The emerging roles of stereotactic ablative radiotherapy for metastatic renal cell carcinoma

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.

Atypical Response in Metastatic Non-Small Cell Lung Cancer Treated with PD-1/PD-L1 Inhibitors: Radiographic Patterns and Clinical Value of Local Therapy

PURPOSE

To explore the clinical characteristics, management, and survival outcomes of advanced NSCLC patients treated with PD-1/PD-L1 inhibitors who presented with an atypical response (AR).

METHODS

A total of 926 PD-1/PD-L1-inhibitor-treated patients with metastatic NSCLC from three academic centers were retrospectively reviewed. All measurable lesions were evaluated by RECIST version 1.1.

RESULTS

Fifty-six (6.1%) patients developed AR. The median time to the occurrence of AR was 2.0 months. Patients with no fewer than 3 metastatic organs at baseline were more prone to develop AR in advanced NSCLC (p = 0.038). The common sites of progressive lesions were lymph nodes (33.8%) and lungs (29.7%). The majority (78.2%) of patients with AR had only 1-2 progressive tumor lesions, and most (89.1%) of the progressive lesions developed from originally existing tumor sites. There was no significance in terms of survival between patients with AR and those with typical response (TR). Local therapy was an independent predictor for PFS of patients with AR (p = 0.025).

CONCLUSIONS

AR was not an uncommon event in patients with metastatic NSCLC treated with PD-1/PD-L1 inhibitors, and it had a comparable prognosis to those with TR. Proper local therapy targeting progressive lesions without discontinuing original PD-1/PD-L1 inhibitors may improve patient survival.

Role of metastasectomy in the management of renal cell carcinoma

Treatment of metastatic renal cell carcinoma (mRCC) has evolved with the development of a variety of systemic agents; however, these therapies alone rarely lead to a complete response. Complete consolidative surgery with surgical metastasectomy has been associated with improved survival outcomes in well-selected patients in previous reports. No randomized control trial exists to determine the effectiveness of metastasectomy. Therefore, reviewing observational studies is important to best determine which patients are most appropriate for metastasectomy for mRCC and if such treatment continues to be effective with the development of new systemic therapies such as immunotherapy. In this narrative review, we discuss the indications for metastasectomies, outcomes, factors associated with improved survival, and special considerations such as location of metastasis, number of metastases, synchronous metastases, and use of systemic therapy. Additionally, alternative treatment options and trials involving metastasectomy will be reviewed.

Stereotactic Body Radiotherapy in Contralateral Kidney Oligometastasis From Renal Cell Carcinoma in a Nephrectomized Patient

Background: Renal cell carcinoma (RCC) frequently metastasizes to distal organs such as the lungs, abdomen, bones, and brain. Although rare cases of adrenal gland metastasis from RCC have been described, to our knowledge, no cases have reported the use of stereotactic body radiotherapy (SBRT) in contralateral kidney oligometastasis in a nephrectomized patient with RCC.

Case Report: We report a rare case of single contralateral renal metastasis from RCC in a 65-year-old female that occurred 1 year after right radical nephrectomy. At diagnosis of relapse, the patient received targeted therapy with sunitinib for 9 consecutive months, resulting in a partial regression of renal metastasis. To preserve the organ and consolidate response, SBRT was administered to the residual mass. Targeted therapy was temporarily discontinued 15 days before and after SBRT. Total SBRT dose was 40 Gy in 5 daily fractions given with volumetric modulated arc and image-guided technique. Three months later, magnetic resonance imaging documented a complete regression of disease, a result that persisted at the last follow-up 19 months after SBRT.

Conclusion: The combination of sequential targeted therapy and SBRT provided an excellent outcome in a patient with a solitary kidney who experienced contralateral kidney metastasis from RCC. This treatment approach was well tolerated and controlled the disease.

Atypical Response Patterns in Renal Cell Carcinoma Treated with Immune Checkpoint Inhibitors-Navigating the Radiologic Potpourri

BACKGROUND

Atypical response patterns have been a topic of increasing relevance since the advent of immune checkpoint inhibitors (ICIs), challenging the traditional RECIST (Response Evaluation Criteria in Solid Tumors) method of tumor response assessment. Newer immune-related response criteria can allow for the evolution of radiologic pseudoprogression, but still fail to capture the full range of atypical response patterns encountered in clinical reporting.

METHODS

We did a detailed lesion-by-lesion analysis of the serial imaging of 46 renal cell carcinoma (RCC) patients treated with ICIs with the aim of capturing the full range of radiologic behaviour.

RESULTS

Atypical response patterns observed included pseudoprogression (n = 15; 32.6%), serial pseudoprogression (n = 4; 8.7%), dissociated response (n = 22; 47.8%), abscopal response (n = 9; 19.6%), late response (n = 5; 10.9%), and durable response after cessation of immunotherapy (n = 2; 4.3%). Twenty-four of 46 patients (52.2%) had at least one atypical response pattern and 18 patients (39.1%) had multiple atypical response patterns.

