Prognostic factors and overall survival of breast cancer in Benin: a hospital-based study

Abstract

Background: In Benin, a country in West Africa, breast cancer is the leading cancer in women, both in terms of incidence and mortality. However, evidence on the mortality of breast cancer and its associated factors is lacking in this country. Our aim was to describe and analyze the clinical, histopathological, and prognostic aspects of breast cancer in Benin.

Methods: A descriptive and analytical study was carried out at the CNHU-HKM and the CHU-MEL, two major tertiary referral hospitals for breast cancer management located in Cotonou, the capital city of Benin. All breast cancer medical records with histological evidence and immunohistochemistry studies were retrospectively collected between January 1, 2014, and September 30, 2020, in these two tertiary referral hospitals and analyzed in the current study.

Results: Finally, 319 medical records were included. The mean age at diagnosis was 48.74 years. The tumors were most frequently classified as T4 (47.6%) with lymph node involvement N2 (34.5%), and metastases were clinically noted in 21.9% of cases. Stage was reported in the medical records of 284 patients. Tumors were diagnosed at very late AJCC stages: stage III (47.5%) and stage IV (24.7%). Grades SBR 2 (49.2%) and SBR 3 (32.6%) were the most frequent grades. Triple-negative breast cancer (31.3%) was the most common molecular type. The overall 5-year survival was 48.49%. In multivariable analysis, the poor prognostic factors were lymph node invasion (HR = 2.63; p = 0.026; CI: [1.12, 6.17]), the presence of metastasis (HR = 3.64; p < 0.001); CI: [2.36, 5.62] and the immunohistochemical profile (HR = 1.29; p < 0.001; CI: [1.13, 1.48]).

Conclusions: Breast cancer in Beninese is predominant in young adults and is often diagnosed at a late stage. The survival of breast cancer patients in Benin can be improved by enhancing early diagnosis and multidisciplinary management.

Keywords: Benin; Breast cancer; Prognostic factors; Sub-saharan africa; Survival.

Fig. 1

Characteristics of Beninese breast cancer patients by stage at diagnosis and molecular subtype. (A) Distribution of breast cancer cases by stage (AJCC Stage I to Stage IV) at diagnosis (n = 284). (B) Distribution of breast cancer cases by molecular subtype (Luminal A, Luminal B Her2+, Luminal B Her2-, Her2 or triple negative) (n = 319)

Fig. 2

Kaplan‒Meier survival curves for Beninese breast cancer patients. (A) Overall survival curves of patients. (B) Overall survival curves of patients according to the time between the onset of symptoms and the first consultation (approximately 6 months). (C) Overall survival curves of patients according to the age of the patient at the time of diagnosis (approximately 35 years old)

Fig. 3

Kaplan‒Meier survival curves for Beninese breast cancer patients with different characteristics. (A) Overall survival curves of patients according to tumor stage at diagnosis (T1 to T4). (B) Overall survival curves of patients according to lymph node involvement at diagnosis (patients with lymph node involvement (N+) or without lymph node involvement (N0)). (C) Overall survival curves of patients according to metastases at diagnosis (patients with metastases (M1) or without metastases (M0)). (D) Overall survival curves for patients according to the histopronostic grade of the tumor at diagnosis (grade 1 tumors (SBR1), grade 2 tumors (SBR2) or grade 3 tumors (SBR3)). The log-rank test showed significant differences in survival among groups in the four panels (all P < 0.01)

Fig. 4

Kaplan‒Meier survival curves for Beninese breast cancer patients at different stages at diagnosis or of different molecular subtypes. (A) Overall survival curves of patients according to stage at diagnosis (Stage I to Stage IV). (B) Overall survival curves of patients according to molecular subtype. The log-rank test showed significant differences in survival among groups in the two panels (all P < 0.01)