Hoppe, Bradford S.

Abstract Multiple clinical trials have assessed de-escalation strategies from combined modality therapy (CMT) to chemotherapy-alone for the treatment of early-stage classical Hodgkin lymphoma (cHL), confirming similar outcomes. The application of these data to the real-world is limited, however. We conducted a retrospective, multicenter cohort study comparing CMT vs chemotherapy-alone in patients with early-stage cHL (stage IA-IIB) treated between January 2010 and December 2020. Positron emission tomography (PET) scans after chemotherapy cycle 2 (PET2) were independently reviewed by a nuclear radiologist (Deauville score ≥4, positive; ≤3, negative). Patient outcomes were compared by using an intention-to-treat analysis. Among 125 patients (CMT, n = 63; chemotherapy-alone, n = 62) with a median follow-up of 59.8 months (95% CI, 48.6-71.0), no differences in overall survival were observed (5-year overall survival, CMT 98.0% vs chemotherapy-alone 95.1%; log-rank test, P = .38). However, there was reduced progression-free survival (PFS) with chemotherapy-alone among all patients (2-year PFS, CMT 95.1% vs chemotherapy-alone 75.3%; log-rank test, P = .005) and in those with bulky (n = 43; log-rank test, P < .001), unfavorable (n = 81; log-rank test, P = .002), or PET2-positive (n = 15; log-rank test, P = .02) disease. No significant differences in PFS were seen for patients with non-bulky (log-rank test, P = .35), favorable (log-rank test, P = .62), or PET2-negative (log-rank test, P = .19) disease. Based on our real-world experience, CMT seems beneficial for patients with early-stage cHL, especially those with PET2-positive and unfavorable disease. Chemotherapy-alone regimens can lead to comparable outcomes for patients with favorable, non-bulky, or PET2-negative disease. We conclude that although results seen in clinical trials are replicated in certain patient subgroups, other subgroups not fitting trial criteria do poorly when radiotherapy is excluded.

AbstractDespite advancements in local‐regional and systemic therapies, non‐small cell cancer (NSCLC) remains a leading cause of death worldwide. Among those treated with standard‐of‐care modalities, 30–60% experience disease recurrence. Carbon ion radiotherapy (CIRT) is a form of densely ionizing radiotherapy with unique physical and biological advantages over traditional photon and proton modalities. CIRT is expected to have a superior biological impact on tumors, and is believed to be less impacted by the presence of tumor hypoxia or cell cycle state. It also shows highly conformal physical dose deposition due to reduced lateral scattering of the particles, limiting the radiation dose delivered to adjacent organs at risk. To implement CIRT as a viable option in the treatment of NSCLC, technical aspects of treatment delivery – including appropriate beam arrangements, dose calculation algorithms, radiobiological models, and methods of motion management – must be thoroughly investigated. Furthermore, randomized clinical trials comparing CIRT versus traditional radiation modalities must be performed to show the benefits and risks associated with this novel treatment modality. This review discusses the rationale for utilizing CIRT in NSCLC, available clinical data to date, and the potential for future investigations that may pave the path for improving outcomes in those diagnosed with NSCLC.

Hodgkin lymphoma (HL) is a highly curable form of cancer, and current treatment regimens are focused on improving treatment efficacy while decreasing the risk of late effects of treatment. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for pediatric HL provide recommendations on the workup, diagnostic evaluation, and treatment of classic HL, including principles of pathology, imaging, staging, systemic therapy, and radiation therapy. This portion of the NCCN Guidelines focuses on the management of pediatric classic HL in the upfront and relapsed/refractory settings.

