Stereotactic Radiotherapy for Oligoprogression in Metastatic Renal Cell Cancer Patients Receiving Tyrosine Kinase Inhibitor Therapy: A Phase 2 Prospective Multicenter Study

Multidisciplinary systemic and local therapies for metastatic renal cell carcinoma: a narrative review

INTRODUCTION

Systemic and local therapies for patients with metastatic renal cell carcinoma (mRCC) are often challenging despite the evolution of multimodal cancer therapies in the last decade. In this review, we will focus on recent multidisciplinary approaches for patients with mRCC.

AREAS COVERED

Systemic therapies for patients with mRCC have been garnering attention particularly after the approval of immuno-oncology (IO) agents, including anti-programmed death 1/programmed death-ligand 1. IO combinations have significantly prolonged overall survival in patients with mRCC in the first-line setting. Regarding local therapies, cytoreductive nephrectomy (CN) has become less common in the post-Cancer du Rein Metastatique Nephrectomie et Antiangiogéniques (CARMENA) trial era, even though CN may still benefit selected patients with mRCC. In addition, metastasis-directed local therapies, namely metastasectomy or stereotactic radiotherapy, particularly for oligo-metastatic lesions or brain metastases, may have a prognostic impact. Several ablative techniques are also evolving while maintaining high local control rates with acceptable safety.

EXPERT OPINION

Multimodal cancer therapies are essential for conquering complex cases of mRCC. Modern systemic therapies including IO-based combination therapy as well as local therapies including CN, metastasectomy, stereotactic radiotherapy, and ablative techniques appear to improve oncologic outcomes of patients with mRCC, although appropriate patient selection is indispensable.

The Landscape of Stereotactic Ablative Radiotherapy (SABR) for Renal Cell Cancer (RCC)

Renal cell cancer (RCC) has traditionally been considered radioresistant. Because of this, conventional radiotherapy (RT) has been predominantly relegated to the palliation of symptomatic metastatic disease. The implementation of stereotactic ablative radiotherapy (SABR) has made it possible to deliver higher ablative doses safely, shifting the renal radioresistance paradigm. SABR has increasingly been adopted into the multidisciplinary framework for the treatment of locally recurrent, oligoprogressive, and oligometastatic disease. Furthermore, there is growing evidence of SABR as a non-invasive definitive therapy in patients with primary RCC who are medically inoperable or who decline surgery, unsuited to invasive ablation (surgery or percutaneous techniques), or at high-risk of requiring post-operative dialysis. Encouraging outcomes have even been reported in cases of solitary kidney or pre-existing chronic disease (poor eGFR), with a high likelihood of preserving renal function. A review of clinical evidence supporting the use of ablative radiotherapy (SABR) in primary, recurrent, and metastatic RCC has been conducted. Given the potential immunogenic effect of the high RT doses, we also explore emerging opportunities to combine SABR with systemic treatments. In addition, we explore future directions and ongoing clinical trials in the evolving landscape of this disease.

Sharing the Burden: The Case for Definitive Local Therapy in Place of Immune Checkpoint Blockade for Patients With a Low-Volume Burden of Metastatic Disease

COMMENTARY

Sharing the burden of low-volume metastatic cancer between ICB and local treatments.

Patterns of initial ovarian cancer recurrence on niraparib maintenance monotherapy in patients with no baseline evidence of disease after first-line chemotherapy: An ad hoc subgroup analysis of PRIMA/ENGOT-OV26/GOG-3012

OBJECTIVES

Patterns of disease recurrence on poly(ADP-ribose) polymerase inhibitor maintenance therapy are unclear and may affect subsequent treatment. This ad hoc subgroup analysis of the phase 3 PRIMA/ENGOT-OV26/GOG-3012 study evaluated patterns of initial recurrence in patients with advanced ovarian cancer (AOC).

METHODS

PRIMA included participants at high risk for disease progression. This ad hoc analysis only evaluated participants randomized to niraparib maintenance without evidence of disease at baseline. The number and site(s) of initial recurrent lesions at investigator-assessed progressive disease (PD) were evaluated.

RESULTS

Of the 314 niraparib-treated patients analyzed, 190 developed ≥1 new lesion (median number of new lesions, 1.0; interquartile range, 1-2). In total, 93.2% (177/190) of patients developed 1-3 lesions at first disease progression. The most common sites of recurrence were the peritoneum (30.0% [57/190]), lymph nodes (26.3% [50/190]), and liver (20.5% [39/190]). Similar results were observed when patients with PD were stratified by biomarker status, disease stage at diagnosis, and type of debulking surgery. Patients with homologous recombination-proficient tumors, stage III disease, or a history of primary debulking developed a median of 2.0 new lesions at first progression; patients with homologous recombination-deficient tumors, stage IV disease, or a history of interval debulking developed a median of 1.0 new lesion.

CONCLUSIONS

Many patients with AOC without lesions at first-line maintenance treatment initiation develop oligometastatic disease at first recurrence. Prospective evaluation is required to determine whether these patients have improved outcomes when local therapies are combined with continuous, systemic, targeted maintenance therapy.

Definitions and unmet needs in the management of oligomestatic renal cell carcinoma in the modern era

PURPOSE OF REVIEW

Oligometastatic renal cell carcinoma (RCC) is a complex entity, potentially leading to a specific clinical management of these patients. Recent and ongoing trials have raised several unresolved questions that could impact clinical routine practice, advocating for the integration of novel treatment options (systemic treatment, cytoreductive surgery, or stereotactic body radiotherapy - SBRT) with varied modalities and objectives.

RECENT FINDINGS

Immunotherapy represents a breakthrough in the systemic treatment of mRCC. However, many questions are still unsolved regarding the perfect timing for starting systemic and whether the systemic treatment could improve the activity of metastases-directed strategies. Moreover, the widespread use of adjuvant immunotherapy will challenge the treatment paradigm in the oligorecurrent scenario. Radical surgery of metastases and more recently SBRT - both eventually associated with systemic treatment - actually represent two important approaches to be considered in oligometastatic patients.

SUMMARY

Oligometastatic RCC represents a status including a wide spectrum of clinical conditions that requires a tailored treatment approach. The correct management integrates local approaches (either metastasectomy or SRBT) and systemic (immune)-therapy. Several unmet needs have to be investigated, mainly regarding the lack of prospective randomized trials that directly compare modern therapies and different integration strategies.

Systematic review of the efficacy of stereotactic ablative radiotherapy for oligoprogressive disease in metastatic cancer

BACKGROUND

Stereotactic Ablative Radiotherapy (SABR) for the treatment of oligometastatic disease can improve survival and delay the requirement for systemic therapy. The benefits of SABR in oligoprogressive disease are less well-defined. Here, we evaluate the available evidence investigating the efficacy of SABR in the treatment of oligoprogressive disease.

METHODS

A systematic review was carried out following PRISMA guidelines. Medline and Embase databases were searched using the terms "stereotactic radiotherapy" OR "SABR" OR "Stereotactic Ablative Body Radiotherapy" OR "SBRT" OR "SRT" AND "oligoprogression" in May 2022, June 2023, and February 2024. Studies were excluded where: SABR was used as a radical treatment, a specific oligoprogressive cohort could not be identified, publication was as a conference abstract or where fewer than 10 patients were recruited. Studies treating only brain metastases were also excluded. The site of primary tumour, oligoprogressive sites, rates of overall survival (OS), progression free survival (PFS), local control (LC) and time to next systemic therapy were collected.

RESULTS

Thirty-three full text studies were included. These consisted of single centre and multi-institutional observational studies, case series and phase II trials. Twenty-two studies were related to a specific tumour type: 12 urological cancer (9 prostate, 3 renal cancer), 6 non-small cell lung cancer, 2 colorectal cancer, 2 breast cancer and 11 were studies covering multiple tumour sites (5 studies involving SABR to a single organ and 6 studies involving SABR to multi-organ). Median PFS was >6 months in patients with oligoprogressive prostate, non-small cell lung cancer and renal cancer patients.

