Fracture rate after conventional external beam radiation therapy to the spine in multiple myeloma patients.

BACKGROUND CONTEXT: Conventional external beam radiation therapy (cEBRT) is used in multiple myeloma (MM) to treat severe pain, spinal cord compression, and disease-related bone disease. However, radiation may be associated with an increased risk of vertebral compression fractures (VCFs), which could substantially impair survival and quality of life. Additionally, the use of the Spinal Instability Neoplastic Score (SINS) in MM is debated in MM. PURPOSE: To determine the incidence of VCFs after cEBRT in patients with MM and to assess the applicability of the SINS score in the prediction of VCFs in MM. STUDY DESIGN: Retrospective multicenter cohort study. PATIENT SAMPLE: MM patients with spinal myeloma lesions who underwent cEBRT between January 2010 and December 2021. OUTCOME MEASURES: Frequency of new or progressed VCFs and subdistribution hazard ratios for potentially associated factors. METHODS: Patient and treatment characteristics were manually collected from the patients' electronic medical records. Computed tomography (CT) scans from before and up to 3 years after the start of radiation were used to score radiographic variables at baseline and at follow-up. Multivariable Fine and Gray competing risk analyses were performed to evaluate the diagnostic value of the SINS score to predict the postradiation VCF rate. RESULTS: A total of 127 patients with 427 eligible radiated vertebrae were included in this study. The mean age at radiation was 64 years, and 66.1% of them were male. At the start of radiation, 57 patients (44.9%) had at least one VCF. There were 89 preexisting VCFs (18.4% of 483 vertebrae). Overall, 39 of 127 patients (30.7%) reported new fractures (number of vertebrae (n)=12) or showed progression of existing fractures (n=36). This number represented 11.2% of all radiated vertebrae. Five of the 39 (12.8%) patients with new or worsened VCFs received an unplanned secondary treatment (augmentation [n=2] or open surgery [n=3]) within 3 years. Both the total SINS score (SHR 1.77; 95% confidence interval (CI) 1.54-2.03; p<.001) and categorical SINS score (SHR 10.83; 95% CI 4.20-27.94; p<.001) showed an independent association with higher rates of new or progressed VCFs in adjusted analyses. The use of bisphosphonates was independently associated with a lower rate of new or progressed VCFs (SHR 0.47 [95% CI 0.24-0.92; p=.027]). CONCLUSIONS: This study demonstrated that new or progressed VCFs occurred in 30.7% of patients within 3 years, in a total of 11.2% of vertebrae. The SINS score was found to be independently associated with the development or progression of VCFs and could thus be applied in MM for fracture prediction and possibly prevention.

Metabolic parameters predict survival and toxicity in chimeric antigen receptor T-cell therapy-treated relapsed/refractory large B-cell lymphoma.

CD19-targeted chimeric antigen receptor (CAR) T-cell therapy has revolutionized treatment for patients with relapsed/refractory large B-cell lymphoma (LBCL). However, data available concerning the impact of the prognostic value of quantitative 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) parameters on the CAR T-related outcomes and toxicities are limited. Therefore, we aimed to evaluate the predictive value of pre- and post-CAR T metabolic parameters on survival and toxicities following CAR T-cell therapy. Fifty-nine patients with PET/CT scans done pre-and post-CAR T infusion were retrospectively identified and analyzed in a single institution database of LBCL patients treated with commercial CD19-targeted CAR T-cell therapy. The median follow-up was 10.7 months [interquartile range (IQR): 2.6-25.5 months]. The overall response (complete response-CR and partial response) and CR rates post-CAR T were 76% (n = 45) and 53% (n = 31), respectively. On univariate analysis, low pre-CAR T total lesion glycolysis (TLG) and metabolic tumor volume (MTV) predicted improved overall response post-CAR T (OR = 4.7, p = 0.01, OR = 9.5, p = 0.03, respectively) and CR post-CAR T (OR = 12.4, p = 0.0004, OR = 10.9, p = 0.0001, respectively). High TLG pre-CAR T was correlated with cytokine release syndrome (CRS, OR = 3.25, p = 0.04). High MTV pre-CAR T was correlated with developing immune effector cell neurotoxicity syndrome (ICANS) events (OR = 4.3, p = 0.01), and high SUV pre-CAR T was associated with grade 3-4 neurological events (OR = 12, p = 0.01). High MTV/TLG/SUVmax post-CAR T were significantly associated with inferior Overall survival (OS). On multivariate analysis, high TLG pre-CAR T (HR = 2.4, p = 0.03), age ≥60 (HR = 2.7, p = 0.03), and bulky disease (≥5 cm) at the time of apheresis (HR = 2.5, p = 0.02) were identified to be independent prognostic factors for inferior PFS. High MTV post-CAR T was identified as the most prognostic factor associated with inferior OS.

