Stereotactic ablative body radiotherapy for primary kidney cancer (TROG 15.03 FASTRACK II): a non-randomised phase 2 trial

The 2024 State of Science report from the European Organisation for Research and Treatment of Cancer's Radiation Oncology Scientific Council

BACKGROUND

Radiotherapy (RT) is a central pillar of a multimodal cancer treatment approach. The ongoing advances in the fields of RT, imaging technologies, cancer biology, and others yield the potential to refine the use of RT. The European Organisation for Research and Treatment of Cancer (EORTC) hosted a dedicated workshop to identify and prioritize key research questions and to define future RT-based treatment strategies to improve the survival and quality of life of cancer patients.

METHODS

An initial call for relevant RT research topics led to the formation of workgroups to develop these into new clinical research proposals and projects. The EORTC Radiation Oncology Scientific Council (ROSC) State of Science workshop was held in Brussels, Belgium, in February 2024, bringing together EORTC members and international stakeholders to connect and work on the proposals.

RESULTS

Four topics of interest were identified: I) De-escalation of RT, minimizing toxicity while maintaining patients' quality of life, II) Technology-driven RT utilizing advances in treatment techniques, such as spatially fractionated RT to improve outcomes in patients with bulky disease and localized high tumor burden, III) Biology-driven RT, integrating the rapid advances in cancer biology and functional imaging to guide and personalize RT, and IV) New indications adding value and expanding the use of RT.

CONCLUSION

The EORTC ROSC State of Science workshop prioritized clinical questions to be addressed in prospective clinical research projects to advance RT care and improve patient outcomes.

Thermal ablation for local tumor recurrence after previous partial nephrectomy: Perioperative and oncological outcomes

OBJECTIVES

Percutaneous thermal ablation (PTA) has emerged as an alternative to salvage radical nephrectomy (RN) for the treatment of renal cell carcinoma (RCC) local recurrence. We report perioperative and oncological outcomes of patients treated with PTA for RCC local recurrence.

MATERIALS AND METHODS

Twenty-seven patients with on-site recurrence received PTA from 2008 to 2022. Primary endpoints were perioperative outcomes, complications, and readmission rates. Secondary endpoints were on site and out site tumor recurrence. Last, we collected renal function outcomes after PTA.

RESULTS

Median (IQR) treatment time was 75 (63-106) minutes. Intraoperative complications occurred in 1 (3.7%) patient, while postoperative in 2 (7.4%). Three patients (11%) received incomplete ablation, which required in one an adjunctive PTA and in 2 RN. Overall, 4 (16%) patients developed on site recurrence after a median follow-up of 30 (23-43) months: complete local control was achieved with subsequent PTA in 3 patients, while one developed bone metastases and, therefore, no other local treatments were performed. Moreover, 6 (24%) patients developed out-site recurrence after a median follow-up of 16 (10-23) months. Last, median creatinine drop at 1 month and at 1 year after PTA was -0.03 (-0.11 to 0.01) and -0.11 (-0.20 to -0.05), while median eGFR drop was 2 (0-7.65) and 9.5 (5-13.45).

CONCLUSION

PTA is a safe and feasible approach for management of on-site recurrences after PN. Low perioperative complication rates and optimal local cancer control were achieved in most patients, with no significant impairment of residual renal function.

Stereotactic Body Radiation Therapy Alone or in Combination with Immunotherapy in Kidney Cancer: A Systematic Review

BACKGROUND AND OBJECTIVE

Despite its radioresistant reputation, renal cell carcinoma (RCC) is sensitive to high dose per fraction stereotactic ablative body radiotherapy (SABR). As SABR also triggers immunomodulatory effects, a combination of SABR and immunotherapy for RCC might improve patient outcomes. The current systematic review will discuss all prospective studies on SABR alone or combined with immunotherapy.

METHODS

A systematic review was conducted in January 2025 according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement on the PubMed and Cochrane databases. Thirty-eight studies were included in this review.

KEY FINDINGS AND LIMITATIONS

In the primary setting, 15 prospective studies have proved SABR to be a valuable alternative for (partial) nephrectomy for high-risk or medically inoperable patients, with good tolerability and excellent local control. No prospective studies have reported on SABR combined with immunotherapy in nonmetastatic patients. In the oligometastatic setting, two phase 2 trials have investigated SABR in lieu of systemic treatment. This showed encouraging results, with the majority of patients being free from systemic therapy at 1 yr. SABR combined with immunotherapy in the metastatic setting has been investigated in multiple phase 1 and 2 trials, where the most promising option seems to be SABR to multiple-preferentially all-lesions. Cytoreductive SABR and SABR to oligoprogressive lesions combined with immunotherapy are attractive future strategies.

CONCLUSIONS AND CLINICAL IMPLICATIONS

SABR is a valid alternative in localised RCC when (partial) nephrectomy is not an option. In the metastatic setting, several early-phase trials have investigated SABR alone and in combination with immunotherapy, warranting future large, randomised trials.

Stereotactic Body Radiotherapy for Multiple Renal Cell Carcinoma Lesions in a Patient With Polycystic Kidney Disease After Partial Nephrectomy

Renal cell carcinoma (RCC) is the most common malignant tumor of the kidney. Stereotactic body radiotherapy (SBRT) has recently emerged as a promising non-invasive treatment option for patients with localized RCC. However, data on SBRT in cases involving multiple renal lesions and pre-existing chronic kidney disease remain limited. We report a case of a 69-year-old male with a history of polycystic kidney disease and prior partial nephrectomy for RCC, who was found to have four new renal lesions during follow-up. At diagnosis of relapse, the patient was treated with SBRT using Cybernife®. All four lesions were treated simultaneously, with a total dose of 30 Gy in five consecutive fractions. No acute toxicity was observed. At the last follow-up, 29 months after SBRT, the MRI confirmed the stable disease observed at the previous controls. Renal function remained stable throughout the follow-up period. This case supports the use of SBRT as a safe and effective alternative to surgery for patients with multiple RCC lesions and compromised renal function. Even with a reduced dose, SBRT achieved long-term disease control and preservation of renal function suggesting its suitability in selected complex cases.

