Clinical perspectives on dosimetry in molecular radiotherapy.

Molecular radiotherapy is the use of systemically administered unsealed radioactive sources to treat cancer. Theragnostics is the term used to describe paired radiopharmaceuticals localising to a specific target, one optimised for imaging, the other for therapy. For many decades, molecular radiotherapy has developed empirically. Standard administered activity schedules have been used without the prior estimation of the resulting tumour radiation absorbed dose by theragnostic imaging, or its subsequent measurement by serial scanning. This pragmatic approach has benefited many patients, however others who should have benefited have failed to do so as the radiation absorbed dose in the tumour was suboptimal. The accurate prediction and measurement of tumour and organ at risk radiation absorbed doses allows treatment to be personalised, and offers the prospect of improved clinical outcomes. To deliver this for all molecular radiotherapy patients would require not only a significant financial investment in equipment and skilled personnel, but also a change in attitude of those who believe that simple - or simplistic - schedules are easier to deliver, and that accurate dosimetry is too much trouble. Further clinical studies are required to demonstrate beyond doubt that the advantages of individualised treatment planning outweigh the inconvenience, and that the expense is justified by enhanced results.

Prognostic value of postoperative stimulated thyroglobulin in differentiated thyroid cancer.

BACKGROUND: Thyroglobulin (Tg) level is used for long-term follow-up of differentiated thyroid cancer (DTC). However, the prognostic value of the postoperative level and the level which can be considered risky are not clear in literature. PURPOSE: To evaluate the prognostic value of postoperative Tg in DTC for subsequent disease-free status. Also, to determine the cutoff with the highest sensitivity and specificity. METHODS: A retrospective analysis was performed of 62 patients with non-metastatic DTC presenting to our department from January 2018 to December 2019. Three groups were formed according to postoperative stimulated thyroglobulin (sTg) level: <1ng/ml, 1-5ng/ml, and >5ng/ml. Outcomes were compared at 12 months. ROC curve analysis determined the cutoff with the highest sensitivity and specificity. RESULTS: Seven the 62 patients showed persistent or recurrent disease at 12 months after diagnosis. Comparing outcomes in the 3 sTg groups showed thyroglobulin to be a significant prognostic variable. A cut-off of 3.15ng/ml had the highest sensitivity and specificity on ROC curve analysis. CONCLUSION: Postoperative stimulated thyroglobulin is a useful prognostic tool in the postoperative categorization of patients and can subsequently be tested for its value to guide radioactive iodine therapy.

The radiotherapy utilization rate in pediatric tumors: An analysis of 13,305 patients.

PURPOSE: Although the radiotherapy utilization rate (RUR) is determined for most adult cancers, it is seldom reported in childhood tumors, particularly in low- and middle-income countries (LMIC) where the majority of pediatric cancer patients reside. This study aims to investigate the real-life RUR for pediatric tumors in a large LMIC center. MATERIALS AND METHODS: The electronic files of patients treated at a single institution during 2010-2017 were reviewed and the RUR was defined as the percentage of patients who received at least one radiotherapy (RT) course from the total number of patients. RESULTS: A total of 4390 out of 13,305 pediatric cancer patients received at least one RT course with a RUR of 33%. The curative, salvage, and palliative RURs were 27.8%, 2%, and 5.7%, respectively. There was a considerable variation in the RUR between various tumors, ranging from 0% in choroid plexus papilloma and other rare tumors to 100% in intracranial germinoma. Moreover, the RUR varied among different stages within each tumor type. Overall, 753 patients received 920 palliative RT courses (range 1-9) at a median dose of 30 Gy. The most commonly irradiated metastatic sites were the bone (34%) and the brain (9.8%). CONCLUSION: This is the first analysis to provide valuable insights into the RUR for childhood tumors. Together with population-based pediatric cancer registries, this will help decipher pediatric RT needs and deficits. Additionally, the underutilization of palliative RT calls for multidisciplinary palliative care provision for pediatric cancer patients.

Pediatric low grade focal brainstem glioma: outcomes of different treatment strategies and prognostic factors.

Background: This study explores the prognostic factors and outcomes of different treatment modalities in focal brain stem glioma (FBSG). Materials & methods: Pediatric FBSG patients diagnosed during 2010-2017 were retrospectively reviewed for clinical and therapeutic data. Results: A total of 71 cases were identified and the median age was 6.4 years. The 5-year overall- and progression-free survival were 74.5 and 70.6%, respectively. Radiotherapy was the main line of treatment (66.2%) and there were no survival differences between radiotherapy, chemotherapy and surveillance groups. Two independent poor prognostic factors were identified on multivariate analysis: age <8 years and cervicomedullary tumor site (p = 0.02 for both). Conclusion: Surveillance, radiotherapy and chemotherapy have comparable clinical outcomes in pediatric FBSG.