Radiation therapy as a bridging and salvage strategy in patients with relapsed or refractory multiple myeloma undergoing BCMA-targeted CAR T-cell therapy.

Radiation therapy (RT) may play an important role prior to and following BCMA-targeted CAR T-cell therapy in multiple myeloma (MM). We report a series of 13 patients: 5 patients received bridging RT pre-CAR T, 4 patients received salvage RT post-CAR T failure, and 4 patients received both. There was no worsening of CAR-T- or RT-related toxicities. The RT in-field local control rate was 100%, with a median follow-up after each RT course of 7.3 months. RT as a bridging and salvage strategy is safe, feasible, and offers excellent local control in MM patients treated with CAR T-cell therapy.

Clinical outcomes of radiation therapy for transgender and gender-expansive people with cancer.

Introduction: Approximately 1.6 million people in the US identify as transgender, many of whom undergo gender-affirming medical or surgical therapies. While transgender individuals are diagnosed with cancer at similar rates as those who are cisgender, the impacts of radiation therapy on outcomes of gender-affirming care in transgender, nonbinary, and gender-expansive people with cancer are understudied. We report on the experiences and outcomes of transgender and gender-expansive patients receiving radiation therapy for cancer treatment. Methods: This study is a multi-institutional retrospective review of patients evaluated from 2005-2019 identified as transgender or gender-expansive in the medical record and treated with radiation therapy. Results: We identified 23 patients who received radiation to 32 sites, including 12 (38%) to the brain, head, or neck, 8 (25%) to the thorax, and 7 (22%) to the pelvis. Seventeen patients (74%) received gender-affirming hormone therapy and 13 patients (57%) underwent gender-affirming surgery. Four patients had pelvic radiation before or after gender-affirming pelvic surgery, including two trans women who had pelvic radiation after vaginoplasty. Four patients had radiation to the chest or thorax and gender-affirming chest or breast surgery, including two trans men with breast cancer. Two pediatric patients developed hypopituitarism and hypogonadism secondary to radiation therapy and, as adults, changed their hormone replacement therapy to affirm their transgender identities. Discussion: Transgender people with cancer undergo radiation therapy for a wide range of cancers. Understanding their prior gender-affirming medical or surgical treatments and future gender affirmation goals may identify important considerations for their oncologic care.

Salvage radiotherapy in relapsed/refractory large B-cell lymphoma after failure of CAR T-cell therapy.

Despite the success of CD19-targeted chimeric antigen receptor (CAR T)-cell therapy in patients with relapsed/refractory large B-cell lymphoma (LBCL), there is a need for effective salvage strategies post-CAR T-cell therapy failure. We conducted a multi-institutional retrospective study of patients who relapsed following CAR T-cell therapy (axicabtagene ciloleucel [axi-cel] or tisagenlecleucel [tisa-cel]) and received salvage therapies (radiation therapy [RT] alone, systemic therapy alone, or combined modality therapy [CMT]). A total of 120 patients with post-CAR T relapsed LBCL received salvage therapies (RT alone, 25 patients; CMT, 15 patients; systemic therapy alone, 80 patients). The median follow-up from CAR T-cell infusion was 10.2 months (interquartile range, 5.2-20.9 months). Failure occurred in previously involved sites prior to CAR T-cell therapy in 78% of patients (n=93). A total of 93 sites were irradiated in 54 patients who received any salvage RT post-CAR T failure. The median dose/fractionation were 30 Gy (range, 4-50.4 Gy) and 10 fractions (range, 1-28 fractions). The 1-year local control rate for the 81 assessable sites was 84%. On univariate analysis, the median overall survival (OS) from the start date of RT was significantly higher among patients who received comprehensive RT versus focal RT (19.1 months vs. 3.0 months; P=<0.001). Twenty-three of 29 patients who received comprehensive RT had limited-stage disease. Among these, there was no difference in median OS among the patients who received RT alone versus those who received RT followed by additional therapies (log-rank P=0.2). On multivariate survival analysis, achieving PR or CR post-CAR T (hazard ratio =0.5; 95% confidence interval: 0.3-0.9; P=0.01) was independently associated with superior OS. Our findings suggest that RT can provide local control for LBCL relapsed post-CAR T-cell therapy, particularly in patients with limited-stage relapsed disease treated with comprehensive RT.

