Probability of a high recurrence score for breast cancer on the Oncotype DX test in males: a case series

Abstract

Abstract Introduction: Male breast cancer (MBC) is a rare disease that accounts for 1% of breast cancers. The Oncotype DX test (a genomic signature that assesses the expression of 21 genes to estimate the recurrence score [RS]) has been widely used in MBC to select patients for adjuvant chemotherapy. Objective: To describe 5 cases of MBC in which a nomogram was used to predict the probability of having a high Oncotype DX score for breast cancer and the need to perform genomic signature. Materials and methods: Case series study in which five patients with MBC treated between 2007 and 2020 at a cancer institution in Teresina (Brazil) were included. A nomogram was performed to evaluate five clinical and pathological variables (age, body size, tumor size, grade, recurrence score status, and histologic type of carcinoma). Case series: The mean age of the patients at diagnosis was 69 years (mean tumor size: 2.6cm). All patients received hormone therapy with tamoxifen, three received chemotherapy, and one received radiation therapy after breast surgery (mastectomy). During a median follow-up period of 88 months, one case had a recurrence (bone metastasis). Based on the nomogram results, two patients had a high probability of a high RS (36% and 45%) and only one patient (case 3) underwent Oncotype DX testing (RS: 20). Conclusions: In the present series of five cases, based on the nomogram results, only two patients (cases 3 and 4) had a high probability of a high Oncotype DX recurrence score; however, due to financial constraints, this test was only performed on one of these two patients. The patient who underwent the test (case 3) did not receive adjuvant chemotherapy and remained alive with bone metastases until the end of the follow-up period. Conversely, the patient who could not undergo the examination (case 4) received adjuvant chemotherapy and was alive without any signs of disease.