CONCLUSIONS

SABR appears to have clinical benefit in oligoprogresssive prostate, lung, and renal patients. However, the optimal management of patients with oligoprogressive disease is still somewhat uncertain due to lack of prospective data. This will hopefully become clearer in the near future with the publication of further randomised trials.

The current landscape of stereotactic body radiation therapy for metastatic castration-resistant prostate cancer

BACKGROUND

The onset of castration-resistance is associated with dismal outcomes in patients with prostate cancer (PCa). Metastasis directed therapy has been investigated in multiple disease settings and may improve outcomes in selected patients. Our systematic review aims to summarize evidence with stereotactic body radiotherapy (SBRT) in castration-resistant prostate cancer (CRPC).

METHODS

The literature search was performed on March 2024, on Pubmed, using the keywords "SBRT" AND "CRPC", and "stereotactic ablative radiotherapy (SABR)" AND "CRPC". This search retrieved a total of 108 articles, 19 were included.

RESULTS

The literature is largely dominated by retrospective series. In men with metachronous oligoprogression, SBRT with androgen receptor pathway inhibitor significantly increased progression-free survival (PFS) including biochemical progression-free survival in a randomized phase II trial (hazard ratio of 0.35, p < 0.001). In patients continuing ADT, the bPFS ranged between 9.5 months to 17.9 months, and next systemic treatment-free survival (NEST-FS) reached up to 2 years. In men with induced oligoprogression, SBRT enabled NEST-FS up to 3 years. SBRT was well tolerated, with less than 5% grade 3 toxicity reported across studies.

CONCLUSION

In the population of patients with oligometastatic CRPC, SBRT enables long-term biochemical response and PFS. In the oligoprogressive setting, SBRT could be integrated to prolong the duration and efficacy of systemic therapies. Nevertheless, the level of evidence remains very low and inclusion within prospective trials remain the preferred option for this population of patients.

Delphi consensus on stereotactic ablative radiotherapy for oligometastatic and oligoprogressive renal cell carcinoma-a European Society for Radiotherapy and Oncology study endorsed by the European Association of Urology

The purpose of this European Society for Radiotherapy and Oncology (ESTRO) project, endorsed by the European Association of Urology, is to explore expert opinion on the management of patients with oligometastatic and oligoprogressive renal cell carcinoma by means of stereotactic ablative radiotherapy (SABR) on extracranial metastases, with the aim of developing consensus recommendations for patient selection, treatment doses, and concurrent systemic therapy. A questionnaire on SABR in oligometastatic renal cell carcinoma was prepared by a core group and reviewed by a panel of ten prominent experts in the field. The Delphi consensus methodology was applied, sending three rounds of questionnaires to clinicians identified as key opinion leaders in the field. At the end of the third round, participants were able to find consensus on eight of the 37 questions. Specifically, panellists agreed to apply no restrictions regarding age (25 [100%) of 25) and primary renal cell carcinoma histology (23 [92%] of 25) for SABR candidates, on the upper threshold of three lesions to offer ablative treatment in patients with oligoprogression, and on the concomitant administration of immune checkpoint inhibitor. SABR was indicated as the treatment modality of choice for renal cell carcinoma bone oligometatasis (20 [80%] of 25) and for adrenal oligometastases 22 (88%). No consensus or major agreement was reached regarding the appropriate schedule, but the majority of the poll (54%-58%) retained the every-other-day schedule as the optimal choice for all the investigated sites. The current ESTRO Delphi consensus might provide useful direction for the application of SABR in oligometastatic renal cell carcinoma and highlight the key areas of ongoing debate, perhaps directing future research efforts to close knowledge gaps.

The efficacy and safety of stereotactic body radiotherapy combined with systematic therapy for metastatic renal cell carcinoma: a systematic review and meta-analysis

There is considerable interest in the potential of stereotactic body radiation therapy (SBRT) combined with systemic therapy such as tyrosine kinase inhibitors (TKIs) or immune checkpoint inhibitors (ICIs). However, its efficacy and safety remain unclear. The purpose of this study was to evaluate the efficacy and safety of conducting SBRT during ICI or TKI treatment in different disease settings for patients with metastatic renal cell carcinoma (mRCC). A total of 16 studies were ultimately included. Under the random effects model, the pooled 1-year local control rate (1-yr LCR) and objective response rate (ORR) were 90% (95% confidence interval [CI]: 80%-95%, I 2 = 67%) and 52% (95% CI: 37%-67%, I 2 = 90%), respectively. SBRT concomitant with different systemic therapy yield significant different 1-yr LCR (p < 0.01) and ORR (p = 0.02). Regarding survival benefits, the pooled 1-year progression-free survival (1-yr PFS) and 1-year overall survival (1-yr OS) rates were 45% (95% CI: 29%-62%, I 2 = 91%) and 85% (95% CI: 76%-91%, I 2 = 66%), respectively. 1-yr PFS and 1-yr OS in different disease settings demonstrated significant difference (p < 0.01). As for toxicity, the pooled incidence of grade 3-4 adverse events was 14% (95% CI: 5%-26%, I 2 = 90%). This study highlights the feasibility of utilizing these strategies in mRCC patients, especially those with a low metastatic tumor burden.

Safety and Efficacy of Stereotactic Body Radiation Therapy for Ultra-central Thoracic Tumors: A Single Center Retrospective Review

PURPOSE

We sought to evaluate the toxicity and efficacy of stereotactic body radiation therapy (SBRT) for ultracentral thoracic tumors at our institution.

METHODS AND MATERIALS

Patients with ultracentral lung tumors or nodes, defined as having the planning target volume (PTV) overlapping or abutting the central bronchial tree and/or esophagus, treated at our institution with SBRT between 2009 and 2019 were retrospectively reviewed. All SBRT plans were generated with the goal of creating homogenous dose distributions. The primary endpoint was incidence of SBRT-related grade ≥3 toxicity, defined using the Common Terminology Criteria for Adverse Events (V5.0). Secondary endpoints included local failure (LF), progression-free survival (PFS), and overall survival. Competing risk analysis was used to estimate incidence and identify predictors of severe toxicity and LF, while the Kaplan-Meier method was used to estimate PFS and OS.

RESULTS

A total of 154 patients receiving 162 ultracentral courses of SBRT were included. The most common prescription was 50 Gy in 5 fractions (42%), with doses ranging from 30 to 55 Gy in 5 fractions (BED10 range, 48-115 Gy). The incidence of severe toxicity was 9.4% at 3 years. The most common severe toxicity was pneumonitis (n = 4). There was 1 possible treatment-related death from pneumonitis/pneumonia. Predictors of severe toxicity included increased PTV size, decreased PTV V95%, lung V5 Gy, and lung V20 Gy. The incidence of LF was 14% at 3 years. Predictors of LF included younger age and greater volume of overlap between the PTV and esophagus. The median PFS was 8.8 months, while the median overall survival was 44.0 months.

CONCLUSIONS

In the largest case series of ultracentral thoracic SBRT to date, homogenously prescribed SBRT was associated with relatively low rates of severe toxicity and LF. Predictors of toxicity should be interpreted in the context of the heterogeneity in toxicities observed.

Stereotactic body radiotherapy for oligoprogression with or without switch of systemic therapy

Background

Oligoprogression is defined as cancer progression of a limited number of metastases under active systemic therapy. The role of metastasis-directed therapy, using stereotactic body radiotherapy (SBRT), is controversial as is the continuation versus switch of systemic therapy. We report outcomes of oligoprogressive patients after SBRT, and compare those patients that continued or switched their current line of systemic therapy.

Material/Methods

We included patients who developed up to 5 progressive extracranial metastases under systemic therapy for any solid organ malignancy and were treated with SBRT to all lesions at our institution between 01/2014 and 12/2019. Overall survival (OS) and progression-free survival (PFS) were analyzed using the Kaplan-Meier method, and the interval to the next systemic therapy line determined using cumulative incidence functions. Multivariable Cox regression models were used to analyze the influence of baseline and post-progression variables on OS, PFS and survival with the next systemic therapy after SBRT.

