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.

Risk-Tailoring Radiotherapy for Endometrial Cancer: A Narrative Review

Endometrial cancer is the most common gynecologic cancer in the United States and it contributes to the second most gynecologic cancer-related deaths. With upfront surgery, the specific characteristics of both the patient and tumor allow for risk-tailored treatment algorithms including adjuvant radiotherapy and systemic therapy. In this narrative review, we discuss the current radiation treatment paradigm for endometrial cancer with an emphasis on various radiotherapy modalities, techniques, and dosing regimens. We then elaborate on how to tailor radiotherapy treatment courses in combination with other cancer-directed treatments, including chemotherapy and immunotherapy. In conclusion, this review summarizes ongoing research that aims to further individualize radiotherapy regimens for individuals in an attempt to improve patient outcomes.

The effects of radiation therapy on the heart: implications for management

Chemotherapy, radiotherapy, and surgery constitute the three primary modalities employed in the treatment of patients with cancer. Radiotherapy, in particular, is a mainstay of treatment for patients with cancers of the breast, esophagus, lung, and lymph nodes. Prior studies have shown, however, that radiotherapy can impact the heart. Radiation exposure, in fact, can lead to pathophysiological changes that may result in short- and long-term radiation-induced cardiac toxicities. Such toxicities can cause substantial morbidity and may manifest clinically in the weeks to years after the completion of treatment. As a result, in both modern clinical practice and clinical trials, the heart has been recognized as an organ-at-risk, and radiotherapy treatment plans seek to minimize the dose that it receives. In this review, we focus on the impacts of radiotherapy on underlying cardiac risk factors, the pathophysiology of radiotherapy-induced cardiac changes, and the clinical impacts of radiotherapy on the heart. Due to the location of the heart, we focus primarily on patients who have received radiotherapy for cancers of the breast, esophagus, lung, and lymph nodes, and those who have received cardiac-directed therapy. We then elaborate on the ongoing attempts to further lower the doses delivered to the heart during therapeutic courses of radiation.

Immune Escape in Glioblastoma: Mechanisms of Action and Implications for Immune Checkpoint Inhibitors and CAR T-Cell Therapy

Glioblastoma, the most common primary brain cancer in adults, is characterized by a poor prognosis and resistance to standard treatments. The advent of immunotherapy has revolutionized the treatment of several cancers in recent years but has failed to demonstrate benefit in patients with glioblastoma. Understanding the mechanisms by which glioblastoma exerts tumor-mediated immune suppression in both the tumor microenvironment and the systemic immune landscape is a critical step towards developing effective immunotherapeutic strategies. In this review, we discuss the current understanding of immune escape mechanisms in glioblastoma that compromise the efficacy of immunotherapies, with an emphasis on immune checkpoint inhibitors and chimeric antigen receptor T-cell therapy. In parallel, we review data from preclinical studies that have identified additional therapeutic targets that may enhance overall treatment efficacy in glioblastoma when administered alongside existing immunotherapies.

Gender Differences in the Research Productivity of Radiation Oncology Resident Graduates in the United States: 2015 to 2019

Purpose

It is well-documented that gender disparities exist in academic radiation oncology departments. The purpose of this study was to analyze gender differences in research productivity during residency among recent graduates of radiation oncology training programs in the United States (US).

Methods and Materials

We used several publicly available sources to create a database of US radiation oncology residents who graduated between 2015 and 2019. We systematically collected gender information from the National Plan and Provider Enumeration System National Provider Identifier Registry and Medicare claims registry. Postresidency employment information was collected using several publicly available sources. PubMed was queried to identify first-author publications of residents. A secondary analysis of metadata including impact factor, number of citations, modified Hirsch index (h index), and type of publication was performed. A multivariable linear regression was performed to evaluate the effect of gender on research productivity during residency.

Results

There were 910 total graduates identified during this period and who were entered into this database, of whom all had available gender information. Female trainees comprised 29.0% (n = 264) of RO residents and had fewer first-author publications and citations, had lower mean modified h index, and were published in journals with lower impact factors. On multivariable linear regression analysis, female gender was independently associated with decreased total number of publications (P = .005), mean number of citations (P < .001), and modified h index (P = .001) when controlling for residency size and advanced (PhD or master's) degrees.

Conclusions

In the US, female RO trainees had lower research productivity, which was not explained by advanced degrees or residency size. A significant gender gap in trainee research productivity persists, which has known implications in terms of academic achievement, promotions, and career trajectory. Future interventions to improve resident research productivity and mentorship are warranted.

