TROG 15.03/ANZUP International Multicenter Phase II Trial of Focal Ablative STereotactic RAdiotherapy for Cancers of the Kidney (FASTRACK II)

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.

MR-LINAC, a New Partner in Radiation Oncology: Current Landscape

Technological advances in radiation oncology are oriented towards improving treatment precision and tumor control. Among these advances, magnetic-resonance-image-guided radiation therapy (MRgRT) stands out, with technological advances to deliver targeted treatments adapted to a tumor's anatomy on the day while minimizing incidental exposure to organs at risk, offering an unprecedented therapeutic advantage compared to X-ray-based IGRT delivery systems. This new technology changes the traditional workflow in radiation oncology and requires an evolution in team coordination to administer more precise treatments. Once implemented, it paves the way for newer indication for radiation therapy to safely deliver higher doses than ever before, with better preservation of healthy tissues to optimize patient outcomes. In this narrative review, we assess the technical aspects of the novel linear accelerators that can deliver MRgRT and summarize the available published experience to date, focusing on oncological results and future challenges.

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.