Results

Among 135 patients with oligoprogressive disease of which the most common primary tumor was lung cancer (n = 46, 34.1 %), 96 continued their current line of systemic therapy after oligoprogression. Among 39 who switched systemic therapy, 28 (71.8 %) paused or discontinued, while 11 (28.2 %) immediately started another systemic treatment. After a median follow-up of 27.2 months, patients that switched and those who continued systemic therapy after oligoprogression had comparable median OS (32.1 vs. 38.2 months, p = 0.47) and PFS (4.3 vs. 3.4 months, p = 0.6). The intervals to the next systemic therapy line were comparable between both cohorts (p = 0.6). An ECOG performance status of 2 and immediately starting a new systemic therapy after oligoprogression were associated with a poorer survival without next systemic therapy, while the de-novo OMD state was associated with better survival without next systemic therapy compared to the induced state.

Conclusion

Oncological outcomes of patients that continued or switched systemic therapy after SBRT for oligoprogression were comparable, potentially indicating that further lines of treatment may be safely delayed in selected cases.

SABR for oligometastatic renal cell carcinoma

Stereotactic ablative body radiotherapy (SABR) aims to accurately deliver a higher than conventional dose of radiotherapy to a well-defined target tumour incorporating advanced immobilisation and imaging techniques. SABR is an emerging treatment option for primary kidney cancer especially when surgery is contraindicated. Increasingly, SABR is being incorporated into the management of low-volume stage IV kidney cancers to delay the need for systemic therapy or to prolong the duration of ongoing systemic treatment. This review will evaluate the evidence and limitations of SABR for oligometastatic renal cell carcinoma.

Role of radiotherapy in the management of brain oligometastases

The management of patients with brain oligometastases is complex and relies on specific reasoning compared to extracranial oligometastases. The levels of evidence are still low because patients with brain oligometastases are frequently excluded from randomized clinical trials. Stereotactic radiotherapy should be preferred in this indication over whole brain irradiation, both for patients with metastases in place and for those who have undergone surgery. The decision of local treatment and its timing must be a multidisciplinary reflection taking into account the histological and molecular characteristics of the tumor as well as the intracranial efficacy of the prescribed systemic treatments. Great caution must be observed when using stereotactic radiotherapy and concomitant systemic treatments because interactions are still poorly documented. We present the recommendations of the French society of radiation oncology on the management of brain oligometastatic patients with radiotherapy.

Navigating the ICI Combination Treatment Journey: Patterns of Response and Progression to First-Line ICI-Based Combination Treatment in Metastatic Renal Cell Carcinoma

The use of immune checkpoint inhibitors (ICIs) in combination with tyrosine kinase inhibitors or other ICIs has significantly improved the prognosis for patients with mccRCC. This marks a major milestone in the treatment of mccRCC. Nonetheless, most patients will discontinue first-line therapy. In this narrative review, we analyze the different patterns of treatment discontinuation in the four pivotal phase III trials that have shown an improvement in overall survival in mccRCC first-line therapy, starting from 1 January 2017 to 1 June 2023. We highlight the different discontinuation scenarios and their influences on subsequent treatment options, aiming to provide more data to clinicians to navigate a complex decision-making process through a narrative review approach. We have identified several causes for discontinuations for patients treated with ICI-based combinations, such as interruption for drug-related adverse events, ICI treatment completion, treatment discontinuation due to complete response or maximum clinical benefit, or due to progression (pseudoprogression, systemic progression, and oligoprogression); for each case, an extensive analysis of the trials and current medical review has been conducted.

The Diagnosis and Treatment Approach for Oligo-Recurrent and Oligo-Progressive Renal Cell Carcinoma

One-third of renal cell carcinomas (RCCs) without metastases develop metastatic disease after extirpative surgery for the primary tumors. The majority of metastatic RCC cases, along with treated primary lesions, involve limited lesions termed "oligo-recurrent" disease. The role of metastasis-directed therapy (MDT), including stereotactic body radiation therapy (SBRT) and metastasectomy, in the treatment of oligo-recurrent RCC has evolved. Although the surgical resection of all lesions alone can have a curative intent, SBRT is a valuable treatment option, especially for patients concurrently receiving systemic therapy. Contemporary immune checkpoint inhibitor (ICI) combination therapies remain central to the management of metastatic RCC. However, one objective of MDT is to delay the initiation of systemic therapies, thereby sparing patients from potentially unnecessary burdens. Undertaking MDT for cases showing progression under systemic therapies, known as "oligo-progression", can be complex in considering the treatment approach. Its efficacy may be diminished compared to patients with stable disease. SBRT combined with ICI can be a promising treatment for these cases because radiation therapy has been shown to affect the tumor microenvironment and areas beyond the irradiated sites. This may enhance the efficacy of ICIs, although their efficacy has only been demonstrated in clinical trials.

Incorporating Stereotactic Ablative Radiotherapy into the Multidisciplinary Management of Renal Cell Carcinoma

Stereotactic ablative radiotherapy (SABR) has challenged the conventional wisdom surrounding the radioresistance of renal cell carcinoma (RCC). In the past decade, there has been a significant accumulation of clinical data to support the safety and efficacy of SABR in RCC. Herein, we review the use of SABR across the spectrum of RCC. We performed an online search of the Pubmed database from January 1990 through April 2023. Studies of SABR/stereotactic radiosurgery targeting primary, extracranial, and intracranial metastatic RCC were included. For SABR in non-metastatic RCC, this includes its use in small renal masses, larger renal masses, and inferior vena cava tumor thrombi. In the metastatic setting, SABR can be used at diagnosis, for oligometastatic and oligoprogressive disease, and for symptomatic reasons. Notably, SABR can be used for both the primary renal tumor and metastasis-directed therapy. Management of RCC is evolving rapidly, and the role that SABR will have in this landscape is being assessed in a number of ongoing prospective clinical trials. The objective of this narrative review is to summarize the evidence corroborating the use of SABR in RCC.

An Overview of Systemic Targeted Therapy in Renal Cell Carcinoma, with a Focus on Metastatic Renal Cell Carcinoma and Brain Metastases

The most commonly diagnosed malignancy of the urinary system is represented by renal cell carcinoma. Various subvariants of RCC were described, with a clear-cell type prevailing in about 85% of all RCC tumors. Patients with metastases from renal cell carcinoma did not have many effective therapies until the end of the 1980s, as long as hormonal therapy and chemotherapy were the only options available. The outcomes were unsatisfactory due to the poor effectiveness of the available therapeutic options, but then interferon-alpha and interleukin-2 showed treatment effectiveness, providing benefits but only for less than half of the patients. However, it was not until 2004 that targeted therapies emerged, prolonging the survival rate. Currently, new technologies and strategies are being developed to improve the actual efficacy of available treatments and their prognostic aspects. This article summarizes the mechanisms of action, importance, benefits, adverse events of special interest, and efficacy of immunotherapy in metastatic renal cell carcinoma, with a focus on brain metastases.

Survival in Metastatic Renal Cell Carcinoma Treated With Immunotherapy and Stereotactic Radiation Therapy or Immunotherapy Alone: A National Cancer Database Analysis

Purpose

Immunotherapy (IO) has significantly improved outcomes in metastatic renal cell carcinoma (mRCC). Preclinical evidence suggests that responses to IO may be potentiated via immunomodulatory effects of stereotactic radiation therapy (SRT). We hypothesized that clinical outcomes from the National Cancer Database (NCDB) would demonstrate improved overall survival (OS) in patients with mRCC receiving IO + SRT versus IO alone.

Methods and Materials

Patients with mRCC receiving first-line IO ± SRT were identified from the NCDB. Conventional radiation therapy was allowed in the IO alone cohort. The primary endpoint was OS stratified by the receipt of SRT (IO + SRT vs IO alone). Secondary endpoints included OS stratified by the presence of brain metastases (BM) and timing of SRT (before or after IO). Survival was estimated using Kaplan-Meier methodology and compared via the log-rank test.

