Decade Long Disease, Secondary Malignancy, and Brainstem Injury Outcomes in Pediatric and Young Adult Medulloblastoma Patients Treated with Proton Radiotherapy

BACKGROUND

Survivors of pediatric medulloblastoma experience long term morbidity associated with the toxic effects of post-operative radiotherapy. Proton radiotherapy limits radiation dose to normal tissues thereby reducing side effects of treatment while maintaining high cure rates. However, long term data on disease outcomes and long-term effects of proton radiotherapy remain limited.

METHODS

178 Pediatric medulloblastoma patients treated with proton radiotherapy between 2002-2016 at the Massachusetts General Hospital comprise the cohort of patients who were treated with surgery, radiation therapy and chemotherapy. We evaluated EFS, OS, and LC using the Kaplan Meier method. The cumulative incidence of brainstem injury and secondary malignancies was assessed.

RESULTS

Median follow-up was 9.3 years. 159 patients (89.3%) underwent a gross total resection (GTR). The 10-year OS for the entire cohort, standard risk, and intermediate/high risk patients was 79.3%, 86.9%, and 68.9% respectively. The 10-year EFS for entire cohort, SR, and IR/HR cohorts was 73.8%, 79.5%, and 66.2%. The 10-year EFS and OS for patients with GTR/NTR were 75.3% and 81.0% versus 57.7% and 61.0% for STR. On univariate analysis, IR/HR status was associated with inferior EFS, while both anaplastic histology and IR/HR status was associated with worse overall survival. The 10-year cumulative incidence of secondary tumors and brainstem injury was 5.6% and 2.1%, respectively.

CONCLUSIONS

In this cohort study of pediatric medulloblastoma, proton radiotherapy was effective and disease outcomes were comparable to historically treated photon cohorts. The incidence of secondary malignancies and brainstem injury was low in this cohort with mature follow up.

Absence of nucleotide-binding oligomerization domain-containing protein 2 variants in patients with leprosy and tuberculosis

Crohn's disease-associated NOD 2 variants (Arg702Trp and 3020insC) were found to be monomorphic (wild), and 7 subjects were heterozygous for Gly908Arg SNP in 263 patients with tuberculosis, 260 patients with leprosy and 270 healthy controls residing in northern Indian states. This is the first report to suggest the minimal role of these variants in susceptibility/resistance to TB and leprosy in this population.

High efficiencies of gene transfer with immobilized recombinant retrovirus: kinetics and optimization

We used a combination of mathematical modeling and experiments to investigate the rate-limiting steps of retroviral transduction on surface-bound fibronectin (FN) and identify the conditions that maximize the efficiency of gene transfer. Our results show that fibronectin-assisted gene transfer (FAGT) is a strong function of the time and temperature of virus incubation in FN-coated plates. Gene transfer increases sharply at short times, reaches a maximum at intermediate times, and eventually declines as a result of loss of retroviral activity. The maximum transduction efficiency and the time at which this is attained increase with decreasing temperature of virus incubation. Depending on the temperature and the type of target cells, the initial rate of gene transfer increases by 3- to 10-fold and the maximum transduction efficiency increases by 2- to 4-fold as compared to traditional transduction (TT). Interestingly, Polybrene (PB) inhibits FAGT in a dose-dependent manner by inhibiting binding of retrovirus to FN. In contrast to traditional transduction, FAGT yields higher than 10-fold transduction efficiencies with concentrated retrovirus stocks. Gene transfer is directly proportional to the concentration of the virus-containing medium with no sign of saturation for the range of concentrations tested. These results suggest that immobilization of recombinant retrovirus can be rationally optimized to yield high efficiency of gene transfer to primary cells and improve the prospect of gene therapy for the treatment of human disease.