Faculty Bibliography

Metastasis-directed therapy (MDT)-local therapy that is intended to eradicate specific metastatic lesions-has hitherto been used with varying degrees of clinical efficacy and acceptance as a meaningful therapy for metastatic disease. Over the past 25 years, however, the momentum for using MDT to manage patients with metastatic solid tumours has increased, driven by several factors. Among these factors is the recognition that patients with limited metastatic burden could potentially derive survival benefits from MDT. Furthermore, although current systemic therapies are increasingly effective, they are infrequently curative. In addition, technological advances have broadened the spectrum of metastatic lesions that can be treated with ablative intent. Here we aim to briefly review the status of evidence for the clinical benefit of MDT based on current data mainly from trials in patients with oligometastatic disease, discuss the myriad of clinical states that might fall under and beyond the definition of oligometastasis, review technological advances in MDT and their applications beyond oligometastasis, and discuss the need for the continued co-evolution of MDT and systemic therapy as we seek to understand which patients with metastatic cancer can achieve durable remission and how to optimally manage those who cannot.

PURPOSE:Guidelines recommend short-course (≤10 fractions) external-beam radiation therapy (EBRT) for bone metastases. Stereotactic body radiation therapy (SBRT) may also improve outcomes; however, routine use is not recommended outside clinical trials. We assessed national radiation therapy trends in complex techniques for bone metastases and associated expenditures. METHODS AND MATERIALS:d or Wilcoxon rank sum tests for categorical and continuous variables, respectively. We identified associations with modality, fractionation, and expenditures using multivariable logistic/linear regression. RESULTS:Among 467,781 radiation episodes for 17 cancer diagnoses, the overall proportion of episodes dedicated to bone metastases (9.4%) was stable from 2015 to 2017, although treatments were increasing in the hospital-affiliated outpatient setting (P < .005). We identified 40,993 episodes for bone metastases, of which 63% were short-course EBRT, 24% were long-course EBRT, 7% were SBRT, and 6% were IMRT. Techniques more common in the hospital-affiliated outpatient setting included short-course EBRT (OPD, 69%, vs FREE, 56%) and SBRT (OPD, 9%, vs FREE, 5%). Techniques more common among free-standing centers included long-course EBRT (OPD, 19%, vs FREE, 31%) and IMRT (OPD, 4%, vs FREE, 9%). From 2015 to 2017, long-course EBRT decreased by an absolute 8%; short-course EBRT, SBRT, and IMRT increased by 4%, 2.5%, and 1%, respectively. The SBRT/IMRT uptake did not differ by setting (P = .4). Differences in expenditures between SBRT and short-course EBRT decreased by a relative 8% in professional and 12% in technical fees. CONCLUSIONS:Approximately 1 in 4 patients received long-course EBRT, with small reductions in use largely replaced by complex treatment modalities. However, expenditures for complex modalities also decreased over time. As alternative payment models take effect, quality metrics are needed to ensure appropriate, effective, and safe delivery of complex technologies.

BACKGROUND:/Objectives: Pancreatic adenocarcinoma (PDAC) metastatic to the leptomeninges is a rare and lethal event. Leptomeningeal disease (LMD) research is limited in PDAC, and insights into clinical descriptors, possible disease predictors, and treatment strategies is necessitated. METHODS:Memorial Sloan Kettering databases were queried with Institutional Review Board approval to identify patients with LMD and PDAC treated between January 2000 and June 2020. Medical record review was used to abstract clinical, genomic, pathologic, and radiographic data. Overall survival was calculated from date of PDAC diagnosis to date of death. Previously published literature on LMD from PDAC was reviewed. RESULTS:Four patients with LMD from PDAC were identified, two males and two females. Age at diagnosis ranged from 57 to 68 years. All four patients had predominant lung metastasis and a relatively low burden of intra-abdominal disease. Somatic testing indicated alterations typical of PDAC and no PDAC defining pathogenic germline mutations were identified. An extended clinical course prior to LMD diagnosis was observed in all patients, ranging from 16 to 148 months. Upon diagnosis of LMD, three patients elected for supportive care and one patient received a limited course of craniospinal radiation. The median survival following diagnosis of LMD was 1.6 months (range 0.5-2.8 months). CONCLUSIONS:LMD from PDAC is a rare occurrence that may be more frequent in patients with lung metastasis and/or a more indolent clinical course. Following diagnosis of LMD, prognosis is poor, and survival is short. New treatment strategies for this manifestation of PDAC are needed.