PSMA-Guided Metastasis-Directed Therapy for Oligometastatic Renal Cell Carcinoma: The Proof-of-Concept PEDESTAL Study

Metastasis-directed therapy (MDT) in oligometastatic renal cell carcinoma (RCC) is typically based on conventional imaging. Prostate-specific membrane antigen (PSMA) PET/CT has shown superiority over conventional imaging. Our objective was to perform a proof-of-concept study to evaluate the efficacy of PSMA-guided MDT in oligometastatic RCC. Methods: A PSMA PET/CT database was queried for oligometastatic RCC patients undergoing MDT from 2014 to 2020. The primary endpoint was progression-free survival. Secondary endpoints included freedom from local progression, freedom from change in systemic therapy strategy, and overall survival. Results: A search of 3,095 PSMA PET/CT scans identified 83 RCC patients and 34 receiving MDT to 60 sites. The median follow-up was 4.1 y. Six patients (18%) had synchronous metastatic disease. The median number of metastases was 1 (interquartile range, 1-2). Common sites included bone (19, 32%) and lung (19, 32%). Radiation therapy was delivered to 56 metastases (93%), including stereotactic ablative body and conventional radiotherapy (38 and 18 metastases, respectively), and 4 (7%) underwent surgery. One-, 3-, and 5-y freedom from local progression was 94% (95% CI, 85%-98%), 85% (95% CI, 69%-94%), and 85% (95% CI, 69%-94%), respectively. One-, 3-, and 5-y overall survival was 88% (95% CI, 71%-95%), 71% (95% CI, 52%-84%), and 64% (95% CI, 45%-79%), respectively. One-, 3-, and 5-y progression-free survival was 47% (95% CI, 30%-63%), 26% (95% CI, 13%-42%), and 8% (95% CI, 2%-22%), respectively. One-, 3-, and 5-y freedom from change in systemic therapy strategy was 76% (95% CI, 57%-87%), 65% (95% CI, 45%-79%), and 43% (95% CI, 19%-65%), respectively. Conclusion: In this proof-of-concept study, PSMA-guided MDT provided durable oncologic outcomes for oligometastatic RCC, even at 5 y. To our knowledge, this study had the first cohort uniformly undergoing PSMA-guided MDT and one of the longest follow-ups of MDT for oligometastatic RCC. With increasing availability, PSMA PET/CT can be rapidly instituted to select patients for MDT and improve outcomes for patients with oligometastatic RCC.

Stereotactic Magnetic Resonance Guided Adaptive Radiation Therapy in One Fraction: A Multicenter, Single-Arm, Phase 2 Trial

PURPOSE

Stereotactic body radiation therapy (SBRT) is an advanced technique that enables precise delivery of radiation directly to a tumor, typically in ≤5 fractions. Single-fraction SBRT for visceral tumors is uncommon, likely related to concerns about risks of geographic tumor miss because of suboptimal cone beam computed tomography scan quality on conventional linear accelerators (linacs). Magnetic resonance (MR) guided linacs are a novel technology offering superior imaging that might facilitate the safe delivery of single-fraction SBRT.

METHODS AND MATERIALS

We conducted a multicenter phase 2 trial of single-fraction SBRT delivered on a 0.35 Tesla MR-linac for primary or metastatic lesions of the lung (30-34 Gy; biologically effective dose [BED10] = 120-149.6 Gy10), liver (35-40 Gy; BED10 = 157.5-200 Gy10), pancreas (25 Gy; BED10 = 87.5 Gy10), adrenal gland (25 Gy10), kidney (25 Gy10), and abdominal/pelvic lymph nodes (25 Gy10). Primary objectives included feasibility and safety. The trial is registered with ClinicalTrials.gov, NCT04939246.

RESULTS

The study accrued 30 patients with 32 lesions at 2 centers in the United States between June 2021 and June 2023. All patients had 1 lesion except for 2 with 2 lesions each. Target locations included lung (34.4%), adrenal gland (28.1%), lymph node (18.8%), liver (15.6%), and pancreas (3.1%). The primary objectives were met; total in-room time was <90 minutes for 87.1% of delivered plans and 1 acute grade 3 adverse event was possibly related to single-fraction SBRT. No late grade 3-to-5 adverse events were observed. One-year local control and overall survival were 96.2% (95% CI, 88.8%-100%) and 86.3% (95% CI, 73.8%-98.8%), respectively.

CONCLUSIONS

This is the first prospective study to demonstrate that MR guided single-fraction SBRT is feasible, safe, and effective for not only tumors in the peripheral lung, but also the abdomen and pelvis. Future studies should clarify patient selection for single- versus multifraction SBRT.

Clinical practice in stereotactic radiotherapy delivery at treatment unit: a practitioner survey and consensus-based recommendations for multidisciplinary professional development

PURPOSE

Stereotactic radiation therapy (SRT) is on the rise around the world. We aimed to provide recommendations to streamline and assess medical practices in SRT delivery at treatment unit, while complying with legal obligations concerning safety.

MATERIALS AND METHODS

We conducted an online closed practice survey for heads of radiotherapy departments both nationally in comprehensive cancer centers and university hospitals throughout France, and internationally. The aim was to obtain a better understanding of how the delivery of SRT at treatment unit was managed across different centers according to experience, and to the machines and repositioning techniques used. Radiation oncologists (ROs) were also asked to assess the difficulties of technical implementation in the department, and whether residents were involved in the validation and delivery of SRT. Differences among countries regarding legislation governing the validation of SRT sessions at treatment unit were also collected. A videoconference was then held to draw up proposals for regulatory changes based on the results obtained. Finally, recommendations were drawn up by the steering committee and approved by heads of radiotherapy departments in comprehensive cancer centers and university hospitals throughout France.

RESULTS

Thirty-five French centers and 15 centers from 14 foreign countries responded to the questionnaire. The most common stereotactic machines were Varian Truebeam STX® (45%) and Cyberknife® (39.2%). The departments had been performing SRT for more than 10 years in 60.5% of cases, and for less than 5 years in 10.1% of cases. A RO validated the SRT fractions at each session in 62.9% of French departments, while in countries outside France RO validation concerned the first fraction only for 35.3% or was performed only in the event of an issue for 23.5%. RO patient positioning validation of SRT fractions were considered as: time-consuming / task-interrupting (80%); having no added value with regards its systematic use (41.8%); and leading to a loss of machine time (33.1%). Most heads of departments would like to see an evolution towards systematic RO validation for the first session, then validation by a radiation therapist (RTT) for all subsequent sessions, leaving open the possibility of RO intervention when required in case of difficulty. We drew up a task delegation procedure to meet these requirements.

CONCLUSION

Comparing the French practice to international ones confirmed the need to develop and harmonize recommendations in terms of patient positioning validation at treatment unit. Regulatory changes incorporating a competence transfer to RTTs, particularly after the empowerment process, is key. However, these changes need to be adapted to the experience of each Center and to that of each RTT, as assessed with clearly established criteria and learning curve.

