Abstract P1-23-03: Male breast cancer in a retrospective study from the Maria Sklodowska Curie National Research Institute of Oncology in Warsaw, Poland

Background: Male breast cancer is a rare disease accounting for less than 1% of all breast cancer diagnoses worldwide. Male breast cancer is not very well understood. Prospective data in the management of male breast cancer are lacking and majority of treatment strategies are adopted from the established guidelines for breast cancer in women. The understanding of biology, clinical presentation, genetics, and management of MBC is evolving but there still remains a large knowledge gap due to the rarity of this disease.Patients and methods: The aim of this retrospective study is to analyze the epidemiologic, clinical and therapeutic problems with this disease and to compare some cancer aspects between male and female in 67 cases collected at Maria Sklodowska Curie National Research Institute of Oncology in Warsaw between 05.2011 and 02.2021. Patients with a primary diagnosis of breast cancer were identified in the our database.Results: The median age was 65 years (range 22-93 years). Family history was present in 15 (22%) men and in as 17 pts (25%) other cancer were diagnosed (prostate cancer, melanoma, Hodgkin lymphoma, NET, thyroid cancer). Early, locally advanced, and metastatic disease were seen in 44 (65%), 9 (14%), and 14 (21%) men, respectively. Majority (59, 88%) of men had invasive ductal carcinoma histology. In radically treated 44 men, neoadjuvant chemotherapy was given to 20 (29%) patients with pCR in 1 (1.5%) and neoadjuvant hormonotherapy (tamoxifen) in 5 (7.5%) of pts. Estrogen receptor, PR, and human epidermal growth factor receptor 2/neu positive were seen in 62 (92.5%), 60 (89.5%), and 15 (22%) patients, respectively. Triple negative breast cancer were diagnosed in 4 (6%) pts. During the follow-up period locoregional recurrence occurred in 1 (1.5%) and distant metastasis in 15 (22%) men, respectively. Bone was the most representative site of metastases (20, 69%). In contrast to women with breast cancer, who have mainly osteolytic metastases (75-80%), our analysis found that men were predominantly osteoblastic lesions (10, 50% pts with bone mts). There was 31 cases of death (46%). Death was usually due breast cancer progression (29, 43%).Conclusion: This analysis found that men with breast cancer had a higher risk of second primaries cancer. Bone was the most representative site of metastases, but they are mainly osteoblastic lesions.

Citation Format: Agnieszka Irena Jagiello-Gruszfeld, Pawel Winter, Rafal Wojcik, Michal Kunkiel, Renata Sienkiewicz, Roman Dubianski, Anna Majstrak-Hulewska, Zbigniew Nowecki. Male breast cancer in a retrospective study from the Maria Sklodowska Curie National Research Institute of Oncology in Warsaw, Poland [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-23-03.

Oral etoposide in heavily pre-treated metastatic breast cancer: A retrospective study

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Background: Patients with metastatic breast cancer can derive clinical benefit from several subsequent lines of chemotherapy. However, in heavily pre-treated patients, agents with clinical activity, a favourable side effects profile and a convenient administration modality are preferred. Oral etoposide may be an interesting treatment option in this group of patients. Methods: This was a retrospective observational study performed in single institution in 22 patients with MBC refractory to prior anthracycline, taxane, and capecitabine therapy. All patients were treated with oral etoposide at 50 mg/day on days 1-20. Treatment cycles were repeated every 28 days. Results: The median age were 53 years (42-68). The median number of previous chemotherapy lines was 5 (range 2-7). There were no complete or partial responses. Median PFS was 7 months. In 5 patients, the disease stabilized for over 12 months. Interestingly, etoposide activity was unrelated to the number of previous lines and type of metastatic involvement. Oral etoposide was well tolerated with only one patients discontinuing therapy due to toxicity. Conclusions: In real practice oral etoposide is a valuable and safe option for pre-treated metastatic breast cancer patients and might be considered in patients failing other approaches, but still suitable for chemotherapy.

Pathological outcomes of HER2-positive early breast cancer patients treated with neoadjuvant trastuzumab or dual anti-HER2 therapy and carboplatin with docetaxel: A Maria Sklodowska-Curie National Research Institute of Oncology experience

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Background: Pathological complete response (pCR) after neoadjuvant chemotherapy (NACT) for breast cancer predicts the risk of recurrence and increasingly may indicate the need for additional therapy postoperatively. Methods: A retrospective analysis was performed in two cohorts of patients (pts) treated with docetaxel, trastuzumab and carboplatin (TCH) or with docetaxel, carboplatin and dual blockade (TCH-P) in the neoadjuvant setting in patients with early breast cancer (tumor size < 50 mm and > 10 mm and cN0 or cN1) in our Clinic, and who had definitive surgery was conducted. Demographic data, size, grade, tumor type, receptor status prior to neoadjuvant treatment, pathological complete response (pCR) rates, and adverse effects were analyzed. The pCR was defined as ypT0 ypN0. Results: Patient in cohort A (n = 58) received TCH x 6 cycles and in cohort B (n = 25) TCH-P x 6 cycles. Median age was 51 (range 23 to 76 years) in cohort A and 46 (range: 30-68) in cohort B. In cohort A 37 (64%) of pts was HR-positive, in cohort B only 9 (36%) pts . The most common adverse events in both groups were neutropenia, diarrhea, chemotherapy induced polyneuropathy and febrile neutropenia. There are no significant differences in the frequency of adverse events in two cohorts. There was no symptomatic heart failure, but 6 pts (10%) in cohort A and 5 pts (16%) in cohort B had > 10% asymptomatic decrease in LVEF. All patients were evaluable for pCR. Higher rates of pCR were achieved in the HER2pos/HRneg pts: 66% (n = 14) in cohort A, and 87% (n = 14) in cohort B. In group HER2pos/HRpos pts, the pCR rate was 48% (n = 18) vs 55% (n = 5) respectively. Conclusions: In HER2positive early breast cancer, a dual blockade (trastuzumab and pertuzumab) together with carboplatin and docetaxel neoadjuvant chemotherapy achieved higher rates of pCR ( 76%) compared with pts treated with trastuzumab, carboplatin and docetaxel (56%). However, a much higher percentage of pCR was observed in the group of patients with non-luminal cancers, who received a double blockade (87% vs 66%).