The potential role of precision medicine to alleviate racial disparities in prostate, bladder and renal urological cancer care.

Background: Racial disparities in oncological outcomes resulting from differences in social determinants of health (SDOH) and tumour biology are well described in prostate cancer (PCa) but similar inequities exist in bladder (BCa) and renal cancers (RCCs). Precision medicine (PM) aims to provide personalized treatment based on individual patient characteristics and has the potential to reduce these inequities in GU cancers. Objective: This article aims to review the current evidence outlining racial disparities in GU cancers and explore studies demonstrating improved oncological outcomes when PM is applied to racially diverse patient populations. Evidence acquisition: Evidence was obtained from Pubmed and Web of Science using keywords prostate, bladder and renal cancer, racial disparity and precision medicine. Because limited studies were found, preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were not applied but rather related articles were studied to explore existing debates, identify the current status and speculate on future applications. Results: Evidence suggests addressing SDOH for PCa can reverse racial inequities in oncological outcomes but differences in incidence remain. Similar disparities in BCa and RCC are seen, and it would be reasonable to suggest achieving parity in SDOH for all races would do the same. Research applying a PM approach to different ethnicities is lacking although in African Americans (AAs) with metastatic castrate-resistant prostate cancer (mCRPCa) better outcomes have been shown with androgen receptor inhibitors, radium-223 and sipuleucel. Exploiting the abscopal effect with targeted radiation therapy (RT) and immunotherapy has promise but requires further study, as does defining actionable mutations in specific patient groups to tailor treatments as appropriate. Conclusion: For all GU cancers, the historical underrepresentation of ethnic minorities in clinical trials still exists and there is an urgent need for recruitment strategies to address this. PM is a promising development with the potential to reduce inequities in GU cancers, however, both improved understanding of race-specific tumour biology, and enhanced recruitment of minority populations into clinical trials are required. Without this, the benefits of PM will be limited.

Combining theranostic/particle therapy with immunotherapy for the treatment of GU malignancies.

Particle therapy and radiopharmaceuticals are emerging fields in the treatment of genitourinary cancers. With these novel techniques and the ever-growing immunotherapy options, the combinations of these therapies have the potential to improve current cancer cure rates. However, the most effective sequence and combination of these therapies is unknown and is a question that is actively being explored in multiple ongoing clinical trials. Here, we review the immunological effects of particle therapy and the available radiopharmaceuticals and discuss how best to combine these therapies.

Utilization Patterns of Single Fraction Radiation Therapy for Multiple Myeloma.

BACKGROUND: Patients with multiple myeloma (MM) are living longer than ever before thanks to new therapies. As a consequence, radiation therapy (RT) is increasingly important in the management of bone lesions from MM. Current American Society for Radiation Oncology guidelines recommend greater usage of 8 Gy in 1 fraction for treatment of these lesions. The objective of this study is to analyze utilization of 8 Gy in 1 fraction for treatment of MM bone lesions in the United States utilizing the National Cancer Data Base (NCDB). MATERIALS AND METHODS: The NCDB was used to identify patients with MM treated with palliative RT for painful bony lesions in the period between 2004 and 2014. Utilization rate of RT in this patient population as well as single-fraction (SFRT) versus multiple-fraction RT (MFRT) was compared according to demographic, socioeconomic, and logistic details. RESULTS: A total of 95,190 patients met our inclusion criteria. Of these, 10,261 (10.8%) patients received RT, and a total of 243 (2.4%) of these patients received SFRT over the 10-year period. There was an 11.73% annual increase (P = .0001) in SFRT utilization from 2004 to 2014. Older age, black race, longer distance from the treatment facility, lower degree of education, treatment at an academic or integrated healthcare network, worse comorbidities, and more recent diagnoses were all associated with increased usage of SFRT. CONCLUSION: SFRT for the management of MM painful bony metastases remains underutilized. Trends show that radiation oncologists do not appear to be changing their approach to treating this disease.

The evolving toxicity profile of SBRT for lung cancer.

Stereotactic body radiation therapy (SBRT) is an effective and well tolerated treatment for early stage non-small cell lung cancer (NSCLC). The high doses used in thoracic SBRT can sometimes cause adverse effects ranging from mild fatigue and transient esophagitis to fatal events such as pneumonitis or hemorrhage. Efforts continue to expand in both the utility of this technique as well as our understanding of the mechanisms of the adverse effects it can cause. In this review, we discuss the current literature regarding the potential mechanisms, dosimetric constraints and toxicities associated with SBRT alone and in conjunction with definitive chemoradiotherapy and immunotherapy. As the use of SBRT expands to these spheres, we examine the available recommendations for mitigating potential associated treatment related toxicities.

Dosimetric Correlates of Pulmonary Toxicity in Patients with Malignant Pleural Mesothelioma Receiving Radiation Therapy to the Intact Lungs.

