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

Defining oligometastatic state in uro-oncological cancers

PURPOSE OF REVIEW

Oligometastatic tumors illustrate a distinct state between localized and systematic disease and might harbor unique biologic features. Moreover, these tumors represent a different clinical entity, with a potential of long-term disease control or even cure, therefore they receive growing attention in the field of urologic oncology.

RECENT FINDINGS

Currently, there is no consensus on the definition of oligometastatic prostate cancer, most experts limit it to a maximum of three to five lesions and involvement of no more than two organs, excluding visceral metastases. Quality data on oligometastatic bladder cancer is scarce, however, a consensus of experts defined it as a maximum of three metastatic lesions, either resectable or suitable for stereotactic therapy, without restrictions to the number of organs involved. As for kidney cancer, a maximum number of five metastases, without limitations to the location are defined as oligometastatic, with an important implication of timing of developing metastases since diagnosis of the primary tumor.

SUMMARY

Defining oligometastatic state among urological tumors reflecting their distinct biological and clinical behavior is crucial to establish a sound framework for future clinical trials, and to facilitate guideline and policy formulation for improved patient care. Advancements in molecular imaging are expected to transform the field of oligometastatic urologic tumors in the future.

Paradigm Shifting Research: Key Studies in Urologic Oncology

BACKGROUND

Genitourinary malignancies have a substantial impact on men and women in the USA as they include three of the ten most common cancers (prostate, renal, and bladder). Other urinary tract cancers are less common (testis and penile) but still have profound treatment implications related to potential deficits in sexual, urinary, and reproductive function. Evidenced-based practice remains the cornerstone of treatment for urologic malignancies.

METHODS

The authors reviewed the literature in consideration of the four top articles influencing clinical practice in the prior calendar year, 2022.

RESULTS

The PROTECT trial demonstrates favorable 15-years outcomes for active monitoring of localized prostate cancer. The SEMS trial establishes retroperitoneal lymph node dissection as a viable option for patients with seminoma of the testis with limited retroperitoneal lymph node metastases. CheckMate 274 supports adjuvant immunotherapy following radical cystectomy for muscle-invasive bladder cancer with a high risk of recurrence. Data reported from the IROCK consortium reinforce stereotactic ablative radiotherapy as an option for localized renal cell carcinoma.

CONCLUSION

The care for patients with urologic cancers has been greatly improved through advances in surgical, medical, and radiation oncologic treatments realized through prospective randomized clinical trials and large multicenter collaborative groups.

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.

Treatment Landscape of Renal Cell Carcinoma

OPINION STATEMENT

The treatment landscape of renal cell carcinoma (RCC) has evolved significantly over the past three decades. Active surveillance and tumor ablation are alternatives to extirpative therapy in appropriately selected patients. Stereotactic body radiation therapy (SBRT) is an emerging noninvasive alternative to treat primary RCC tumors. The advent of immune checkpoint inhibitors (ICIs) has greatly improved the overall survival of advanced RCC, and now the ICI-based doublet (dual ICI-ICI doublet; or ICI in combination with a vascular endothelial growth factor tyrosine kinase inhibitor, ICI-TKI doublet) has become the standard frontline therapy. Based on unprecedented outcomes in the metastatic with ICIs, they are also being explored in the neoadjuvant and adjuvant setting for patients with high-risk disease. Adjuvant pembrolizumab has proven efficacy to reduce the risk of RCC recurrence after nephrectomy. Historically considered a radioresistant tumor, SBRT occupies an expanding role to treat RCC with oligometastasis or oligoprogression in combination with systemic therapy. Furthermore, SBRT is being investigated in combination with ICI-doublet in the advanced disease setting. Lastly, given the treatment paradigm is shifting to adopt ICIs at earlier disease course, the prospective studies guiding treatment sequencing in the post-ICI setting is maturing. The effort is ongoing in search of predictive biomarkers to guide optimal treatment option in RCC.

Adjuvant immunotherapy for locally advanced renal cell carcinoma

INTRODUCTION

Locally advanced renal cell carcinoma (RCC) presents a therapeutic challenge due to 20-40% relapse risk post-nephrectomy. There has been substantial interest in utilizing immunotherapy interrupting the PD-1/PD-L1 axis in the perioperative space, especially in the adjuvant setting, in order to minimize such risk.

AREAS COVERED

We conducted a PubMed search using the terms 'adjuvant' and 'RCC.' We begin by examining landmark studies in the postoperative space for locally advanced RCC, with special emphasis on immunotherapeutic biologics. Important considerations are outlined in an effort to explain the conflicting data on the benefit of adjuvant immunotherapy as well as to adequately assess the magnitude of potential benefit of the recently approved adjuvant pembrolizumab. Relevant contemporary challenges and opportunities as well as future directions of the field are also discussed.

EXPERT OPINION

Systemic immunotherapy with monoclonal antibodies targeting the PD-1/PD-L1 axis likely holds promise, either alone or potentially in combinations, in minimizing recurrence risk for locally advanced RCC. However, emphasis on post-protocol care, robust endpoint selection, and continued work and validation on predictive biomarkers are needed to confidently select those patients that may benefit the most and minimize biologic and financial toxicity.