Immunotherapy and Radiation Therapy Sequencing in Breast Cancer: A Systematic Review.

PURPOSE: In the past decade, immune checkpoint inhibitors (ICIs) have emerged as a treatment option for metastatic breast cancer (BC). More recently, ICIs have been approved in the perioperative setting. This has led to clinical scenarios where radiation therapy (RT) is given concurrently with ICIs. On the other hand, moderate and ultrahypofractionated schedules of RT are being widely adopted in the adjuvant setting, in addition to an increased use of metastasis-directed therapy. Furthermore, RT can modulate the tumor microenvironment and induce a systemic response at nonirradiated sites, an "abscopal effect." The amplification of antitumor immune response is used as the rationale behind the concomitant use of ICIs and RT. To date, there is a lack of literature on the optimal sequence, timing, dose/fractionation schema, and treated RT volumes with ICIs in patients with BC, especially in the era of ultrahypofractionation. METHODS AND MATERIALS: We conducted a systematic review to delineate the reported treatment details, safety, and efficacy of combining ICI and RT in patients with BC. PubMed, Embase, and Cochrane CENTRAL were searched between 2014 and 2023. Data were extracted to assess the details of ICIs/RT delivery, safety, and efficacy. RESULTS: Of the 12 eligible studies, 9 involved patients with metastatic BC. Most studies were phase 1/2, had a small sample size (range, 8-28), and were heterogenous in patient population and reported outcomes. The combination was reported to be safe. We identified 1 study in the perioperative setting, which did a posthoc analysis of safety/efficacy of ICIs in the adjuvant setting with receipt and pattern of RT. CONCLUSIONS: In conclusion, there are limited data on the dose, timing, fractionation, and volumes of RT in both the adjuvant and metastatic setting in BC. Ongoing/future trials should collect and report such data on RT details, whenever RT is used in combination with ICIs.

Detection of Circulating Tumor DNA After Stereotactic Ablative Radiotherapy in Patients With Unbiopsied Lung Tumors (SABR-DETECT).

For patients with stage I/IIA non-small-cell lung cancer (NSCLC), surgical resection is the standard treatment. However, some of these patients are not candidates for surgery or refuse a surgical option. Definitive stereotactic ablative radiotherapy (SABR) is a standard approach in these patients. Approximately 15% of patients undergoing SABR for localized NSCLC will experience a recurrence within 2 years. Furthermore, many of these patients are deemed appropriate for SABR without a tissue diagnosis, based on the likelihood of malignancy which can be calculated by validated models. A liquid biopsy, detecting ctDNA, would be useful in early detection of recurrences, and documenting a cancer diagnosis in patients without a biopsy. This is a multi-institutional study enrolling patients with suspected stage I/IIA NSCLC and a pretreatment likelihood of malignancy of ≥60% using the validated models for patients without a tissue diagnosis, in cohort 1 (n = 45). The second cohort will consist of biopsied patients (n = 30-60). SABR will be delivered as per risk-adapted protocol. Plasma will be collected for ctDNA analysis prior to the first fraction of SABR, 24 to 72 hours after first fraction, and at 3, 6, 9, 12, 18, and 24-months. The patients will be followed up with imaging at 3, 6, 9, 12, 18, and 24-months. The primary objective is to assess whether a cancer detection liquid biopsy platform can predict recurrence of NSCLC. The secondary objectives are to assess the impact of SABR on detection rates of ctDNA in patients undergoing SABR and to correlate ctDNA positivity and pretreatment probability of malignancy (NCT05921474).

The role of thoracic consolidative radiotherapy in the setting of immunotherapy in extensive stage small cell lung cancer.

The improvement in treatment strategies and outcomes in small cell lung cancer (SCLC) has lagged behind other cancers. The addition of immune checkpoint inhibitors (ICIs), durvalumab and atezolizumab, to the platinum-based chemotherapy in frontline setting has improved the survival in extensive stage SCLC, (ES-SCLC), albeit modestly, and is now the new standard of care. Prior to advent of immunotherapy into the therapeutic armamentarium in ES-SCLC, consolidative thoracic radiotherapy (TRT) was associated with improved thoracic control and survival outcomes. In the era of ICIs, the role of TRT is not well defined, chiefly because TRT was not incorporated in any immunotherapy trials, secondly due to concerns regarding the increased risks of pneumonitis, and finally uncertain magnitude of benefit with this combined approach. In principle, radiation can increase in the immunogenicity of tumor and hence the activity of immune checkpoint blockade, thereby increasing efficacy both locally and distantly. Such an approach has been promising in non-small cell lung cancer with ICIs improving outcomes after concurrent chemoradiation, but remains unanswered in ES-SCLC. It is, thus, possible that the modest improvement in survival by addition of ICIs to chemotherapy in ES-SCLC can be further improved by the incorporation of consolidative TRT in selected patients. Several early phase trials and retrospective studies have suggested that such an approach may be feasible and safe. Prospective trials are ongoing to answer whether adding radiation therapy to chemoimmunotherapy will improve outcomes in ES-SCLC.

