Children's Oncology Group's 2023 blueprint for research: Radiation oncology.

Radiation oncology is an integral part of the multidisciplinary team caring for children with cancer. The primary goal of our committee is to enable the delivery of the safest dose of radiation therapy (RT) with the maximal potential for cure, and to minimize toxicity in children by delivering lower doses to normal tissues using advanced technologies like intensity-modulated RT (IMRT) and proton therapy. We provide mentorship for y ators and are actively involved in educating the global radiation oncology community. We are leaders in the effort to discover novel radiosensitizers, radioprotectors, and advanced RT technologies that could help improve outcomes of children with cancer.

Contextual Predictors of Engagement in a Tailored mHealth Intervention for Adolescent and Young Adult Cancer Survivors.

BACKGROUND: Despite the promise of mobile health (mHealth), engagement is often too low for durable health behavior change, and little is known regarding why certain individuals abandon mHealth tools. PURPOSE: Guided by a mHealth engagement framework, we evaluated contextual predictors of objective engagement with an app for adolescents and young adults (AYA) who survived cancer. METHODS: One hundred and ten AYA survivors (M age = 20.5, 43% female, 30% racial/ethnic minority) were randomized to receive a disease self-management app that delivered 1-2 tailored messages/day for 16 weeks, and contained a survivorship care plan (SCP). Demographic, disease, psychosocial, and setting characteristics were examined as predictors of three objective engagement outcomes: (a) % of active app days, (b) % of messages read, and (c) viewed SCP in the app versus not. A subsample (n = 10) completed qualitative interviews to further assess engagement barriers. RESULTS: Self-reported uninterrupted app access (ß = -0.56, p < .001), iPhone (vs. Android) ownership (ß = 0.30, p < .001), and receiving the intervention in the summer (ß = -0.20, p = .01) predicted more active days. Lower depressed mood (ß = -0.30, p = .047) and uninterrupted app access (ß = -0.50, p < .001) predicted more messages read. Qualitatively, technical glitches and competing priorities were described as engagement barriers, whereas certain types of messages (e.g., health goal messages) were perceived as engaging. Among participants who had uninterrupted app access (n = 76), higher baseline motivation to change, better health perceptions, using the app during the summer, and iPhone ownership predicted higher engagement. CONCLUSIONS: Findings demonstrate the importance of comprehensively assessing and planning for multi-level ecological determinants of mHealth engagement in future trials. CLINICALTRIALS.GOV IDENTIFIER: NCT03363711.

Neuroblastoma.

The survival of patients with high-risk neuroblastoma has improved significantly with the use of intensive multimodality treatment regimens, including chemotherapy, surgery, radiation therapy, myeloablative chemotherapy followed by stem cell rescue, and immunotherapy. This report summarizes the current treatment strategies used in the COG and SIOP for children with neuroblastoma. The improved global collaboration and the adoption of a uniform International Neuroblastoma Risk Group Staging System will help facilitate comparison of homogeneous pretreatment cohorts across clinical trials. Future research strategies regarding the indications for and dosages of radiation therapy to the primary and metastatic sites, and the integration of meta-iodobenzyl guanidine therapy into the multimodal treatment program, are discussed.

Psychosocial impact of the COVID-19 pandemic on cancer patients, survivors and caregivers.

Objective: This study aimed to increase understanding of the effects of the pandemic on cancer patients, survivors and caregivers.Methods: An Internet-based survey was accessed over 2 months by individuals diagnosed with cancer or caregivers (N = 281), with descriptive statistics and chi square analysis used to compare subsets.Results: Most participants reported social isolation (76%) and mental health impact (70%) since the beginning of the COVID19 pandemic; isolation appeared to correlate with mental health impact (p < .00001). Food insecurity and financial hardship correlated significantly with mental health impact; food insecurity also correlated with social isolation.Conclusions: Our findings suggest that mental health during the pandemic in the cancer population may be impacted by social isolation, financial stress, and food insecurity, as well as stress regarding accessing cancer treatments. Awareness by psychosocial healthcare providers of need for resources to support these hardships, as well as framework to identify them, are essential elements of cancer-related care.

Role of Metastatic Site Irradiation in Pediatric Patients With Metastatic Ewing Sarcoma.

