Analysis of Radiation Therapy Quality Assurance in NRG Oncology RTOG 0848.

PURPOSE: NRG/Radiation Therapy Oncology Group 0848 is a 2-step randomized trial to evaluate the benefit of the addition of concurrent fluoropyrimidine and radiation therapy (RT) after adjuvant chemotherapy (second step) for patients with resected pancreatic head adenocarcinoma. Real-time quality assurance (QA) was performed on each patient who underwent RT. This analysis aims to evaluate adherence to protocol-specified contouring and treatment planning and to report the types and frequencies of deviations requiring revisions. METHODS AND MATERIALS: In addition to a web-based contouring atlas, the protocol outlined step-by-step instructions for generating the clinical treatment volume through the creation of specific regions of interest. The planning target volume was a uniform 0.5 cm clinical treatment volume expansion. One of 2 radiation oncology study chairs independently reviewed each plan. Plans with unacceptable deviations were returned for revision and resubmitted until approved. Treatment started after final approval of the RT plan. RESULTS: From 2014 to 2018, 354 patients were enrolled in the second randomization. Of these, 160 patients received RT and were included in the QA analysis. Resubmissions were more common for patients planned with 3-dimensional conformal RT (43%) than with intensity modulated RT (31%). In total, at least 1 resubmission of the treatment plan was required for 33% of patients. Among patients requiring resubmission, most only needed 1 resubmission (87%). The most common reasons for resubmission were unacceptable deviations with respect to the preoperative gross target volume (60.7%) and the pancreaticojejunostomy (47.5%). CONCLUSION: One-third of patients required resubmission to meet protocol compliance criteria, demonstrating the continued need for expending resources on real-time, pretreatment QA in trials evaluating the use of RT, particularly for pancreas cancer. Rigorous QA is critically important for clinical trials involving RT to ensure that the true effect of RT is assessed. Moreover, RT QA serves as an educational process through providing feedback from specialists to practicing radiation oncologists on best practices.

Insights From Image Guided Radiation Therapy Credentialing for the NRG Oncology RTOG 1112 Liver Stereotactic Body Radiation Therapy Trial.

PURPOSE: NRG Oncology trial RTOG 1112 is a randomized phase 3 study of sorafenib with or without stereotactic body radiation therapy for locally advanced hepatocellular carcinoma. Image guided radiation therapy (IGRT) credentialing is essential for this study because of the high doses, respiratory motion, and variety of delivery technologies. This analysis presents the IGRT credentialing experience. METHODS AND MATERIALS: Credentialing of volumetric IGRT requires submission of planning and localization images, planning structures, and resulting IGRT shifts for a patient treated according to the study requirements. A study reviewer uses these data to repeat the registrations and compare to the actual clinical registrations. Agreement within 5 mm was considered acceptable for credentialing. RESULTS: Volumetric images of 130 fractions from 42 institutions between June 2013 and January 2018 were reviewed. The median agreement between clinical registrations and study reviewer was 3 mm, with 95% of all fractions within 5 mm. A subanalysis identified a statistically significant difference between the use of low-contrast soft tissue and high-contrast surrogates (eg, implanted fiducial markers, surgical clips, metallic stents) for registration. Soft tissue and high-contrast surrogate registrations both agreed within 3 mm in 50% of fractions. However, soft tissue registrations exceeded 10 mm in 3% of fractions, while no high-contrast surrogate registrations exceeded 5 mm. CONCLUSIONS: The RTOG 1112 credentialing experience suggests that most institutions perform liver IGRT with sufficient accuracy to deliver stereotactic body radiation therapy safely, as assessed by expert reviewers. Both soft tissue and high-contrast surrogates appear adequate for consistent registration in most instances; however, some disagreements were observed when using soft-tissue registration targets. The use of high-contrast surrogates appears to reduce the small risk of substantial geographic miss owing to mis-registration in liver IGRT.

Patterns of Failure Observed in the 2-Step Institution Credentialing Process for NRG Oncology/Radiation Therapy Oncology Group 1005 (NCT01349322) and Lessons Learned.