European Association of Urology Guidelines on Renal Cell Carcinoma: The 2025 Update

BACKGROUND AND OBJECTIVE

The European Association of Urology (EAU) renal cell carcinoma (RCC) guideline panel has updated their evidence-based guidelines and recommendations for the management of RCC. Here we present a summary of the 2025 RCC guidelines updated with standardised methodology to provide reproducible evidence for the management of RCC.

METHODS

For the 2025 update, a literature search was performed covering the period from May 1, 2023 to May 1, 2024 using the Medline, EMBASE, and Cochrane Libraries. The data search focused on meta-analyses, systematic reviews, randomised controlled trials (RCTs), and retrospective or controlled comparator-arm studies. Evidence was synthesised as outlined for all EAU guidelines.

KEY FINDINGS AND LIMITATIONS

Clinical practise recommendations were updated in all chapters of the RCC guidelines on the basis of a structured literature search. The studies included were predominantly retrospective with matched or unmatched cohorts based on single- or multi-institutional data. Several prospective studies and RCTs provided data that resulted in recommendations based on higher levels of evidence. Specifically, updates include new recommendations on stereotactic body radiotherapy for localised RCC, adjuvant therapy, systemic therapy for clear-cell RCC in later lines, other subtypes, and a new chapter on hereditary RCC.

CONCLUSIONS AND CLINICAL IMPLICATIONS

The 2025 RCC guidelines have been updated by a multidisciplinary panel of experts using methodological standards to provide a contemporary evidence base for the management of RCC.

Planning evaluation of stereotactic magnetic resonance-guided online adaptive radiosurgery for kidney tumors close to the organ at risk: is it valuable to wait for good timing to perform stereotactic radiosurgery?

PURPOSE

This study aimed to investigate changes in target coverage using magnetic resonance-guided online adaptive radiotherapy (MRgoART) for kidney tumors and to evaluate the suitable timing of treatment.

MATERIALS AND METHODS

Among patients treated with 3-fraction MRgoART for kidney cancer, 18 tumors located within 1 cm of the gastrointestinal tract were selected. Stereotactic radiosurgery planning with a prescription dose of 26 Gy was performed using pretreatment simulation and three MRgoART timings with an adapt-to-shape method. The best MRgoART plan was defined as the plan achieving the highest percentage of planning target volume (PTV) coverage of 26 Gy. In clinical scenario simulation, MRgoART plans were evaluated in the order of actual treatment. Waiting for the next timing was done when the PTV coverage of 26 Gy did not achieve 95%-99% or did not increase by 5% or more compared to the pretreatment plan.

RESULTS

The median percentages of PTV receiving 26 Gy in pretreatment and the first, second, and third MRgoART were 82% (range, 19%), 63% (range, 7% to 99%), 88% (range, 31% to 99%), and 95% (range, 3% to 99%), respectively. Comparing pretreatment simulation plans with the best MRgoART plans showed a significant difference (p = 0.025). In the clinical scenario simulation, 16 of the 18 planning series, including nine plans with 95%-99% PTV coverage of 26 Gy and seven plans with increased PTV coverage by 5% or more, would be irradiated at a good timing.

CONCLUSION

MRgoART revealed dose coverage differences at each MRgoART timing. Waiting for optimal irradiation timing could be an option in case of suboptimal timing.

Comparative efficacy and safety of ablative therapies in the management of primary localised renal cell carcinoma: a systematic review and meta-analysis

BACKGROUND

Non-invasive and minimally invasive ablative treatments, including stereotactic body radiotherapy (SBRT), radiofrequency ablation, microwave ablation, and cryoablation, have emerged as key treatment options for managing renal cell carcinoma, especially for patients who are unsuitable for surgery. We aimed to compare the clinical efficacy and safety of these emerging treatment methods in patients with localised renal cell carcinoma.

METHODS

In this systematic review and meta-analysis, we searched PubMed (MEDLINE), Embase, and the Cochrane Library for publications between Jan 1, 2000, and March 1, 2024. Eligible articles were observational studies and randomised controlled trials including at least five adult patients (age ≥18 years) with primary and localised renal cell carcinoma treated with SBRT, radiofrequency ablation, microwave ablation, or cryoablation and that reported on local control outcomes. Two reviewers independently screened titles and abstracts and then full texts of eligible studies were independently evaluated by the same reviewers, with disagreements resolved via discussion or consultation with a third reviewer. Summary estimates were extracted from published reports manually using a standardised data extraction form. The primary endpoint was local control rate at 1 year, 2 years, and 5 years after start of treatment. A meta-analysis was conducted using a DerSimonian and Laird model to summarise local control rates. Publication bias was evaluated using funnel plots and Egger's test. We also recorded the frequency and severity of adverse events after treatment on the basis of the Common Terminology Criteria for Adverse Events (version 5.0) and Clavien-Dindo complication index. The study protocol was prospectively registered with PROSPERO, CRD42024511840.

FINDINGS

We identified 6668 records, of which 330 were assessed via full-text review, and 133 were included in our systematic review and meta-analysis. The eligible studies included data for 8910 patients (mean age 67·9 years [SD 7·3], 2518 [31·4%] of 8018 patients with available data were female and 5500 [68·6%] were male). Local control rates for SBRT were 99% (95% CI 97-100; I2=6%) at 1 year, 97% (95-99; I2=0%) at 2 years, and 95% (89-98; I2=42%) at 5 years; for radiofrequency ablation were 96% (94-98; I2=73%) at 1 year, 95% (92-98; I2=77%) at 2 years, and 92% (88-96; I2=78%) at 5 years; for microwave ablation were 97% (95-99; I2=74%) at 1 year, 95% (92-98; I2=77%) at 2 years, and 86% (75-94; I2=66%) at 5 years; and for cryoablation were 95% (93-96; I2=61%) at 1 year, 94% (91-96; I2=69%) at 2 years, and 90% (87-93; I2=74%) at 5 years. The proportion of patients who reported grade 3-4 adverse events was 3% (121 of 3726) after cryoablation, 2% (39 of 2503) after radiofrequency ablation, 1% (22 of 2069) after microwave ablation, and 2% (11 of 612) after SBRT. Risk of bias was moderate in most studies (70 [53%] of 133) and no publication bias was observed.

INTERPRETATION

All investigated ablative methods continue to represent effective treatment choices in renal cell carcinoma, and these findings support multi-disciplinary discussions of these treatment methods, along with surgery and surveillance, to individualise treatment decisions in these patients. Future research should aim to conduct randomised controlled trials across larger patient populations to further elucidate the long-term oncological and survival outcomes associated with these treatments.

FUNDING

None.

