Hypofractionated re-irradiation for diffuse intrinsic pontine glioma.

BACKGROUND: Re-irradiation (reRT) increases survival in locally recurrent diffuse intrinsic pontine glioma (DIPG). There is no standard dose and fractionation for reRT, but conventional fractionation (CF) is typically used. We report our institutional experience of reRT for DIPG, which includes hypofractionation (HF). METHODS: We reviewed pediatric patients treated with brainstem reRT for DIPG at our institution from 2012 to 2022. Patients were grouped by HF or CF. Outcomes included steroid use, and overall survival (OS) was measured from both diagnosis and start of reRT. RESULTS: Of 22 patients who received reRT for DIPG, two did not complete their course due to clinical decline. Of the 20 who completed reRT, the dose was 20-30 Gy in 2-Gy fractions (n = 6) and 30-36 Gy in 3-Gy fractions (n = 14). Median age was 5 years (range: 3-14), median interval since initial RT was 8 months (range: 3-20), and 12 received concurrent bevacizumab. Median OS from diagnosis was 18 months [95% confidence interval: 17-24]. Median OS from start of reRT for HF versus CF was 8.2 and 7.5 months, respectively (p = .20). Thirteen (93%) in the HF group and three (75%) in the CF group tapered pre-treatment steroid dose down or off within 2 months after reRT due to clinical improvement. There was no significant difference in steroid taper between HF and CF (p = .4). No patients developed radionecrosis. CONCLUSION: reRT with HF achieved survival duration comparable to published outcomes and effectively palliated symptoms. Future investigation of this regimen in the context of new systemic therapies and upfront HF is warranted.

Cryptic ETV6-ABL1 Fusion and MLL2 Truncation Revealed by Integrative Clinical Sequencing in Multiply Relapsed Acute Lymphoblastic Leukemia.

The ETV6-ABL1 fusion is a rare genetic aberration classified as Philadelphia chromosome-like high-risk B-cell precursor acute lymphoblastic leukemia. We present the case of a child with multiply relapsed B-cell precursor acute lymphoblastic leukemia in which next-generation sequencing identified this cryptic fusion, undetected by standard testing, resulting in sustained clinical response to targetted therapy with imatinib. Upon subsequent relapse, repeat next-generation sequencing identified an additional aberration, MLL2-ADCY9, as a possible molecular driver conferring resistance to therapy. This report demonstrates the exciting potential of integrative clinical sequencing in identifying previously undetected actionable findings leading to improved outcomes in pediatric oncology patients.

A Prospective Study on Deep Inspiration Breath Hold Thoracic Radiation Therapy Guided by Bronchoscopically Implanted Electromagnetic Transponders.

BACKGROUND: Electromagnetic transponders bronchoscopically implanted near the tumor can be used to monitor deep inspiration breath hold (DIBH) for thoracic radiation therapy (RT). The feasibility and safety of this approach require further study. METHODS: We enrolled patients with primary lung cancer or lung metastases. Three transponders were implanted near the tumor, followed by simulation with DIBH, free breathing, and 4D-CT as backup. The initial gating window for treatment was ±5 mm; in a second cohort, the window was incrementally reduced to determine the smallest feasible gating window. The primary endpoint was feasibility, defined as completion of RT using transponder-guided DIBH. Patients were followed for assessment of transponder- and RT-related toxicity. RESULTS: We enrolled 48 patients (35 with primary lung cancer and 13 with lung metastases). The median distance of transponders to tumor was 1.6 cm (IQR 0.6-2.8 cm). RT delivery ranged from 3 to 35 fractions. Transponder-guided DIBH was feasible in all but two patients (96% feasible), where it failed because the distance between the transponders and the antenna was >19 cm. Among the remaining 46 patients, 6 were treated prone to keep the transponders within 19 cm of the antenna, and 40 were treated supine. The smallest feasible gating window was identified as ±3 mm. Thirty-nine (85%) patients completed one year of follow-up. Toxicities at least possibly related to transponders or the implantation procedure were grade 2 in six patients (six incidences, cough and hemoptysis), grade 3 in three patients (five incidences, cough, dyspnea, pneumonia, and supraventricular tachycardia), and grade 4 pneumonia in one patient (occurring a few days after implantation but recovered fully and completed RT). Toxicities at least possibly related to RT were grade 2 in 18 patients (41 incidences, most commonly cough, fatigue, and pneumonitis) and grade 3 in four patients (seven incidences, most commonly pneumonia), and no patients had grade 4 or higher toxicity. CONCLUSIONS: Bronchoscopically implanted electromagnetic transponder-guided DIBH lung RT is feasible and safe, allowing for precise tumor targeting and reduced normal tissue exposure. Transponder-antenna distance was the most common challenge due to a limited antenna range, which could sometimes be circumvented by prone positioning.