Results

Of 644 eligible patients, 63 (9.8%) received IO + SRT, and 581 (90.2%) received IO alone. Median follow-up time was 17.7 months (range, 2-24 months). Sites treated with SRT included the brain (71.4%), lung/chest (7.9%), bones (7.9%), spine (6.3%), and other (6.3%). OS was 74.4% versus 65.0% at 1 year and 71.0% versus 59.4% at 2 years for the IO + SRT and IO alone groups, respectively, although this difference did not reach statistical significance (log-rank P = .1077). In patients with BM, however, 1-year OS (73.0% vs 54.7%) and 2-year OS (70.8% vs 51.4%) was significantly higher in those receiving IO + SRT versus IO alone, respectively (pairwise P = .0261). Timing of SRT (before or after IO) did not influence OS (log-rank P = .3185).

Conclusions

Patients with BM secondary to mRCC had prolonged OS with the addition of SRT to IO. Factors such as International mRCC Database Consortium risk stratification, oligometastatic tumor burden, SRT dose/fractionation, and utilization of doublet therapy should be considered in future analyses to better identify patients who may benefit from combined IO + SRT. Further prospective studies are warranted.

Life-threatening hemoptysis in patients with metastatic kidney cancer

Hemoptysis is a complication of intrathoracic tumors, both primary and metastatic, and the risk may be increased by procedural interventions as well as Stereotactic Ablative Radiation (SAbR). The risk of hemoptysis with SAbR for lung cancer is well characterized, but there is a paucity of data about intrathoracic metastases. Here, we sought to evaluate the incidence of life-threatening/fatal hemoptysis (LTH) in patients with renal cell carcinoma (RCC) chest metastases with a focus on SAbR. We systematically evaluated patients with RCC at UT Southwestern Medical Center (UTSW) Kidney Cancer Program (KCP) from July 2005 to March 2020. We queried Kidney Cancer Explorer (KCE), a data portal with clinical, pathological, and experimental genomic data. Patients were included in the study based on mention of "hemoptysis" in clinical documentation, if they had a previous bronchoscopy, or had undergone SAbR to any site within the chest. Two hundred and thirty four patients met query criteria and their records were individually reviewed. We identified 10 patients who developed LTH. Of these, 4 had LTH as an immediate procedural complication whilst the remaining 6 had prior SAbR to ultra-central (UC; abutting the central bronchial tree) metastases. These 6 patients had a total of 10 lung lesions irradiated (UC, 8; central 1, peripheral 1), with a median total cumulative SAbR dose of 38 Gray (Gy/ lesion) (range: 25-50 Gy). Other risk factors included intrathoracic disease progression (n = 4, 67%), concurrent anticoagulant therapy (n = 1, 17%) and concurrent systemic therapy (n = 4, 67%). Median time to LTH from first SAbR was 26 months (range: 8-61 months). Considering that 130 patients received SAbR to a chest lesion during the study period, the overall incidence of LTH following SAbR was 4.6% (6/130). The patient population that received SAbR (n = 130) was at particularly high risk for complications, with 67 (52%) having two or more chest metastaes treated, and 29 (22%) receiving SAbR to three or more lesions. Overall, the risk of LTH following SAbR to a central or UC lesion was 10.5% (6/57). In conclusion, SAbR of RCC metastases located near the central bronchial tree may increase the risk of LTH.

The Effectiveness and Safety of Stereotactic Body Radiation Therapy (SBRT) in the Treatment of Oligoprogressive Breast Cancer: A Systematic Review

Stereotactic body radiotherapy (SBRT) has emerged as a technique to treat oligoprogressive sites among patients with breast cancer who are otherwise doing well on systemic therapy. This study systematically reviewed the efficacy and safety of SBRT in the setting of oligoprogressive breast cancer. A literature search was conducted in the MEDLINE database. Studies regarding SBRT and oligoprogressive breast cancer were included. Key outcomes of interest were toxicity, local control, progression, and overall survival. From 863 references, five retrospective single-center cohort studies were identified. All studies included patients with both oligometastatic and oligoprogressive disease; 112 patients with oligoprogressive breast cancer were identified across these studies. Patient age ranged from 22 to 84, with a median of 55 years of age. Most patients had hormone-receptor-positive and HER2-negative disease. SBRT doses varied from 24 to 60 Gy in 1-10 fractions based on the location/size of the lesion. Forty toxicity events were reported, of which the majority (n = 25, 62.5%) were grade 1-2 events. Among 15 patients who received SBRT concurrently with a CDK4/6 inhibitor, 37.5% of patients experienced grade 3-5 toxicities. Progression-free and overall survival ranged from 17 to 57% and 62 to 91%, respectively. There are limited data on the role of SBRT in oligoprogressive breast cancer, and prospective evaluation of this strategy is awaited to inform its safety and efficacy.

Beyond the Knife in Renal Cell Carcinoma: A Systematic Review-To Ablate or Not to Ablate?

Intensified systemic therapy in metastatic renal cell carcinoma (mRCC) has led to improved patient outcomes. Patients commonly require local control of one or a few metastases. The aim was to evaluate metastasis-directed ablative therapies in extracranial mRCC. Two databases and one registry were searched, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach, for all prospective and matched-pair case-control mRCC studies of radiofrequency ablation (RFA), cryotherapy, microwave ablation (MWA), and stereotactic body radiotherapy (SBRT). Eighteen studies were identified. Fourteen investigated SBRT in 424 patients. Four thermal ablation studies were identified: two cryotherapy (56 patients) and two RFA studies (90 patients). The median participant number was 30 (range 12-69). The combined median follow-up was 17.3 months (range 8-52). Four SBRT studies reported local control (LC) at 12 months, median 84.4% (range 82.5-93). Seven studies (six SBRT and one cryotherapy) reported an LC rate of median 87% (79-100%). Median overall survival (OS) was reported in eight studies (five SBRT, two cryotherapy, and one RFA) with a median of 22.7 months (range 6.7-not reached). Median progression-free survival was reported in seven studies (five SBRT, one cryotherapy, and one RFA); the median was 9.3 months (range 3.0-22.7 months). Grade ≥ 3 toxicity ranged from 1.7% to 10%. SBRT has excellent local control outcomes and acceptable toxicity. Only four eligible thermal ablative studies were identified and could not be compared with SBRT. Translationally rich definitive studies are warranted.

Comparison of different dose accumulation strategies to estimate organ doses after stereotactic magnetic resonance-guided adaptive radiotherapy

INTRODUCTION

Re-irradiation is frequently performed in the era of precision oncology, but previous doses to organs-at-risk (OAR) must be assessed to avoid cumulative overdoses. Stereotactic magnetic resonance-guided online adaptive radiotherapy (SMART) enables highly precise ablation of tumors close to OAR. However, OAR doses may change considerably during adaptive treatment, which complicates potential re-irradiation. We aimed to compare the baseline plan with different dose accumulation techniques to inform re-irradiation.

PATIENTS & METHODS

We analyzed 18 patients who received SMART to lung or liver tumors inside prospective databases. Cumulative doses were calculated inside the planning target volumes (PTV) and OAR for the adapted plans and theoretical non-adapted plans via (1) cumulative dose volume histograms (DVH sum plan) and (2) deformable image registration (DIR)-based dose accumulation to planning images (DIR sum plan). We compared cumulative dose parameters between the baseline plan, DVH sum plan and DIR sum plan using equivalent doses in 2 Gy fractions (EQD2).