Metastasis-directed therapy in oligometastatic and oligoprogressive renal cell carcinoma

PURPOSE OF REVIEW

This review addresses the evolving role of metastasis-directed therapy (MDT) in the management of oligometastatic and oligoprogressive renal cell carcinoma (RCC). With advances in both surgical techniques and stereotactic ablative radiotherapy (SABR), it is timely to explore how MDT can improve patient outcomes in these distinct disease states. The review highlights the potential of MDT to delay systemic therapy and improve quality of life while noting the lack of randomized clinical trial data guiding its use.

RECENT FINDINGS

Recent literature emphasizes the outcomes of MDT, including metastasectomy and SABR, in managing oligometastatic and oligoprogressive RCC. Key studies suggest that MDT may prolong progression-free survival and delay systemic therapy. SABR has demonstrated high local control rates and manageable toxicity, offering a less invasive alternative to surgery. Despite these findings, there remains uncertainty about MDT's long-term impact on overall survival due to the absence of prospective randomized trials.

SUMMARY

MDT holds promise in treating RCC by offering symptom relief, improving quality of life, and potentially delaying systemic therapy. However, the long-term benefits, particularly regarding survival outcomes, remain unclear. Further research, including prospective trials, is needed to better define the role of MDT in clinical practice, particularly in the absence of clear guidelines for patient selection.

Stereotactic Body Radiation Therapy (SBRT) for Renal Cell Carcinoma with Inferior Vena Cava Tumor Thrombus

The prognosis for untreated renal cell carcinoma (RCC) with inferior vena cava tumor thrombus (IVC TT) is poor, and the only curative treatment option is extirpative surgery. However, radical nephrectomy with IVC thrombectomy is associated with high rates of morbidity and mortality. Historically, RCC was considered radioresistant, but it appears to be sensitive to higher doses per fraction. Stereotactic body radiation therapy (SBRT), which delivers high ablative radiation doses to focal targets, has been shown to be an effective treatment option for both non-metastatic and metastatic RCC. Emerging data also suggest its role in the management of RCC with IVC TT. This article reviews the available evidence on the use of SBRT in RCC patients with IVC TT, considering its application as curative, palliative, and neoadjuvant therapy.

Results of Stereotactic Body Radiation Therapy for Primary Renal Cell Carcinoma in a Large Multicenter Series

BACKGROUND AND OBJECTIVE

For inoperable patients, stereotactic body radiation therapy (SBRT) is a noninvasive treatment approach for primary renal cell carcinoma (RCC). We aimed to evaluate local control (LC) of primary RCC treated with SBRT.

METHODS

This multicenter retrospective study involved 16 centers in Australia, France, Italy, and the Netherlands. The primary endpoint was the LC probability, and the secondary endpoints were progression-free survival, overall survival (OS), cumulative incidence of cancer-related deaths, toxicities, and renal function evolution after SBRT.

KEY FINDINGS AND LIMITATIONS

A total of 144 patients, treated between 2008 and 2020, with a median follow-up of 43 mo (interquartile range [IQR], 24.0-81.2), were included. The median age was 76 yr (IQR, 67.0-82.0) and the median tumor size was 4.4 cm (IQR, 3.3-5.6). The median baseline estimated glomerular filtration rate (eGFR) was 60 ml/min/1.73 m2. Of the patients, 40% had mild to moderate eGFR (30-60 ml/min). The two main treatment regimens were 42 Gy in three fractions and 26 Gy in one fraction. The LC probability was 98% at 1 yr (95% confidence interval [CI], 94-99) and 96% (95% CI, 92-99) at 5 yr. The median OS was 58 mo and the cumulative incidence of cancer-related deaths was 8% (95% CI, 3-15) at 5 yr. Seventy-one patients (49%) experienced at least one toxicity, including grade 1 in the majority (32%), grade 2 (14%), and grade 3 (1%). Two patients (1%) underwent dialysis (grade 4). The median eGFR loss was -7 ml/min (IQR, -17; 0) at the last follow-up.

CONCLUSIONS AND CLINICAL IMPLICATIONS

This large series of primary RCC treated with SBRT demonstrates excellent LC and renal function preservation, and is associated with an acceptable toxicity profile. SBRT is an alternative treatment for inoperable patients.

Posterior retroperitoneal adrenalectomy for metastatic disease: a multi-site Australian series

BACKGROUND

Posterior retroperitoneoscopic adrenalectomy (PRA) for isolated adrenal metastasis is minimally invasive, may prolong survival and improve quality of life. The current evidence base is scant.

METHODS

A multi-site retrospective analysis of all cases of PRA for adrenal metastasis between 2011 and 2023, by four high-volume adrenal surgeons was performed. Perioperative morbidity, disease-free and survival outcomes were reported.

RESULTS

Of 51 patients, 34(67%) male, mean age 63 ± 12 years, mean BMI 28; 49 PRAs for adrenal metastatectomy were completed (one abandoned due to tumour unresectability, one conversion to anterior laparoscopic approach) across 11 hospitals (49% public). Primary tumours included: 11 colorectal, 11 renal, 8 lung, 6 hepatocellular, 4 sarcoma, 3 breast, 2 melanoma, 2 ovarian and 1 each of pancreatic, oesophageal, testicular and prostate cancer. There were 12 synchronous (<6 months) and 39 metachronous (>6 months after primary diagnosis) tumours; 21 (42%) left sided, none bilateral. Mean operative time was 95 ± 34 minutes, mean maximal tumour diameter was 34 mm ± 13 mm and median length of hospitalization 1 ± 1 days. There were 8 (16%) complications; 1 ICU admission, 1 re-admission for pneumonia and 6 Clavien-Dindo grade I complications. There were 10 (20%) mortalities and a median overall survival of 29 months (range 7-123, n = 41). Disease recurred in 15 (40%) patients (n = 37), with a median disease-free interval of 18 months (range 1-68). Port site recurrence occurred in 2 patients, both simultaneously with disseminated metastases.

CONCLUSION

In carefully selected patients with adrenal metastases, PRA by high-volume adrenal surgeons has minimal morbidity and short hospitalization. Surgery should be considered prior to local ablation.

Salvage stereotactic ablative body radiotherapy after thermal ablation of primary kidney cancer

OBJECTIVE

To evaluate the effectiveness and safety of salvage stereotactic ablative body radiotherapy (SABR) for recurrent renal cell carcinoma (RCC) after thermal ablation (TA).

MATERIALS AND METHODS

This study was a multi-institutional retrospective analysis of patients with recurrent RCC following TA who received SABR between 2016 and 2020. The primary study outcome was freedom from local failure, evaluated radiographically based on Response Evaluation Criteria in Solid Tumours (RECIST) v1.1. Distant failure, cancer-specific survival (CSS), overall survival (OS), treatment-related toxicity and renal function changes following SABR were the secondary outcomes. The Kaplan-Meier method was used to estimate freedom from local and distant failure, CSS and OS.