PURPOSE: To investigate patterns of failure in institutional credentialing submissions to NRG/RTOG 1005 with the aim of improving the quality and consistency for future breast cancer protocols. METHODS AND MATERIALS: NRG/RTOG 1005 allowed the submission of 3-dimensional conformal radiation therapy (3DCRT), intensity-modulated radiation therapy (IMRT), and simultaneous integrated boost (SIB) breast plans. Credentialing required institutions to pass a 2-step quality assurance (QA) process: (1) benchmark, requiring institutions to create a plan with no unacceptable deviations and ≤1 acceptable variation among the dose volume (DV) criteria, and (2) rapid review, requiring each institution's first protocol submission to have no unacceptable deviations among the DV criteria or contours. Overall rates, number of resubmissions, and reasons for resubmission were analyzed for each QA step. RESULTS: In total, 352 institutions participated in benchmark QA and 280 patients enrolled had rapid review QA. Benchmark initial failure rates were similar for 3DCRT (18%), IMRT (17%), and SIB (18%) plans. For 3DCRT and IMRT benchmark plans, ipsilateral lung most frequently failed the DV criteria, and SIB DV failures were seen most frequently for the heart. Rapid review contour initial failures (35%) were due to target rather than organs at risk. For 29% of the rapid review initial failures, the planning target volume boost eval volume was deemed an unacceptable deviation. CONCLUSIONS: The review of the benchmark and rapid review QA submissions indicates that acceptable variations or unacceptable deviations for the ipsilateral lung and heart dose constraints were the most commonly observed cause of benchmark QA failure, and unacceptable deviations in target contouring, rather than normal structure contouring, were the most common cause of rapid review QA failure. These findings suggest that a rigorous QA process is necessary for high quality and homogeneity in radiation therapy in multi-institutional trials of breast cancer to ensure that the benefits of radiation therapy far outweigh the risks.

Benchmark Credentialing Results for NRG-BR001: The First National Cancer Institute-Sponsored Trial of Stereotactic Body Radiation Therapy for Multiple Metastases.

PURPOSE: The NRG-BR001 trial is the first National Cancer Institute-sponsored trial to treat multiple (range 2-4) extracranial metastases with stereotactic body radiation therapy. Benchmark credentialing is required to ensure adherence to this complex protocol, in particular, for metastases in close proximity. The present report summarizes the dosimetric results and approval rates. METHODS AND MATERIALS: The benchmark used anonymized data from a patient with bilateral adrenal metastases, separated by <5 cm of normal tissue. Because the planning target volume (PTV) overlaps with organs at risk (OARs), institutions must use the planning priority guidelines to balance PTV coverage (45 Gy in 3 fractions) against OAR sparing. Submitted plans were processed by the Imaging and Radiation Oncology Core and assessed by the protocol co-chairs by comparing the doses to targets, OARs, and conformity metrics using nonparametric tests. RESULTS: Of 63 benchmarks submitted through October 2015, 94% were approved, with 51% approved at the first attempt. Most used volumetric arc therapy (VMAT) (78%), a single plan for both PTVs (90%), and prioritized the PTV over the stomach (75%). The median dose to 95% of the volume was 44.8 ± 1.0 Gy and 44.9 ± 1.0 Gy for the right and left PTV, respectively. The median dose to 0.03 cm3 was 14.2 ± 2.2 Gy to the spinal cord and 46.5 ± 3.1 Gy to the stomach. Plans that spared the stomach significantly reduced the dose to the left PTV and stomach. Conformity metrics were significantly better for single plans that simultaneously treated both PTVs with VMAT, intensity modulated radiation therapy, or 3-dimensional conformal radiation therapy compared with separate plans. No significant differences existed in the dose at 2 cm from the PTVs. CONCLUSIONS: Although most plans used VMAT, the range of conformity and dose falloff was large. The decision to prioritize either OARs or PTV coverage varied considerably, suggesting that the toxicity outcomes in the trial could be affected. Several benchmarks met the dose-volume histogram metrics but produced unacceptable plans owing to low conformity. Dissemination of a frequently-asked-questions document improved the approval rate at the first attempt. Benchmark credentialing was found to be a valuable tool for educating institutions about the protocol requirements.

Rationale of technical requirements for NRG-BR001: The first NCI-sponsored trial of SBRT for the treatment of multiple metastases.

INTRODUCTION: In 2014, the NRG Oncology Group initiated the first National Cancer Institute-sponsored, phase 1 clinical trial of stereotactic body radiation therapy (SBRT) for the treatment of multiple metastases in multiple organ sites (BR001; NCT02206334). The primary endpoint is to test the safety of SBRT for the treatment of 2 to 4 multiple lesions in several anatomic sites in a multi-institutional setting. Because of the technical challenges inherent to treating multiple lesions as their spatial separation decreases, we present the technical requirements for NRG-BR001 and the rationale for their selection. METHODS AND MATERIALS: Patients with controlled primary tumors of breast, non-small cell lung, or prostate are eligible if they have 2 to 4 metastases distributed among 7 extracranial anatomic locations throughout the body. Prescription and organ-at-risk doses were determined by expert consensus. Credentialing requirements include (1) irradiation of the Imaging and Radiation Oncology Core phantom with SBRT, (2) submitting image guided radiation therapy case studies, and (3) planning the benchmark. Guidelines for navigating challenging planning cases including assessing composite dose are discussed. RESULTS: Dosimetric planning to multiple lesions receiving differing doses (45-50 Gy) and fractionation (3-5) while irradiating the same organs at risk is discussed, particularly for metastases in close proximity (≤5 cm). The benchmark case was selected to demonstrate the planning tradeoffs required to satisfy protocol requirements for 2 nearby lesions. Examples of passing benchmark plans exhibited a large variability in plan conformity. DISCUSSION: NRG-BR001 was developed using expert consensus on multiple issues from the dose fractionation regimen to the minimum image guided radiation therapy guidelines. Credentialing was tied to the task rather than the anatomic site to reduce its burden. Every effort was made to include a variety of delivery methods to reflect current SBRT technology. Although some simplifications were adopted, the successful completion of this trial will inform future designs of both national and institutional trials and would allow immediate clinical adoption of SBRT trials for oligometastases.