CONCLUSIONS

There is a high incidence of atypical response patterns in RCC patients receiving ICIs and the study contributes to the growing literature on the abscopal effect. The recognition of these interesting and overlapping radiologic patterns challenges the oncologist to tweak treatment options such that the clinical benefits of ICIs are potentially maximized.

Renal Cancer is Not Radioresistant: Slowly but Continuing Shrinkage of the Tumor After Stereotactic Body Radiation Therapy

Purpose:

To evaluate the safety and efficacy of stereotactic body radiation therapy for primary lesion of renal cell carcinoma with long-term and regular follow-up of tumor size and renal function.

Methods:

This prospective study included 13 patients treated with stereotactic body radiation therapy for primary lesion of stage I renal cell carcinoma between August 2007 and June 2016 in our institution. Diagnosis of renal cell carcinoma was made by 2 radiologists using computed tomography or magnetic resonance imaging. A dosage of 60 Gy in 10 fractions or 70 Gy in 10 fractions was prescribed. The higher dose was selected if dose constraints were satisfied. Tumor response on imaging examination, local progression-free rate, overall survival, and toxicity were assessed.

Results:

The mean follow-up period was 48.3 months (range: 11-108 months). The tumors showed very slow but continuous response during long-term follow-up. Three cases (23.1%) showed transient progression during the short follow-up. The mean duration until the day on which partial response was confirmed among the partial or complete response cases was 22.6 months (95% confidence interval, 15.3-30.0 months). Local progression-free rate was 92.3% for 3 years and overall survival rate 91.7% for 2 years and 71.3% for 3 years. Twelve cases (92.3%) had impaired renal function at baseline. Renal function decreased slowly and mildly in most of the cases, but 2 cases of solitary kidney showed grade 4 or 5 renal dysfunction.

Conclusion:

All renal tumors decreased in size slowly but continuously for years after stereotactic body radiation therapy. Renal cancer can be treated radically with stereotactic body radiation therapy as a radiosensitive tumor, but careful attention should be given in cases with solitary kidney.

Management of advanced kidney cancer: Canadian Kidney Cancer Forum (CKCF) consensus update 2017

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Renal cell carcinoma with isolated breast metastasis

Renal cell carcinoma (RCC) is a highly prevalent disease worldwide with many cases being metastasised to various organs during the time of initial presentation. Metastatic RCC to the breast is a rare entity and can mimic primary breast carcinoma. In this article, we present a 63-year-old Caucasian woman presented with a breast mass that was detected by screening mammography and found to have a biopsy proven grade-II clear RCC in the breast tissue. Despite the high incidence and prevalence of primary breast cancer, metastasis from extramammary should be suspected in patients with a prior history of other cancers. In this brief literature review, we also highlight the survival benefit from surgery and close follow-up in selected group of patients with metastatic, metachronous and solitary RCC.

Stereotactic Ablative Radiotherapy for the Treatment of Clinically Localized Renal Cell Carcinoma

Thermal ablation is currently the most studied treatment option for medically inoperable patients with clinically localized renal cell carcinoma (RCC). Recent evidence suggests that stereotactic ablative radiotherapy (SABR) may offer an effective noninvasive alternative for these patients. In this review, we explore the current literature on SABR for the primary treatment of RCC and make recommendations for future studies so that an accurate comparison between SABR and other ablative therapies may be conducted.

Abscopal Effects: Case Report and Emerging Opportunities

The abscopal effect is a phenomenon observed in the treatment of metastatic cancer where localized irradiation of a particular tumor site causes a response in a site distant to the irradiated volume. The mechanisms of the abscopal effect are speculated to be of several origins, including distant effects on p53, elaboration of inflammatory agents including cytokines, and, most recently, secondary to immune mechanisms. In this case report, we present a rare report of a patient with hepatocellular carcinoma with lung metastases who, after receiving radiation treatment to the liver, had a treatment response in the liver and a complete response in the lung. Recent advances in the understanding of the primary role of immune-modulated cytotoxicity, especially with the success of immune checkpoint inhibitors, have the potential to turn the abscopal effect from a rare phenomenon into a tool to guide antineoplastic therapy and provide a new line of research.

The development of stereotactic body radiotherapy in the past decade: a global perspective

In the past 10 years, there has been an exponential increase in the incorporation of stereotactic body radiotherapy, also known as stereotactic ablative radiotherapy, into the armamentarium against various types of cancer in different settings worldwide. In this article in the 10th year anniversary issue of Future Oncology, representatives from the USA, Canada, Japan, Germany, The Netherlands, Australia and Singapore will provide individual perspectives of the development of stereotactic body radiotherapy in their respective countries.