RESULTS

Seventeen patients with 18 biopsy-confirmed RCCs were included, with a median (interquartile range [IQR]) age at time of SABR of 75.2 (72.6-68.7) years, a median (IQR) tumour size of 3.5 (1.9-4.1) cm and follow-up (reverse Kaplan-Meier method) of 3.36 (95% confidence interval [CI] 1.6-4.1) years. Six of the 17 patients had a solitary kidney. Five patients had failed repeat TA prior to SABR. The median (IQR) time from TA procedure to SABR was 3.03 (1.5-5.1) years. No patient experienced local progression, with a local control rate of 100%. Four patients, two with baseline metastatic disease, experienced distant progression. The distant progression-free survival, CSS and OS at 3 years were 72.1% (95% CI 51.9%-100%), 92.3% (95% CI 78.9%-100%) and 82.1% (95% CI 62.1%-100%), respectively. The median (IQR) glomerular filtration rate before SABR was 58 (40-71) mL/min, and at last follow-up, it was 48 (33-57) mL/min. No patient experienced grade 3+ toxicity or went on to develop end-stage renal disease.

CONCLUSION

The results showed that SABR appears to be an effective and safe salvage strategy in patients with recurrent RCC following TA.

Stereotactic ablative radiotherapy for primary kidney cancer - An international patterns of practice survey

Purpose

To conduct an international survey of radiation oncologists treating primary renal cell carcinoma (RCC) with SABR to ascertain the general patterns of SABR use, common dose/treatment/follow-up details, and expected outcomes.

Materials and methods

A 51-question survey was created containing the following themes: prevalence and clinical scenarios in which RCC SABR is used, dose-fractionation schedules, treatment delivery details, follow-up/outcome assessments, and implementation barriers. The survey was distributed widely across multiple influential radiation oncology societies and social media, and ran from January to April 2023.

Results

A total of 255 respondents participated, mostly from academic centers within Europe/North America. Of these, 40 % (n = 102) currently offer SABR (50 % having begun within the last 3 years). Common barriers in non-users included lack of referrals by urologists and lack of supportive practice guidelines. Of respondents who do offer SABR, 77 % treat both small (4 cm or less) and large (>4 cm) renal masses. Dose-fractionation strategies varied from 27-52 Gy (3-5 fractions) for multifraction regimens, and 15-34 Gy for single fractions. Apart from treatment for medically inoperable disease, scenarios in which SABR was likely to be offered were for recurrence post surgery/thermal ablation and for oligometastatic kidney lesions. Uncommon scenarios included RCC with renal vein/inferior vena cava thrombosis, and as cytoreductive therapy in metastatic RCC. Expected local control outcomes were generally above 70 %, higher for small versus large renal masses.

Conclusions

SABR is a relatively newer indication for primary RCC, offered by less than 50% of respondents, with both consistent and variable practice patterns observed.

Stereotactic Body Radiation Therapy for Primary Renal Cell Carcinoma: A Case-Based Radiosurgery Society Practice Guide

Traditionally, renal cell carcinoma (RCC) was considered a radioresistant tumor, thereby limiting definitive radiation therapy management options. However, several recent studies have demonstrated that stereotactic body radiation therapy (SBRT) can achieve high rates of local control for the treatment of primary RCC. In the setting of expanding use of SBRT for primary RCC, it is crucial to provide guidance on practical considerations such as patient selection, fractionation, target delineation, and response assessment. This is particularly important in challenging scenarios where a paucity of evidence exists, such as in patients with a solitary kidney, bulky tumors, or tumor thrombus. The Radiosurgery Society endorses this case-based guide to provide a practical framework for delivering SBRT to primary RCC, exemplified by 3 cases. This article explores topics of tumor size and dose fractionation, impact on renal function and treatment in the setting of a solitary kidney, and radiation's role in the management of inferior vena cava tumor thrombus. Additionally, we review existing evidence and expert opinion on target delineation, advanced techniques such as magnetic resonance imaging guided SBRT, and SBRT response assessment.

Long-term Renal Function Outcomes After Stereotactic Ablative Body Radiotherapy for Primary Renal Cell Carcinoma Including Patients with a Solitary Kidney: A Report from the International Radiosurgery Oncology Consortium of the Kidney

BACKGROUND AND OBJECTIVE

Renal function preservation is particularly important following nonoperative treatment of localized renal cell carcinoma (RCC) since patients are often older with medical comorbidities. Our objective was to report long-term renal function outcomes after stereotactic ablative radiotherapy (SABR) including patients with a solitary kidney.

METHODS

Patients with primary RCC treated with SABR with ≥2 yr of follow-up at 12 International Radiosurgery Consortium for Kidney institutions were included. Renal function was measured by estimated glomerular filtration rate (eGFR).

KEY FINDINGS AND LIMITATIONS

In total, 190 patients (56 with a solitary kidney) underwent SABR and were followed for a median of 5.0 yr (interquartile range [IQR]: 3.4-6.8). In patients with a solitary kidney versus bilateral kidneys, pre-SABR eGFR (mean [standard deviation]) was 61.1 (23.2) versus 58.0 (22.3) ml/min (p = 0.32) and the median tumor size was 3.65 cm (IQR: 2.59-4.50 cm) versus 4.00 cm (IQR: 3.00-5.00 cm; p = 0.026). At 5 yr after SABR, eGFR decreased by -14.5 (7.6) and -13.3 (15.9) ml/min (p = 0.67), respectively, and there were similar rates of post-SABR dialysis (3.6% [n = 2/56] vs 3.7% [n = 5/134]). A multivariable analysis demonstrated that increasing tumor size (odds ratio [OR] per 1 cm: 1.57; 95% confidence interval [CI]: 1.14-2.16, p = 0.0055) and baseline eGFR (OR per 10 ml/min: 1.30; 95% CI: 1.02-1.66, p = 0.034) were associated with an eGFR decline of ≥15 ml/min at 1 yr.

CONCLUSIONS AND CLINICAL IMPLICATIONS

With long-term follow-up after SABR, kidney function decline remains moderate, with no observed difference between patients with a solitary kidney and bilateral kidneys. Tumor size and baseline eGFR are dominant factors predictive of long-term renal function decline.

PATIENT SUMMARY

With long-term follow-up, stereotactic ablative radiotherapy (SABR) yields moderate long-term renal function decline and low dialysis rates even in patients with a solitary kidney. SABR thus represents a promising noninvasive, nephron-sparing option for patients with localized renal cell carcinoma.

