Pediatric Transplant Interventions

The field of pediatric organ transplantation has grown significantly in recent decades, with interventional radiology (IR) playing an essential role in managing pre and post-transplant complications. Pediatric transplant patients face unique challenges compared to adults, including donor-recipient size mismatch, and complications of a growing child with changing physiology. Interventional radiologists play a major role in pediatric renal and liver transplant. IR interventions begin early in the child's pretransplant journey, with diagnostic procedures such as biopsies, angiograms, and cholangiograms. These procedures are essential for understanding the etiology of organ failure and identifying potential transplant candidates. Minimally invasive therapeutic procedures may serve as bridges to transplant and may include vascular access optimization for hemodialysis, transjugular intrahepatic portosystemic shunts (TIPS) creation, and tumor embolization or ablation. After transplant, image-guided biopsies for the surveillance of graft rejection and treatment of vascular or luminal stenoses, pseudoaneurysms, and anastomotic leaks can maintain the function and longevity of the transplant organ. Careful consideration must be given to patient size and evolving anatomy, radiation exposure, and the need for deeper sedation for pediatric patients. Despite these challenges, the integration of IR in pediatric transplant care has proven beneficial, offering minimally invasive alternatives to surgery, faster recovery times, and improved outcomes.

Role of Resin Microsphere Y90 Dosimetry in Predicting Objective Tumor Response, Survival and Treatment Related Toxicity in Surgically Unresectable Colorectal Liver Metastasis: A Retrospective Single Institution Study

Simple Summary

Colorectal liver metastases are difficult to treat, with only a minority of patients eligible for surgical resection. Yttrium-90 selective internal radiation therapy is an alternative treatment currently used for patients who have progressed on chemotherapy. A technique called dosimetry allows clinicians to analyze how much radiation was delivered to target lesions post-treatment. The aim of this study is to evaluate the relationship of various dosimetric parameters with objective tumor response, overall survival, and treatment related toxicity with the potential goal of optimizing Yttrium-90 treatment in this patient population. Additionally, other potential predictors of survival outcomes, including clinical and demographic factors, were also evaluated. We found that delivering a mean tumor dose ≥100 Gy when using resin microspheres was significantly associated with objective tumor response and prolonged overall survival. In this study, no mean non-tumoral liver dose threshold was found to predict treatment related toxicity.

Abstract

Purpose: To Evaluate the correlation between tumor dosimetric parameters with objective tumor response (OR) and overall survival (OS) in patients with surgically unresectable colorectal liver metastasis (CRLM) undergoing resin-based Ytrrium-90 selective internal radiation therapy (Y90 SIRT). Materials and Methods: 45 consecutive patients with CRLM underwent resin-based Y90 SIRT in one or both hepatic lobes (66 treated lobes total). Dose volume histograms were created with MIM Sureplan^® v.6.9 using post-treatment SPECT/CT. Dosimetry analyses were based on the cumulative volume of the five largest tumors in each treatment session and non-tumoral liver (NTL) dose. Receiver operating characteristic (ROC) curve was used to evaluate tumor dosimetric factors in predicting OR by Response Evaluation Criteria for Solid Tumors at 3 months post-Y90. Additionally, ROC curve was used to evaluate non-tumoral liver dose as a predictor of grade ≥ 3 liver toxicity and radioembolization induced liver disease (REILD) 3 months post Y90. To minimize for potential confounding demographic and clinical factors, univariate and multivariate analysis of survival with mean tumor dose as one of the factors were also performed. Kaplan-Meier estimation was used for OS analysis from initial Y90 SIRT. Results: 26 out of 45 patients had OR with a median OS of 17.2 months versus 6.8 months for patients without OR (p < 0.001). Mean tumor dose (TD) of the five largest tumors was the strongest predictor of OR with an area under the curve of 0.73 (p < 0.001). Minimum TD, and TD to 30%, 50%, and 70% of tumor volume also predicted OR (p’s < 0.05). Mean TD ≥ 100 Gy predicted a significantly prolonged median OS of 19 vs. 11 months for those receiving TD < 100 Gy (p = 0.016). On univariate analysis, mean TD < 100 Gy, presence of any genomic mutation, presence of MAPK pathway mutation, bilobar hepatic metastases and diffuse metastatic disease (>10 lesions per liver lobe) were found to be predictors of shorter median OS. On multivariate analysis, mean TD < 100 Gy, presence of any genomic mutation, and diffuse hepatic metastatic disease were found to be independent predictors of shorter OS. Overall, six (13.3%) patients developed grade ≥ 3 liver toxicity post Y90 of whom two (4.4%) patients developed REILD. No dose threshold predicting grade ≥ 3 liver toxicity or REILD was identified. Conclusions: Mean TD ≥ 100 Gy in patients with unresectable CRLM undergoing resin-based Y90 SIRT predicts OR and prolonged OS.