PURPOSE: We aimed to determine dose-volume constraints that correlate with severe (grade ≥3) radiation pneumonitis (RP) in patients diagnosed with malignant pleural mesothelioma, treated using volumetric modulated arc therapy. METHODS AND MATERIALS: Data from 40 patients with malignant pleural mesothelioma who underwent pleurectomy decortication and adjuvant radiation therapy at our institution between December 2010 and October 2016 were retrospectively analyzed. Dosimetric variables for the absolute volume and percentage volume of the ipsilateral lung, contralateral lung, and heart were recorded. Events of RP were assessed using the Common Terminology Criteria for Toxicity and Adverse Events, version 4.0. The statistical analysis with Wilcoxon rank-sum, Spearman rank correlation, and receiver operating characteristic curves was computed using MATLAB V9.1, RV3.4, and SAS V9.4. RESULTS: Of the 40 patients, 26 patients (65%) were male. The median age at the time of diagnosis was 66.5 years (range, 44-84 years). The median prescription dose was 45 Gy (range, 30-54 Gy). Five patients (12.5%) had grade ≥3 RP. The incidence of grade≥ 3 RP showed a significant correlation (P < .05) with the absolute volume and percentage volume of the ipsilateral lung spared of ≥20 Gy (55 cc; 7%) and spared of ≥30 Gy (200 cc; 23%). Dosimetric variables of the contralateral lung, total lung, and heart did not show a correlation with incidence of grade ≥3 RP. CONCLUSIONS: In our cohort, sparing the ipsilateral lung of at least 55 cc of 20 Gy and 200 cc of 30 Gy correlated with a reduced incidence of severe (grade ≥3) RP.

Low-dose-rate brachytherapy for prostate cancer: outcomes at >10 years of follow-up.

OBJECTIVE: To examine biochemical control, survival, and late morbidity with definitive low-dose-rate brachytherapy (LDR-BT) for patients with prostate cancer surviving for >10 years after treatment. PATIENTS AND METHODS: We identified 757 men with localised prostate cancer who underwent definitive LDR-BT in the period 1990-2006 and were followed for >10 years at our institution. Biochemical failure-free survival (BFFS), distant metastases-free survival (DMFS), prostate cancer-specific survival (PCSS), and overall survival (OS) were selected as study endpoints. Survival was examined using the log-rank test, Kaplan-Meier method, and Cox regression modelling. Urinary, quality of life (QoL), and potency scores at baseline and last follow-up were recorded. RESULTS: The median follow-up was 12.5 years (range, 10.1-21.8 years). At the time of analysis, 88.6% of patients were alive, 1.5% died from prostate cancer and 13.9% developed biochemical failure, with 82% of failures occurring in the first decade of follow-up. Overall, 2.3% developed distant metastases. On multivariate analyses, stage T3a-T3b, prostate-specific antigen level of >20 ng/mL, intermediate- and high-risk disease predicted worse BFFS; whereas age >70 years at diagnosis and stage T3a-T3b predicted worse OS. A total biologically effective dose of ≥150 Gy and androgen-deprivation therapy were associated with improved BFFS, but not OS. The overall 17-year rates for BFFS, DMFS, PCSS, and OS were 79, 97, 97, and 72%, respectively. Respective 17-year BFFS rates for low-, intermediate- and high-risk patients were 86, 80, and 65% (P < 0.001), whereas OS rates for the same groups were 82, 73, and 60%, respectively (P = 0.09). Amongst those patients who were potent at baseline, 25% remained potent at the last follow-up. Urinary function and QoL were mainly unaffected. CONCLUSIONS: LDR-BT yields excellent survival rates, with a 17-year PCSS rate of 97%. In all, 18% of patients with biochemical relapse failed at >10 years after implantation, which justifies their continued follow-up.

Low-dose cranial boost in high-risk adult acute lymphoblastic leukemia patients undergoing bone marrow transplant.

PURPOSE: Acute lymphoblastic leukemia (ALL) has a predilection for CNS involvement. Patients with high-risk ALL are often managed with transplant using a radiation-based conditioning regimen. Historically, a high-dose prophylactic cranial boost (CB) of ≥12 Gy was given to reduce risk of central nervous system (CNS) recurrence. However, the use of CB has fallen out of favor because of toxicity concerns. In high-risk adults undergoing transplant at our institution, we have used a low-dose 6 Gy CB to reduce toxicity while conditioning adults with fully developed brains. The safety, efficacy, and utility of a low-dose CB in adults are poorly studied; herein, we report their outcomes and toxicity. METHODS AND MATERIALS: We identified all high-risk ALL patients undergoing total body irradiation as part of their conditioning regimen. Those who received 6 Gy CB or no CB were included (55 total). Their charts were reviewed and statistical analyses were completed with R, version 2.15.2. RESULTS: In patients undergoing CB, 3-year CNS disease-free survival and overall survival were 94.7% and 62.7%. In those not undergoing CBs, survivals were 81.8% and 51.5%. Notably, within the CB cohort, patients without prior CNS involvement had no CNS failures. In contrast, in the non-CB cohort, there were 2 CNS failures in patients with no history of CNS involvement. In the CB cohort, the only notable acute toxicity was parotitis (2.8%). Late toxicity in the CB cohort included 1 instance of cataracts (2.8%) without any evidence of cognitive impairment or potential radiation induced secondary malignancy. CONCLUSIONS: A dose of 6 Gy CB is well-tolerated in the adult ALL population as part of a radiation-based conditioning regimen. Low-dose CB may be considered in adult patients with high-risk ALL without prior CNS involvement to reduce the likelihood of recurrence.