Influence of molecular imaging on patient selection for treatment intensification prior to salvage radiation therapy for prostate cancer: a post hoc analysis of the PROPS trial.

BACKGROUND: The impact of molecular imaging (MI) on patient management after biochemical recurrence (BCR) following radical prostatectomy has been described in many studies. However, it is not known if MI-induced management changes are appropriate. This study aimed to determine if androgen deprivation therapy (ADT) management plan is improved by MI in patients who are candidates for salvage radiation therapy. METHODS: Data were analyzed from the multicenter prospective PROPS trial evaluating PSMA/Choline PET in patients being considered for salvage radiotherapy (sRT) with BCR after prostatectomy. We compared the pre- and post-MI ADT management plans for each patient and cancer outcomes as predicted by the MSKCC nomogram. A higher percentage of predicted BCR associated with ADT treatment intensification after MI was considered as an improvement in a patient's management. RESULTS: Seventy-three patients with a median PSA of 0.38 ng/mL were included. In bivariate analysis, a positive finding on MI (local or metastatic) was associated with decision to use ADT with an odds ratio of 3.67 (95% CI, 1.25 to 10.71; p = 0.02). No factor included in the nomogram was associated with decision to use ADT. Also, MI improved selection of patients to receive ADT based on predicted BCR after sRT : the predicted nomogram 5-year biochemical-free survivals were 52.5% and 43.3%, (mean difference, 9.2%; 95% CI 0.8 to 17.6; p = 0.03) for sRT alone and ADT±sRT subgroups, while there was no statistically significant difference between subgroups before MI. CONCLUSIONS: PSMA and/or Choline PET/CT before sRT can potentially improve patient ADT management by directing clinicians towards more appropriate intensification.

Isolated Hodgkin lymphoma of the intracranial dura: A case report and review of the literature.

Primary dural Hodgkin lymphoma (PDHL) is an extremely rare subset of Hodgkin lymphoma (HL). Its existence is controversial, as Hodgkin lymphoma is not traditionally thought to arise from the central nervous system (CNS) or its meninges and only 0.02% of patients with Hodgkin lymphoma have any CNS involvement. We report a case of a 71-year-old Caucasian man who presented with progressive fatigue and sudden onset slurred speech, disorientation, and memory loss. Brain imaging identified a large extra-axial right frontal mass, and he underwent urgent subtotal resection. Pathology and subsequent workup revealed Stage IAE classical Hodgkin lymphoma of the right frontal dura, with no extra-cranial disease or leptomeningeal spread detected. The patient was subsequently treated with ABVD chemotherapy (completed 2.5 of 4 planned cycles) and 36 Gy in 20 fractions of consolidative involved-site radiotherapy (ISRT). He has been followed for 5 years with no clinical or radiological signs of recurrence. This is the second confirmed case of intracranial PDHL reported in the literature, with the longest follow-up for any case of PDHL.

Planning for the Effect of the SC.24 Trial on Spine Stereotactic Body Radiation Therapy Utilization at a Tertiary Cancer Center.

