Partha S Choudhury
Rajiv Gandhi Cancer Institute and Research Centre, India
Title: Precision management in castration resistant prostate cancer (CRPC) : A theranostic approach
Biography
Biography: Partha S Choudhury
Abstract
The term theranostics is the combination of a diagnostic tool that helps to define the right therapeutic tool for specific disease. It signifies the “we treat what we see & see what we treat” concept. A diagnostic radionuclide is labelled with the target and once expression is documented, the same target is labelled with a therapeutic radionuclide and treatment is executed. In Nuclear Medicine theranostics is easy to apply because of an easy switch from diagnosis to therapy with the same vector. This concept is utilized in few malignancies and prostate cancer is one of them. PSMA expression in normal and other tumor is less than prostate cancer cell. Its expression increases with higher grade and hormone resistance. We have reported excellent sensitivity and detection capability of PSMA for sub centimeter sized lymphnodes at staging . Besides evaluation of recurrence, 68Ga-PSMA PET can be utilized in advanced prostate cancer for detection of metastasis. 68Ga-PSMA also serves the basis of treatment of CRPC with 177Lu PSMA. Progression to androgen independence is the main cause of morbidity & death in these patients. Based on the theranostic concept the aims of treatment with 177Lu PSMA are to improve outcome by early interventions in suboptimal responders, sparing low risk patients from over treatment, reduce treatment related side effects, ensure effective palliation & improve quality of life. Tumor targeting with 177Lu PSMA saves normal tissue & delivers high dose to tumor. Easy radiopharmaceutical labelling & high expression in all cancer cells makes it an optimal target for radionuclide therapy. It is safe with a low toxicity profile. In our experience at RGCI & RC (our institute) we have seen objective regression in lesions and symptomatic relief & found it to be a safe & effective method for treating end stage androgen independent, progressive CRPC. We believe that treatment of recurrent prostate cancer is feasible with 177Lu PSMA with a positive objective response & a low side effect profile where achievable tumor dose is demonstrated by Ga-68 PSMA scan before therapy.