Upper Urinary Tract Stereotactic Body Radiotherapy Using a 1.5 Tesla Magnetic Resonance Imaging-Guided Linear Accelerator: Workflow and Physics Considerations

Background/Objectives: Advancements in radiotherapy technology now enable the delivery of ablative doses to targets in the upper urinary tract, including primary renal cell carcinoma (RCC) or upper tract urothelial carcinomas (UTUC), and secondary involvement by other histologies. Magnetic resonance imaging-guided linear accelerators (MR-Linacs) have shown promise to further improve the precision and adaptability of stereotactic body radiotherapy (SBRT). Methods: This single-institution retrospective study analyzed 34 patients (31 with upper urinary tract non-metastatic primaries [RCC or UTUC] and 3 with metastases of non-genitourinary histology) who received SBRT from August 2020 through September 2024 using a 1.5 Tesla MR-Linac system. Treatment plans were adjusted by using [online settings] for "adapt-to-position" (ATP) and "adapt-to-shape" (ATS) strategies for anatomic changes that developed during treatment; compression belts were used for motion management. Results: The median duration of treatment was 56 min overall and was significantly shorter using the adapt-to-position (ATP) (median 54 min, range 38-97 min) in comparison with adapt-to-shape (ATS) option (median 80, range 53-235 min). Most patients (77%) experienced self-resolving grade 1-2 acute radiation-induced toxicity; none had grade ≥ 3. Three participants (9%) experienced late grade 1-2 toxicity, potentially attributable to SBRT, with one (3%) experiencing grade 3. Conclusions: We conclude that MR-Linac-based SBRT, supported by online plan adaptation, is a feasible, safe, and highly precise treatment modality for the definitive management of select upper urinary tract lesions.

Current State of Stereotactic Body Radiation Therapy for Genitourinary Malignancies

ABSTRACT

Stereotactic body radiation therapy (SBRT) involves the delivery of high-dose, highly precise radiation therapy to focal sites of gross tumor involvement. Recent advances in radiation planning and image guidance have facilitated rapid growth in the evidence for and use of SBRT, particularly for genitourinary malignancies, where the underlying radiobiology often suggests greater tumor sensitivity to SBRT than to conventionally fractionated radiation. Here, we review the evolution of SBRT for patients with prostate adenocarcinoma and renal cell carcinoma. We discuss state-of-the-art trials, indications, and future directions in the SBRT-based management of both localized and metastatic disease. With rapidly growing enthusiasm and evidence, clinical and translational research efforts on the biology and outcomes of SBRT over the coming decade will be crucial to refining the indications, technical approach, and synergistic combinations of SBRT with highly active systemic therapies and improve the efficacy and quality-of-life outcomes for patients with genitourinary malignancies.

French AFU Cancer Committee Guidelines - Update 2024-2026: Management of kidney cancer

OBJECTIVE

To update the French recommendations for the management of kidney cancer.

METHODS

A systematic review of the literature was conducted for the period from 2014 to 2024. The most relevant articles concerning the diagnosis, classification, surgical treatment, medical treatment, and follow-up of kidney cancer were selected and incorporated into the recommendations. The recommendations have been updated specifying the level of evidence (strong or weak).

RESULTS

Kidney cancer following prolonged occupational exposure to trichloroethylene should be considered an occupational disease. The reference examination for the diagnosis and staging of kidney cancer is the contrast-enhanced thoraco-abdominal CT scan. PET scans are not indicated in the staging of kidney cancer. Percutaneous biopsy is recommended in situations where its results will influence therapeutic decisions. It should be used to reduce the number of surgeries for benign tumors, particularly avoiding unnecessary radical nephrectomies. Kidney tumors should be classified according to the pTNM 2017 classification, the WHO 2022 classification, and the ISUP nucleolar grade. Metastatic kidney cancers should be classified according to IMDC criteria. Surveillance of tumors smaller than 2cm should be prioritized and can be offered regardless of patient age. Robot-assisted laparoscopic partial nephrectomy is the reference surgical treatment for T1 tumors. Ablative therapies and surveillance are options for elderly patients with comorbidities for tumors larger than 2cm. Stereotactic radiotherapy is an option to discuss for treating localized kidney tumors in patients not eligible for other treatments. Radical nephrectomy is the first-line treatment for locally advanced localized cancers. Pembrolizumab is recommended for patients at high risk of recurrence after surgery for localized kidney cancer. In metastatic patients, cytoreductive nephrectomy can be immediate in cases of good prognosis, delayed in cases of intermediate or poor prognosis for patients stabilized by medical treatment, or as "consolidation" in patients with complete or major partial response at metastatic sites after systemic treatment. Surgical or local treatment of metastases can be proposed for single lesions or oligometastases. Recommended first-line drugs for metastatic clear cell renal carcinoma are combinations of axitinib/pembrolizumab, nivolumab/ipilimumab, nivolumab/cabozantinib, and lenvatinib/pembrolizumab. Patients with non-clear cell metastatic kidney cancer should be presented to the CARARE Network and prioritized for inclusion in clinical trials.

CONCLUSION

These updated recommendations are a reference that will enable French and French-speaking practitioners to optimize their management of kidney cancer.

[Practice-changing trials: Urological radiation oncology]

Herein, we provide a non-exhaustive selection of the main clinical trials presented in 2023-2024 related to radiation-oncology used in the treatment of urological cancers including prostate cancer (radiotherapy of localized prostate cancer, post-prostatectomy irradiation, reirradiation, biochemical recurrence following local treatment, radiotherapy for metastatic cancer), muscle invasive bladder cancer and primary kidney cancer.

Primary site stereotactic ablative body radiotherapy in localized, recurrent, and metastatic renal cell carcinoma

Background and purpose

Stereotactic ablative body radiotherapy (SABR) is an effective treatment for localized renal cell carcinoma (RCC). However, the role of primary site SABR for locally recurrent or metastatic RCC is unclear. Here, we report outcomes of primary SABR across a diverse cohort of localized, recurrent, and metastatic RCC patients treated at our institution.

Materials and methods

RCC patients treated with SABR to lesions of the kidney or nephrectomy bed at our institution with at least 6 months of follow-up were included for analysis. Local control, overall survival, and freedom from distant failure were estimated using the Kaplan-Meier method. Estimated glomerular filtration rate (eGFR) was assessed at baseline and following SABR.