Radium-223 for Metastatic Castrate-Resistant Prostate Cancer

Prostate cancer is a significant cause of morbidity and mortality among men worldwide. Although most patients present with localized or regional disease and experience excellent outcomes with treatment, approximately 10% to 20% of patients develop castrate-resistant prostate cancer (CRPC) within 5 years of diagnosis. Bone metastases, which can cause pain and adversely affect quality of life, are common among this population. Radium-223 has a relatively short half-life and decays via α-decay. Its daughter products, α-particles, have a short path length in tissue and exhibit high linear energy transfer. Together, these properties allow radium-223 to achieve relatively high cell kill in its target tissue while sparing the surrounding normal tissues. Administered in the clinic as radium-223 dichloride (Xofigo), radium-223 acts as a calcium mimetic in the human body, forming complexes with hydroxyapatite. In areas of high bone turnover, such as the osteoblastic bone metastases that are common in patients with CRPC, radium-223 is preferentially incorporated into the bone matrix, where it can exert an antitumor effect. In May 2013, the U.S. Food and Drug Administration approved Xofigo for use in patients with CRPC who have symptomatic bone metastases and no visceral metastases. In this topic discussion, we review the mechanism of action and clinical efficacy of radium-223 in patients with metastatic CRPC. We also discuss its administration and handling, distribution and elimination, and associated toxicities.

Characterization and Prediction of Signal Intensity Changes in Normal Liver Parenchyma on Gadoxetic Acid-enhanced MRI Scans after Liver-directed Radiation Therapy

Purpose To better characterize and understand the significance of focal liver reaction (FLR) development in a large cohort of patients who underwent gadoxetic acid-enhanced MRI after being treated with radiation therapy (RT) for hepatobiliary tumors. Materials and Methods This retrospective study evaluated 100 patients (median age, 65 years [first and third quartiles, 60-69 years]; 80 men) who underwent RT for hepatocellular carcinoma, bile duct tumors, or liver metastases at Mount Sinai Hospital between March 1, 2018, and February 29, 2020. CT simulation scans were fused to MRI scans obtained 1-6 months and 6-12 months after RT, using the hepatobiliary phase of the MRI. To define FLR volume, two radiation oncologists independently delineated the borders of the hypointensity observed on MRI scans in the liver region where RT was delivered. Biologically effective dose (BED) thresholds for the formation of FLRs were calculated, along with albumin-bilirubin (ALBI) scores and grades, and overall survival. Results Most patients developed FLRs, which decreased in volume over time. Median BED threshold values for FLR development were 63.6 Gy at 1-6 months and 88.7 Gy at 6-12 months. While higher baseline ALBI scores were associated with a lower rate of FLRs, there was a significant association between FLR volume and increase in ALBI score at 1-6 months (P = .048). Twelve- and 24-month survival estimates for the cohort were 81% and 48%, respectively. Histopathologic analysis of seven explanted liver specimens demonstrated findings consistent with radiation-induced liver disease. Conclusion FLRs were a clear measure of liver damage after RT and were associated with the development of liver dysfunction and focal radiation-induced liver disease. Keywords: MRI, Radiation Therapy Supplemental material is available for this article. © RSNA, 2022.

Moving beyond Definitive Therapy: Increasing Physical Activity in Survivors of Cancers of the Head and Neck

As chemotherapeutic, radiation, and surgical techniques have improved, there has been a dramatic improvement in survival in patients diagnosed with cancers of the head and neck. As a result, a heightened focus on survivorship by clinicians will increasingly prove necessary. In particular, medical care teams will have to pay special attention to mitigating the long-term sequelae of definitive cancer treatments, many of which act as barriers to exercise. This is unfortunate, as the benefits of exercise in patients with cancer have become increasingly recognized. In this review, we discuss the potential benefits of and barriers to exercise in survivors of cancers of the head and neck. We also review existing exercise guidelines and strategies by which clinicians can promote exercise in this unique patient population.