Palliative care and radiation therapy have played an expanding role in the management of patients with advanced cancers. Recent advances in our understanding of oligometastatic disease have led to increasing demand for familiarity with ablative techniques. Recognizing the demands of hospitalized patients for rapid access to care, we created an inpatient radiation oncology consult service (IROC) with consolidated expertise in palliative radiation and ablative techniques. In this quality improvement cohort study, we analyzed inpatient radiation oncology consults placed before and after IROC implementation and found that IROC led to increased delivery of specialty care and decreased hospital length of stay (median 8 days v 7 days, P = .005). This difference was most pronounced for patients for whom radiation therapy was indicated (14.5 v 11 days, P = .007). Our institutional experience demonstrates the value of recognizing metastatic disease as a distinct discipline and providing rapid access to palliative treatments for patients with advanced malignancies.

PURPOSE/OBJECTIVE:Immune checkpoint inhibition (ICI) alone is not active in mismatch repair-proficient (MMR-P) metastatic colorectal cancer (mCRC), nor does radiotherapy (RT) alone result in objective systemic benefit. However, combined RT plus ICI can induce systemic anti-tumor immunity in pre-clinical and clinical models. EXPERIMENTAL DESIGN/METHODS:In this single-center, phase II study, patients with chemotherapy-refractory MMR-P mCRC received durvalumab 1500 mg plus tremelimumab 75 mg every 4 weeks plus RT. The primary endpoint was objective response rate (ORR) in non-irradiated lesions. Treatment and efficacy were correlated with peripheral immune cell profiles. RESULTS:We enrolled 24 patients, and report outcomes after a median follow up of 21.8 (range: 15.9 to 26.3) months. The ORR was 8.3% (2 patients) (95% confidence interval [CI], 1.0% to 27.0%). The median progression-free survival was 1.8 (95% CI, 1.7 to 1.9) months, median overall survival was 11.4 (95% CI, 10.1 to 17.4) months. Twenty five percent of patients (n=6) had treatment-related grade 3-4 adverse events. We observed increased circulating CD8+ T lymphocyte activation, differentiation, and proliferation in patients with objective response. CONCLUSION/CONCLUSIONS:This combination of RT plus ICI study did not meet the prespecified end point criteria to be considered worthwhile for further study. However, rare instances of systemic immune augmentation and regression in non-irradiated lesions were observed (an abscopal response). Combination durvalumab and tremelimumab plus RT is feasible in MMR-P mCRC with a manageable safety profile. Further studies of novel immunotherapy combinations, and identification of biomarkers predictive of abscopal response are warranted.

BACKGROUND:In patients with metastatic cancer, the bone is the third-most common site of involvement. Radiation to painful bone metastases results in high rates of pain control and is an integral part of bone metastases management. Up to one-third of inpatient consults are requested for painful bone metastases, and up to 60% of these patients had evidence of these lesions visible on prior imaging. Meanwhile recent advances have reduced potential side effects of radiation. Therefore, there is an opportunity to further improve outcomes for patients using prophylactic palliative radiation to manage asymptomatic bone metastases. METHODS/STUDY DESIGN/METHODS:In this trial, 74 patients with metastatic solid tumors and high-risk asymptomatic or minimally symptomatic bone metastases will be enrolled and randomized to early palliative radiation or standard of care. This will be the first trial to assess the efficacy of prophylactic palliative radiation in preventing skeletal related events (SREs), the primary endpoint. This endpoint was selected to encompass patient-centered outcomes that impact quality of life including pathologic fracture, spinal cord compression, and intervention with surgery or radiation. Secondary endpoints include hospitalizations, Bone Pain Index, pain-free survival, pain-related quality of life, and side effects of radiation therapy. DISCUSSION/CONCLUSIONS:In this study, we propose a novel definition of high-risk bone metastases most likely to benefit from preventive radiation and use validated questionnaires to assess pain and impact on quality of life and health resource utilization. Observations from early patient enrollment have demonstrated robustness of the primary endpoint and need for minor modifications to Bone Pain Index and data collection for opioid use and hospitalizations. With increasing indications for radiation in the oligometastatic setting, this trial aims to improve patient-centered outcomes in the polymetastatic setting. TRIAL REGISTRATION/BACKGROUND:ISRCTN Number/Clinical trials.gov, ID: NCT03523351 . Registered on 14 May 2018.