RESULTS

Individual patients presented relevant increases of near-maximum doses inside the proximal bronchial tree, spinal cord, heart and gastrointestinal OAR when comparing adaptive treatment to the baseline plans. The spinal cord near-maximum doses were significantly increased in the liver patients (D2% median: baseline 6.1 Gy, DIR sum 8.1 Gy, DVH sum 8.4 Gy, p = 0.04; D0.1 cm³ median: baseline 6.1 Gy, DIR sum 8.1 Gy, DVH sum 8.5 Gy, p = 0.04). Three OAR overdoses occurred during adaptive treatment (DIR sum: 1, DVH sum: 2), and four more intense OAR overdoses would have occurred during non-adaptive treatment (DIR sum: 4, DVH sum: 3). Adaptive treatment maintained similar PTV coverages to the baseline plans, while non-adaptive treatment yielded significantly worse PTV coverages in the lung (D95% median: baseline 86.4 Gy, DIR sum 82.4 Gy, DVH sum 82.2 Gy, p = 0.006) and liver patients (D95% median: baseline 87.4 Gy, DIR sum 82.1 Gy, DVH sum 81.1 Gy, p = 0.04).

CONCLUSION

OAR doses can increase during SMART, so that re-irradiation should be planned based on dose accumulations of the adapted plans instead of the baseline plan. Cumulative dose volume histograms represent a simple and conservative dose accumulation strategy.

State of the Art: Multidisciplinary Management of Oligometastatic Renal Cell Carcinoma

Oligometastatic renal cell carcinoma (OM-RCC) refers to patients who have limited (typically up to 5) metastatic lesions. Although management principles may overlap, OM-RCC is distinguishable from oligoprogressive RCC, which describes progression of disease to a limited number of sites while receiving systemic therapy. Cytoreductive nephrectomy and metastasectomy are common surgical considerations in OM-RCC, and indications are discussed in this review. It is evident that stereotactic ablative radiotherapy is effective in RCC and is being applied increasingly in the oligometastatic setting. Finally, we will review advances in systemic therapy and the role of active surveillance before the initiation of systemic therapy.

Metastases-directed stereotactic body radiotherapy in combination with targeted therapy or immunotherapy: systematic review and consensus recommendations by the EORTC-ESTRO OligoCare consortium

Stereotactic body radiotherapy (SBRT) for patients with metastatic cancer, especially when characterised by a low tumour burden (ie, oligometastatic disease), receiving targeted therapy or immunotherapy has become a frequently practised and guideline-supported treatment strategy. Despite the increasing use in routine clinical practice, there is little information on the safety of combining SBRT with modern targeted therapy or immunotherapy and a paucity of high-level evidence to guide clinical management. A systematic literature review was performed to identify the toxicity profiles of combined metastases-directed SBRT and targeted therapy or immunotherapy. These results served as the basis for an international Delphi consensus process among 28 interdisciplinary experts who are members of the European Society for Radiotherapy and Oncology (ESTRO) and European Organisation for Research and Treatment of Cancer (EORTC) OligoCare consortium. Consensus was sought about risk mitigation strategies of metastases-directed SBRT combined with targeted therapy or immunotherapy; a potential need for and length of interruption to targeted therapy or immunotherapy around SBRT delivery; and potential adaptations of radiation dose and fractionation. Results of this systematic review and consensus process compile the best available evidence for safe combination of metastases-directed SBRT and targeted therapy or immunotherapy for patients with metastatic or oligometastatic cancer and aim to guide today's clinical practice and the design of future clinical trials.

Stereotactic Ablative Radiation Therapy for Colorectal Liver Metastases

INTRODUCTION

Stereotactic Ablative Radiation Therapy (SABR) is a therapeutic option for patients with inoperable oligometastatic colorectal carcinoma (CRC). Given the scarcity of prospective data on outcomes of SABR for metastatic CRC, this study aims to review SABR outcomes and determine predictive factors of local control (LC) and survival in patients with liver metastases from CRC.

MATERIALS AND METHODS

A retrospective review of SABR for CRC liver metastases between 2011 and 2019 was undertaken. Endpoints included LC, overall survival (OS), progression-free survival (PFS) and time to restarting systemic therapy. Univariate (UVA) and multivariable analyses (MVA) were performed to identify predictive factors.

RESULTS

Forty-eight patients were identified. The total number of tumors treated was 58. Median follow-up was 26.6 months. LC at 1, 2 and 3 years was 92.7%, 80.0%, and 61.2% respectively. Median time to local failure was 40.0 months (95% CI 31.8-76.1 months). Median OS was 31.9 months (95% CI 20.6-40.0 months). OS at 1, 2, and 3 years was 79.2%, 61.7%, and 44.9% respectively. Thirty-three patients (69%) restarted systemic therapy after completion of SABR. Median time to restarting chemotherapy was 11.0 months (95% CI 7.1-17.6 months). Systemic therapy free survival at 1, 2, and 3 years was 45.7%, 29.6%, and 22.6% respectively. On MVA, inferior LC was influenced by GTV volume ≥40 cm³ (HR: 3.805, 95% CI 1.376-10.521, P = .01) and PTV D100% BED <100 Gy₁₀ (HR 2.971, 95% CI 1.110-7.953; P = .03). Inferior OS was associated with PTV volume ≥200 cm³ (HR 5.679, 95% CI 2.339-13.755; P < .001).

CONCLUSION

SABR is an effective therapeutic option for selected patients with CRC liver metastases providing acceptable LC within the first 2 years. In many cases, it provides meaningful chemotherapy-free intervals. Higher biological effective doses are required to enhance LC.

Stereotactic body radiation therapy for kidney cancer. Where do we stand?

At present, surgery is still the gold standard for the local treatment of renal cancer. Nonetheless, in several clinical scenarios, stereotactic body radiation therapy (SBRT) also known as stereotactic ablative body radiotherapy (SABR) is emerging as a highly effective ablative technique in fragile patients and those with significant comorbidities, as well as in cases where percutaneous therapy (cryoablation or radiofrequency) is not viable. However, considering the intrinsic radioresistance of renal tumors, the optimal treatment schemes have not been established. In oligometastatic patients, it has been reported that the control of the oligometastases can be a potentially curable approach. Being a technique than can be administered exclusively or in combination with systemic therapy, treatment individualization based on patient characteristics is key. Another scenario under investigation is oligoprogression, where SBRT offers the possibility of delaying further lines of systemic therapy by eliminating subclones of resistant tumor with ablative doses, with the additional opportunity of stimulating the immune system (immunomodulatory role). In this review, we have conducted an analysis of recently published studies that test the role of this technique in different clinical scenarios of this disease. We have found promising results that make SBRT a potent therapeutic approach with low toxicity. We also comment on ongoing studies that will generate the necessary evidence needed for the implementation of this technique in our daily clinical practice.

Review of Prospective Trials Assessing the Role of Stereotactic Body Radiation Therapy for Metastasis-directed Treatment in Oligometastatic Genitourinary Cancers

CONTEXT

Emerging evidence supports the use of stereotactic body radiation therapy (SBRT) as metastatic-directed therapy (MDT) for oligometastatic genitourinary cancers; however, the prospective data to guide its application as an alternative standard of care remain limited.

OBJECTIVE

To review prospective trials that assess the role of SBRT for patients with genitourinary cancers within a modern framework of oligometastatic disease (OMD) and to highlight clinical scenarios where SBRT may offer a benefit to patients with metastatic cancer.

EVIDENCE ACQUISITION

We performed a critical review of PubMed and clinicaltrials.gov in April 2022 according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, combined with expert input to identify prospective studies investigating the role of SBRT for oligometastatic prostate, renal, or bladder cancer.

EVIDENCE SYNTHESIS

The most commonly studied application of SBRT has been for metachronous oligorecurrent hormone-sensitive prostate cancer (HSPC). Further prospective study is needed to define the role of SBRT in delaying time to next therapy or inducing synergy with other systemic therapies.

CONCLUSIONS

SBRT has been associated with high rates of local control and minimal risk of toxicity with multiple trials assessing an MDT-alone approach for oligorecurrent HSPC. From a tumor-agnostic perspective, the clinical benefit of SBRT for OMD has been associated with the ability to extend overall survival. As methods of cancer detection and treatment evolve, expansion of studies that prospectively evaluate SBRT MDT, stratifying by tumor histology and oligometastatic state, is needed to inform optimal patient selection and treatment strategy.