Differential roles for Nr4a1 and Nr4a2 in object location vs. object recognition long-term memory.

Nr4a1 and Nr4a2 are transcription factors and immediate early genes belonging to the nuclear receptor Nr4a family. In this study, we examine their role in long-term memory formation for object location and object recognition. Using siRNA to block expression of either Nr4a1 or Nr4a2, we found that Nr4a2 is necessary for both long-term memory for object location and object recognition. In contrast, Nr4a1 appears to be necessary only for object location. Indeed, their roles in these different types of long-term memory may be dependent on their expression in the brain, as NR4A2 was found to be expressed in hippocampal neurons (associated with object location memory) as well as in the insular and perirhinal cortex (associated with object recognition memory), whereas NR4A1 showed minimal neuronal expression in these cortical areas. These results begin to elucidate how NR4A1 and NR4A2 differentially contribute to object location versus object recognition memory.

Comparative expression of NFkappaB proteins in melanocytes of normal skin vs. benign intradermal naevus and human metastatic melanoma biopsies.

Nuclear factor kappa B (NFkappaB) is an essential regulator of gene transcription for hundreds of genes, including many critically involved in apoptosis. NFkappaB complexes containing cRel generally activate pro-apoptotic genes, while those with RelA activate anti-apoptotic genes. We have previously shown that NFkappaB binding by RelA is constitutively elevated in human metastatic melanoma cultures relative to normal melanocytes. Here we extended our investigation to immunohistochemical analysis of human tissue biopsies. We found that RelA expression is significantly elevated in melanocytes of human naevi and melanomas relative to normal skin, but expression of its inhibitor IkappaB-alpha is significantly lower in metastatic melanomas than in intradermal naevi. Antibodies specific for the nuclear localization signal of RelA also showed significantly increased staining in metastatic melanoma biopsies. Notably, in melanomas and in naevi, we also found that RelA is phosphorylated at serine 529, and this activated form accumulates in the nuclei of melanomas. This suggests that increased expression and phosphorylation of RelA occurs at the stage of the benign naevus, but IkappaB-alpha is able to sequester RelA in the cytoplasm and regulate RelA transcriptional transactivation. We also found that antibodies against cRel show a progressive increase in staining from naevi to melanoma. However, staining for IkappaB-epsilon, which primarily inhibits the nuclear localization of cRel was also progressively increased, and cRel expression was predominantly cytoplasmic in melanomas. These results confirm that the altered expression of RelA found in metastatic melanoma cells in tissue culture is relevant to human tumors and offer new insights into the deregulation of NFkappaB signaling.

During human melanoma progression AP-1 binding pairs are altered with loss of c-Jun in vitro.

We demonstrated previously that c-Jun, JunB and c-Fos RNA were dysregulated in metastatic melanoma cells compared with normal human melanocytes. The purpose of this study was to evaluate the distribution in composition of AP-1 dimers in human melanoma pathogenesis. We investigated AP-1 dimer pairing in radial growth phase-like (RGP) (w3211) and vertical growth phase-like (VGP) (w1205) human melanoma cells and metastatic cell lines (cloned from patients, c83-2c, c81-46A, A375, respectively) compared with melanocytes using electrophoretic mobility shift assay (EMSA), Western blot and transfection analyses. There are progressive variations in AP-1 composition in different melanoma cell lines compared with normal melanocytes, in which c-Jun, JunD and FosB were involved in AP-1 complexes. In w3211, c-Jun, JunD and Fra-1 were involved in AP-1 binding, while in w1205, overall AP-1 binding activity was decreased significantly and supershift binding was detected only with JunD antibodies. In metastatic c81-46A and A375 cells, only JunD was involved in AP-1 binding activity, but in a third (c83-2c) c-Jun, JunD and Fra-1 were present. Western blot evaluation detected c-Jun in melanocytes and w3211, but this component was decreased significantly or was not detectable in w1205, c81-46A and A375 cells. In contrast, JunD protein was elevated in c81-46A and c83-2c cells compared with melanocytes and RGP and VGP cell lines. Normal melanocytes and c83-2c cells (which have c-Jun involved in AP-1 binding), transfected with c-Jun antisense and treated with cisplatin, showed higher viability compared with untransfected cells, while in c81-46A cells (in which only JunD is detectable) no change in cell viability was observed following treatment with cisplatin and c-jun antisense transfection. A dominant-negative c-Jun mutant (TAM67) significantly increased the soft agar colony formation of w3211 and c83-2c cells. These results suggest that components of AP-1, especially c-Jun, may offer a new target for the prevention or treatment of human melanoma progression.