Normal Tissue Integral Dose as a Result of Prostate Radiation Therapy: A Quantitative Comparison Between High-Dose-Rate Brachytherapy and Modern External Beam Radiation Therapy Techniques.

Purpose: Quantification of integral radiation dose delivered during treatment for prostate cancer is lacking. We performed a comparative quantification of dose to nontarget body tissues delivered via 4 common radiation techniques: conventional volumetric modulated arc therapy, stereotactic body radiation therapy, pencil-beam scanning proton therapy, and high-dose-rate brachytherapy. Methods and Materials: Plans for each radiation technique were generated for 10 patients with typical anatomy. For brachytherapy plans, virtual needles were placed to achieve standard dosimetry. Standard planning target volume margins or robustness margins were applied as appropriate. A "normal tissue" structure (entire computed tomography simulation volume minus planning target volume) was generated for integral dose computation. Dose-volume histogram parameters for targets and normal structures were tabulated. Normal tissue integral dose was calculated by multiplying normal tissue volume by mean dose. Results: Normal tissue integral dose was lowest for brachytherapy. Pencil-beam scanning protons, stereotactic body radiation therapy, and brachytherapy resulted in 17%, 57%, and 91% absolute reductions compared with standard volumetric modulated arc therapy, respectively. Mean nontarget tissues receiving 25%, 50%, and 75% of the prescription dose were reduced by 85%, 76%, and 83% for brachytherapy relative to volumetric modulated arc therapy, by 79%, 64%, and 74% relative to stereotactic body radiation therapy, and 73%, 60%, and 81% relative to proton therapy. All reductions observed using brachytherapy were statistically significant. Conclusions: High-dose-rate brachytherapy is an effective technique for reducing dose to nontarget body tissues relative to volumetric modulated arc therapy, stereotactic body radiation therapy, and pencil-beam scanning proton therapy.

Superior sulcus non-small cell lung cancers (Pancoast tumors): Current outcomes after multidisciplinary management.

OBJECTIVE: Despite neoadjuvant chemoradiotherapy, Pancoast tumors still present surgical and oncologic challenges. To optimize outcomes, we used a multidisciplinary care paradigm with medical and radiation oncology, and involvement of spine neurosurgery for most T3 and all T4 tumors. Spine neurosurgery permitted resection of transverse process for T3 and vertebral body resection for T4 tumors. METHODS: Retrospective analysis of single institution, prospective database of patients undergoing resection for cT3 4M0 Pancoast tumors. Patients were grouped as cT3 with combined resection with spine neurosurgery (T3 Neuro), cT3 without spine neurosurgery (T3 NoNeuro), and cT4. Overall survival, progression-free survival were analyzed by Kaplan-Meier and compared between groups using log-rank test. Cumulative incidence of local-regional and distant recurrence were compared using Gray test. P value <.05 was considered significant. RESULTS: From 2000 to 2021, 155 patients underwent surgery: median age was 58 years, and 81 were (52%) men. Most patients received neoadjuvant platinum-based neoadjuvant chemoradiotherapy (n = 127 [82%]). Operations were 48 cT3 Neuro, 41 cT3 NoNeuro, 66 cT4. R0 resection was achieved in 49 (94%) cT3 NoNeuro, 35 (85%) cT3 Neuro, and 57 (86%) cT4 patients (P = .4). Complete or major pathologic response occurred in 71 (55%) patients. Lower local-regional cumulative incidence was seen in cT3 Neuro versus cT3 NoNeuro (P = .05) and after major pathologic response. Overall survival and progression-free survival were associated with complete response, pathologic stage, and nodal status but not cT category. CONCLUSIONS: This treatment paradigm was associated with a high frequency of R0 resection, complete response, and major pathologic response. cT3 and cT4 tumors had similar outcomes. Novel therapies are needed to improve complete response.