PATIENT SUMMARY

We review outcomes from prospective trials assessing the role of stereotactic body radiation therapy (SBRT) for oligometastatic genitourinary cancers, which have predominantly investigated SBRT for oligorecurrent prostate cancer. Much work remains to define how SBRT alone compares with other standard of care treatments for prostate cancer or the role of SBRT in tumor control or delaying time to next therapy in oligometastatic renal and bladder cancer.

Application of individualized multimodal radiotherapy combined with immunotherapy in metastatic tumors

Radiotherapy is one of the mainstays of cancer treatment. More than half of cancer patients receive radiation therapy. In addition to the well-known direct tumoricidal effect, radiotherapy has immunomodulatory properties. When combined with immunotherapy, radiotherapy, especially high-dose radiotherapy (HDRT), exert superior systemic effects on distal and unirradiated tumors, which is called abscopal effect. However, these effects are not always effective for cancer patients. Therefore, many studies have focused on exploring the optimized radiotherapy regimens to further enhance the antitumor immunity of HDRT and reduce its immunosuppressive effect. Several studies have shown that low-dose radiotherapy (LDRT) can effectively reprogram the tumor microenvironment, thereby potentially overcoming the immunosuppressive stroma induced by HDRT. However, bridging the gap between preclinical commitment and effective clinical delivery is challenging. In this review, we summarized the existing studies supporting the combined use of HDRT and LDRT to synergistically enhance antitumor immunity, and provided ideas for the individualized clinical application of multimodal radiotherapy (HDRT+LDRT) combined with immunotherapy.

Genomic and Transcriptomic Predictors of Response from Stereotactic Body Radiation Therapy in Patients with Oligoprogressive Renal Cell Carcinoma

Stereotactic body radiation therapy (SBRT) has been shown to be safe and effective for delaying systemic treatment change among patients with metastatic renal cell carcinoma (mRCC). In this study, we sought to assess the genomic signatures of patients with mRCC who underwent SBRT for oligoprogression. A total of 30 patients with oligoprogressive disease were identified, the majority of whom had clear cell renal cell carcinoma (83.3%) and were receiving first-line treatment (53.3%). Genomic and transcriptomic sequencing were available in 20 and 16 patients, respectively. Duration of systemic treatment (DOT) was categorized as that prior (DOT[P]) and subsequent (DOT[S]) to radiation treatment. The median DOT(P) and DOT(S) were 15.1 and 18.3 mo, respectively, with a median DOT(S)/DOT(P) ratio of 1.4. Patients who had a DOT(S)/DOT(P) ratio of ≥1 had increased expression in pathways related to cell proliferation and development. In contrast, among patients with a ratio of ≤1, the reactive oxygen species pathway was enriched. This study highlights the potential role of genomics and transcriptomics to refine radiation treatment selection in patients with mRCC. PATIENT SUMMARY: In this study, we looked at mutations and genomic expressions among kidney cancer patients who responded better to stereotactic body radiotherapy. We found that enriched expression of certain pathways might play a role in response to radiotherapy.

The Emerging Role of Extracranial Stereotactic Ablative Radiotherapy for Metastatic Renal Cell Carcinoma: A Systematic Review

CONTEXT

Although the management of metastatic renal cell carcinoma (mRCC) has been revolutionized by the advent of new systemic agents, still few patients experience a long-term durable response. Stereotactic ablative radiotherapy (SABR) is nowadays commonly used as metastasis-directed therapy (MDT), but limited data exist on how best to implement this strategy as part of a multimodal approach.

OBJECTIVE

To evaluate the potential role of extracranial SABR in mRCC and to identify future therapeutic developments of SABR in different disease settings.

EVIDENCE ACQUISITION

A systematic review was conducted in May 2022 according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement on the PubMed database. Thirty-four studies were selected for inclusion in this systematic review.

EVIDENCE SYNTHESIS

SABR has been used with four main goals: (1) eradication of the whole metastatic burden in synchronous and metachronous oligometastatic patients, resulting in a long-term local control (LC) rate of >90% and median progression-free survival (PFS) ranging between 8 and 15 mo; (2) eradication of oligoprogressive lesions, enabling an extension of the duration of the systemic therapy by approximately 9 mo; (3) improvement of the response to systemic therapy in polymetastatic patients, resulting in an overall response rate ranging from 17% to 56%; and (4) cytoreduction in polymetastatic mRCC patients, with LC rates ranging between 71% and 100%, and preservation of the renal function, but unclear PFS and overall survival impact. Overall, the combination of SABR and systemic agents has been associated with overall good tolerance, with grade ≥3 toxicity ranging from 0% to 13%.

CONCLUSIONS

Current data highlight the role of SABR as an emerging MDT treatment option in both oligometastatic and oligoprogressive extracranial mRCC, able to ensure long-term disease control and delay the use of next-line systemic therapies. The use of SABR for cytoreduction in the de novo metastatic disease and as an immunological booster in the polymetastatic setting remains investigational and warrants further investigations.

PATIENT SUMMARY

Radiotherapy delivered with ablative doses (>6 Gy per fraction) is a promising treatment strategy for patients diagnosed with metastatic renal cell carcinoma. Excellent outcome results have been observed in patients with a limited number of metastases, improving metastasis-free survival by several months. For patients with a few metastases progressing under systemic therapy, radiotherapy allows an extension of the duration of the ongoing therapy by several months.

Stereotactic Body Radiotherapy and Immunotherapy for Older Patients with Oligometastases: A Proposed Paradigm by the International Geriatric Radiotherapy Group

The standard of care for metastatic disease is systemic therapy. A unique subset of patients with limited metastatic disease defined as distant involvement of five anatomic sites or less (oligometastases) have a better chance of remission or improved survival and may benefit from local treatments such as surgery or stereotactic body radiotherapy (SBRT). However, to prevent further spread of disease, systemic treatment such as chemotherapy, targeted therapy, and hormonal therapy may be required. Older patients (70 years old or above) or physiologically frail younger patients with multiple co-morbidities may not be able to tolerate the conventional chemotherapy due to its toxicity. In addition, those with a good performance status may not receive optimal chemotherapy due to concern about toxicity. Recently, immunotherapy with checkpoint inhibitors (CPI) has become a promising approach only in the management of program death ligand 1 (PD-L1)-positive tumors. Thus, a treatment method that elicits induction of PD-L1 production by tumor cells may allow all patients with oligometastases to benefit from immunotherapy. In vitro studies have demonstrated that high dose of radiotherapy may induce formation of PD-L1 in various tumors as a defense mechanism against inflammatory T cells. Clinical studies also corroborated those observations. Thus, SBRT, with its high precision to minimize damage to normal organs, may be a potential treatment of choice for older patients with oligometastases due to its synergy with immunotherapy. We propose a protocol combining SBRT to achieve a minimum radiobiologic equivalent dose around 59.5 Gy to all tumor sites if feasible, followed four to six weeks later by CPI for those cancer patients with oligometastases. All patients will be screened with frailty screening questionnaires to identify individuals at high risk for toxicity. The patients will be managed with an interdisciplinary team which includes oncologists, geriatricians, nurses, nutritionists, patient navigators, and social workers to manage all aspects of geriatric patient care. The use of telemedicine by the team may facilitate patient monitoring during treatment and follow-up. Preliminary data on toxicity, local control, survival, and progression-free survival may be obtained and serve as a template for future prospective studies.

Evaluation of 5 Fraction Stereotactic Body Radiation Therapy (SBRT) for Osseous Renal Cell Carcinoma Metastases

OBJECTIVES

The best fractionation for stereotactic body radiotherapy (SBRT) in renal cell carcinoma (RCC) metastases has not been well defined. In addition, the literature on outcomes using 5-fraction SBRT in the setting of osseous metastases has not been well reported.

MATERIALS AND METHODS

Thirty-nine patients with 69 RCC osseous metastases were treated using 5-fraction SBRT at a single institution using 2 dose-fractionation schemes. Overall survival and local-control (LC) outcomes of the 2 fractionation schemes were studied using Kaplan-Meier curves.