Evaluation of Carbon Fiber and Titanium Surgical Implants for Proton and Photon Therapy.

PURPOSE: Impending and actual pathologic fractures secondary to metastatic bone disease, lymphoma, or multiple myeloma often require intramedullary fixation followed by radiation therapy. Because of carbon's low atomic number, there are reduced computed tomography (CT) imaging artifacts and dose perturbation when planning postoperative radiation for carbon fiber (CF) rods. Herein, we characterize the dosimetric properties of CF implants compared with titanium alloy (TA) for proton and photon. METHODS AND MATERIALS: TA and CF samples were acquired from an implant manufacturer. Material characteristics were evaluated by CT scans with and without metal artifact reduction (MAR). Relative stopping power (RSP) was determined from the range pull-back of each sample in a 20-cm range proton beam. Photon transmission measurements were made in a solid water phantom and compared with the modeled dosimetry from the RayStation planning system. RESULTS: CF caused no visible CT artifacts, and MAR was not necessary for Hounsfield unit (HU) determination (median, 364 HU) or contouring, whereas TA (median, 3071 HU) caused substantial artifacts, which were improved, but not eliminated by MAR. The proton RSP was measured as 3.204 for TA and 1.414 for CF. For 6 MV photons, the measured transmission was 89.3% for TA and 98% for CF. CF RSP calculation and transmission from CT HU showed a physical density overestimate compared with measurements, which would cause a slight, but acceptable, dose uncertainty (<10% proton range or 1% photon transmission). CONCLUSIONS: With a density similar to bone, CF implants did not cause imaging artifacts and minimal dose perturbation compared with TA. Although the CF proton RSP is underestimated and the photon attenuation is overestimated by the HU, both effects are relatively small and may be most easily accounted for by planning with a 2-mm expansion around organs at risk beyond or in close proximity to the implant.

Systematic review for deep inspiration breath hold in proton therapy for mediastinal lymphoma: A PTCOG Lymphoma Subcommittee report and recommendations.

PURPOSE: To systematically review all dosimetric studies investigating the impact of deep inspiration breath hold (DIBH) compared with free breathing (FB) in mediastinal lymphoma patients treated with proton therapy as compared to IMRT (intensity-modulated radiation therapy)-DIBH. MATERIALS AND METHODS: We conducted a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline using the PubMed database to identify studies of mediastinal lymphoma patients with dosimetric comparisons of proton-FB and/or proton-DIBH with IMRT-DIBH. Parameters included mean heart (MHD), lung (MLD), and breast (MBD) doses, among other parameters. Case reports were excluded. Absolute differences in mean doses > 1 Gy between comparators were considered to be clinically meaningful. RESULTS: As of April 2021, eight studies fit these criteria (n = 8), with the following comparisons: proton-FB vs IMRT-DIBH (n = 5), proton-DIBH vs proton-FB (n = 5), and proton-DIBH vs IMRT-DIBH (n = 8). When comparing proton-FB with IMRT-DIBH in 5 studies, MHD was reduced with proton-FB in 2 studies, was similar (<1 Gy difference) in 2 studies, and increased in 1 study. On the other hand, MLD and MBD were reduced with proton-FB in 3 and 4 studies, respectively. When comparing proton-DIBH with proton-FB, MHD and MLD were reduced with proton DIBH in 4 and 3 studies, respectively, while MBD remained similar. Compared with IMRT-DIBH in 8 studies, proton-DIBH reduced the MHD in 7 studies and was similar in 1 study. Furthermore, MLD and MBD were reduced with proton-DIBH in 8 and 6 studies respectively. Integral dose was similar between proton-FB and proton-DIBH, and both were substantially lower than IMRT-DIBH. CONCLUSION: Accounting for heart, lung, breast, and integral dose, proton therapy (FB or DIBH) was superior to IMRT-DIBH. Proton-DIBH can lower dose to the lungs and heart even further compared with proton-FB, depending on disease location in the mediastinum, and organ-sparing and target coverage priorities.

Assessing the role of radiotherapy in patients with refractory or relapsed high-grade B-cell lymphomas treated with CAR T-cell therapy.

