022 and December 31, 2025, with follow-up censored at the date of last documented contact in the records, and all data collection and analyses performed entirely retrospectively. On 30 April 2026, all patients whose last documented visit occurred more than one month earlier were contacted by telephone to verify their vital status and the absence of clinically reported signs of cancer recurrence. It was designed to compare the clinical, therapeutic, and outcome profiles of two groups of breast cancer patients defined according to age at the time of treatment: 50 years or younger, and older than 50 years. This age cut-off was chosen to explore the potential impact of age on tumor characteristics, treatment strategies, and observed outcomes. The 50-year age cutoff was chosen a priori because it corresponds roughly to the menopausal transition and is commonly used in breast cancer literature and in our local practice to distinguish “younger” from “older” patients in terms of tumor biology, comorbidities, and treatment decision-making.

All women with breast cancer who received radiotherapy during the study period and whose medical records contained the data required for analysis were eligible for inclusion. Cases with incomplete information on key study variables were excluded to reduce information bias. During the study period, we reviewed 103 medical records of women with breast cancer managed in the radiotherapy department. Five patients were excluded because their initial oncologic treatment had been delivered abroad and they were referred only for post-radiation follow-up (n = 3) or for the management of metastatic lesions (n = 2), which did not allow consistent baseline and treatment documentation. The final study cohort therefore comprised 98 patients with complete local treatment and follow-up data, including 58 patients aged 50 years or younger and 40 patients older than 50 years.

The collected variables were grouped into several domains. Sociodemographic and background variables included age, residence, medical history, family history, and lifestyle-related factors. Medical history comprised hypertension, diabetes, asthma, viral hepatitis, HIV status, and surgical history. Gyneco-obstetric and hormonal variables included contraceptive use and menopausal status at diagnosis.

Clinical and pathological variables included histological subtype, Scarff-Bloom-Richardson (SBR) histological grade, hormone receptor status, HER2 status, tumor stage, pT and pN classifications, and molecular subtype. When available, complete breast and nodal response was also recorded.

Therapeutic variables included neoadjuvant chemotherapy, adjuvant chemotherapy, hormonotherapy, type of breast surgery, irradiated target volume, nodal irradiation, axillo-susclavicular irradiation, early adverse effects, and treatment interruptions.

Data were retrospectively extracted from medical records, pathology reports, radiotherapy treatment charts, and departmental registers. The information was entered into a database and checked for consistency before statistical analysis.

All analyses were performed using SPSS version 2021. Categorical variables were summarized as frequencies and percentages and compared between the two age groups using the chi-square test or Fisher’s exact test when expected cell counts were insufficient. Pathology and biomarker variables (receptor status, HER2, molecular subtype, and pathological response) were analyzed only in patients with available data for the corresponding variable. The number of patients with missing information for each biomarker is reported in the tables. When analyses were based on a reduced denominator, this is explicitly indicated in the table footnotes and in the Results. Survival was estimated using the Kaplan-Meier method and compared between groups using the Mantel-Cox log-rank test. Statistical significance was set at p < 0.05. In addition to univariable analyses, we explored multivariable models (logistic and Cox regression) to assess the association between age group and selected outcomes (treatment interruption, survival) while accounting for comorbidities and menopausal status. Because the number of events was very small (7 treatment interruptions and 6 deaths), these models yielded unstable estimates with large confidence intervals and convergence warnings. We therefore report these analyses only as exploratory and do not base our main conclusions on multivariable modeling.

The primary endpoint was overall survival (OS), defined as the time from the date of diagnosis or date of histologic confirmation to death from any cause or last documented follow-up; patients who were alive at the last recorded contact were censored on that date. Secondary outcome variables included complete breast and nodal response, early adverse effects, and treatment interruption. Complete breast and nodal response were defined as the absence of residual tumor histologically detectable disease in the breast sample after surgery and regional lymph nodes resected after completion of initial treatment (neoadjuvant chemotherapy), as documented in the medical record. Early adverse effects were defined as acute toxicities occurring during radiotherapy or within 180 days after its completion, based on clinician-documented treatment-related events in the records. Treatment interruption was defined as any unplanned break in the radiotherapy course resulting in a prolongation of the scheduled treatment duration, regardless of cause.