Preoperative Stereotactic Radiosurgery for Glioblastoma

Glioblastoma is a devastating primary brain tumor with a median overall survival of approximately 15 months despite the use of optimal modern therapy. While GBM has been studied for decades, modern therapies have allowed for a reduction in treatment-related toxicities, while the prognosis has largely been unchanged. Adjuvant stereotactic radiosurgery (SRS) was previously studied in GBM; however, the results were disappointing. SRS is a highly conformal radiation technique that permits the delivery of high doses of ionizing radiation in 1-5 sessions while largely sparing surrounding healthy tissues. Furthermore, studies have shown that the delivery of ablative doses of ionizing radiation within the central nervous system is associated with enhanced anti-tumor immunity. While SRS is commonly used in the definitive and adjuvant settings for other CNS malignancies, its role in the preoperative setting has become a topic of great interest due to the potential for reduced treatment volumes due to the treatment of an intact tumor, and a lower risk of nodular leptomeningeal disease and radiation necrosis. While early reports of SRS in the adjuvant setting for glioblastoma were disappointing, its role in the preoperative setting and its impact on the anti-tumor adaptive immune response is largely unknown. In this review, we provide an overview of GBM, discuss the potential role of preoperative SRS, and discuss the possible immunogenic effects of this therapy.

Characterization of rib fracture development following liver directed stereotactic body radiation therapy

Purpose

Rib fractures are a well-described complication following thoracic stereotactic body radiation therapy (SBRT). However, there are limited data in the setting of liver-directed SBRT.

Methods

Patients who underwent liver SBRT from 2014 to 2019 were analyzed. Logistic regression models were used to identify the demographic, clinical, and dosimetric factors associated with the development of rib fractures.

Results

Three hundred and forty-three consecutive patients were reviewed with median follow-up of 9.3 months (interquartile range [IQR]: 4.7-17.4 months); 81% of patients had primary liver tumors and 19% had liver metastases. Twenty-one patients (6.2%) developed rib fractures with a median time to diagnosis of 7 months following SBRT (IQR: 5-19 months). Of those patients, 11 experienced concomitant chest wall pain, while 10 patients had an incidental finding of a rib fracture on imaging. On univariate analysis, female gender (odds ratio [OR]: 2.29; p = 0.05), V30 Gy (OR: 1.02; p < 0.001), V40 Gy (OR: 1.08; p < 0.001), maximum chest wall dose (OR: 1.1; p < 0.001), and chest wall D30 cm³ (OR: 1.09; p < 0.001) were associated with an increased probability of developing a rib fracture. On multivariate analysis, maximum chest wall dose (OR: 1.1; p < 0.001) was associated with developing a rib fracture. Receipt of more than one course of SBRT (p = 0.34), left versus right sided lesion (p = 0.69), osteoporosis (p = 0.54), age (p = 0.82), and PTV volume (p = 0.55) were not significant.

Conclusions

Rib fractures following liver SBRT were observed in 6.2% of patients with the majority being asymptomatic. To mitigate this risk, clinicians should minimize dose delivery to the chest wall. Female patients may be at increased risk.

Comparison of Pathologic Complete Response Rates and Oncologic Outcomes in Patients With Surgically Resectable Esophageal Cancer Treated With Neoadjuvant Chemoradiation to 50.4 Gy vs 41.4 Gy

Background

Excellent outcomes and high rates of pathologic complete response (pCR) have been reported in patients with operable esophageal carcinoma using 41.4 Gy of radiation with concurrent carboplatin and paclitaxel. With pCR rates similar to studies using higher doses, it remains unclear whether doses greater than 41.4 Gy result in improved outcomes. This study aims to compare pCR rates and oncologic outcomes in patients treated with neoadjuvant chemoradiation to 50.4 Gy vs 41.4 Gy.

Methods

We reviewed the charts of patients with operable esophageal carcinoma who were treated with neoadjuvant chemoradiation followed by oncologic resection. Our primary endpoint was the pCR rate. Secondary endpoints were overall survival, progression-free survival (PFS), and toxicity. 

Results

We identified 43 patients meeting inclusion criteria. Nineteen patients were treated with 41.4 Gy and 24 were treated with 50.4 Gy. Cohorts were well-matched, except for a significantly higher percentage of patients with adenocarcinoma (AC) (89.5% vs 54.2%, p = 0.02), usage of intensity-modulated radiation therapy (IMRT) (100% vs 47.6%; p = 0.002), and usage of carboplatin, plus paclitaxel (100% vs 75%; p = 0.003) in the 41.4 Gy group. The pCR rate for the cohort was 44.2%. No differences in the pCR rate (41.7% vs 47.4%), three-year overall survival (OS) (73.7% vs 77.5%), or three-year PFS (52.8% vs 43.7%) were observed. Late toxicity rates also did not vary significantly (p = 0.2). No grade 4 or 5 events were observed.