BACKGROUND: The use of radiation therapy to treat metastases in patients with metastatic Ewing sarcoma (MES) has been controversial and variable. The authors report outcomes and patterns of failure after metastatic site irradiation (MSI). PROCEDURE: A total of 27 pediatric patients with MES were treated with chemotherapy and received radiation therapy to their primary site. Ten patients additionally received MSI, which consisted of whole-lung irradiation (WLI) in patients with lung metastases. Metastatic sites were followed from diagnosis to the first relapse. RESULTS: Median follow-up was 29 months. Seventy-eight percent of patients relapsed. Two-year progression-free survival (PFS) and overall survival with and without MSI were 30 versus 29% (log rank P=0.38) and 60 versus 70% (log rank P=0.11), respectively. The median time to relapse among patients who relapsed was 19.5 versus 12.3 months for those receiving MSI versus those who did not (P=0.04).Seven of 20 (35%) patients with lung metastases received WLI±other MSI. Two-year PFS with and without MSI was 43% versus 23% (log rank P=0.02). Among patients with a complete response to computed tomography, 5 of 14 (36%) patients received MSI. Two-year PFS with and without MSI was 60% versus 33% (log rank P=0.04).In the cohort of patients who relapsed, among all metastatic sites at diagnosis, the disease recurred at 15% of irradiated sites and 31% of unirradiated sites. On logistic regression, no factors were statistically associated with increased risk of recurrence at initial sites of metastases. CONCLUSIONS: Relapses frequently occur at sites of prior unirradiated disease in patients with MES. WLI may improve 2-year PFS, regardless of chemotherapy response. Further investigation of the role of MSI is warranted.

Survivorship care planning in skin cancer: An unbiased statistical approach to identifying patterns of care-plan use.

BACKGROUND: Nearly 1 in 5 Americans will develop skin cancer, and as a result, survivors of skin cancer compose one of the largest groups of cancer survivors. Survivorship care plans (SCPs) are an important tool for improving patient outcomes and provide critical information to both survivors and health care professionals. Recent efforts have been made to expand SCP utilization; however, which patients currently receive SCPs is poorly understood. METHODS: This study used 596 individuals with a diagnosis of melanoma (n = 391) or nonmelanoma skin cancer (n = 205) who had used an Internet-based SCP tool from May 2010 to December 2016 to model the patient and provider characteristics that determine SCP utilization. RESULTS: Survivors were predominantly white (95.3%) and female (56.5%). Survivors who received a treatment summary were more likely to also receive an SCP. University and nonuniversity cancer centers used SCPs at a higher rate than other care settings. Survivors whose care was managed by a team rather than just an individual physician were also more likely to receive an SCP. Survivors older than 70 years at diagnosis were almost twice as likely to receive a plan as survivors who were diagnosed at a younger age. CONCLUSIONS: With a convenience sample of skin cancer survivors, it is possible to model factors that predict the receipt of SCPs. Important variables include the diagnosis age, treatment setting, physician type, and treatment-summary utilization. A closer examination of these variables identified several disparities in care-plan use and, therefore, opportunities to improve the distribution of SCPs. Further validation in additional cohorts of survivors is necessary to confirm these conclusions. Cancer 2018;124:183-91. © 2017 American Cancer Society.

Insurance coverage decisions for pediatric proton therapy.

Proton beam therapy (PBT) holds promise for pediatric patients, but level 1 evidence is not available. In this context, we examined insurance coverage decisions at our facility from 2010 to 2015. PBT was initially denied for 11% of pediatric cases. However, nearly all denials were overturned on appeal-a process that often delayed care by more than a week. Despite unfavorable language in coverage policies, real-world decisions were eventual approval in >99% of cases. Payers appear to have largely accepted the current level-of-evidence for pediatric PBT, but all parties spend significant time and resources on appeals. Streamlined approval processes could align incentives among stakeholders.

Cardiac Toxicity After Craniospinal Irradiation: A Late Effect That May be Eliminated With Proton Therapy.

BACKGROUND: Craniospinal irradiation (CSI) is commonly required for pediatric patients with central nervous system malignancies. Traditionally, CSI is given using x-rays to deliver radiation to the brain and spine, exposing normal anterior structures, including heart, to unnecessary radiation. OBSERVATIONS: We present a patient treated with x-ray CSI for medulloblastoma with spinal metastasis (3600 cGy CSI with focal boost to 5000 cGy), who subsequently developed significant cardiac toxicity, likely related to radiation exposure. CONCLUSIONS: Spinal irradiation can cause significant cardiac risk due to exit dose through anterior structures. This toxicity may be avoided with proton therapy, which eliminates visceral exit dose.