RESULTS

Of the 69 lesions included in the study, 20 were treated with 30 grays (Gy) in 5 fractions and 49 were treated with 40 Gy in 5 fractions. The median age of patients at diagnosis was 58.4 years. The 1-year LC rate for all treated lesions was 85.5% (59/69) with an LC of 90% (18/20) for lesions receiving 30 Gy and 83.7% (41/49) in lesions receiving 40 Gy. There was no statistically significant difference in 1-year LC rate between the 2 fractionation schemes (P-value, 0.553).

CONCLUSIONS

Patients with osseous RCC metastases undergoing 5 fractions of SBRT had favorable LC outcomes. There was no difference in survival or LC between the 40 Gy and 30 Gy treatment arms.

Stereotactic body radiotherapy and tyrosine kinase inhibitors in patients with oligometastatic renal cell carcinoma: a multi-institutional study

PURPOSE

Few studies have determined the viability of stereotactic body radiotherapy (SBRT) and tyrosine kinase inhibitors (TKIs) in the treatment of metastatic renal cell carcinoma (mRCC). We examined the results of RCC patients who had five or fewer lesions and were treated with TKI and SBRT.

METHODS

The clinical data of 42 patients with 96 metastases treated between 2011 and 2020 were retrospectively evaluated. The prognostic factors predicting overall survival (OS) and progression-free survival (PFS) were assessed in uni- and multivariable analyses.

RESULTS

Median follow-up and time between TKI therapy and SBRT were 62.3 and 3.7 months, respectively. The 2‑year OS and PFS rates were 58.0% and 51.3%, respectively, and 2‑year local control rate was 94.1% per SBRT-treated lesion. In univariable analysis, the time between TKI therapy and SBRT and treatment response were significant prognostic factors for OS and PFS. In multivariable analysis, a time between TKI therapy and SBRT of less than 3 months and complete response were significant predictors of better OS and PFS. Only 12 patients (28.6%) had a systemic treatment change at a median of 18.2 months after SBRT, mostly in patients with a non-complete treatment response after this therapy. Two patients (4.8%) experienced grade III toxicity, and all side effects observed during metastasis-directed therapy subsided over time.

CONCLUSION

We demonstrated that SBRT in combination with TKIs is an effective and safe treatment option for RCC patients with ≤ 5 metastases. However, distant metastasis was observed in 60% of the patients, indicating that distant disease control still has room for improvement.

The Emerging Role of Radiation Therapy in Renal Cell Carcinoma

Simple Summary

Stereotactic ablative radiation therapy (SAbR) is a safe and effective local therapy for renal cell cancer (RCC) with emerging and evolving indications. In this review we provide an overview of the evidence to support SAbR for RCC in a variety of clinical settings.

Abstract

Advancements in radiation delivery technology have made it feasible to treat tumors with ablative radiation doses via stereotactic ablative radiation therapy (SAbR) at locations that were previously not possible. Renal cell cancer (RCC) was initially thought to be radioresistant, even considered toxic, in the era of conventional protracted course radiation. However, SAbR has been demonstrated to be safe and effective in providing local control to both primary and metastatic RCC by using ablative radiation doses. SAbR can be integrated with other local and systemic therapies to provide optimal management of RCC patients. We will discuss the rationale and available evidence for the integration and sequencing of SAbR with local and systemic therapies for RCC.

Local Therapy for Oligoprogressive Disease: A Systematic Review of Prospective Trials

OBJECTIVES

The successes of local therapy for oligometastatic cancers cannot be extrapolated to oligoprogressive disease (OPD) because they are distinct clinical entities. Given the limited prospective data on OPD to date, summative analyses are urgently needed.

METHODS

Inclusion criteria for this PRISMA-guided systematic review were as follows. First, only prospective data were included. Second, progression had to have occurred on active/ongoing systemic therapy. Third, the number of progressing areas of disease had to be explicitly listed and ≤5 in number. Fourth, all progressing sites had to undergo local therapy (radiotherapy/surgery/non-radiation ablative procedures).

RESULTS

Eight trials met criteria (summing 290 patients), the vast majority of which utilized stereotactic radiotherapy as the local modality (most commonly, 19-20 Gy in 1 fraction, 27-33 Gy in 3 fractions, or 35-50 Gy in 5 fractions). A study on NSCLC demonstrated that stereotactic radiotherapy improved progression-free survival (PFS) and overall survival compared to historical values with systemic therapy alone. Two additional studies on EGFR-mutated NSCLC also showed acceptable PFS with local therapy, particularly in patients who oligoprogressed on osimertinib. The only randomized trial analyzed herein showed that local therapy improved PFS for NSCLC but not breast cancer. Two trials in castration-resistant prostate cancer illustrated that a substantial proportion of patients did not require any changes in hormonal therapy and/or delayed the need to change systemic therapies. Lastly, two trials of renal cell carcinoma showed high (90-100%) local control and median PFS of 9 months, and potentially a prolonged time to change systemic therapy. Lastly, from all patients in all trials, local therapy was tolerated well, with only 7 instances of grade 3+ toxicities.

CONCLUSIONS

Based on the limited data, local therapy for OPD is safe and yields encouraging short-term preliminary outcomes, but trials with larger sample sizes and longer follow-up are required for more robust conclusions.

The Role of Stereotactic Ablative Body Radiotherapy in Renal Cell Carcinoma

CONTEXT

Stereotactic ablative body radiotherapy (SABR) is an emerging treatment modality for primary and metastatic renal cell carcinoma (RCC).

OBJECTIVE

To review and summarise the evidence on the use of SABR in RCC in a narrative review.

EVIDENCE ACQUISITION

We performed an online search of the PubMed database from January 2000 through December 2021. Studies of SABR/stereotactic radiosurgery (SRS) targeting primary, extracranial, or intracranial metastatic RCC were included.

EVIDENCE SYNTHESIS

Two meta-analyses (including 54 studies), and 13 prospective and 20 retrospective studies were included in this review. In aggregate, SABR for 589 primary RCCs in 575 patients resulted in a local control rate of above 90% with grade 3-4 toxicity of 0-9%. Similarly, the local control rate ranged between 90% and 97% with SRS in 1225 patients with intracranial metastatic RCC. SABR was able to delay systemic therapy for at least 1 yr in 70-90% of oligometastatic RCC patients with grade 3-4 toxicity of <10%. As per the early data, the combination of SABR with systemic therapy for metastatic RCC, such as targeted therapy or immunotherapy, appears safe, feasible, and tolerable.

CONCLUSIONS

We outlined data supporting SABR in the key clinical scenarios of primary and metastatic, including oligometastatic, RCC in lieu of systemic therapy, in combination with systemic therapy, and palliation of brain and spinal metastases.

PATIENT SUMMARY

Stereotactic ablative body radiotherapy (SABR) is a relatively new treatment option in kidney cancer. Here, we review the published literature on the experience of using SABR in kidney cancer. The accumulated evidence demonstrates that SABR can be used safely and effectively to treat selected cases of primary or secondary kidney cancer.

The oligometastatic spectrum in the era of improved detection and modern systemic therapy

Metastases remain the leading cause of cancer-related mortality. The oligometastasis hypothesis postulates that a spectrum of metastatic spread exists and that some patients with a limited burden of metastases can be cured with ablative therapy. Over the past decade, substantial advances in systemic therapies have resulted in considerable improvements in the outcomes of patients with metastatic cancers, warranting re-examination of the oligometastatic paradigm and the role of local ablative therapies within the context of the improved therapeutic responses, shifting patterns of disease recurrence and possible synergy with systemic treatments. Herein, we reframe the oligometastatic phenotype as a dynamic state for which locally ablative, metastasis-directed therapy improves clinical outcomes, including by prolonging survival and increasing cure rates. Important risk factors defining the metastatic spectrum are highlighted that inform both staging and therapy. Finally, we synthesize the literature on combining local therapies with modern systemic treatments, identifying general themes to optimally integrate ablative therapies in this context.