Purpose: The goal of this study was to assess the potential real-world effect of the recently reported SC.24 trial on spine stereotactic body radiation therapy (SBRT) utilization. We estimated the proportion of patients treated with conventional radiation therapy (CRT) who would have been eligible for spine SBRT per trial inclusion criteria and analyzed the potential estimated increased costs to our institution. Methods and Materials: This was a retrospective review of patients who received spine CRT at our institution between August and October 2020. Data abstracted included demographics, SC.24 eligibility criteria, provider-reported pain response, and survival. A cost analysis and time survey was performed using institutional and provincial data. Results: Of 73 patients reviewed, 24 patients (33%) were eligible. The most common exclusion factors included irradiation of ≥3 consecutive spinal segments (n = 32, 44%), Eastern Cooperative Oncology Group performance status >2 (n = 17, 23%), and symptomatic spinal cord compression (n = 13, 18%). Of eligible patients, the mean age was 68.92 years, median spinal instability in neoplasia score was 8 (interquartile range, 7-9), and median Eastern Cooperative Oncology Group performance status was 2 (interquartile range, 1-2). The most common primary cancer types among eligible patients were lung (n = 10) and breast (n = 4). The median survival of eligible patients was 10 months (95% confidence interval, 4 months to not reached) with 58% surviving longer than 3 months. Of patients who had subjective pain documented after CRT, 54% had at least some response. The cost of spine SBRT was estimated at CA$4764.80 compared with $3589.10 for CRT, and tasks for spine SBRT took roughly 3 times as long as those for CRT. Conclusions: One-third of patients who received palliative spine CRT met eligibility criteria for SC.24. This possible expanded indication for spine SBRT can have a substantial effect on resource utilization. These data may be useful in guiding resource planning at institutions looking to commence a spine SBRT program.

Proton Radiotherapy for Management of Medulloblastoma: A Systematic Review of Clinical Outcomes.

Purpose: The aim of this study was to comprehensively review all studies examining clinical outcomes of craniospinal irradiation with proton radiotherapy for medulloblastoma (MB) to determine whether theoretical dosimetric advantages have translated into superior clinical outcomes (including survival and toxicities) compared with traditional photon-based techniques. Methods and Materials: We performed a systematic review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Articles reporting on clinical outcomes of pediatric and/or adult patients with MB treated with proton radiotherapy were included. Evidence quality was assessed using a modified Newcastle Ottawa scale and GRADE score. Results: Thirty-five studies were included, with a total of 2059 patients reported (representing an estimated 630-654 unique patients). None of the studies were randomized, 12 were comparative, 9 were prospective, 3 were mixed, and 22 were retrospective. Average mean/median follow-up was 5.0 years (range, 4 weeks to 12.6 years). The majority of studies (n = 19) reported on treatment with passive scatter proton beams exclusively. Average study quality was 6.0 out of 9 (median, 6; standard deviation, 1.6). Nine studies scored ≥8 out of 9 on the modified Newcastle Ottawa Scale; an overall "moderate" GRADE score was assigned. Well-designed comparative cohort studies with adequate follow-up demonstrate superior neurocognitive outcomes, lower incidence of hypothyroidism (23% vs 69%), sex hormone deficiency (3% vs 19%), greater heights, and reduced acute toxicities in patients treated with protons compared to photons. Overall survival (up to 10 years), progression-free survival (up to 10 years), brain stem injury, and other endocrine outcomes were similar to those reported for photon radiation. There was insufficient evidence to make conclusions on endpoints of quality of life, ototoxicity, secondary malignancy, alopecia, scoliosis, cavernomas, and cerebral vasculopathy. Conclusions: Moderate-grade evidence supports proton radiotherapy as a preferred treatment for craniospinal irradiation of MB based on equivalent disease control and comparable-to-improved toxicity versus photon beam radiation therapy.

PSMA PET/CT guided intensification of therapy in patients at risk of advanced prostate cancer (PATRON): a pragmatic phase III randomized controlled trial.

BACKGROUND: Positron emission tomography targeting the prostate specific membrane antigen (PSMA PET/CT) has demonstrated unparalleled performance as a staging examination for prostate cancer resulting in substantial changes in management. However, the impact of altered management on patient outcomes is largely unknown. This study aims to assess the impact of intensified radiotherapy or surgery guided by PSMA PET/CT in patients at risk of advanced prostate cancer. METHODS: This pan-Canadian phase III randomized controlled trial will enroll 776 men with either untreated high risk prostate cancer (CAPRA score 6-10 or stage cN1) or biochemically recurrent prostate cancer post radical prostatectomy (PSA > 0.1 ng/mL). Patients will be randomized 1:1 to either receive conventional imaging or conventional plus PSMA PET imaging, with intensification of radiotherapy or surgery to newly identified disease sites. The primary endpoint is failure free survival at 5 years. Secondary endpoints include rates of adverse events, time to next-line therapy, as well as impact on health-related quality of life and cost effectiveness as measured by incremental cost per Quality Adjusted Life Years gained. DISCUSSION: This study will help create level 1 evidence needed to demonstrate whether or not intensification of radiotherapy or surgery based on PSMA PET findings improves outcomes of patients at risk of advanced prostate cancer in a manner that is cost-effective. TRIAL REGISTRATION: This trial was prospectively registered in ClinicalTrials.gov as NCT04557501 on September 21, 2020.

