Radiology and Oncology

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 labelled with the target and once expression is documented, the same target is labelled with a therapeutic radionuclide and treatment is executed. In addition a molecular biomarker based targeted treatment can be tailored with either biomarker or molecular imaging. The concept is utilized in few malignancies especially NET & prostate cancer currently. Molecular imaging modalities exploit the receptor expression aspects of the pathophysiology for both diagnostic imaging & therapeutic purposes. The receptor expression changes with tumor grades and hormone resistance. We have reported excellent sensitivity and detection capability of both primary and metastatic disease. Besides evaluation of recurrence, 68Ga-labelled radiopharmaceuticals can be utilized for detection of metastasis and selection of patients for therapy. 68Ga- DOTA or PSMA serves the basis of treatment of these conditions with 177Lu . Based on the theranostic concept the aims of treatment with 177Lu 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 DOTA or 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, with a low toxicity profile. In our experience at RGCI & RC (our institute) we have seen objective regression in lesions and symptomatic relief. It has been found to be a safe & effective method for treating end stage androgen independent, progressive CRPC and metastatic NET. Similarly a personalized treatment model based on molecular biomarkers and imaging in breast cancer is possible based on imaging of estrogen receptors and 18F FES imaging in breast cancer. In this presentation, I am going to discuss our experience in precision oncology based on the above concepts.