Early Magnetic Resonance Imaging After Gamma Knife Radiosurgery of Brain Metastases

Gamma knife radiosurgery (GKRS) is often performed to treat brain metastases (BrMs). Widely referenced guidelines have suggested post-treatment imaging studies at 3-month intervals. However, clinicians frequently obtain magnetic resonance imaging (MRI) studies at <3 months after GKRS. We performed a retrospective medical record review study to assess the utility of early (<3 months) MRI after GKRS in patients with BrMs. A total of 415 GKRS procedures were performed. For 325 patients, early MRI studies were obtained. A total of 31 patients had new or worsened neurological symptoms. The early MRI studies showed adverse findings in 25 patients (78%), which in 23 (72%) had resulted in a change in treatment. For 294 patients, no new or worsened neurological symptoms were found on early MRI studies. Of these 294 patients, 86 (29%) had ≥1 adverse finding on MRI, and 60 (20%) had a change in management as a result. However, no rapidly growing tumors or other emergent adverse findings were seen. Early MRI (within 3 months) after post GKRS will frequently show adverse findings even in asymptomatic patients, more often in patients aged <65 years and patients with multiple treated BrMs. However, according to the nature of the adverse findings observed in our retrospective study, it is unlikely that the clinical outcomes would have been affected if the post-GKRS MRI studies had been deferred to 3 months after treatment. Our data support deferring post-GKRS MRI to 3 months after treatment in the absence of new neurological signs or symptoms

Epidemiology, diagnosis, and optimal management of glioma in adolescents and young adults

Neoplasms of the central nervous system (CNS) are the most frequently encountered solid tumors of childhood, but are less common in adolescents and young adults (AYA), aged 15–39 years. Gliomas account for 29%–35% of the CNS tumors in AYA, with approximately two-thirds being low-grade glioma (LGG) and the remaining being high-grade glioma (HGG). We review the epidemiology, work-up, and management of LGG and HGG, focusing on the particular issues faced by the AYA population relative to pediatric and adult populations. Visual pathway glioma and brainstem glioma, which represent unique clinical entities, are only briefly discussed. As a general management approach for both LGG and HGG, maximal safe resection should be attempted. AYA with LGG who undergo gross total resection (GTR) may be safely observed. As age increases and the risk factors for recurrence accumulate, adjuvant therapy should be more strongly considered with a strong consideration of advanced radiation techniques such as proton beam therapy to reduce long-term radiation-related toxicity. Recent results also suggest survival advantage for adult patients with the use of adjuvant chemotherapy when radiation is indicated. Whenever possible, AYA patients with HGG should be enrolled in a clinical trial for the benefit of centralized genetic and molecular prognostic review and best clinical care. Chemoradiation should be offered to all World Health Organization grade IV patients with concurrent and adjuvant chemotherapy after maximal safe resection. Younger adolescents with GTR of grade III lesions may consider radiotherapy alone or sequential radiotherapy and chemotherapy if unable to tolerate concurrent treatment. A more comprehensive classification of gliomas integrating pathology and molecular data is emerging, and this integrative strategy offers the potential to be more accurate and reproducible in guiding diagnostic, prognostic, and management decisions

How Histopathologic Tumor Extent and Patterns of Recurrence Data Inform the Development of Radiation Therapy Treatment Volumes in Solid Malignancies

The ability to deliver highly conformal radiation therapy using intensity-modulated radiation therapy and particle therapy provides for new opportunities to improve patient outcomes by reducing treatment-related morbidities following radiation therapy. By reducing the volume of normal tissue exposed to radiation therapy (RD, while also allowing for the opportunity to escalate the dose of RT delivered to the tumor, use of conformal RT delivery should also provide the possibility of expanding the therapeutic index of radiotherapy. However, the ability to safely and confidently deliver conformal RT is largely dependent on our ability to clearly define the clinical target volume for radiation therapy, which requires an in-depth knowledge of histopathologic extent of different tumor types, as well as patterns of recurrence data. In this article, we provide a comprehensive review of the histopathologic and radiographic data that provide the basis for evidence-based guidelines for clinical tumor volume delineation. (C) 2018 Elsevier Inc. All rights reserved

Proton beam therapy for malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare disease with a poor prognosis. Surgical techniques have made incremental improvements over the last few decades while new systemic therapies, including immunotherapies, show promise as potentially effective novel therapies. Radiation therapy has historically been used only in the palliative setting or as adjuvant therapy after extrapleural pneumonectomy, but recent advances in treatment planning and delivery techniques utilizing intensity-modulated radiation therapy and more recently pencil-beam scanning (PBS) proton therapy, have enabled the delivery of radiation therapy as neoadjuvant or adjuvant therapy after an extended pleurectomy and decortication or as definitive therapy for patients with recurrent or unresectable disease. In particular, PBS proton therapy has the potential to deliver high doses of irradiation to the entire effected pleura while significantly reducing doses to nearby organs at risk. This article describes the evolution of radiation therapy for MPM and details how whole-pleural PBS proton therapy is delivered to patients at the Maryland Proton Treatment Center

Assessment of single isocenter linear accelerator radiosurgery for metastases and base of skull lesions

