Histological Classification, Grading, Staging, and Prognostic Indexing of Female Breast Cancer in an African Population: A 10-year Retrospective Study

Background: Breast cancer (BC) is a heterogeneous disease characterized with diverse genetic and ethnic/racial variations that may influence tumor characteristics and prognosis. We studied different histological types of BC and their prognostic indicators in part of Southwestern Nigeria.

Materials And Methods: A 10-year retrospective study of archival tissue-paraffin blocks and records of surgical cases (documented as BCs) between January 2005 and December 2014 was done. Tumor classification was made after the World Health Organization guidelines. Modified Bloom-Richardson score and TNM staging system were used in grading and staging the tumors. Nottingham prognostic index was employed in scoring the prognosis.

Results: The mean age was 49.7 years (20-89 years). The age group from 50 to 59 years was most affected. Out of 343 total cases, the most common histological type was invasive ductal carcinoma of no special type (88.9%). The majority (51.9%) had tumor sizes ranging 2-5 cm (pT2) and some (39.1%) with >5 cm (pT3) were all at palpable stages. The tumors were mostly Grades II and III types. Observation for lymph node metastasis confirmed that 261 (76.1%) were pN0 (negative), 77 (22.4%) were pN1, and 5 (1.5%) were pN2. Prediction of a chance of survival showed moderate prognosis in the majority (48.7%) of the cases.

Conclusion: Although early detection of BC in this region was considerably poor, there was a better outcome compared with some other black populations. Clinical presentation, histological type, and prognostic indices varied from existing reports in many ethnic/racial groups. Indexing of BC pattern on a regional standpoint may serve a new direction toward better management considering the associated geographic disparity.