Palliation of metastatic disease compromises a significant portion of radiation treatments in the United States. These patients present a unique challenge in resource-limited settings, as expeditious treatment is often required to prevent serious morbidity. In order to reduce the risk of infection with severe acute respiratory syndrome coronavirus-2 and maximize the benefit to patients, we present evidence-based recommendations for radiation in patients with oncologic emergencies. Radiation oncologists with expertise in the treatment of metastatic disease at a high-volume comprehensive cancer center reviewed the available evidence and recommended best practices for the treatment of common oncologic emergencies, with attention to balancing the risk of infection with severe acute respiratory syndrome coronavirus-2 and the potential morbidity of delaying treatment. Many prospective trials and national guidelines support the use of abbreviated courses of radiotherapy for patients with oncologic emergencies. As such, in the setting of the current coronavirus disease 2019 pandemic, the use of hypofractionated radiation therapy for patients requiring palliation for oncologic emergencies achieves desirable functional outcomes without compromising care.

PURPOSE/OBJECTIVE:We report on the clinical performance of a fully automated approach to treatment planning based on a Pareto optimal, constrained hierarchical optimization algorithm, named Expedited Constrained Hierarchical Optimization (ECHO). METHODS AND MATERIALS/METHODS:From April 2017 to October 2018, ECHO produced 640 treated plans for 523 patients who underwent stereotactic body radiation therapy (RT) for paraspinal and other metastatic tumors. A total of 182 plans were for 24 Gy in a single fraction, 387 plans were for 27 Gy in 3 fractions, and the remainder were for other prescriptions or fractionations. Of the plans, 84.5% were for paraspinal tumors, with 69, 302, and 170 in the cervical, thoracic, and lumbosacral spine, respectively. For each case, after contouring, a template plan using 9 intensity modulated RT fields based on disease site and tumor location was sent to ECHO through an application program interface plug-in from the treatment planning system. ECHO returned a plan that satisfied all critical structure hard constraints with optimal target volume coverage and the lowest achievable normal tissue doses. Upon ECHO completion, the planner received an e-mail indicating the plan was ready for review. The plan was accepted if all clinical criteria were met. Otherwise, a limited number of parameters could be adjusted for another ECHO run. RESULTS:(range, 6.9-633.2). The median time to produce 1 ECHO plan was 63.5 minutes (range, 11-340 minutes) and was largely dependent on the field sizes. Of the cases, 79.7% required 1 run to produce a clinically accepted plan, 13.3% required 1 additional run with minimal parameter adjustments, and 7.0% required ≥2 additional runs with significant parameter modifications. All plans met or bettered the institutional clinical criteria. CONCLUSIONS:We successfully implemented automated stereotactic body RT paraspinal and other metastatic tumors planning. ECHO produced high-quality plans, improved planning efficiency and robustness, and enabled expedited treatment planning at our clinic.

A small subset of pituitary adenomas grows despite maximal treatment with standard therapies; namely, surgery and radiotherapy. These aggressive tumors demonstrate 2 patterns of growth: they may be locally aggressive or metastasize distantly, either hematogenously or through the spinal fluid. Further surgery and radiotherapy may be helpful for palliation of symptoms, but they are rarely definitive in the management of these malignant tumors. The only chemotherapy with established activity in the treatment of pituitary tumors is the alkylating agent temozolomide. At most, 50% of patients exhibit an objective response to temozolomide and the median time to progression is short; thus, there remains a significant unmet need for effective treatments within this patient population. Several targeted agents have reported activity in this tumor type-including small molecule inhibitors, checkpoint inhibitors, and other biologics-but remain investigational at this time.

The PI5P4Ks have been demonstrated to be important for cancer cell proliferation and other diseases. However, the therapeutic potential of targeting these kinases is understudied due to a lack of potent, specific small molecules available. Here, we present the discovery and characterization of a pan-PI5P4K inhibitor, THZ-P1-2, that covalently targets cysteines on a disordered loop in PI5P4Kα/β/γ. THZ-P1-2 demonstrates cellular on-target engagement with limited off-targets across the kinome. AML/ALL cell lines were sensitive to THZ-P1-2, consistent with PI5P4K's reported role in leukemogenesis. THZ-P1-2 causes autophagosome clearance defects and upregulation in TFEB nuclear localization and target genes, disrupting autophagy in a covalent-dependent manner and phenocopying the effects of PI5P4K genetic deletion. Our studies demonstrate that PI5P4Ks are tractable targets, with THZ-P1-2 as a useful tool to further interrogate the therapeutic potential of PI5P4K inhibition and inform drug discovery campaigns for these lipid kinases in cancer metabolism and other autophagy-dependent disorders.