Abstract Background Yttrium-90 ibritumomab tiuxetan [(90)Y-IT; Zevalin] is a radio-immunoconjugate (RIC) which targets CD20. This study evaluates the utilization and cost-effectiveness of (90)Y-IT in the first line treatment for patients with previously untreated low-grade FL (UFL) and marginal zone lymphoma (UMZL) treated at our institution with (90)Y-IT. Methods We utilized the Advanced Text Explorer (ATE) and the Lymphoma SPORE databases to identify two groups of patients with UFL, WHO grade 1-2, and UMZL who received treatment with either (90)Y-IT or bendamustine plus rituximab (BR) at Mayo Clinic Cancer Center between January 2003 and December 2019. We excluded all patients who had >25% bone marrow involvement with lymphoma for the BR group as this was a requirement for (90)Y-IT treatment. Inverse propensity weighting was utilized to balance the groups for baseline patients and disease characteristics. We use progression-free survival (PFS) as a denominator for the cost effectiveness/utilization evaluation. We identified meaningful and retrospectively measurable outcomes to compare between the groups. we extracted the following data; number of clinic visits in the first year after therapy, emergency room visits, number of hospital admissions, number of hospitalization days, numbers of days on the floor and ICU, number of infections, number of neutropenic fever hospitalizations, number of C-difficile events, number of blood products transfusions, overall use of growth factors due to therapy induced neutropenia, average number of times a growth factor was used, and the number of therapeutic use days. We defined days of therapeutic use as the number of days a treatment was administered on. We also calculated the average cost of the induction treatment when utilizing either (90)Y-IT or BR. The therapeutic cost included only the cost of the medications/therapies and their administration. Results Our cohort consists of a total of 143 patients - 64% (92/143) received BR and 36% (51/143) received (90)Y-IT (see Table-1 for clinical characteristics).The median follow-up from the time of therapeutic administration for the (90)Y-IT group was 5.3 years (95% CI; 4.2, 6.2) with one death and 4.7 years (95% CI; 3.9, 4.9) for the BR group with 6 deaths. The ORR was 100% in (90)Y-IT group with 94% achieving complete response (CR) while ORR in the BR group was 98% with 95% achieving CR. Rituximab maintenance was utilized in 33% of BR patients compared to only 6% in patients who received (90)Y-IT, p=0.002. After utilizing inverse propensity weighting (Figure-1), 5 years PFS was 76% for the (90)Y-IT group and 75% for the BR group, p=0.63 (Figure-2). We evaluated the average treatment effect of (90)Y-IT compared to BR on utilization outcomes, Table-2. (90)Y-IT required an average of 4.5 clinic visits less within the first year after treatment compared to BR group, p<0.001. (90)Y-IT patients had an average of 10 days less of therapeutic use days compared to the BR group, p<0.001. Patienta had similar admission rates to the hospital in both groups. However, when patients were admitted to the hospital in the first year after treatment, those who received (90)Y-IT spent an average of 1.5 days less in the hospital compared to the BR group, p=0.046. The overall use of growth factors was 40% less in the (90)Y-IT group as compared to the BR group, p<0.001. The therapeutic cost of induction of (90)Y-IT was 54% less than that of 6 cycles of BR. Transformation to a high grade of lymphoma was seen in 4 patients in the BR group and 2 patients in the (90)Y-IT group. There was only one case of myelodysplastic syndrome in the BR group and none in the (90)Y-IT group. Conclusion Radio-immunoconjugate therapy with (90)Y-IT is a very convenient and cost-effective treatment for low-grade UFL and UMZL. This is especially important amidst the COVID-19 pandemic as it requires less contact with the health system with decreased number of therapeutic days, clinic visits, use of growth factors and number of hospitalization days. The cost of the therapeutic agents and their administration was also significantly lower for the (90)Y-IT which could help reducing the burden on the health system. Figure 1 Figure 1. Disclosures Cerhan: Regeneron Genetics Center: Other: Research Collaboration; Genentech: Research Funding; Celgene/BMS: Other: Connect Lymphoma Scientific Steering Committee, Research Funding; NanoString: Research Funding. Tun: Mundipharma, Celgene, BMS, Acrotech, TG therapeutics, Curis, DTRM: Research Funding; Gossamer Bio, Acrotech: Consultancy. OffLabel Disclosure: We are describing the use of Yttrium-90 ibritumomab tiuxetan in the first line setting in comparison to the bendamustine plus rituximab which is the standard of care

