Imaging and treatment of Neuroendocrine tumors (NET) & prostate cancer are examples of successful implementation of the theragnostic concept and a valid examples of personalized medicine.
Biologically NET’s are functioning or nonfunctioning. The functioning ones are associated with clinical syndrome & increased bio-markers. Nonfunctioning tumors have histopathological (HP) features of NET but no clinical syndromes. These have high expression of somatostatin receptors which have five different G – protein coupled somatostatin receptor sub-types (SSTR 1-5) cloned & pharmacologically characterized. SSTR 2 is expressed in approx. 90% of GI NET & 80% of pancreatic NET.
In insulinomas however < 50% expresses SSTR-2. Histopathological grading also contributes to treatment selection. Well differentiated NET G-1, mitotic count < 2/10 HPF with Ki 67 < 2% & G2: mitotic count 2-20 / 10 HPF with Ki 67 2-20% show good expression of somatostation receptor and are candidates for receptor based therapy.
177-Lu DOTATATE therapy can be successfully applied to these patients with excellent results and can even lead to cure in metastatic NET which has failed conventional therapy. In selected cases it has also been used to downstage the tumor, in a neoadjuvant setting, followed by curative surgery.
It is known that metastatic prostate cancer responds to well established innovative anti androgen treatment. In addition to other conventional treatment methods the recently approved androgen receptor antagonist enzalutamide & CYP17A1 inhibitor abiraterone has been reported to have 3.9 & 4.8 months survival benefit respectively. Progression to androgen independence is the main cause of morbidity & death in these patients. Based on the theragnostic concept the main aims of treatment are to improve outcomes by early interventions in suboptimal responders sparing low risk patients from over treatment, to reduce acute & late treatment related side effects, achieve best possible therapeutic gain, ensure effective palliation & improve quality of life. Tumor targeting with 177Lu PSMA has the potential advantage of saving the normal tissue while delivering high dose to tumor, easy radiopharmaceutical labelling & high expression in all cancer cells thus making it an optimal target for radionuclide therapy. It is safe with a low toxicity profile achieving good therapeutic benefit. We have seen objective regression in lesions and symptomatic relief.
In our experience at RGCIRC we have found it to a safe & effective method for treating end stage androgen independent, progressive CRPC where achievable tumor dose is demonstrated by Ga-68 PSMA scan before therapy.
The Institute has 3 bed dedicated ward for Radionuclide therapy approved by Bhaba Atomic Research Center (BARC) and Atomic Energy Regulatory Board (AERB), Government of India
Treatment for the following cancers is being performed on a regular basis: