核医学と放射線治療

NETs are rare, heterogeneous group of neoplasm presented as chronic oncologic disease. Somatostatin analogue is the standard first line systemic therapy for mainly hormone control. No standard second line systemic treatment is available except everolimus which has no reported complete response. PRRT is an innovative molecular targeted treatment based on theragnostic concept for well differentiated NETs. We presented here a 63-year-old lady with grade 1 NET of rectum with lymphnodal and liver metastasis. She underwent sigmoid colostomy for bowel symptoms and started on sandostatin LAR. After progression, patient was treated with 4 cycles of 7.4GBq of 177Lu-DOTATATE at 10 weeks interval. No hematological and renal toxicity were noticed. Patient showed complete response in liver lesions & lymphnodes and partial response in rectal lesion on 68Ga-DOTANOC PET-CT. After multispecialty clinic board discussion, patient underwent curative surgery for residual rectal lesion and colostomy closer later on. Our case highlights a common presentation of NETs but an uncommon outcome with currently approved drugs. With this potential of disease cure in metastasis, PRRT may also be offered for locally advance disease as an adjuvant treatment for down staging.fv

Purpose: To evaluate differences in shunt fraction and possible factors contributing to these differences in patients undergoing Tc-99m macroaggregated albumin (MAA) mapping prior to selective internal radiation therapy (SIRT) with Y-90 microspheres. Materials and methods: Retrospective analysis was performed on data from 130 patients with hepatocellular carcinoma (HCC) or liver metastases, who underwent Y-90 radioembolization over a 6-year period. All patients who received treatment had undergone Tc-99m MAA mapping. Overall 141 Tc-99m MAA injections and 199 Y-90 treatments were performed. Three patients did not qualify for Y-90 treatment following Tc-99m MAA mapping due to high pulmonary shunt fraction. We compared pulmonary shunt fraction between patients with HCC and those with metastatic liver disease and between patients who had mapping of the entire liver, versus selective mapping of the affected segment. Three types of statistical analysis tests were performed: Kolmogorov-Smirnov (KS), Mann- Whitney (MW) and Fligner-Killeen (FK) tests. Results: Although HCC and non-HCC groups had similar distribution of shunt fractions qualitatively, relatively large shunt fractions were slightly more common in HCC group. In diffuse injections, most of the shunt fractions were concentrated between 0 and 5%, but with a long tail to the right. In more selective injections, most were concentrated between 0 and 10%. There was a trend for overall higher median shunt fraction in the diffuse mapping group compared with the selective mapping group, however this was only statistically significant in the HCC patients subset (median shunt of 3.2% in diffuse vs. 6.1% in selective group; p=0.001). Conclusions: Shunt fraction is overall higher in HCC, likely due to underlying cirrhosis as well as intratumoral arteriovenous shunting. Shunt fraction also tends to be higher when the affected liver is selectively injected compared with when the entire liver is being mapped.

After Yttrium (Y⁹⁰) Ibritumomab tiuxetan (Zevalin) and Iodine (131I) tositumomab (Bexxar) were approved by the FDA, the improved response of B-cell NHL to this novel RIT makes it a promising alternative to more aggressive treatment like HSCT. In this study, we describe the experience of a single community-based cancer with RIT and HSCT in patients with B-cell NHL in terms of response, survival and toxicity. Retrospectively, we reviewed 75 patients with B cell NHL who were treated with either RIT (N=50) or HSCT (N=25) between 2003 and 2013. Choice of treatment modality, i.e. RIT vs. HSCT was based on discretion of treating Oncologist taking into consideration patient’s age, performance status, comorbidity and preferences. RIT-treated patients were older. HSCT was more likely to be used in aggressive lymphoma and as a consolidation of primary therapy. RIT was used mainly in indolent lymphoma and as salvage treatment. Overall response rates were better in HSCT-treated patients (100% vs. 76%). Median overall survival was higher in HSCT-treated patients (221 vs. 79.4 months). Similar results were obtained when we compared OS in patients younger than 60 years (221 vs. 79.4 months) and in patients with aggressive lymphoma (221 vs. 59.7 months). PFS was not met in HSCT, while it was 16.2 months in RIT. Myelodysplastic syndrome (MDS) occurred in both groups (12% HSCT vs. 2% RIT). Thrombocytopenia was more prevalent with RIT. All other toxicities were significantly more common with HSCT. This study shows that, in clinical practice, younger patients with aggressive B-cell NHL and without significant comorbidity are more likely to be offered HSCT. On the other hand, RIT was offered to older patients with indolent histology. Our results show that RIT is a reasonable alternative salvage treatment modality for B-cell NHL patients who are not candidates for HSCT.