Survivorship and the chronic cancer patient: Patterns in treatment-related effects, follow-up care, and use of survivorship care plans.

BACKGROUND: The survivorship needs of patients living with chronic cancer (CC) and their use of survivorship care plans (SCPs) have been overlooked and underappreciated. METHODS: A convenience sample of 39,088 SCPs completed for cancer survivors with an Internet-based SCP tool was examined; it included 5847 CC survivors (15%; CC was defined as chronic leukemia and/or recurrent/metastatic cancer of another nature). Patient-reported treatment effects and follow-up care patterns were compared between CC survivors and survivors treated with curative intent (CI). Responses from a follow-up survey regarding SCP satisfaction and use were reviewed. RESULTS: CC survivors had greater odds of experiencing multiple treatment-related effects than survivors treated with CI; these effects included fatigue, cognitive changes, dyspnea, peripheral neuropathy, lymphedema, and erectile dysfunction. Nearly half of CC survivors were managed by an oncologist alone, and they were less likely than CI patients to be comanaged by a primary care provider and an oncologist. Fewer SCPs were generated by health care providers (HCPs) for CC survivors versus CI survivors. A smaller proportion of CC users versus CI users rated their experience and satisfaction with the SCP tool as very good or excellent, and CC users were less likely to share the HCP summary with their health care team. CONCLUSIONS: A substantial number of CC survivors, often considered incurable but treatable, seek survivorship support. Tools to facilitate participation, communication, and coordination of care are valuable for these patients, and future iterations of SCPs should be designed to address the particular circumstances of living with CC. Cancer 2017;123:4268-4276. © 2017 American Cancer Society.

Survivorship after lower gastrointestinal cancer: Patient-reported outcomes and planning for care.

BACKGROUND: There is significant need for quality follow-up care to optimize long-term outcomes for the growing population of lower gastrointestinal (GI) cancer survivors. Patient-reported outcomes (PROs) provide valuable information regarding late and long-term effects (LLTEs). METHODS: A convenience sample from 1129 colon, rectal, and anal cancer survivors (n = 792; 218, and 119, respectively) who participated in an Internet-based survivorship care plan (SCP) tool between May 2010 and October 2014 was used to examine patient-reported demographics, treatment, and toxicity data. Responses from a follow-up survey were reviewed. RESULTS: The median age of diagnosis was 51 years, and 81% of survivors were Caucasian. The most commonly reported LLTEs for all survivors were neuropathy, fatigue, cognitive changes, changes in GI function, urogenital and sexual dysfunction, and dermatologic effects. The prevalence of these effects varied with time since diagnosis, treatment modality, and treatment center. Individuals who had survived anal cancer reported a high prevalence of sexual dysfunction and radiation-induced dermatologic effects. Over 87% of users reported satisfaction levels of good to excellent using the SCP tool, and 69% reported that they intend to share the SCP with their health care team. CONCLUSIONS: For lower GI cancer survivors, it is feasible to obtain PROs from an Internet-based survivorship tool. Survivors report a wide spectrum of LLTEs, and these can be used to inform counseling at the time of diagnosis and to help anticipate and respond to disease-related and treatment-related sequelae during follow-up. The authors are among the first to report on PROs in anal cancer survivors. Further investigation on the impact of SCPs on health care communication and use is needed. Cancer 2017;123:1860-1868. © 2017 American Cancer Society.

Adult cancer survivorship: evolution, research, and planning care.

Increases in the number of adult cancer survivors and other issues have forced the oncology community to examine, evaluate, and alter the cancer care paradigm. Pediatric oncologists are grappling with the task of transitioning a growing population of adult survivors of childhood cancer to adult medicine, while oncologists caring for adult cancer survivors are seeking models of follow-up care that are acceptable to patients and providers. Workforce and access-to-care issues suggest that primary care providers will see more cancer survivors in their practices across time, although it is unclear how prepared they are for this task. Translational research is needed to develop evidence-based clinical care and survivorship care plans. A broad picture of the evolving field of adult cancer survivorship is presented. The recent focus on young adult survivors of childhood cancer, an overview of translational research needed to inform the physical and psychosocial care of cancer survivors, and the roles of primary and specialty care providers managing this population is examined. Finally, an overview of evolving treatment summary and care plan initiatives is presented.

Proton pencil beam scanning for mediastinal lymphoma: treatment planning and robustness assessment.