Conclusion

In this small series, there were no differences in the pCR rate, PFS, or OS between those treated with 50.4 Gy and 41.4 Gy. Larger, multi-institutional series are needed to validate these findings.

The Safety and Efficacy of Radiation Therapy with Concurrent Dexamethasone, Cyclophosphamide, Etoposide, and Cisplatin-Based Systemic Therapy for Multiple Myeloma

INTRODUCTION

The concurrent delivery of radiation therapy (RT) with salvage chemotherapies in the management of relapsed and refractory multiple myeloma (MM) is an area of ongoing investigation. This study examined the safety and efficacy of palliative RT given in the setting of concurrent dexamethasone, cyclophosphamide, etoposide, and cisplatin (DCEP).

PATIENTS AND METHODS

Fifty-five patients with MM received RT to 64 different sites within three weeks of receiving DCEP from 2010 to 2020. A median dose of 20 Gray (range 8-32.5 Gy) was delivered in a median of 5 fractions (range 1-15). Patients received a median of 1 cycle (range 1-5) of DCEP. Rates of hematologic and RT toxicity were recorded along with pain, radiographic, and laboratory responses to treatment.

RESULTS

RT was completed in 98% of patients. 21% of patients experienced RTOG grade 3+ hematologic toxicity before RT, which increased to 35% one-month post-RT (P = .13) before decreasing to 12% at 3 to 6 months (P = .02). The most common toxicity experienced was thrombocytopenia. Grade 1 to 2 non-hematologic RT-related toxicity was reported in 15% of patients while on treatment and fell to 6% one-month after completing RT. Pain resolved in 94% of patients with symptomatic lesions at baseline. Stable disease or better was observed in 34/39 (87%) of the targeted lesions on surveillance imaging.

CONCLUSION

RT administered concurrently with DCEP was well-tolerated by most of the patients in this series, with low rates of hematologic and RT-related toxicity. RT was also very effective, with the vast majority of patients demonstrating resolution of their pain and a significant response on follow-up imaging.

Functional Larynx Preservation in Patients With Locally Advanced Squamous Cell Carcinoma of the Larynx and Hypopharynx Treated With Induction Chemotherapy vs. Concurrent Chemoradiation Alone

Objectives

Chemoradiation therapy (CRT) has been established as a standard treatment for locally advanced hypopharynx/larynx squamous cell carcinoma (SCC) but the role of induction chemotherapy (IC) remains unclear. The primary outcome of this study is to determine whether functional larynx-preservation survival (FLPS) is improved with the addition of IC in these patients. Secondary outcomes were overall survival (OS), progression-free survival (PFS), distant metastasis-free survival (DMFS), and laryngectomy rates.

Methods

Records for patients with AJCC 8th edition clinical stage III-IVB laryngeal and hypopharyngeal SCC treated with CRT +/- IC from 2005-2019 were reviewed. FLPS was defined as time until death, progression, laryngectomy, or non-functional larynx. Kaplan-Meier curves were generated for FLPS, OS, PFS, and DMFS. Outcomes were compared using the stratified log-rank test. Laryngectomy rates were compared using Fisher’s exact test.

Results

We included 52 patients with laryngeal and 38 with hypopharyngeal SCC (n=90); 19 patients with laryngeal SCC and 19 with hypopharyngeal SCC received IC (median three cycles). There were no differences in the three-year FLPS (61% vs 67.8%; p=0.88), OS (73.9% vs 86.2%; p=0.42), PFS (53.6% vs 62.6%; p=0.44), or DMFS (65.2% vs 71.5%, p= 0.85) between patients who did and did not receive IC all patients. Laryngectomy rates did not differ with and without IC (18.4 % vs 7.7%; p=0.19).

Conclusion

In this study of advanced laryngeal and hypopharyngeal SCC, IC did not improve three-year FLPS, OS, PFS, or laryngectomy rates compared to CRT alone. A large prospective series would provide a more robust understanding of the role of IC in this group of patients. 

The Holman Research Pathway in Radiation Oncology: 2010 to 2019

PURPOSE

There has not been an assessment of the Holman Research Pathway (HRP) in radiation oncology (RO) in nearly 10 years. In this study, we sought to review the demographic characteristics, research productivity during and after residency, job placements, and National Institutes of Health (NIH) grant funding of RO residents who completed the HRP in the modern era.