An estimated 30-40% of patients with diffuse large B cell lymphoma (DLBCL) will either relapse or have refractory disease with first-line chemoimmunotherapy. The standard approach for relapsed/refractory disease is salvage chemotherapy followed by autologous stem cell transplantation, but this approach cures fewer than 20% of patients in the modern era. This low cure rate is a result of refractory disease despite salvage therapy, medical ineligibility for transplantation, or relapse following transplantation. CD19-targeted chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment paradigm for patients with relapsed or refractory disease, leading to response rates that range between 52% to 93%, and overall survival rates at one year between 48% and 83%. However, the time from apheresis to infusion of CAR T-cell therapy currently takes several weeks, leaving many patients in need of bridging therapy to control disease progression. Radiation therapy (RT) has been utilized as a bridging therapy prior to CAR T infusion in select patients, with some remarkable responses in chemorefractory disease. Furthermore, the potential synergy between RT and CAR T-cells due to immunomodulatory mechanisms has generated considerable excitement, as it has been hypothesized that RT could also be considered as a salvage therapy following CAR T failure, based on limited case series published to date. Prospective trials are warranted to validate the significance of this modality following CAR T-cell therapy.

Prospective observational trial of low-dose skin electron beam therapy in mycosis fungoides using a rotational technique.

INTRODUCTION: Low-dose total skin electron beam therapy provides a durable treatment response for skin lesions caused by cutaneous T-cell lymphoma. We prospectively assessed the durability of response and quality of life for patients receiving low-dose total skin electron beam therapy using a novel rotational technique and dosing regimen. METHODS: Patients completed baseline Skindex-29 quality-of-life surveys and had baseline Modified Severity-Weighted Assessment Tool score recorded. Patients received 12 Gy in 12 fractions with a dual-field rotational technique. The primary outcome was overall response rate, with the secondary outcomes being time to treatment response, duration of clinical benefit, and quality-of-life change. RESULTS: We enrolled 20 patients and recorded an overall response rate of 90%. The median time to treatment response was 6.5 weeks. The baseline Modified Severity-Weighted Assessment Tool score was 55.6 and it declined to a median of 2.2 at last follow-up (P < .001). The median duration of clinical benefit was 21 months. There was a decline in the Skindex-29 total score and every subdomain when each follow-up visit was compared (P = .004). CONCLUSIONS: This prospective study demonstrated a very high overall response rate and improvement in skin-related quality of life. Low-dose rotational total skin electron beam therapy can be implemented routinely in clinical practice.

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.

Immortal Time Bias in National Cancer Database Studies.

PURPOSE: In studies evaluating the benefit of adjuvant therapies, immortal time bias (ITB) can affect the results by incorrectly reporting a survival advantage. It does so by including all deceased patients who may have been planned to receive adjuvant therapy within the observation cohort. Given the increase in National Cancer Database (NCDB) analyses evaluating postoperative radiation therapy (PORT) as an adjuvant therapy, we sought to examine how often such studies accounted and adjusted for ITB. METHODS AND MATERIALS: A systematic review was undertaken to search MEDLINE and EMBASE from January 2014 until May 2019 for NCDB studies evaluating PORT. After appropriate exclusion criteria were applied, 60 peer-reviewed manuscripts in which PORT was compared with postoperative observation or maintenance therapy were reviewed. The manuscripts were reviewed to evaluate whether ITB was accounted for, the method with which it was adjusted for, impact factor, year of publication, and whether PORT was beneficial. RESULTS: Of the 60 publications reviewed, 23 studies (38.3%) did not include an adjustment for ITB. Most studies that did adjust for ITB employed a single landmark (LM) time (n = 31), 4 used a sequential landmark analyses, and 2 used a time-dependent Cox model. In 23 of 31 studies (74.2%) that did adjust for ITB via a single LM time, the rationale behind why the specified LM time was chosen was not clearly explained. There was no relationship between adjusting for ITB and year of publication (P = .074) or whether the study was published in a high-impact journal (P = .55). CONCLUSIONS: Studies assessing adjuvant radiation therapy by analyzing the NCDB are susceptible to ITB, which overestimates the effect size of adjuvant therapies and can provide misleading results. Adjusting for this bias is essential for accurate data representation and to better quantify the impact of adjuvant therapies such as PORT.

Utilization of hypofractionated radiotherapy in treatment of glioblastoma multiforme in elderly patients not receiving adjuvant chemoradiotherapy: A National Cancer Database Analysis.