BACKGROUND: Modern radiotherapy (RT) for lymphoma is highly personalized. While advanced imaging is largely employed to define limited treatment volumes, the use of proton pencil beam scanning (PBS) for highly conformal lymphoma RT is still in its infancy. Here, we assess the dosimetric benefits and feasibility of PBS for mediastinal lymphoma (ML). MATERIALS AND METHODS: Ten patients were planned using PBS for involved-site RT. The initial plans were calculated on the average four-dimensional computed tomography (4D-CT). PBS plans were compared with 3D conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), and proton double scattering (DS). In order to evaluate the feasibility of PBS and the plan robustness against inter- and intra-fractional uncertainties, the 4D dose was calculated on initial and verification CTs. The deviation of planned dose from delivered dose was measured. The same proton beamline was used for all patients, while another beamline with larger spots was employed for patients with large motion perpendicular to the beam. RESULTS: PBS provided the lowest mean lung dose (MLD) and mean heart dose (MHD) for all patients in comparison with 3D-CRT, IMRT, and DS. For eight patients, internal target volume (ITV) D98% was degraded by <3%; and the MLD and MHD deviated by <10% of prescription over the course of treatment when the PBS field was painted twice in each session. For one patient with target motion perpendicular to the beam (>5 mm), the degradation of ITV D98% was 9%, which was effectively mitigated by employing large spots. One patient exhibited large dose degradation due to pericardial effusion, which required replanning across all modalities. CONCLUSIONS: This study demonstrates that PBS plans significantly reduce MLD and MHD relative to 3D-CRT, IMRT, and DS and identifies requirements for robust free-breathing ML PBS treatments, showing that PBS plan robustness can be maintained with repainting and/or large spots.

Proton therapy and radiation sensitivity in dyskeratosis congenita.

BACKGROUND: Patients with dyskeratosis congenita (DC) have an increased risk of cancer, but also exhibit heightened radiation sensitivity. Proton therapy improves sparing of normal tissue, and thus may reduce radiation toxicity in patients with DC. OBSERVATIONS: We present a pediatric patient with DC who was treated with adjuvant proton therapy for oropharyngeal cancer. He experienced more severe skin toxicity and mucositis than expected. With reduced fractions per week and extensive supportive care, he completed the full radiation course. CONCLUSIONS: Proton therapy can improve normal tissue sparing, allowing successful delivery of radiation therapy in DC patients.

Metastatic site radiation therapy for Ewing sarcoma and rhabdomyosarcoma: Consensus guidelines from the National Pediatric Cancer Foundation.

BACKGROUND: Despite the urgent need for improved outcomes in patients with metastatic Ewing sarcoma (EWS) and rhabdomyosarcoma (RMS), it is unknown how to best approach metastatic site radiation therapy for these patients and whether such treatment provides a significant oncologic benefit that outweighs the toxicities. METHODS: We gathered a panel of pediatric radiation oncologists from academic hospitals to identify and discuss current controversies regarding the role of radiation in the management of metastatic EWS and RMS. The panel reviewed existing clinical data and ongoing trials to address five key questions: 1) the role of whole lung irradiation (WLI) in treating lung metastases 2) number of metastatic sites warranting radiotherapy and the radicality of such an approach; 3) radiation techniques, including stereotactic body radiation therapy (SBRT); 4) the timing of metastatic-site radiation therapy; and 5) the utility of metastatic site radiation therapy for relapsed metastatic disease. RESULTS: After a review of existing data, consensus recommendations were developed to support the decision-making process in metastatic-site irradiation with the goal of improving long-term disease control. Patients with pulmonary metastases should receive WLI. In patients with limited (<8 sites) metastatic disease, a comprehensive approach should be taken to treat all sites of metastatic disease diagnosed at presentation. SBRT should be considered as a preferred treatment technique. The timing of metastatic-site treatment should coincide with the end of systemic therapy. However, if there is a dosimetric advantage or improved compliance, concurrent treatment with the primary site may be preferred. CONCLUSIONS: A consensus guideline was established to address several critical questions regarding the role of radiation in the treatment of metastatic EWS and RMS. The study highlights the existing controversies, provides a structured approach, and underscores the need for future studies to further evaluate the therapeutic ratio of metastatic-site directed therapy.

Patterns of recurrence after radiotherapy for high-risk neuroblastoma: Implications for radiation dose and field.