Because the study was based on secondary use of medical records, all data were handled anonymously and confidentially before analysis. According to the source manuscript, the study was authorized by the ethics committee of the Centre Hospitalier Universitaire de Bogodogo and conducted in accordance with local confidentiality and data protection requirements.

Hypertension and diabetes were significantly more frequent in patients older than 50 years than in those aged 50 years or younger. In contrast, asthma, viral hepatitis, HIV infection, prior surgery, family history of cancer, alcohol consumption, physical activity, and fruit-rich diet did not differ significantly between the two groups. All patients in both groups were non-smokers. Table 1 summarizes the sociodemographic characteristics across age groups.

Menopause at diagnosis was significantly more frequent in women older than 50 years. No statistically significant between-group differences were observed for contraceptive use, histological type, SBR grade, estrogen receptor positivity, progesterone receptor positivity, HER2 status, tumor stage, pT classification, pN classification, molecular subtype, or complete breast and nodal response when assessable. Clinical and biological characteristics stratified by age group are shown in Table 2. For biomarker analyses (ER, PR, HER2, molecular subtype), only patients with documented pathology reports were included; the corresponding denominators are shown in each table. Pathological complete response was assessed in the subset of patients with evaluable post-treatment assessment, as indicated by the footnotes.

Table 1. Sociodemographic and comorbidity characteristics by age group.

No smokers were reported in the cohort. Note: Percentages are calculated within each age group: ≤50 years (n = 58) and >50 years (n = 40).

Table 2. Clinical and pathological features by age group.

*Invasive Ductal Carcinoma, Not Otherwise Specified (IDC-NOS); **Scarff-Bloom-Richardson; ***Percentages for pathological complete response (PCR) are calculated among evaluable patients only (n = 33 for ≤50 years; n = 18 for >50 years), based on the counts provided in the source table. Percentages for biomarker variables and pathological complete response are calculated among patients with available data for the corresponding variable; missing data were excluded from these specific analyses and the denominators are reported in the table. Note: Percentages are calculated within each age group: ≤50 years (n = 58) and >50 years (n = 40).

Most patients underwent total mastectomy and received adjuvant radiotherapy. Chest wall irradiation was the predominant target volume in both groups, and nodal irradiation was performed in approximately three-quarters of cases. Rates of neoadjuvant chemotherapy, adjuvant chemotherapy, hormonotherapy, nodal irradiation, axillo-susclavicular irradiation, and early adverse effects were similar between the two groups. However, treatment interruption was significantly more frequent in patients older than 50 years.Table 3 reports treatment characteristics according to age group. Percentages are calculated within each age group: ≤50 years (n = 58) and >50 years (n = 40), except for nodal target volumes, for which percentages are calculated among patients who received nodal irradiation in each age group.

Table 3. Treatment characteristics by age group.

All patients underwent surgery and radiotherapy in both age groups. ^†Percentages for nodal target volume are calculated among patients who received nodal irradiation: n = 45 in the ≤50 years group and n = 31 in the >50 years group. SCF = supraclavicular field.

At the date of last follow-up, survival remained high in both groups, with no statistically significant difference. The estimated mean survival time was longer in the group aged 50 years or younger than in the group older than 50 years; however, comparison of the survival curves did not show a statistically significant difference (Table 4 and Figure 1).

Table 4. Outcome data according to age group.

Figure 1. Kaplan-Meier overall survival curves according to age group.

Figure 1 compares overall survival between patients aged 50 years or younger and those older than 50 years. Although the estimated mean survival time was longer in the younger group, the difference between the survival curves was not statistically significant (log-rank p = 0.625).