To assess the utilization and outcomes of adjuvant monotherapy with hypofractionated radiation (RT) among elderly patients not receiving traditional adjuvant chemoradiotherapy (cRT) for glioblastoma multiforme (GBM). A retrospective analysis using the National Cancer Data Base with GBM patients aged 65 years or older treated between 2005 and 2012 was conducted. Patients who underwent hypofractionated RT (40 Gy), conventional RT (60 Gy), chemotherapy, or best supportive care alone were included. Statistical methods included logistic regression for utilization and Cox regression for survival analysis. A total of 9556 patients were analyzed. On multivariate analysis (compared to those receiving conventional RT), patients more likely to be treated with hypofractionated RT were older (75-84 years old OR 2.05; p < 0.01 and ≥ 85 years old OR 3.32; p < 0.01), with a Charlson/Deyo score of 2 or higher (OR 1.80; p = 0.05), from communities > 50 miles from their treatment facility (50-100 miles OR 8.03; p < 0.01 and > 100 miles OR 7.16; p < 0.01), treated at an Academic/Research facility (OR 2.85; p = 0.04), and diagnosed between 2011 and 2012 (OR 4.15; p < 0.01). On Cox regression, hypofractionated RT (HR 0.65; p < 0.01), conventional RT (HR 0.60; p < 0.01), and chemotherapy alone (HR 0.69; p < 0.01) were all associated with decreased risk of death compared to no adjuvant therapy. Among patients receiving adjuvant treatment, utilization of hypofractionated RT increased from 7 to 19% during the study period. Among elderly patients with GBM not receiving cRT, the utilization of adjuvant monotherapy with hypofractionated RT has increased over time. Retrospective evidence suggests it may be better than best supportive care alone and as good as conventionally fractionated RT alone.

Reduced Mortality Risk in the Recent Era in Early-Stage Hodgkin Lymphoma Patients Treated With Radiation Therapy With or Without Chemotherapy.

PURPOSE: To determine the effect of treatment changes over time on all-cause mortality risk in patients with early-stage Hodgkin lymphoma (HL) after radiation therapy. The long-term survivorship of those with HL necessitates quantification of the late risk of mortality from HL and other causes. METHODS AND MATERIALS: An institutional review board-approved retrospective study was conducted using a multi-institutional database of 1541 stage I and II HL patients treated from 1968 to 2007 with radiation therapy alone or combined-modality treatment. The analytic methods included cumulative incidence function, Kaplan-Meier estimates and log-rank tests for overall survival (OS) differences, and Cox proportional hazards modeling. RESULTS: The median age at diagnosis was 27 years. At a median follow-up of 15.2 years (35% of patients with >20 years of follow-up), 395 patients had died of all causes, including 85 HL, 168 second malignancy (25 hematologic and 143 nonhematologic), 70 cardiovascular, and 21 pulmonary deaths. The cumulative incidence of non-HL mortality had surpassed HL mortality at 8.3 years. For patients treated from 1968 to 1982, 1983 to 1992, and 1993 to 2007, the 15-year OS rates were 78%, 85%, and 88%, respectively (P=.0016). On Cox proportional hazards analysis, age, B symptoms, and number of disease sites were significantly associated with all-cause mortality in the first decade of follow-up, with a trend toward significance for radiation field extent. CONCLUSIONS: The all-cause mortality risk was significantly lower for patients treated in the most recent era during the first decade of follow-up, likely due to improved HL therapy resulting in a higher cure rate and lower treatment-related toxicity from smaller radiation fields. Current efforts toward radiation treatment reduction might further reduce the long-term mortality risk for these patients.

Central Nervous System Disease, Education, and Race Impact Radiation Refusal in Pediatric Cancer Patients.

To investigate the determinants of radiation therapy refusal in pediatric cancer, we used the Surveillance, Epidemiology, and End Results registry to identify 24,421 patients who met the eligibility criteria, diagnosed between 1974 and 2012. Patients had any stage of cancer, were aged 0 to 19, and received radiation therapy or refused radiation therapy when it was recommended. One hundred twenty-eight patients (0.52%) refused radiation therapy when it was recommended. Thirty-two percent of patients who refused radiation therapy ultimately died from their cancer, at a median of 7 months after diagnosis (95% confidence interval, 3-11 mo), as compared with 29.0% of patients who did not refuse radiation therapy died from their cancer, at a median of 17 months after diagnosis (95% confidence interval, 17-18 mo). On multivariable analysis, central nervous system (CNS) site, education, and race were associated with radiation refusal. The odds ratio for radiation refusal for patients with CNS disease was 1.62 (P=0.009) as compared with patients without CNS disease. For patients living in a county with ≥10% residents having less than ninth grade education, the odds ratio for radiation refusal was 1.71 (P=0.008) as compared with patients living in a county with <10% residents having less than ninth grade education. Asian, Pacific Islander, Alaska Native, and American Indian races had an odds ratio of 2.12 (P=0.002) for radiation refusal as compared with black or white race. Although the radiation refusal rate in the pediatric cancer population is low, we show that CNS site, education level, and race are associated with a significant difference in radiation refusal.