Metastatic Clear Cell Renal Cell Carcinoma to Pancreas and Distant Organs 24 Years After Radical Nephrectomy: A Case Report and Literature Review

Background

Clear cell renal cell carcinoma (CCRCC) is a common urological neoplasm, and even though surgical resection is effective for localized CCRCC, the prognosis of metastatic CCRCC is poor. Currently, there is a paucity of recognized effective therapeutic protocols for metastatic CCRCC.

Case presentation

A 76-year-old Asian man underwent radical left nephrectomy for CCRCC 26 years ago; this patient visited our hospital with abdominal pain due to multiple abdominal metastases 24 years after the nephrectomy. After metastasectomy, he underwent targeted therapy combined with a programmed death receptor-1 (PD-1) inhibitor, and the current imaging results indicate remarkable tumor remission.

Conclusions

Metachronous pancreatic metastasis from CCRCC after nephrectomy is rare, but clinicians and patients should not ignore this possibility. The combination of targeted therapy and immunotherapy can result in satisfactory outcomes in cases where metastatic CCRCC continues to progress despite metastasectomy and targeted therapy. The combination of local and systemic therapy can be an effective therapeutic protocol for metastatic CCRCC, but there is no consensus on suitable therapeutics.

Management of Metastatic Clear Cell Renal Cell Carcinoma: ASCO Guideline

PURPOSE

To provide recommendations for the management of patients with metastatic clear cell renal cell carcinoma (ccRCC).

METHODS

An Expert Panel conducted a systematic literature review to obtain evidence to guide treatment recommendations.

RESULTS

The panel considered peer-reviewed reports published in English.

RECOMMENDATIONS

The diagnosis of metastatic ccRCC should be made using tissue biopsy of the primary tumor or a metastatic site with the inclusion of markers and/or stains to support the diagnosis. The International Metastatic RCC Database Consortium risk criteria should be used to inform treatment. Cytoreductive nephrectomy may be offered to select patients with kidney-in-place and favorable- or intermediate-risk disease. For those who have already had a nephrectomy, an initial period of active surveillance may be offered if they are asymptomatic with a low burden of disease. Patients with favorable-risk disease who need systemic therapy may be offered an immune checkpoint inhibitor (ICI) in combination with a vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor (TKI); patients with intermediate or poor risk should be offered a doublet regimen (no recommendation was provided between ICIs or an ICI in combination with a VEGFR TKI). For select patients, monotherapy with either an ICI or a VEGFR TKI may be offered on the basis of comorbidities. Interleukin-2 remains an option, although selection criteria could not be identified. Recommendations are also provided for second- and subsequent-line therapy as well as the treatment of bone metastases, brain metastases, or the presence of sarcomatoid features. Participation in clinical trials is highly encouraged for patients with metastatic ccRCC.Additional information is available at www.asco.org/genitourinary-cancer-guidelines.

Bone-only oligometastatic renal cell carcinoma patients treated with stereotactic body radiotherapy: a multi-institutional study

PURPOSE

This study aimed to analyze the prognostic factors associated with overall survival (OS) and progression-free survival (PFS) in patients with bone-only metastatic renal cell carcinoma (RCC) who have five or fewer lesions treated with stereotactic body radiotherapy (SBRT).

METHODS

The clinical data of 54 patients with 70 bone metastases undergoing SBRT treated between 2013 and 2020 with a dose of at least 5 Gy per fraction and a biologically effective dose (BED) of at least 90 Gy were retrospectively evaluated.

RESULTS

The majority of lesions were located in the spine (57.4%) and had only one metastasis (64.8%). After a median follow-up of 22.4 months, the 1‑ and 2‑year OS rates were 84.6% and 67.3%, respectively, and median OS was 43.1 months. The 1‑ and 2‑year PFS rates and median PFS were 63.0%, 38.9%, and 15.3 months, respectively. In SBRT-treated lesions, the 1‑year local control (LC) rate was 94.9%. Age, metastasis localization, and number of fractions of SBRT were significant prognostic factors for OS in univariate analysis. In multivariate analysis, patients with spinal metastasis had better OS compared to their counterparts, and patients who received single-fraction SBRT had better PFS than those who did not. No patient experienced acute or late toxicities of grade 3 or greater.

CONCLUSION

Despite excellent LC at the oligometastatic site treated with SBRT, disease progression was observed in nearly half of patients 13 months after metastasis-directed local therapy, particularly as distant disease progression other than the treated lesion, necessitating an effective systemic treatment to improve treatment outcomes.

Phase II Trial of Stereotactic Ablative Radiation for Oligoprogressive Metastatic Kidney Cancer

BACKGROUND

Patients with metastatic renal cell carcinoma (mRCC) treated with systemic therapy sometimes progress at limited sites.The best treatment approach for patients with oligoprogression remains unclear.

OBJECTIVE

To determine the ability of stereotactic ablative radiation (SAbR) to extend ongoing systemic therapy in mRCC patients with oligoprogression.

DESIGN, SETTING, AND PARTICIPANTS

A single-arm phase II clinical trial was conducted at a university medical center and county hospital, including 20 patients with mRCC on first- to fourth-line systemic therapy with three or fewer sites of progression (including new sites) involving ≤30% of all sites.

INTERVENTION

SAbR to oligoprogressing metastases at outset and longitudinally, while radiated sites remain controlled and overall disease oligoprogressive.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary objective was to extend ongoing systemic therapy by >6 mo in >40% of patients. Secondary endpoints included overall survival, toxicity, and patient-reported quality of life.

RESULTS AND LIMITATIONS

Twenty patients were enrolled. Upfront and sequential SAbR was administered to a total of 37 sites. The local control rate was 100%. At a median follow-up of 10.4 mo (interquartile range: 5.8-16.4), SAbR extended the duration of the ongoing systemic therapy by >6 mo in 14 patients (70%, 95% confidence interval [CI]: 49.9-90.1). The median time from SAbR to the onset of new systemic therapy or death was 11.1 mo (95% CI: 4.5-19.3). The median duration of SAbR-aided systemic therapy was 24.4 mo (95% CI: 15.3-42.2). Median overall survival was not reached. One patient developed grade 3 gastrointestinal toxicity possibly related to treatment. There was no significant decline in quality of life. Limitations include nonrandomized design and a small patient cohort.

CONCLUSIONS

SAbR extended the duration of the ongoing systemic therapy for patients with oligoprogressive mRCC without undermining quality of life. These data support the evaluation of SAbR for oligoprogressive mRCC in a prospective randomized clinical trial.

PATIENT SUMMARY

Patients with metastatic kidney cancer on systemic therapy but progressing at limited sites may benefit from focused radiation to progressive sites. Focused radiation was safe and effective, and extended the duration of the ongoing systemic therapy.

Surgical and focal treatment for metastatic renal cell carcinoma: A literature review

Accompanied by the development of systemic therapy for metastatic renal cell carcinoma, the concept of focal treatment, including surgical treatment, has been changing. Although immediate cytoreductive nephrectomy was essentially considered for synchronous metastatic renal cell carcinoma patients, the CARMENA trial and SURTIME trial revealed the negative impact of immediate cytoreductive nephrectomy. Therefore, immediate cytoreductive nephrectomy is currently considered only for a limited number of patients. Besides, deferred cytoreductive nephrectomy seems to have efficacy for overall survival in prior retrospective studies. Two randomized controlled trials, the PROBE trial (NCT04510597) and the NORDIC-SUN trial (NCT03977571), are underway to elucidate deferred cytoreductive nephrectomy. Metastasectomy is also considered in metastatic renal cell carcinoma patients because previous studies demonstrated the overall survival benefit of metastasectomy. However, since all reports were retrospective studies, physicians could exclude the patients who were not expected to show the efficacy of metastasectomy. Therefore, an adequate patient selection for metastasectomy is important. A common factor predicting better overall survival was complete resection. Radiotherapies for metastatic lesions during systemic therapy showed approximately 90% local disease control rate at 1 year. However, no report has demonstrated that radiotherapy improves survival so far. Since surgical and focal treatments for metastatic renal cell carcinoma patients generally have minimal evidence, further investigations are needed.