Newer technology for stereotactic radiosurgery (SRS) should be assessed for different multi-leaf collimators (MLC). Assess plan quality of an automated, frameless, linear accelerator based (linac) planning and delivery system (HyperArc) for SRS using both standard MLC (SMLC) and high definition MLC (HDMLC) compared to a cobalt-60 based SRS system (Gamma Knife, GK). We re-planned twenty GK Perfexion-treated SRS patients (27 lesions) for HyperArc using SMLC and HDMLC. We assessed plan quality using the following metrics: gradient index (GI), Paddick and RTOG conformity indices (CI , CI ), volume receiving half of prescription isodose (PIV ) and maximum dose to 0.03 cc for brainstem, optic chiasm and optic nerves, and V12Gy for brain-GTV. Linac plans had better conformity with HDMLC being most conformal. GK exhibited better GI. PIV demonstrated no statistically significant difference between HDMLC and GK, and SMLC was nominally worse than GK. Mean PIV was generally 0.85 cc larger for SMLC than HDMLC. For TV > 1.0 cc, the relative differences in CI , GI, and PIV for SMLC vs. HDMLC were less than 21%. For TV less than < 1.0 cc, there were more obvious relative differences for SMLC vs. HDMLC in CI (mean 146%, max 700%), GI (mean 49%, max 162%), and PIV (mean 77%, max 522%). Organ at risk doses were met in all plans. New linac-based plans positively compare to GK plans overall. HDMLC should be strongly considered for treatment of lesions < 1.0 cc given the significant improvements in conformity and PIV over SMLC

Cancer Screening Patterns and Concerns in Caregivers of Patients Undergoing Radiation Therapy

Evolving cancer screening guidelines can confuse the public. Caregivers of patients undergoing radiation oncology may represent a promising outreach target for disseminating and clarifying screening information. We aimed to: (1) determine the incidence of cancer screening in this cohort, and (2) identify barriers to and deficiencies in screening. We distributed a 21-item survey on cancer screening history and related concerns to caregivers ≥ 18 years old at one urban and two suburban radiation oncology centers. Reported screening habits were compared with American Cancer Society/American Urological Association guidelines for breast, cervical, colon, and prostate cancer. Statistical analysis included Pearson χ(2) tests. A total of 209 caregivers (median age, 55.5 years; 146 women) were surveyed. Although 92% had primary care physicians (PCPs), only 58% reported being informed about recommended screening intervals. Participants ≤ 49 years old were less likely to report PCP discussion of cancer screening than older participants (41% and 66%, respectively; P = .006). Ninety-eight respondents (47%) had one or more screening concern(s). Among screening-eligible caregivers, 23 (18%) reported not undergoing regular colonoscopies. Fourteen women (13%) did not have Papanicolaou smears at recommended intervals, and 21 (18%) did not have annual mammograms. Six men (21%) did not undergo annual prostate screening. Decreased recommended screening with colonoscopy and mammography correlated with younger age. This survey of relatively unexplored caregivers identified cancer screening deficiencies and concerns that might be addressed by targeted interventions. With approximately 60% of patients with cancer receiving radiation therapy, advice in the radiation oncology setting could positively affect cancer screening behaviors in caregivers

Can radiomics combined with clinical data predict checkpoint inhibitor pneumonitis?

e14555 Background: Immunotherapy (ImT) is increasingly utilized in patients with advanced non-small cell lung cancer (aNSCLC). Checkpoint-inhibitor pneumonitis (CIP) is an uncommon and potentially life-threatening adverse event (AE) associated with ImT. For patients with aNSCLC, CIP signs and symptoms can be misclassified in the setting of underlying lung disease and incidence may be underreported. The ability to identify patients at risk for CIP prior to ImT could prevent significant morbidity. Previously, we reported that radiomics, a datamining technique that extracts patterns from medical imaging, had identified texture features on pre-ImT CT that correlate with CIP. In this study, we hypothesized that such features combined with clinical data can predict CIP. Methods: In an IRB-approved database of 129 patients with aNSCLC treated with nivolumab, 9 controls were identified with clinical diagnosis of CIP. For all patients, uninvolved lung in the last pre-ImT CT was mined for textures associated with CIP. In the 9 controls, 3 features were identified that correlated with CIP. Imaging and patient charts were reviewed for signs and symptoms of CIP within the first 6 months after ImT administration. Non-controls with progressive clinical symptoms or radiographic findings consistent with CIP and unexplained by disease progression, infection or other medical interventions were treated as CIP-positives. Lastly, the area under the receiver operating curve (AUC) for predicting CIP was built progressively combining uncorrelated laboratory, imaging, and clinical data. Results: In all, 25 patients (19%) were identified with any-grade CIP. A model based on pre-ImT platelets (PLT) and neutrophil-to-lymphocyte ratio (NLR) had an AUC for predicting CIP of 0.648. The radiomics features associated with CIP were average gray value (p = .002), 3D normalized entropy (p = 0.022), and kurtosis (p = 0.011). When combined these 3 features had an AUC of 0.735. Combining both radiomics and laboratory data produced an AUC of 0.779. This increased to 0.793 with the addition of ECOG performance status and sex. Finally, incorporating smoking status yielded an AUC of 0.802. Paired sample difference in AUC between the final model and that including only PLT and NLR was significant (p = 0.003). Conclusions: In patients with aNSCLC treated with ImT, CIP is an uncommon but potentially serious AE. The ability to identify patients at higher risk for CIP could prevent significant morbidity. A model combining radiomics of pre-ImT imaging, laboratory, and clinical data showed better prediction for CIP than laboratory data alone. Future directions include validation of this model on an external cohort and with patients on different ImT regimens