Case report: Breast metastasis in a prostate cancer patient.

Abstract

At the age of 63, the patient was first diagnosed with prostate cancer, initial stage pT2a, pN0, cM1, Gleason score 4 + 3 = 7, iPSA 8.8 ng/ml. Staging with magnetic resonance imaging (MRI) of the pelvis indicated extended local tumor including infiltration of the bladder, no suspicious lymph nodes were found. A radical prostatovesiculoectomy was performed. 5 years later, a local recurrence occurred, after which salvage radiotherapy of the prostate bed was carried out. This was followed by another local recurrence 8 years later with bladder floor infiltration, leading to surgical resection of the bladder (cystectomy) and the creation of an ilium conduit for urinary diversion (stage of relapse: pT4, cN0, M1, R1, L0, V0, Gleason 5 + 5 = 10). 3 years later there was an increasingly progressive course with disseminated bone metastases and a recurrent local relapse in the prostate bed. In the same year, irradiation of the bone metastases and taxane-containing chemotherapy (3 cycles Docetaxel) were performed for palliation. Due to subsequent further morphological disease progression, increasing PSA and aggravation of pain, we opted for radionuclide therapy with Lutetium-177-PSMA as compassionate use due to the lack of other therapy options. Before Lutetium-177PSMA therapy, Gallium-68-PSMA PET/CT was carried out showing intense expression in local recurrence, multiple bone metastases in the whole skeletal system as well as in pelvic and retroperitoneal lymph nodes classified as PSMA-RADS 5 according to [1]. In addition, the PET/CT examination showed intense expression of PSMA in a mass in the left breast (▶ Fig. 1). As initially, breast cancer was suspected this lesion was classified as PSMA-RADS 3C. However, a breast biopsy under local anesthesia with histological evaluation did not confirm this suspicion. Surprisingly, the histological examination revealed metastases from prostate cancer in the left breast (▶ Fig. 2). Subsequently, the first cycle of Lutetium-177-PSMA therapy was performed. Prophylactic cooling of the parotid glands was started 30 minutes before intravenous application of 6500 MBq Lu-177-PSMA, accompanied by 1000ml NaCl. One day after the application of Lutetium-177PSMA, intense activity accumulation in the metastasis in the left breast was observed in post-therapeutic whole-body scintigraphy (▶ Fig. 3). Overall, the therapy was tolerated well without side effects. After an inpatient stay of 3 days, the patient was discharged in reduced general condition. However, the patient died a few weeks later, thus further therapy cycles could not be continued and response could not be evaluated.