ABSTRACT
A PENTEC analysis of published investigations of central nervous system (CNS) subsequent neoplasms (CNS-SN) in childhood cancer survivors who received radiation therapy (RT) to the brain was performed to estimate the effect of RT dose and gender on the risk of CNS-SN following RT. Through the PENTEC initiative, a systematic literature review was performed to identify published data on CNS-SN after prior cranial RT in childhood cancer survivors. Using the Covidence platform 2,156 studies were screened for potential inclusion. The incidences of CNS-SNs, RT dose, age, gender, primary cancer diagnosis, and latent time from primary diagnosis to CNS-SN were extracted, to assess the factors influencing risk for subsequent meningiomas or subsequent malignant CNS tumors (e.g., gliomas). The odds ratio for CNS-SNs in different dose intervals were calculated and excess odds ratio (EOR) per Gy of developing subsequent meningiomas or malignant tumors was estimated using inverse-variance weighted linear regression to model the risk for CNS-SN versus dose. Forty studies of independent patient cohorts provided information on 736 subsequent malignant tumors with average median latency 10.3 years, and 32 studies provided information on 1,035 subsequent meningiomas with average median latency 20.5 years. Dose-response was derived from 6 studies of 248 subsequent malignant tumors and 7 studies of 557 subsequent meningiomas. The pooled EOR/Gy was 0.45 (95% CI: 0.25, 0.66) for meningiomas and 0.16 (95% CI: 0.11, 0.20) for malignant CNS tumors. The average cumulative incidence of developing a meningioma or malignant CNS tumor at 15 years of follow-up was 2.4% (range, 1.2-6.3%) or 0.9% (range, 0.4-1.8%), respectively. Females had a higher risk of meningioma than males (OR=1.5, 95% CI: 1.2, 1.8;6 studies;50,346 patients) whereas no gender difference was seen in risk of malignant tumors (OR=0.9, 95% CI: 0.7, 1.2;4 studies;32,446 patients). This PENTEC systematic review shows a significant radiation dose-response relationship and higher risk among females for meningioma, akin to the general population, and a highly significant but somewhat less steep relationship for subsequent malignant tumors with no effect of gender. Further evaluation of the effect of age and chemotherapy in relation to dose and gender is necessary to elucidate the risk of CNS-SN after RT. [ FROM AUTHOR] Copyright of International Journal of Radiation Oncology, Biology, Physics is the property of Pergamon Press - An Imprint of Elsevier Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)
ABSTRACT
Purpose/Objective(s): RT plays an important role in the treatment of NHL. Early in the COVID-19 pandemic, in order to decrease patient and staff exposure to potential infection, the International Lymphoma Radiation Oncology Group [ILROG] published emergency guidelines to support hypofractionation across multiple dose regimens. For NHL, ILROG recommended substitution of the familiar 2 Gy x2 regimen with a 4 Gy x1 alternative. This preliminary report describes our center's experience with a regimen of a single dose of 4 Gy (“Big Boom”). Materials/Methods: We present our initial findings of patients treated with 4 Gy x1 between March 30, 2020 through November 30, 2020 (n = 40 lesions;36 patients). We utilized Lugano PET criteria and clinical assessments to determine patient outcomes. Outcomes included initial clinical/radiographic response and acute toxicities. Patients were treated with either a definitive (curative) or a palliative intent (to relieve symptoms and not necessarily to achieve long-term disease control). Results: Table 1 summarizes the patient and treatment characteristics. 29 patients (72%) were treated with a definitive intent, and 11 (28%) with a palliative intent. Median time to initial assessment for all sites was 2.2 months (range: 0.6-4.4), with overall median follow up time of 3.8 months (range: 1.0-7.3). The overall initial response rate was 85% for all sites, with 59% achieving complete response (CR) and 26% achieving a partial response (PR) (n = 39 lesion sites;35 patients – 1 patient deceased shortly after RT [unrelated to radiation]). 4 initial partial response/no response (PR/NR) sites later became CR with either additional full dose RT (2 Gyx12) or no other treatments. The median follow-up time for those 4 lesions sites was 4.2 months (range: 2.3-9.2). 9 patients reported grade 1 toxicity, and none had grade 2+ toxicity. Conclusion: Given the initial high response rate and the ease of using a “one and done” treatment method, we propose that the early response rates of using a 4 Gyx1 regimen are similar to that of 4 Gy in 2 fractions. Longer term follow-up is required to confirm the durability of these results. As we continue to accrue and evaluate, data will be updated at the time of the meeting and potentially joined with other centers participating in the comprehensive ILROG-COVID guidelines research effort.