Modern Radiation Treatment Planning Parameters and Outcomes in Pediatric Tectal Gliomas

Purpose

Pediatric low-grade tectal gliomas are rare, indolent tumors of the brain stem. We reviewed outcomes of pediatric patients who received a diagnosis of low-grade tectal gliomas and report dosimetric parameters for those receiving radiation therapy (RT).

Methods and Materials

We retrospectively reviewed all pediatric patients (age <18 years) at our institution diagnosed with a low-grade glioma between 1993 and 2020 (n = 288). Twenty-three patients with tectal gliomas were identified. Patients who received RT (n = 8) had detailed dosimetric analyses performed. Doses to critical structures and any resulting toxicities were reviewed. Minimum follow-up was 2 years and complete follow-up was available for all patients.

Results

Twenty-three patients, with a median age of 8.9 years, were included (range, 0.5-16.2 years). At a median follow-up of 7.4 years (range, 2-24 years), all were alive at the end of the study period. Three patients (13%) were treated with upfront RT; none of these patients developed local failure (LF) after a median follow-up of 10.6 years. One patient was treated with upfront chemotherapy with no evidence of progression afterward. Nineteen patients were initially observed after diagnosis and 26% of them (n = 5) experienced local progression. All 5 were treated with salvage RT, with 1 patient requiring further treatment with chemotherapy. Fractionation schedules for patients undergoing upfront or salvage RT included 50.4 Gy in 28 fractions (n = 4), 54 Gy in 30 fractions (n = 2), and 51 Gy in 30 fractions (n = 2). For patients treated after 2007, the gross tumor volume was delineated on a T2 magnetic resonance imaging with an average gross tumor volume-to-planning target volume expansion of 4.5 mm (range, 3-5 mm). Detailed dosimetric parameters were available for all patients treated with RT.

Conclusions

Our review supports the indolent behavior for most tectal gliomas. For the subset of tumors with evidence of progression, modern photon RT results in excellent oncologic outcomes with minimal late effects.

Federated learning enables big data for rare cancer boundary detection

Although machine learning (ML) has shown promise across disciplines, out-of-sample generalizability is concerning. This is currently addressed by sharing multi-site data, but such centralization is challenging/infeasible to scale due to various limitations. Federated ML (FL) provides an alternative paradigm for accurate and generalizable ML, by only sharing numerical model updates. Here we present the largest FL study to-date, involving data from 71 sites across 6 continents, to generate an automatic tumor boundary detector for the rare disease of glioblastoma, reporting the largest such dataset in the literature (n = 6, 314). We demonstrate a 33% delineation improvement for the surgically targetable tumor, and 23% for the complete tumor extent, over a publicly trained model. We anticipate our study to: 1) enable more healthcare studies informed by large diverse data, ensuring meaningful results for rare diseases and underrepresented populations, 2) facilitate further analyses for glioblastoma by releasing our consensus model, and 3) demonstrate the FL effectiveness at such scale and task-complexity as a paradigm shift for multi-site collaborations, alleviating the need for data-sharing.

Rate of Organ Space Infection Is Reduced with the Use of an Air Leak Test During Major Hepatectomies

BACKGROUND

Organ/space surgical site infections (OSIs) constitute an important postoperative metric. We sought to assess the impact of a previously described air leak test (ALT) on the incidence of OSI following major hepatectomies.

METHODS

A single-institution hepatobiliary database was queried for patients who underwent a major hepatectomy without biliary-enteric anastomosis between January 2009 and June 2015. Demographic, clinicopathologic, and intraoperative data-including application of ALT-were analyzed for associations with postoperative outcomes, including OSI, hospital length of stay (LOS), morbidity and mortality rates, and readmission rates.

RESULTS

Three hundred eighteen patients were identified who met inclusion criteria, of whom 210 had an ALT. ALT and non-ALT patients did not differ in most disease and treatment characteristics, except for higher rates of trisegmentectomy among ALT patients (53 vs. 34 %, p = 0.002). ALT patients experienced lower rates of OSI and 90-day morbidity than non-ALT patients (5.2 vs. 13.0 %, p = 0.015 and 24.8 vs. 40.7 %, p = 0.003, respectively). In turn, OSI was the strongest independent predictor of longer LOS (OR = 4.89; 95 % CI, 2.80-6.97) and higher rates of 30- (OR = 32.0; 95 % CI, 10.9-93.8) and 45-day readmissions (OR = 29.4; 95 % CI, 10.2-84.6).

CONCLUSIONS

The use of an intraoperative ALT significantly reduces the rate of OSI following major hepatectomy and may contribute to lower post-discharge readmission rates.