Investigation of the Prognostic Significance of Neuroendocrine Differentiation in Gleason Score 7 to 10 Prostate Adenocarcinoma in Patients With Distant Metastasis After Definitive Radiotherapy.

OBJECTIVES: We investigated the prognostic implications of neuroendocrine differentiation (NED) in prostate adenocarcinoma detected by chromogranin A (CgA) in patients who developed distant metastasis (DM) after radiotherapy. METHODS: Patients with Gleason score 7 to 10 conventional acinar prostate adenocarcinoma treated with definitive radiotherapy and with core biopsy CgA staining completed were reviewed. Patients who developed DM, defined as disease beyond the primary tumor or pelvic lymph nodes, underwent detailed chart review. Statistical analysis included Kaplan-Meier estimates and descriptive statistics to compare based on quantification of CgA staining. RESULTS: Thirty-five patients had confirmed DM. Twenty-five patients had less than 1% of cells staining positive for CgA, and 10 patients had more than 1%. Median overall survival (OS) time was 3.26 and 1.04 years, respectively (P = .52). Median cause-specific survival (CSS) was 6.15 and 1.04 years, respectively (P = .21). Fifty-six percent of patients with CgA less than 1% died of prostate cancer compared with 90% of those with CgA more than 1% (P = .059). There were no significant differences in sites of metastatic disease or administration of systemic therapies. CONCLUSIONS: No significant differences in OS and CSS were observed based on NED detected by CgA. Reduced median survival time and increased cancer-related death in cases with focal NED generates the hypothesis of inferior outcomes among patients with documented DM.

The Role of Postoperative Radiation Therapy for pN2 Non-small-cell Lung Cancer.

BACKGROUND: The role for postoperative radiation therapy (PORT) for patients with non-small-cell lung cancer (NSCLC) with mediastinal lymph node (LN) involvement (pN2 disease) is controversial. We compared surgery alone with PORT among patients with pN2 NSCLC. We then performed subset analyses to better delineate patients that might benefit from PORT. PATIENTS AND METHODS: We conducted a propensity score (PS)-matched, inverse probability of treatment weighting (IPTW) Surveillance, Epidemiology, and End Results (SEER) analysis of patients with pN2 disease from 1989 to 2016 with surgery alone or PORT. Multiple imputation with chained equations was used for missing LN data. RESULTS: A total of 8631 patients were included in this analysis; 4579 underwent surgery alone, and 4052 underwent PORT. Following PS matching and IPTW, there was no difference in overall survival (OS) (hazard ratio [HR], 0.99; P = .76). However, PORT improved OS among a subset of patients with a LN positive to sampled ratio ≥ 50% (HR, 0.90; P = .01). Moreover, there was a trend towards improved OS among this subset, even with chemotherapy (HR, 0.91; P = .09). CONCLUSION: PORT is not associated with an improvement or detriment in OS for all patients with pN2 NSCLC. However, patients with a positive to sampled LN ratio ≥ 50% may benefit, regardless of chemotherapy status. Nevertheless, PORT will remain the standard of care as we await the results of the ongoing LUNG ART trial.

KRAS mutant tenosynovial giant cell tumor in a pediatric patient: a case report.

Tenosynovial giant cell tumors (TSGCT) are a group of rare, benign soft tissue tumors with common histologic and cytogenetic features, with a median age of diagnosis being 47 years. Generally divided into localized and diffuse subtypes, TSGCTs are typically driven by overexpression of macrophage colony stimulating factor receptor-1 (CSF1R). Treatment of TSGCT is tumor resection, followed by radiation therapy in cases of incomplete resection. Even when the tumor is completely removed, recurrence rates can be as high as 30% in some anatomical locations. Here we report the identification of a previously undescribed KRAS p.G12D activating mutation within a pediatric TSGCT patient, who clinically presented with an enlarging right lower extremity mass pathologically consistent with TSGCT. The patient continues to be in remission three years after complete surgical removal. KRAS mutations are usually found in adult cancers, such as lung and pancreatic, as well as giant cell lesion of the jaw. This case demonstrates the utility of integrative clinical sequencing in identifying lesions with aggressive potential and aiding in complex diagnoses.