Results

Fifty-three patients received primary site SABR. Thirty-seven (70 %) patients had localized RCC, and 16 (30 %) had metastatic RCC. Seven (13 %) had locally recurrent RCC after prior surgery or ablation. The median tumor size was 4.5 cm (IQR 3.7-6.3). At a median follow-up of 23 months (IQR 12-35), 2-year local control was 100 %, and 3-year local control was 94.4 % (95 % CI 84.4 %-100 %). Among patients with initially localized disease, the 2-year freedom from distant failure was 94.6 % (95 % CI 87.6 %-100 %), and the 2-year overall survival was 66.5 % (95 % CI 51.9 %-85.2 %). Twelve (23 %) patients experienced acute grade 1-2 treatment-related toxicity (nausea, vomiting, or small bowel). There were no acute grade 3-4 toxicities. Two (3.8 %) patients developed late grade 3 gastrointestinal toxicity. The median baseline eGFR was 51 mL/min/1.73 m2 (IQR 38-77). At 1-year post-SABR, the median eGFR decline was 5 mL/min/1.73 m2 (IQR -3 to 9). One patient required dialysis following SABR.

Conclusion

This analysis demonstrates excellent local control rates across patients with localized, recurrent, and metastatic RCC treated with SABR. Treatment was associated with minimal eGFR decline.

Stereotactic Body Radiotherapy for Renal Cell Carcinoma-A Review of Use in the Primary, Cytoreductive and Oligometastatic Settings

Renal cell carcinoma (RCC) has been increasing in incidence by around 1.5% per year for several years. However, the mortality rate has been decreasing by 1.6% per year, and this can be attributed to stage migration and improvements in treatment. One treatment modality that has emerged in recent years is stereotactic body radiotherapy (SBRT), which is an advanced radiotherapy technique that allows the delivery of high-dose radiation to the tumor while minimizing doses to the organs at risk. SBRT has developed a role in the treatment of early-stage, oligometastatic and oligoprogressive RCC. In localized disease, phase II trials and meta-analyses have shown that SBRT provides a very high probability of long-term local control with a low risk of severe late toxicity. In oligometastatic (OMD) RCC, the same level of evidence has similarly shown good local control and minimal toxicity. SBRT could also delay the necessity to start or switch systemic treatments. Medical societies have started to incorporate SBRT in their guidelines in the treatment of localized disease and OMD. A possible future role of SBRT involves cytoreduction. It is theorized that SBRT can lower tumor burden and enhance immune-related response, but it cannot be recommended until the results of the phase II trials are published.

Stereotactic Body Radiotherapy (SBRT) for the Treatment of Primary Localized Renal Cell Carcinoma: A Systematic Review and Meta-Analysis

CONTEXT

Surgery is the gold standard for the local treatment of primary renal cell carcinoma (RCC), but alternatives are emerging. We conducted a systematic review and meta-analysis to assess the results of prospective studies using definitive stereotactic body radiotherapy (SBRT) to treat primary localised RCC.

EVIDENCE ACQUISITION

This review was prospectively registered in PROSPERO (CRD42023447274). We searched PubMed, Embase, Scopus, and Google Scholar for reports of prospective studies published since 2003, describing the outcomes of SBRT for localised RCC. Meta-analyses were performed for local control (LC), overall survival (OS), and rates of adverse events (AEs) using generalised linear mixed models (GLMMs). Outcomes were presented as rates with corresponding 95% confidence intervals (95% CIs). Risk-of-bias was assessed using the ROBINS-I tool.

EVIDENCE SYNTHESIS

Of the 2983 records, 13 prospective studies (n = 308) were included in the meta-analysis. The median diameter of the irradiated tumours ranged between 1.9 and 5.5 cm in individual studies. Grade ≥ 3 AEs were reported in 15 patients, and their estimated rate was 0.03 (95%CI: 0.01-0.11; n = 291). One- and two-year LC rates were 0.98 (95%CI: 0.95-0.99; n = 293) and 0.97 (95%CI: 0.93-0.99; n = 253), while one- and two-year OS rates were 0.95 (95%CI: 0.88-0.98; n = 294) and 0.86 (95%CI: 0.77-0.91; n = 224). There was no statistically significant heterogeneity, and the estimations were consistent after excluding studies at a high risk of bias in a sensitivity analysis. Major limitations include a relatively short follow-up, inhomogeneous reporting of renal function deterioration, and a lack of prospective comparative evidence.

CONCLUSIONS

The short-term results suggest that SBRT is a valuable treatment method for selected inoperable patients (or those who refuse surgery) with localised RCC associated with low rates of high-grade AEs and excellent LC. However, until the long-term data from randomised controlled trials are available, surgical management remains a standard of care in operable patients.

Adjuvant treatment for renal cell carcinoma: current status and future

PURPOSE OF REVIEW

Renal cell carcinoma (RCC) is resistant to chemotherapy. Adjuvant interferon and tyrosine kinase inhibitors were ineffective. Immune checkpoint inhibitors (ICIs), however, have shed new hope in this setting. In the current review, updated evidence of adjuvant therapy in RCC is summarized.

RECENT FINDINGS

KEYNOTE-564 demonstrated survival benefits of adjuvant Pembrolizumab in RCC. EAU guidelines now recommend adjuvant pembrolizumab to ccRCC patients at an increased risk of recurrence, as defined in the study. At a median follow-up of 24 months, the disease-free survival (DFS) was significantly longer for the Pembrolizumab group than placebo group [DFS 77.3 vs. 68.1%; hazard ratio for recurrence or death, 0.68; 95% confidence interval (95% CI), 0.53-0.87; P = 0.002]. From its updated analysis, at median follow up of 57.2 months, overall survival (OS) benefit of Pembrolizumab was demonstrated (hazard ratio for death, 0.62; 95% CI, 0.44-0.87; P = 0.005). A number of other adjuvant ICI trials have though been negative.

SUMMARY

Pembrolizumab is currently the only adjuvant therapy for RCC showing survival benefits, amid a number of negative trials on adjuvant immunotherapy. Currently, there is no role for adjuvant tyrosine-kinase inhibitors and radiotherapy for RCC. Meanwhile, a multidisciplinary approach and shared decision-making should be adopted.

Durable Local Control With Preserved Renal Function for Stereotactic Body Radiotherapy in Cryoablation-Refractory Clear Cell Renal Carcinoma

Renal cell carcinoma (RCC) is the most common type of kidney cancer, accounting for most renal cancers. Oligoprogressive RCC (OP-RCC) describes metastatic RCC wherein one or a few metastatic sites continue to progress, while the majority of metastatic sites are stable on systemic therapy. Treatment options for the primary site for OP-RCC include cytoreductive nephrectomy, stereotactic body radiation therapy (SBRT), or ablative techniques, although there is no currently agreed-upon standard for treatment. This report describes a 76-year-old male with OP-RCC who was treated with salvage SBRT after failing cytoablation therapy. A review of the current literature on SBRT as a treatment option for OP-RCC is presented and discussed. This case demonstrates that SBRT may be a viable salvage treatment option for patients with OP-RCC that provides good local disease control while preserving long-term renal function.

