Using benchmarked lung radiation dose constraints to predict pneumonitis risk: Developing a nomogram for patients with mediastinal lymphoma

Purpose: We identified lung dosimetric constraints to assist in predicting the radiation pneumonitis (RP) risk in patients with mediastinal lymphoma and then identified the clinical prognostic factors that were associated with the achievement of key dosimetric constraints. Methods and Materials: In 190 patients who received mediastinal intensity modulated radiation therapy, we used univariate χ2 and multivariate logistic models to identify the predictors of RP and achievement of lung dose-volume histogram (DVH) constraints and build a predictive nomogram for RP. Results: An increased risk of RP was strongly associated with mean lung dose (MLD) > 13.5 Gy (odds ratio [OR]: 8.13; 95% confidence interval [CI], 3.01-21.93; P  55% (OR: 7.01; 95% CI, 2.94-16.72; P < .001). Therefore, patients had low RP risk (8%) if both MLD ≤13.5 and V5 ≤55 constraints were achieved, moderate risk (24%) if only MLD was achieved, and the highest risk (48%) if MLD was not achieved. Deep-inspiration breath-hold (DIBH) technique during treatment strongly prognosticated achieving MLD and V5 DVH constraints (OR,3.88; 95% CI, 1.84-8.19; P < .001). Specifically, 86% of patients who were treated with DIBH versus 63% without DIBH achieved DVH constraints (P < .001). This translated into a “number needed to treat” with DIBH of 4 patients to enable 1 additional patient to achieve both constraints. In comparison, the clinical characteristics were marginal prognosticators: DVH constraints were more likely achieved in nonbulky disease (OR: 3.01; 95% CI, 0.89-4.53; P = .09) and patients who had not previously received salvage chemotherapy (OR, 2.44; 95% CI, 0.98-6.11; P = .06). Nomogram-predicted risks of RP ranged from 4% to 60% on the basis of MLD and V5, total radiation dose, and use of salvage chemotherapy. Conclusions: Achieving mean lung and V5 DVH constraints is critical to reduce RP risk in patients with lymphoma who receive mediastinal intensity modulated radiation therapy. The use of the DIBH technique is a promising risk-modifying treatment approach in patients with mediastinal lymphoma and especially in patients with a history of nonmodifiable risk factors for RP such as bulky disease and salvage chemotherapy

Racial disparities in guideline-concordant cancer care and mortality in the United States

Purpose: We identified the frequency of racial disparities in guideline-concordant cancer care for select common disease sites in the United States and the impact of guideline concordance on mortality disparities. Methods and materials: Using Surveillance, Epidemiology, and End Results Medicare data, we evaluated patients age >65 years of black or non-Hispanic white race who were diagnosed with stage III breast (n = 3607), stage I (n = 14,605) or III (n = 15,609) non-small cell lung, or stage III prostate (n = 3548) cancer between 2006 and 2011. Chemotherapy, surgery, and radiation therapy (RT) treatments were identified using claims data. Pearson χ2 was used to test the associations between race and guideline concordance on the basis of National Comprehensive Cancer Network curative treatment guidelines. Mortality risks were modeled using Cox proportional hazards. Results: Black patients were less likely to receive guideline-concordant curative treatment than non-Hispanic white patients for stage III breast cancer postmastectomy RT (53% black, 61% white; P = .0014), stage I non-small cell lung cancer stereotactic radiation or surgery (61% black, 75% white; P < .0001), stage III non-small cell lung cancer chemotherapy in addition to RT or surgery (36% black, 41% white; P = .0001), and stage III prostate cancer RT or prostatectomy (82% black, 95% white; P < .0001). Disparities in guideline concordance impacted racial mortality disparities. Specifically, hazard ratios that demonstrated elevated all-cause mortality risks in black patients were lowered (and more closely approached hazard ratio of 1.00) after adjusting for guideline concordance. A similar impact for cause-specific mortality was observed. Conclusions: Racial disparities in the receipt of curative cancer therapy impacted racial mortality disparities across multiple cancer sites. Benchmarking adherence to guideline-concordant care could represent an opportunity to stimulate improvements in disparities in cancer treatment and survival