AbstractBackgroundChildren with chest wall Ewing sarcoma with malignant pulmonary effusion or pleural stranding require hemithorax radiation, often with plans that exceed lung constraints. We investigated disease control and pneumonitis in children requiring hemithorax radiation.ProcedureEleven children (median age 13 years) received hemithorax radiotherapy. Symptomatic radiation pneumonitis was considered National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) grade 1+ with respiratory symptoms. Mean lung dose (MLD), volume of lung exposed to a dose ≥5 Gy (V5), ≥20 Gy (V20), and ≥35 Gy (V35) were recorded. Adult and pediatric lung constraints were obtained from Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) guidelines and Children's Oncology Group (COG) protocols, respectively.ResultsMedian hemithorax dose was 15 Gy (1.5 Gy/fraction). Median total dose was 51 Gy (1.8 Gy/fraction). Most plans delivered both protons and photons. The ipsilateral MLD, V5, and V20 were 27.2 Gy, 100%, and 48.3%; the bilateral MLD, V20, and V35 were 14.1 Gy, 22.8%, and 14.3%, respectively. One hundred percent, 36%, and 91% of treatments exceeded recommended adult ipsilateral lung constraints of V5 <65%, V20 <52%, and MLD of 22 Gy; 64%, 45%, and 82% exceeded COG bilateral lung constraints of V20 <20%, MLD <15 Gy, and MLD <12 Gy, respectively; 82% of treatments exceeded the COG ipsilateral lung constraint of V20 <30%. At a median 36 months (range 12–129), the symptomatic radiation pneumonitis incidence was 0%. Two patients progressed with nonpulmonary metastatic disease and died at a median 12 months following radiotherapy.ConclusionsExisting guidelines may overestimate pneumonitis risk, even among young children receiving multiagent chemotherapy. For children with chest wall Ewing sarcoma and other thoracic malignancies, more data are needed to refine pediatric dose–effect models for pulmonary toxicity.

AbstractData comparing outcomes in prostate cancer and factors affecting treatment choice are sparse. To inform the design of a comparative effectiveness clinical trial, we engaged patients in developing a 28‐question survey about decision making on treatment and research participation and dispersed it among men greater than or equal to 50 years of age. The 1046 respondents ranked long‐term clinical outcomes as most important in making treatment decisions, specific functional outcomes as slightly less important, and duration, location, and cost of treatment as least important. Treatment choice was strongly impacted by side effect profile. Responses to whether the subject would agree to participation in a randomized trial between two types of radiation with minimal differences in outcomes were “yes” in 15%, “no” in 39%, and “undecided” in 46%. Responses to whether the subject would agree to participation in a randomized trial between two treatment durations with similar outcomes were yes in 36%, no in 24%, and undecided in 40%. Findings suggest many potential patients have strong treatment preferences and are averse to randomization, particularly when outcomes of importance may be affected. Patient engagement in study design and novel nonrandomized trial designs may offer a path to increase clinical trial success.

AbstractBackgroundPositron emission tomography (PET)‐based measures of baseline total‐body tumor burden may improve risk stratification in intermediate‐risk Hodgkin lymphoma (HL).Materials and methodsEvaluable patients were identified from a cohort treated homogeneously with the same combined modality regimen on the Children's Oncology Group AHOD0031 study. Eligible patients had high‐quality baseline PET scans. Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were each measured based on 15 thresholds for every patient. Univariate and multivariable Cox regression and Kaplan–Meier survival analyses assessed for an association of MTV and TLG with event‐free survival (EFS).ResultsFrom the AHOD0031 cohort (n = 1712), 86 patients were identified who (i) were treated with four cycles of doxorubicin, bleomycin, vincristine, etoposide, prednisone, cyclophosphamide (ABVE‐PC) chemotherapy followed by involved field radiotherapy, and (ii) had a baseline PET scan that was amenable to quantitative analysis. Based on univariate Cox regression analysis, six PET‐derived parameters were significantly associated with EFS. For each of these, Kaplan–Meier analyses and the log‐rank test were used to compare patients with highest tumor burden (i.e., highest 15%) to the remainder of the cohort. EFS was significantly associated with all six PET parameters (all p < .029). In a multivariable model controlling for important covariates including disease bulk and response to chemotherapy, MTV2BP was significantly associated with EFS (p = .012).ConclusionMultiple baseline PET‐derived volumetric parameters were associated with EFS. MTV2BP was highly associated with EFS when controlling for disease bulk and response to chemotherapy. Incorporation of baseline MTV into risk‐based treatment algorithms may improve outcomes in intermediate‐risk HL.