Impact of Genomic Mutation and Timing of Y90 Radioembolization in Colorectal Liver Metastases

PURPOSE

To investigate timing of Yttrium-90 radioembolization (Y90) during treatment course, genomics, and other clinical factors as predictors of overall survival (OS) in colorectal liver metastasis (CRLM) that have progressed on at least one line of chemotherapy.

MATERIALS AND METHODS

This was a retrospective study from 2013 to 2018 of patients with CRLM and genomic analysis prior to Y90 at a multihospital tertiary referral center. OS from liver metastasis diagnosis and predictors of OS were analyzed using Kaplan-Meier estimation with log-rank and Cox regression analyses.

RESULTS

Overall, 58 patients with CRLM who progressed on at least one line of chemotherapy who had genomic analysis prior to Y90 were identified. Median OS after hepatic metastasis was 29.9 months. Of these, 16 (28%) patients received Y90 after failure of the first-line systemic chemotherapy. There was significantly prolonged OS in patients receiving Y90 immediately following failure of the first-line chemotherapy folinic acid, fluorouracil, oxaliplatin ((FOLFOX) ± bevacizumab) versus following multiple lines of chemotherapy (median OS of 46.3 vs. 26.6 months, P = 0.005). The presence of genetic mutation in tumor, MAPK pathway wild type, left-sided primary tumor, low MELD score, and non-diffuse unilobar disease were also found to be predictors prolonged survival on log-rank analysis (P's < 0.05). On multivariate analysis, receiving Y90 after failure of the first line of chemotherapy, low baseline MELD score, and baseline ECOG performance score of 0 were all found to be independent predictors of prolonged OS from the time of metastatic disease diagnosis (P's < 0.05).

CONCLUSION

In patients with CRLM, receiving Y90 after failing the first line of chemotherapy, lack of genetic mutation, low MELD score, and lower tumor burden appear to be independent predictors of prolonged OS.

LEVEL OF EVIDENCE

Level 4, case-control study.

Predictors of survival in chemorefractory colorectal liver metastases treated with Y90 radioembolization

e15044

Background: The aim of the study was to evaluate molecular signatures and timing of yttrium-90 (Y90) as prognostic factors of survival following Y90 radioembolization (RE) in patients with chemorefractory colorectal liver metastases (CRLM). Methods: In a retrospective single-institution study, patients with unresectable, chemorefractory CRLM who had undergone genomic analysis prior to Y90 RE from 2013 to 2018 were identified. Timing of Y90 (following failure of first line vs following multiple lines of chemotherapy) and oncogenic mutation status (MAPK and PI3K pathways) were evaluated as predictors of survival length following Y-90. Survival was measured from first Y90 using Kaplan-Meier estimation and predictors of outcome were identified using log-rank analysis. Results: Overall, 58 patients with chemorefractory CRLM who underwent genomic analysis prior to Y-90 were identified. Of these, 26 (44.8%) had MAPK mutations, and 2 (3.5%) had PI3K mutations. Median survival after first Y-90 RE was 12.9 months. There was significantly prolonged overall survival (OS) in patients receiving Y90 immediately following failure of the first line of chemotherapy (FOLFOX ± bevacizumab) versus patients who underwent multiple lines of chemotherapy prior to Y90 (median OS of 16.9 vs 11.4 months for others; p = 0.023). When stratifying the cohort based on the timing of Y90, patients with WT-MAPK (n = 8) had prolonged OS if they underwent Y-90 following failure of the first line of chemotherapy (median OS of 22.3 vs 12.9 mo; p = 0.019). Patients with WT-PI3K (n = 19) had prolonged OS if they underwent Y90 following failure of the first line of chemotherapy (median OS of 16.9 vs 12 mo; p = 0.037). When analyzing the entire cohort non-stratified by timing of Y90, genetic mutation was not found to be a predictor of prolonged OS. Conclusions: Y90 RE after failure of first line of chemotherapy in CRLM appears to confer prolonged survival specifically for WT-MAPK and WT-PI3K oncogenes. Conversely, the prognosis of more favorable genetic status appears to be negated if Y90 RE is performed after failure of second or third line chemotherapies.

Putting the "No" in Non Nocere: Surgery, Anesthesia, and a Patient's Right to Withdraw Consent

[Full article available at http://rimed.org/rimedicaljournal-2017-10.asp].