Establishing a Provincial Registry for Recurrent Prostate Cancer: Providing Access to PSMA PET/CT in Ontario, Canada.

Prostate Specific Membrane Antigen (PSMA) positron emission tomography/computed tomography (PET/CT) is becoming established as a standard of care for the (re)staging of high-risk primary and prostate cancer recurrence after primary therapy. Despite the favorable performance of this imaging modality with high accuracy in disease detection, the availability of PSMA PET/CT varies across jurisdictions worldwide due to variability in the selection of PSMA PET/CT agent, regulatory approvals and funding. In Canada, PSMA based radiopharmaceuticals are still considered investigational new drug (IND), creating limitations in the deployment of these promising imaging agents. While regulatory approval rests with Health Canada, as a single payer health system, funding for Health Canada approved drugs and devices is decided by Provincial Health Ministries. Ontario Health (Cancer Care Ontario) (OH-CCO) is the agency of the Ministry of Health (MOH) in Ontario responsible for making recommendations to the MOH around the organization and funding of cancer services within Ontario (population of 15 million), and the PET Steering Committee of OH-CCO is responsible for providing recommendations on the introduction of new PET radiopharmaceuticals and indications. For Health Canada approved PET radiopharmaceuticals like 18F-FDG, OH-CCO (on behalf of the MOH) provides coverage based on levels of evidence and specific PET Registries are established to aid in real-world evidence collection to inform OH-CCO regarding emerging PET applications. In the case of PSMA PET/CT, adapting this model to an IND PSMA PET/CT agent, 18F-DCFPyL, necessitated the creation of a hybrid Registry-Study model to leverage the existing OH-CCO Registry structure while respecting the need for a Health Canada Clinical Trials Application (CTA) for the deployment of this agent in the province. Within the first 2 years of the registry, over 1700 men have been imaged resulting in a change in management (compared to pre-PET management plans) in over half of the men imaged. In this article, we describe the organization and deployment of the PSMA PET/CT (PREP) Registry throughout the province to provide access for men with suspected prostate cancer recurrence along with key stakeholder perspectives and preliminary results.

Prostate-specific membrane antigen targeted PET/CT for recurrent prostate cancer: a clinician's guide.

INTRODUCTION: PSMA-targeted PET/CT is a 'Next Generation Imaging' technique with superior sensitivity and specificity for detecting recurrent prostate cancer compared with conventional imaging, allowing more accurate staging and re-staging. AREAS COVERED: This article reviews the role of PSMA-targeted PET/CT in clinical management of men with recurrent prostate cancer. EXPERT OPINION: Through enhanced spatial characterization of recurrent prostate cancer, PSMA-targeted PET/CT has shown significant impact on management decisions. In particular, by identifying men with recurrence confined to the prostate or pelvic nodes, PSMA-targeted PET/CT enables selective deployment of localized salvage therapies for management of biochemical failure after primary treatment with prostatectomy or radiotherapy. In oligometastatic disease, PSMA-targeted PET/CT may improve patient selection and treatment accuracy for metastasis-directed therapy and early phase II studies show encouraging results in delaying the need for systemic therapy. Further, quantitative PSMA-targeted PET/CT for monitoring response and therapeutic PSMA-targeted radiopharmaceuticals are emerging as encouraging treatment options in the setting of castrate-resistant disease.

Primary Parotid Merkel Type Small Cell Neuroendocrine Carcinoma with Oligometastasis to the Brain and Adrenal Gland: Case Report and Review of Literature.

Oligometastatic disease is a hypothesized intermediate stage of disease between localized and widespread metastatic cancer. Localized treatment of oligometastatic lesions may offer survival advantages in addition to systemic treatment. In this case report, we describe a patient who presented with small cell neuroendocrine carcinoma "Merkel type" (SNECM) of the parotid gland which had metastasized to the brain and adrenal gland. He was treated with chemotherapy followed by stereotactic radiotherapy and volumetric modulated arc therapy for oligometastasis. He maintains good functional status with low burden of disease at 20-months after diagnosis. SNECM is a rare and aggressive parotid cancer with immunohistochemical and morphologic similarities to Merkel cell carcinoma (MCC). There are only 44 cases of parotid SNECM in the English literature. This is the first case to describe management of oligometastatic SNECM and we review literature on management of both SNECM and metastatic MCC.