10027 Background: Thoracic radiotherapy (RT) is a risk factor for cardiac disease among survivors of childhood cancer based on studies considering RT doses to the entire heart. Dose to specific cardiac substructures may provide more precise dose-response associations to guide RT planning. We report associations between RT dose to cardiac substructures and risk of specific cardiac outcomes. Methods: We determined the cumulative incidences of CTCAE grade 3 – 5 coronary artery disease (CAD), heart failure (HF), and valvular disease (VD) among 25,481 5-year childhood cancer survivors diagnosed 1970 – 1999 in the CCSS. Median age at diagnosis was 6.1 years (0 – 20 years) and at last follow-up 29.8 years (5.6 – 65.9 years). For the 12,228 individuals receiving RT, fields were reconstructed on an age scaled computational phantom. Mean doses to the entire heart, cardiac chambers, valves, and left main, anterior descending (LAD), circumflex, and right coronary (RCA) arteries were estimated. Adjusted piecewise exponential models (including cumulative anthracycline dose) evaluated associations between mean RT dose to each structure and outcomes. Results: At 30 years from diagnosis, the cumulative incidences of grades 3 – 5 CAD, HF, and VD were 2.3% (95% CI 2.0 – 2.5), 2.6% (95% CI 2.4 – 2.9), and 0.6% (95% CI 0.5 – 0.8) respectively. Low dose RT (mean 5 – 9.9 Gy) to the RCA (relative rate [RR] = 2.6, 95% CI 1.6 – 4.1, p < 0.001), LAD (RR = 1.9, 95% CI 1.1 – 3.3, p = 0.019), and left ventricle (RR = 2.2, 95% CI 1.3 – 3.7, p = 0.002) was associated with increased risk of CAD relative to those not exposed; mean dose of 5 – 9.9 Gy to the entire heart was not (RR = 1.1, 95% CI = 0.8 – 1.6, p = 0.59). Table shows the associated cumulative incidences of CAD for these structures. Mean RT doses of 5 – 9.9 Gy to the aortic valve (RR = 4.6, 95% CI 1.5 – 14.0, p = 0.008) and tricuspid valve (RR = 5.5, 95% CI 2.0 – 15.1, p = 0.001) were associated with risk of VD compared to those with no RT; mean heart dose 5 – 9.9 Gy was not (RR = 0.6, 95% CI = 0.2 – 1.3, p = 0.16). No cardiac structure was significantly associated with an increased risk of HF at a mean dose of 5 – 9.9 Gy. Mean RT doses below 5 Gy were not associated with increased risks of CAD, HF, or VD; doses ≥10 Gy to nearly all substructures and the entire heart were. Conclusions: Low dose RT to the coronary arteries and cardiac valves (5 – 9.9 Gy) from RT is associated with increased risk of CAD and VD, respectively. Sensitivity to low dose RT may vary across the heart and doses to specific structures may be more predictive of late cardiac disease than whole heart dose. These data can guide RT planning to prioritize substructures for avoidance.[Table: see text]

Abstract Background Out‐of‐field neutron dissemination during double‐scattered proton therapy has raised concerns of increased second malignancies, disproportionally affecting pediatric patients due to the proportion of body exposed to scatter dose and inherent radiosensitivity of developing tissue. We sought to provide empiric data on the incidence of early second tumors. Methods Between 2006 and 2019, 1713 consecutive children underwent double‐scattered proton therapy. Median age at treatment was 9.1 years; 371 were ≤3 years old. Thirty‐seven patients (2.2%) had tumor predisposition syndromes. Median prescription dose was 54 Gy (range 15–75.6). Median follow‐up was 3.3 years (range 0.1–12.8), including 6587 total person‐years. Five hundred forty‐nine patients had ≥5 years of follow‐up. A second tumor was defined as any solid neoplasm throughout the body. Results Eleven patients developed second tumors; the 5‐ and 10‐year cumulative incidences were 0.8% (95% CI, 0.4–1.9%) and 3.1% (95% CI, 1.5–6.2%), respectively. Using age‐ and gender‐specific data from the Surveillance, Epidemiology, and End Results (SEER) program, the standardized incidence ratio was 13.5; the absolute excess risk was 1.5/1000 person‐years. All but one patient who developed second tumors were irradiated at ≤5 years old ( p < .0005). There was also a statistically significant correlation between patients with tumor predisposition syndromes and second tumors ( p < .0001). Excluding patients with tumor predisposition syndromes, 5‐ and 10‐year rates were 0.6% (95% CI, 0.2–1.7%) and 1.7% (95% CI, 0.7–4.0%), respectively, with all five malignant second tumors occurring in the high‐dose region. Conclusion Second tumors are rare within the decade following double‐scattered proton therapy, particularly among children irradiated at >5 years old and those without tumor predisposition syndrome.