There is now an increasing trend for targeting cancers to go beyond early diagnosis and actually improve Progression-Free Survival and Overall Survival. Identifying patients who might benefit from a particular targeted treatment is the main focus for Precision Medicine. Radiolabeled ligands can be used as predictive biomarkers which can confirm target expression by cancers using positron emission tomography (PET). The same ligand can subsequently be labeled with a therapeutic radionuclide for targeted radionuclide therapy. This combined approach is termed “Theranostics”. The prostate-specific membrane antigen (PSMA) has emerged as an attractive diagnostic and therapeutic target for small molecule ligands in prostate cancer. It can be labeled with either positron emitters for PET-based imaging or beta and alpha emitters for targeted radionuclide therapy. This review article summarizes the important concepts for Precision Medicine contributing to improved diagnosis and targeted therapy of patients with prostate cancer and we identify some key learning points and areas for further research.

This review article summarizes the role of combined ⁶⁸Ga DOTA-peptides and ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in the evaluation of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). Patients with GEP-NENs can initially present themselves to a gastroenterologist or endocrinologist rather than cancer specialist; hence, it is vital for a wider group of clinicians to be familiar with the range of tests available for the evaluation of these patients. The role of PET scanning by using ⁶⁸Ga DOTA-peptides has a high sensitivity in the diagnosis of GEP-NENs and to guide patient selection for treatment with somatostatin analogues (SSA) and/or peptide receptor radionuclide therapy (PRRT). The loss of somatostatin receptor (SSTR) expression was found to be associated with an increased glucose metabolism in cells. However, the routine use of SSTR targeted radiotracers in combination with ¹⁸F-FDG to evaluate glucose utilization in GEP-NENs is still debatable. In our opinion, in patients with NENs, ¹⁸F-FDG PET should be performed in the case of a negative or slightly positive ⁶⁸Ga DOTA-peptides PET scan for assessing the dedifferentiation status, to guide correct therapeutic strategy and to evaluate the prognosis. The approach of combined receptor and metabolic imaging can improve diagnostic accuracy, especially considering the heterogeneity of these lesions. Therefore, ⁶⁸Ga DOTA-peptides and ¹⁸F-FDG PET should be considered complementary in patients with GEP-NENs.

To evaluate treatment outcomes following radioactive iodine (RAI) treatment with a cumulative dose of ≥≥600 mCi in differentiated thyroid carcinoma (DTC) patients, a retrospective review of medical records was done in 176 DTC patients with a cumulative dose of ≥600 mCi from January 1993 to December 2013. All patients were followed up for at least 2 years after receiving 600 mCi of I-131 treatment. Remission criteria were no clinical and imaging evidence of disease and low serum thyroglobulin levels during thyroid-stimulating hormone suppression of <0.2 ng/ml or of <1 ng/ml after stimulation in the absence of interfering antibodies. A total of 176 patients were included in the study: 137 – papillary thyroid cancer, 29 – follicular thyroid cancer, 9 – mixed papillary and follicular thyroid cancer, and 1 – Hurthle cell carcinoma. Most of the patients (118, 67%) had locoregional metastasis, whereas 48 patients (27%) had distant metastases at presentation. The median cumulative dose was 900 mCi (range: 600–2200 mCi). The mean follow-up period was 82.84 ± 42.41 months. Only 16 patients (9.1%) met remission criteria at the end of treatment. The rest of patients (160, 90.9%) were not remitted: stable disease in 94 (53.4%), at least 1 metastasis without I-131 uptake in 34 (19.3%), progressive disease in 21 (11.9%), and death during the whole follow-up period in 11 (6.3%). Two patients (1.1%) developed second primary malignancy. Eighteen cases were suspected of bone marrow suppression (14 cases [7.9%] had anemia and 5 cases [2.8%] had neutropenia). Seven patients (3.9%) developed permanent salivary gland dysfunction. Although the complications after receiving RAI treatment with a cumulative dose of ≥≥600 mCi were low and not severe, the patients with remission were in <10%. Our study suggests that the decision to administer further treatments should be made on an individual basis because beneficial effects may be controversial.