METHODS AND MATERIALS

We created a comprehensive database of RO residents who completed the HRP between 2010 and 2019. Using a variety of data sources, we obtained demographic information, first-author manuscripts published in residency, and first- and last-author manuscripts published in the first 30 months after residency for each resident. In addition, we identified the first and current job and NIH grant funding for each resident.

RESULTS

Ninety-seven RO residents who graduated from 50 medical schools and 25 residency programs were included. The majority were male (82.5%), had a PhD (92.8%), and identified as white (64.9%). Collectively, these residents published 212 first-author, PubMed-searchable manuscripts during residency (mean: 2.2) and 142 first- or last-author, PubMed-searchable manuscripts in the first 30 months after completion of residency (mean: 1.5). The number of first-author publications authored by HRP graduates during residency was highly correlated (r = 0.62; P < .01) with the number of first- and last-author publications they authored during the first 30 months after completing residency. Ninety-six of the 97 residents (99.0%) were employed in full-time clinical positions after completing residency. Seventy-six HRP residents (78.4%) obtained an academic position as their first job after residency, only 4 of whom have since left academia, and 20 (20.6%) obtained a nonacademic position. Of the 75 HRP graduates currently employed in an academic position, 39 (52.0%) have their own laboratories. Twenty-three of the 96 HRP residents (24.0%) who secured employment in full-time clinical positions after residency switched jobs over the study period. Lastly, 33 of the 97 HRP residents (34.0%) have thus far received 47 extramural NIH research grants, 15 of which were R-01 grants.

CONCLUSIONS

Over the past decade, the HRP has proven successful in training a new cohort of physician investigators in RO. Although productive, HRP residents have had relatively homogenous sex, educational, and racial backgrounds. Ensuring sufficient representation of residents from a variety of backgrounds in the HRP in the future will be crucial.

Controversies in radiotherapy for pancreas cancer

The management of pancreatic adenocarcinoma remains an area of controversy and ongoing discovery. Despite advances in surgical and radiation techniques, as well as chemotherapeutic agents, outcomes of patients diagnosed with this devastating malignancy remain poor. This article aims to review the available literature evaluating the efficacy of adjuvant, neoadjuvant, and definitive radiation therapy. We will also highlight areas of ongoing research efforts being carried out to improve outcomes in this patient population.

Promoting exercise in patients with cancers of the head and neck during COVID-19 and beyond

In recent years, the benefits of exercise in patients with cancer have increasingly been recognised. Unfortunately, patients with, and survivors of, cancers of the head and neck often face a constellation of symptomatic and nutritional obstacles that can interfere with their ability to adhere to structured exercise regimens. The spread of COVID-19 has only added to these challenges. In this Viewpoint, the authors detail the impediments faced by patients with cancers of the head and neck in obtaining sufficient exercise, review the evidence supporting the benefits of exercise in patients with cancer and discuss interventions to promote exercise in this patient population.

Delayed Exercise Is Ineffective at Reversing Aberrant Nociceptive Afferent Plasticity or Neuropathic Pain After Spinal Cord Injury in Rats

Neuropathic pain is a debilitating consequence of spinal cord injury (SCI) that correlates with sensory fiber sprouting. Recent data indicate that exercise initiated early after SCI prevents the development of allodynia and modulated nociceptive afferent plasticity. This study determined if delaying exercise intervention until pain is detected would similarly ameliorate established SCI-induced pain. Adult, female Sprague-Dawley rats with a C5 unilateral contusion were separated into SCI allodynic and SCI non-allodynic cohorts at 14 or 28 days postinjury when half of each group began exercising on automated running wheels. Allodynia, assessed by von Frey testing, was not ameliorated by exercise. Furthermore, rats that began exercise with no allodynia developed paw hypersensitivity within 2 weeks. At the initiation of exercise, the SCI Allodynia group displayed marked overlap of peptidergic and non-peptidergic nociceptive afferents in the C7 and L5 dorsal horn, while the SCI No Allodynia group had scant overlap. At the end of 5 weeks of exercise both the SCI Allodynia and SCI No Allodynia groups had extensive overlap of the 2 c-fiber types. Our findings show that exercise therapy initiated at early stages of allodynia is ineffective at attenuating neuropathic pain, but rather that it induces allodynia-aberrant afferent plasticity in previously pain-free rats. These data, combined with our previous results, suggest that there is a critical therapeutic window when exercise therapy may be effective at treating SCI-induced allodynia and that there are postinjury periods when exercise can be deleterious.