Burden and Clinical-pathological Characteristics of Bilateral Breast Cancer at the Kenyatta National Hospital - a Five Year Review

Abstract

Study background: Bilateral breast cancer is an infrequent finding in our setup. As such, not many studies have been carried out on this. The information gathered from this study will be used to guide on management of such patients, prognosticate the outcome and even guide on follow up based on the frequency, prognosis, histological and immunohistopathological features, and therapeutic modalities. Broad objective: To determine the burden and clinical-pathological characteristics of Bilateral Breast Cancer at the Kenyatta National Hospital over a five-year period. Study design and Site: This was a descriptive retrospective study covering a period of five years which coincided with the existence of the breast MDT at K.N.H. The study was conducted at K.N.H. , this being a national referral hospital that attends to many breast cancer patients. It is a better representation of the disease burden and likely outcomes can be reached due to the diversity of patients seeking treatment at K.N.H. It also serves as the teaching hospital for the UoN, Faculty of Health Sciences, for both the undergraduate and postgraduate programs. Materials and Method: Data from medical records of patients who had been treated for bilateral breast cancer for the past five years at K.N.H. was retrieved. The data points were on the demographic findings, family history, treatment modalities, staging, histopathology, and immunohistochemistry. Data Management: Data was checked for completeness and accuracy prior to entry into the Microsoft Excel Spreadsheet, thereafter, transferred to the SPSS version 23 for analysis. If the pvalue of a statistical test is found to be lower than 0.05, it was be considered substantial. Where applicable, the odds ratios and their corresponding 95% confidence interval were reported. Expected main outcome measure (Utility of the study): This study’s results will stimulate the process of developing guidelines on management of patients with bilateral breast cancer in our setup. Results: The study obtained 29 files for the period of five years (2017-2021). Eight files were excluded due to missing data and relevant information. The fourth decade was the most affected period with a mean age of forty-two years. It took approximately 24 months from time of xiii diagnosis to development of contra lateral tumor. Metachronous tumors were the commonest at 71.4% while synchronous tumors were 28.6%. Invasive ductal carcinoma was the only carcinoma detected and the larger the primary tumor the more the chance of developing contra lateral breast malignancy (>5cm higher risk). Nodal involvement did not have a direct correlation with development of BiBc. Patients with BiBc frequently presented with distant metastasis to other organs as compared to when the tumor was unilateral and immunohistochemistry of both tumors was similar for all the patients. Conclusion: Bilateral breast malignancy is an uncommon entity in our setup occurring mostly in the fourth decade of life with an average diagnostic period of two years from time of primary breast cancer diagnosis. Risk factors include age, patients with stage three and four tumors and invasive ductal carcinoma diagnosis on pathology. Bilateral breast malignancies carry a higher risk of metastasis to other organs and close follow up is warranted. Since immunohistochemical markers appear to be similar between primary malignancy and the contra lateral malignancy, there needs to be a revision in terms of treatment as there is a chance that both tumors share similar histopathological aspects.