BACKGROUND: Prognosis for patients with high-risk neuroblastoma (HR-NBL) is guarded despite aggressive therapy, and few studies have characterized outcomes after radiotherapy in relation to radiation treatment fields. METHODS: Multi-institutional retrospective cohort of 293 patients with HR-NBL who received autologous stem cell transplant (ASCT) and EBRT between 1997-2021. LRR was defined as recurrence at the primary site or within one nodal echelon beyond disease present at diagnosis. Follow-up was defined from the end of EBRT. Event-free survival (EFS) and OS were analyzed by Kaplan-Meier method. Cumulative incidence of locoregional progression (CILP) was analyzed using competing risks of distant-only relapse and death with Gray's test. RESULTS: Median follow-up was 7.0 years (range: 0.01-22.4). Five-year CILP, EFS, and OS were 11.9 %, 65.2 %, and 77.5 %, respectively. Of the 31 patients with LRR and imaging review, 15 (48.4 %) had in-field recurrences (>12 Gy), 6 (19.4 %) had marginal failures (≤12 Gy), and 10 (32.3 %) had both in-field and marginal recurrences. No patients receiving total body irradiation (12 Gy) experienced marginal-only failures (p = 0.069). On multivariable analyses, MYCN amplification had higher risk of LRR (HR: 2.42, 95 % CI: 1.06-5.50, p = 0.035) and post-consolidation isotretinoin and anti-GD2 antibody therapy (HR: 0.42, 95 % CI: 0.19-0.94, p = 0.035) had lower risk of LRR. CONCLUSIONS: Despite EBRT, LRR remains a contributor to treatment failure in HR-NBL with approximately half of LRRs including a component of marginal failure. Future prospective studies are needed to explore whether radiation fields and doses should be defined based on molecular features such as MYCN amplification, and/or response to chemotherapy.

Impact of internet-based cancer survivorship care plans on health care and lifestyle behaviors.

BACKGROUND: Survivorship care plans (SCP) are currently recommended by the Institute of Medicine, and will soon be required for accreditation by the American College of Surgeons Commission on Cancer. To the best of the authors' knowledge, the impact of SCPs on cancer survivors has not been previously reported. METHODS: In 2007, the authors created an Internet tool for the creation of SCPs that provides customized guidelines for survivorship care. Users are sent a voluntary follow-up survey 1 month after initial use. RESULTS: From May 2010 through January 2013, 8690 cancer survivors used the SCP tool. The most common diagnoses were breast (45%), hematologic (12%), and gastrointestinal (11%) cancers; the median age of the survivors was 51 years. Of these, 875 (10%) respondents provided information for future electronic contact and 298 responded to a 1-month follow-up survey. They reported that the information provided was "good" to "excellent" in 93% of cases, and new in 65% of cases. With regard to the emotional impact of the SCP, 62% of responding survivors believed that it provided "just enough" information, 72% felt "more informed," and 94% believed they would recommend it to others. The majority of respondents (63%) thought that the SCP changed their health care participation, and 80% shared/planned to share it with their health care team. Of those survivors who had done so, 80% reported that it improved communication with their health care providers. Greater than one-half of survey users (54%) reported that they had made or planned to make a lifestyle change in response to the SCP, most commonly dietary modification and increased exercise. CONCLUSIONS: Survivorship care plans are useful vehicles with which to promote lifestyle and behavioral changes, and to assist survivors with communication with health care providers. These findings support recommendations from the Institute of Medicine and the American College of Surgeons Commission on Cancer.

Patient reported late effects of gynecological cancer treatment.

OBJECTIVE: There are a large number of gynecological cancer survivors in the United States living with long term sequelae of their treatment. Patient reported outcomes are essential in capturing patients' experiences in order to address survivorship issues; however, patient reported toxicities are not often collected or reported. METHODS: A web-based survivorship care plan tool was used to collect patient reported toxicity data for 390 women who had undergone treatment for gynecological cancer. Demographic, diagnosis, treatment modality and toxicity data were reviewed. RESULTS: Median age of diagnosis was 49 years, and 88% (n=334) of the women were Caucasian and had attended at least some college. Only 10% (n=38) had previously been offered a survivorship care plan or survivorship information. Almost half of the patients had ovarian cancer (46%, n=180), 23% had cervical cancer (n=92) and 28% had uterine cancer (n=109). Late effects most commonly reported for all gynecological malignancy survivors using this tool were cognitive changes, sexual side effects, changes in bowel patterns, peripheral neuropathy and skin changes. CONCLUSION: Women with gynecological cancers experience a plethora of late effects; however, very few of them have access to a survivorship plan to cope with these issues. Patient reported side effects, especially sexual dysfunction, occur more commonly than previously reported. Patient-focused tools to evaluate these side effects and access to survivorship plans are needed for comprehensive care of gynecologic cancer survivors.

