Exceptional Response of Rare Plasmacytoid Variant Prostate Cancer Post 177Lu-PSMA Therapy Seen on 68Ga-PSMA PET/CT.

ABSTRACT: Plasmacytoid is a rare variant of acinar prostatic adenocarcinoma. The aggressive type is characterized by an aggressive clinical course, lack of responsiveness to hormonal therapies, and an overall poor prognosis. Here we present pretherapy and posttherapy 68Ga-PSMA PET/CT images showing an exceptional response to 177Lu-PSMA therapy. This case demonstrates the usefulness of both 68Ga-PSMA PET/CT in assessing the tumor PSMA avidity and the potential of 177Lu-PSMA therapy in these patients.

The Outcome and Safety of Re-challenge Lutetium-177 PSMA (177Lu-PSMA) Therapy with Low-Dose Docetaxel as a Radiosensitizer-a Promising Combination in Metastatic Castrate-Resistant Prostate Cancer (mCRPC): a Case Report.

Prostate-specific membrane antigen (PSMA)-directed radioligand therapy (PSMA-RLT) with lutetium-177 (177Lu-PSMA) has been used in metastatic castrate-resistant prostate cancer (mCRPC), and retrospective data have shown this therapy to be favourably safe with attractive clinical responses. Re-challenge 177Lu-PSMA therapy in early responders has been shown to be safe and effective. We report the use of low-dose Taxol-based chemotherapy (modified dose 25 mg/m2 weekly × 6 weeks) as a radiosensitizer with re-challenge 177Lu-PSMA therapy (4 cycles). In a period of 3 years, the patient underwent a total of 8 cycles of 177Lu-PSMA with a cumulative dose of 51.8 GBq. All therapies were uneventful and well tolerated. There was a good response to re-challenge 177Lu-PSMA therapy and low-dose docetaxel (Taxol-177Lu-PSMA) with no recorded tumour resistance.

The association of human immunodeficiency virus and skeletal metastases in breast cancer using Tc-99m methyl diphosphonate bone scan.

Skeletal involvement occurs in 30%-70% of all cancer patients, with breast cancer (BC) being the leading cause for bone metastases in women and prostate cancer in men followed by lung cancer. Human immunodeficiency virus (HIV) is a lentivirus (a member of the retrovirus family) that causes acquired immunodeficiency syndrome. It is yet unknown what is the impact of HIV to the onset and progression of bone disease in BC. The purpose of the study was to determine the association of HIV infection and skeletal metastases in BC using skeletal scintigraphy. A retrospective analysis of 25 female BC patients' bone scans was performed. The 25 bone scans of 12 patients known HIV positive and 13 patients who were known HIV negative, of similar age and histology, were compared. All 13 HIV negative patients had a positive bone scan. Of the 12 HIV-positive patients, 4 patients on highly active antiretroviral therapy (HAART) had positive bone scans for skeletal metastases. The remaining eight HIV-positive patients had negative bone scans, of which six were on HAART and two were not on HAART. In our study, HIV infection was not found to be a contributing risk factor for skeletal metastases. From our small series, it appears that HIV patients and on HAART have a delay in the onset of skeletal metastases in BC.

The Complimentary Role of Methoxy-Isobutyl-Isonitrile and Hand-Held Gamma Probe in Adamantinoma.

Adamantinoma is a rare locally aggressive osteolytic tumor that is found 90% of the time in the diaphysis of the tibia with the remaining lesions found in the fibula and long tubular bones. A case of adamantinoma of the tibia is presented. The added value of nuclear medicine investigations in the workup of this patient is described. A three-phase whole body (99m)Tc-methylene diphosphonate bone and a whole body (99m)Tc-methoxy-isobutyl-isonitrile scans were complimentary in the demarcation of viable bone tumor and the assessment of the remainder of the bone and soft tissue to exclude other sites. Intra-operative assistance with a hand-held gamma probe, guided the biopsy of the most metabolically active tumor tissue. Histology revealed a biphasic tumor composed of epithelial and fibrous components, in keeping with an adamantinoma.