Planning the joint SBRT-IMRT plan in the cases of a significant target overlap requires a careful approach, but is feasible with the proposed guideline and should be achievable for any center electing to participate in the NRG LU-008 trial.

PURPOSE:Stereotactic body radiation therapy (SBRT) has been used with high effectiveness in early-stage non-small cell lung cancer (NSCLC) but has not been studied extensively in locally advanced NSCLC. We conducted a phase 2 study delivering SBRT to the primary tumor followed by conventionally fractionated chemoradiation to the involved lymph nodes for patients with node-positive locally advanced NSCLC. This manuscript serves as both a guide to planning techniques used on this trial and the subsequent phase 3 study, NRG Oncology LU-008, and to report patient dosimetry and toxicity results. METHODS AND MATERIALS:We initiated a phase 2 multicenter single arm study evaluating SBRT to the primary tumor (50-54 Gy in 3-5 fractions) followed by conventionally fractionated chemoradiation to 60 Gy in 2 Gy fractions with doublet chemotherapy to the involved lymph nodes for patients with stage III or unresectable stage II NSCLC. Patients eligible for adjuvant immunotherapy received up to 12 months of durvalumab. We report a detailed guide for the entire treatment process from computed tomography simulation through treatment planning and delivery. The dosimetric outcomes from the 60 patients who completed therapy on study are reported both for target coverage and normal structure doses. We also report correlation between radiation-related toxicities and dosimetric parameters. RESULTS:Sixty patients were enrolled between 2017 and 2022. Planning techniques used were primarily volumetric modulated arc therapy for SBRT to the primary tumor and conventionally fractionated radiation to the involved nodes, with a minority of cases using dynamic conformal arc technique or static dynamic multileaf collimator intensity modulated radiation therapy. Grade 2 or higher pneumonitis was associated with lung dose V5 Gy > 70% and grade 2 or higher pulmonary toxicity was associated with lung dose V10 Gy > 50%. Only 3 patients (5%) experienced grade 3 or higher pneumonitis. Grade 2 or higher esophagitis was associated with esophageal doses, including mean dose > 20 Gy, V60 Gy > 7%, and D1cc > 55 Gy. Only 1 patient (1.7%) experienced grade 3 esophagitis. CONCLUSIONS:SBRT to the primary tumor followed by conventionally fractionated chemoradiation to the involved lymph nodes is feasible with planning techniques as described. Radiation-related toxicity on this phase 2 study was low. This manuscript serves as a guideline for the recently activated NRG Oncology LU-008 phase 3 trial evaluating this experimental regimen.

The value and importance of peer review in radiation oncology has been recognized in the field, but published studies focus on physician peer review of contouring and plan goals. The Radiation Oncology Incident Learning System (ROILS) aggregate reports indicate that the most frequently identified workflow step where events occur is treatment planning. To our knowledge, there is no published report describing the implementation and analysis of a dosimetrist peer review process. The purpose of this study is to examine the effectiveness of a dosimetrist peer review implemented within a commercially available record and verify system. A checklist/questionnaire was created within our R&V system containing commonly verified plan parameters and tasks. In our clinic, the peer review is first completed by a dosimetrist who did not create the plan and then is double checked by a physicist during the initial plan check. Items that are identified as needing correction are noted first by the peer review dosimetrist and then any remaining items are noted by the physicist. A report is generated that contains all the identified items, which are then categorized and analyzed. We analyzed the items that were caught during the peer review and the items that were caught during the subsequent physicist chart check. For calendar year 2016, dosimetrists made 121 total entries in the peer review questionnaire while physicists made 370 total entries, but each entry could contain more than one item needing correction. While the dosimetrist peer review was effective at identifying incorrect charges, the number of items detected by physicists for other categories outnumber those detected by dosimetrists by a margin of 3 to 1. The table below contains the top 5 most identified items by the dosimetrists and physicists. If billing is removed, then the 5th most detected item by dosimetrists is errors in shifts from the simulation isocenter. Dosimetrists performed peer reviews on 84% of new patient charts for 2016. Reasons for a missing peer review include dosimetrist time off and urgent sim and start patients.Abstract 3310RankDosimetristPhysicist1BillingDRR Issue2Setup notes2nd MU Calc Issue3ContouringTolerance Table4Prescription IssuePrescription Issue5Tolerance TableImaging instructions Open table in a new tab We believe this is the first reported implementation and analysis of a formal dosimetrist peer review. While the dosimetrist peer review allowed 75% of the total items through, it was effective at catching certain items, such as billing errors and errors in setup notes. As this is our first analysis of the dosimetrist peer review, this data will serve as our baseline for future comparisons. These results have been shared with the dosimetry staff and additional guidance has been given to improve the detection rate of the dosimetry peer review. We will report updated results at the annual meeting.