Dose prescription for stereotactic body radiotherapy: general and organ-specific consensus statement from the DEGRO/DGMP Working Group Stereotactic Radiotherapy and Radiosurgery

PURPOSE AND OBJECTIVE

To develop expert consensus statements on multiparametric dose prescriptions for stereotactic body radiotherapy (SBRT) aligning with ICRU report 91. These statements serve as a foundational step towards harmonizing current SBRT practices and refining dose prescription and documentation requirements for clinical trial designs.

MATERIALS AND METHODS

Based on the results of a literature review by the working group, a two-tier Delphi consensus process was conducted among 24 physicians and physics experts from three European countries. The degree of consensus was predefined for overarching (OA) and organ-specific (OS) statements (≥ 80%, 60-79%, < 60% for high, intermediate, and poor consensus, respectively). Post-first round statements were refined in a live discussion for the second round of the Delphi process.

RESULTS

Experts consented on a total of 14 OA and 17 OS statements regarding SBRT of primary and secondary lung, liver, pancreatic, adrenal, and kidney tumors regarding dose prescription, target coverage, and organ at risk dose limitations. Degree of consent was ≥ 80% in 79% and 41% of OA and OS statements, respectively, with higher consensus for lung compared to the upper abdomen. In round 2, the degree of consent was ≥ 80 to 100% for OA and 88% in OS statements. No consensus was reached for dose escalation to liver metastases after chemotherapy (47%) or single-fraction SBRT for kidney primaries (13%). In round 2, no statement had 60-79% consensus.

CONCLUSION

In 29 of 31 statements a high consensus was achieved after a two-tier Delphi process and one statement (kidney) was clearly refused. The Delphi process was able to achieve a high degree of consensus for SBRT dose prescription. In summary, clear recommendations for both OA and OS could be defined. This contributes significantly to harmonization of SBRT practice and facilitates dose prescription and reporting in clinical trials investigating SBRT.

CT-Guided Online Adaptive Radiotherapy Delivered via Personalized Ultrafractionated Stereotactic Adaptive Radiotherapy (PULSAR) for a Bulky Thoracic and Abdominal Mass in Oligometastatic Renal Cell Carcinoma

In the context of oligometastatic renal cell carcinoma (RCC), local treatment with stereotactic body radiotherapy (SBRT) may improve oncologic outcomes. However, the location and size can often pose a technical challenge in standard SBRT delivery, and the dose is potentially limited by nearby organs at risk (OARs). Online adaptive radiotherapy (oART) improves radiation delivery by personalizing high-dose fractions to account for daily stochastic variations in patient anatomy or setup. The oART process aims to maximize tumor control and enhances precision by tailoring to a more accurate representation of a patient in near-real time. The proceeding re-optimization can mitigate the uncertainty inherent in the traditional radiation delivery workflow and precludes the need for larger margins that account for anatomical variations and setup errors. Here, we describe a case of oligometastatic RCC with a bulky (>300 cm3) pleural-based left lower lobe mass extending into the upper abdomen treated via personalized ultrafractionated stereotactic adaptive radiotherapy (PULSAR). Three fractions were delivered four weeks apart allowing for tumor shrinkage of these bulky lesions, and oART permitted on-table adaptation of the plan without traditional re-simulation and re-planning required during off-line adaptive radiotherapy. The plan was designed for the Ethos linear accelerator (Varian Medical Systems, Inc., Palo Alto, CA, USA). The prescription dose was 36 Gray (Gy) in three fractions, and the adapted plan was selected in each treatment over the scheduled plan due to better target coverage and reversal of OAR dose violations. The adapted plan met all OAR dose constraints, and it achieved higher target coverage in the first two PULSAR fractions compared to the scheduled plan. In the third fraction, the cumulative point dose was approaching the maximum heart tolerance, and target coverage was accordingly compromised based on clinical judgment. There was evidence of tumor regression throughout the course of treatment, and the patient did not develop any significant radiation-related toxicities. Follow-up imaging has demonstrated the overall stable size of her lesion without any evidence of disease progression. Our case reflects the benefit of adaptive SBRT delivery to a bulky mass near multiple OARs in the setting of oligometastatic RCC. The adapted plan allowed for prioritization of critical structures on a fraction-by-fraction basis while preserving the therapeutic intent of SBRT. Further integration of advanced imaging techniques, optimal disease-specific systemic immunotherapies or targeted therapies, and refinement of patient selection will be crucial in identifying which patients would most benefit from an adaptive approach.

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.

Stereotactic body radiation therapy for primary renal cell carcinoma: A review on behalf of the CC-AFU

INTRODUCTION

The incidence of localized renal cell carcinoma (RCC) is on the rise among individuals aged 70 and older. While the gold standard for treatment remains surgical resection, some elderly and frail patients with comorbidities are not eligible for this procedure. In selected cases, percutaneous thermal ablation, such as cryotherapy, microwave and radiofrequency, offers less invasive options. General anesthesia is sometimes necessary for such treatments, but most of the procedures can be conducted using mild or deep conscious sedation. This approach is preferably recommended for small cT1a tumors situated at a distance from the renal hilum and/or ureter. Active surveillance remains an alternative in the case of small low grade RCC although it may induce anxiety in certain patients. Recent research has highlighted the potentials of stereotactic ablative body radiotherapy (SABR) as a noninvasive, well-tolerated, and effective treatment for small renal tumors. This narrative review aims to explore recent advances in SABR for localized RCC, including appropriate patient selection, treatment modalities and administration, as well as efficacy and tolerance assessment.

MATERIAL AND METHODS

We conducted a literature review using the terms [kidney cancer], [renal cell carcinoma], [stereotactic radiotherapy], [SBRT], and [SABR] in the Medline, PubMed, and Embase databases, focusing on prospective and relevant retrospective studies published in English.

RESULTS

Studies report local control rates ranging from 70% to 100% with SABR, highlighting its efficacy in treating RCC. The decline in glomerular filtration rate (GFR) is approximately -5 to -17mL/min over the years following SABR. Common toxicities are rare, primarily CTCAE grade 1, include fatigue, nausea, chest or back pain, diarrhea, or gastritis.

CONCLUSION

Stereotactic ablative body radiotherapy (SABR) may be considered as a viable option for patients with localized RCC who are not suitable candidates for surgery with a high local control rate and a favorable safety profile. This approach should be discussed in a multidisciplinary meeting and results from ongoing clinical trials are awaited.

LEVEL OF EVIDENCE: 5