General Anesthesia for Pediatric Radiation Therapy in the Era of COVID-19.

Purpose: Managing pediatric patients requiring daily general anesthesia (GA) for radiation therapy (RT) in the setting of COVID-19 is complex, owing to the aerosolizing nature of GA procedures, the risk of cardiopulmonary complications for infected patients, and the treatment of immunocompromised oncology patients in a busy, densely populated radiation oncology clinic. Methods and Materials: We developed an institutional protocol to define procedures for COVID-19 testing and protection of patients, caregivers, and staff, hypothesizing that this protocol would allow patients requiring GA to be safely treated, minimizing COVID-19 transmission risk to both patients and staff, and at the same time maintaining pre-COVID-19 patient volumes. All patients underwent COVID-19 testing before their first treatment and thrice weekly during treatment. For patients who tested positive for COVID-19, RT was delivered in the last end-of-day treatment appointment. A negative pressure room was used for GA induction and recovery, and separate physician/nurse teams were designated for in-room versus out-of-room patient management. Results: Seventy-eight pediatric patients received RT under GA, versus 69 over the same prior year timeframe, and 2 patients received 2 courses of RT under GA, for a total of 80 courses. The mean age was 4.9 years (range, 0.5-19.0 years) and 41 of 78 (52.6%) were male. Two patients (2.6%) received 2 courses of RT under GA, establishing a total of 80 courses. The mean number of treatment fractions was 22.2 (range, 1-40). Two of 78 patients (2.6%) tested positive for COVID-19; both were asymptomatic. Both patients completed treatment as prescribed. Neither patient developed cardiopulmonary symptoms complicating anesthesia, and neither patient experienced grade 3+ acute radiation toxicity. Conclusions: With careful multidisciplinary planning to mitigate COVID-19 risk, pediatric RT with GA was carried out for a large patient volume without widespread infection and without increased toxic effects from either GA or RT.

Risk of Pneumonitis and Outcomes After Mediastinal Proton Therapy for Relapsed/Refractory Lymphoma: A PTCOG and PCG Collaboration.

PURPOSE: Despite high response rates, there has been reluctance to use radiation therapy for patients with relapsed/refractory (r/r) Hodgkin (HL) or aggressive non-Hodgkin lymphoma (NHL) given concerns for subacute and late toxicities. Symptomatic pneumonitis, a subacute toxicity, has an incidence of 17% to 24% (≥grade 2) even with intensity modulated radiation therapy. Proton therapy (PT), which has no exit radiation dose, is associated with a lower dose to lung compared with other radiation techniques. As risk of radiation pneumonitis is associated with lung dose, we evaluated whether pneumonitis rates are lower with PT. METHODS AND MATERIALS: Within an international, multi-institutional cohort, we retrospectively evaluated the incidence and grade of radiation pneumonitis (National Cancer Institute Common Terminology Criteria for Adverse Events v4) among patients with r/r HL or NHL treated with PT. RESULTS: A total of 85 patients with r/r lymphoma (66% HL, 34% NHL; 46% primary chemorefractory) received thoracic PT from 2009 to 2017 in the consolidation (45%) or salvage (54%) setting. Median dose was 36 Gy(RBE). Before PT, patients underwent a median of 1 salvage systemic therapy (range, 0-4); 40% received PT within 4 months of transplant. With a median follow-up of 26.3 months among living patients, 11 patients developed symptomatic (grade 2) pneumonitis (12.8%). No grade 3 or higher pneumonitis was observed. Dose to lung, including mean lung dose, lung V5, and V20, significantly predicted risk of symptomatic pneumonitis, but not receipt of brentuximab, history of bleomycin toxicity, sex, or peritransplant radiation. CONCLUSIONS: PT for relapsed/refractory lymphoma was associated with favorable rates of pneumonitis compared with historical controls. We confirm that among patients treated with PT, pneumonitis risk is associated with mean lung and lung V20 dose. These findings highlight how advancements in radiation delivery may improve the therapeutic ratio for patients with relapsed/refractory lymphoma. PT may be considered as a treatment modality for patients with relapsed/refractory lymphoma in the consolidation or salvage setting.