Stereotactic Ablative Radiation (SAbR) for Oligometastatic RCC

Towards a Consensus on the Management of Metastatic Renal Cell Carcinoma: Insights from a European Delphi Study

BACKGROUND AND OBJECTIVE

Management of metastatic renal cell carcinoma (mRCC) remains complex despite clinical guidelines. The aim of this Delphi study was to achieve consensus among RCC experts on the definition, diagnosis, and first-line treatments for mRCC.

METHODS

Between May 2023 and April 2024, 14 experts from ten European countries completed two Delphi rounds of a 51-item questionnaire covering four topics: (1) oligometastatic RCC; (2) first-line treatment for metastatic clear-cell RCC; (3) treatment duration for metastatic clear-cell RCC; and (4) treatment of non-clear-cell RCC. Agreement was scored as absent/poor (<50%), fair (50-74%), or consensus (≥75%).

KEY FINDINGS AND LIMITATIONS

Consensus was reached for 12 of 51 items (24%) in the first round and 25 of 49 items (51%) by the study end. Notably, 79% of experts defined oligometastatic RCC as five or fewer metastases and agreed that it typically does not require immediate systemic treatment. All experts (100%) emphasized the importance of clinical performance status in guiding treatment for metastatic clear-cell RCC, with 86% agreeing on additional factors such as International Society of Urological Pathology grade and sarcomatoid features. Nivolumab plus cabozantinib was favored for patients with brain or bone metastases (93% and 86% agreement, respectively), while there was fair agreement on pembrolizumab plus lenvatinib for patients with liver metastases. In addition, 71% supported stopping immune checkpoint inhibitors after 2 yr, while 86% agreed on the undefined duration of tyrosine kinase inhibitor therapy.

CONCLUSIONS AND CLINICAL IMPLICATIONS

This Delphi study offers insights into mRCC management, and highlights the importance of multidisciplinary discussions for this challenging disease.

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.

The Role of Surgery in Metastatic Renal Cell Carcinoma in 2024

Renal cell carcinoma (RCC) is the most common solid tumour of the kidney and accounts for 3% of all cancers. While immune checkpoint inhibitor (ICI)-based combination therapies have emerged as the first-line treatment for metastatic renal cell carcinoma (mRCC), the role of surgery has become more controversial. This review summarizes the evidence, current role and future directions for surgery in mRCC management. The survival benefits of cytoreductive nephrectomy (CN) shown in the interferon era have encountered increasing disputes in the tyrosine-kinase inhibitor (TKI) and ICI eras. Undoubtedly, several systematic reviews based on retrospective data have supported the survival benefits of CN. Nevertheless, 2 prospective trials, CARMENA and SURTIME, proved that sunitinib as the upfront therapy resulted in noninferior survival outcomes compared with immediate CN. The safety of CN does have solid ground in the current literature. Several studies suggested that preoperative systemic therapy did not seem to aggravate perioperative complications or mortality rates, in experienced centres. Meticulous patient selection is the rule of thumb in the modern management of mRCC patients. The limitations of the existing prognostication models, however, must be acknowledged. Clinicians should adopt a multidisciplinary and holistic approach and contemplate all patient, disease, surgeon and socio-economical factors, before deciding who should go for surgery. The advent of metastasis-directed therapy (MDT) and survival benefits of adjuvant pembrolizumab shown in the oligometastatic subgroup, where complete metastasectomy could be achieved (M1 NED), calls for more comparative studies against upfront ICI combinations. In summary, CN brings survival benefits to well-selected good-to-intermediate-risk mRCC patients. Individualized and multidisciplinary care is pivotal.

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.

The Pancreas as a Target of Metastasis from Renal Cell Carcinoma: Is Surgery Feasible and Safe? A Single-Center Experience in a High-Volume and Certified Pancreatic Surgery Center in Germany

Background: Secondary malignant tumors of the pancreas are rare, representing 2-5% of all pancreatic malignancies. Nevertheless, the pancreas is one of the target organs in cases of metastatic clear cell renal cell carcinoma (CCRCC). Additionally, recurrent metastasis may occur. Surgical resection remains the best and prognostically most favorable therapeutic option in cases of solitary pancreatic metastasis. Aim: To review retrospectively the clinical tumor registry of the University Hospital of Magdeburg, Germany, for this rare entity, performing a clinical systematic single-center observational study (design). Methods: A retrospective cohort analysis of consecutive patients who had undergone pancreatic resection for metastatic CCRC was performed in a single high-volume certified center for pancreatic surgery in Germany from 2010 to 2022. Results: All patients (n = 17) included in this study had a metachronous metastasis from a CCRCC. Surgery was performed at a median time interval of 12 (range, 9-16) years after primary resection for CCRCC. All 17 patients were asymptomatic at the time of diagnosis. Three of those patients (17.6%) presented with recurrent metastasis in a different part of the pancreas during follow-up. In a total of 17 patients, including those with recurrent disease, a surgical resection was performed; Pancreatoduodenectomy was performed in 6 patients (35%); left pancreatectomy with splenectomy was performed in 7 patients (41%). The rest of the patients underwent either a spleen-preserving pancreatic tail resection, local resection of the tumor lesion or a total pancreatectomy. The postoperative mortality rate was 6%. Concerning histopathological findings, seven patients (41%) had multifocal metastasis. An R0 resection could be achieved in all cases. The overall survival at one, three and five years was 85%, 85% and 72%, respectively, during a median follow-up of 43 months. Conclusions: CCRC pancreatic metastases can occur many years after the initial treatment of the primary tumor. Surgery for such a malignancy seems feasible and safe; it offers very good short- and long-term outcomes, as indicated. A repeated pancreatic resection can also be safely performed.

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.

A Neurosurgical Perspective on Brain Metastases from Renal Cell Carcinoma: Multi-Institutional, Retrospective Analysis

BACKGROUND

While acknowledging the generally poor prognostic features of brain metastases from renal cell carcinoma (BM RCC), it is important to be aware of the fact that neurosurgery still plays a vital role in managing this disease, even though we have entered an era of targeted therapies. Notwithstanding their initial high effectiveness, these agents often fail, as tumors develop resistance or relapse.

METHODS

The authors of this study aimed to evaluate patients presenting with BM RCC and their outcomes after being treated in the Neurosurgical Department of Clinical Emergency Hospital "Bagdasar-Arseni", and the Neurosurgical Department of the National Institute of Neurology and Neurovascular Diseases, Bucharest, Romania. The study is based on a thorough appraisal of the patient's demographic and clinicopathological data and is focused on the strategic role of neurosurgery in BM RCC.

RESULTS

A total of 24 patients were identified with BM RCC, of whom 91.6% had clear-cell RCC (ccRCC) and 37.5% had a prior nephrectomy. Only 29.1% of patients harbored extracranial metastases, while 83.3% had a single BM RCC. A total of 29.1% of patients were given systemic therapy. Neurosurgical resection of the BM was performed in 23 out of 24 patients. Survival rates were prolonged in patients who underwent nephrectomy, in patients who received systemic therapy, and in patients with a single BM RCC. Furthermore, higher levels of hemoglobin were associated in our study with a higher number of BMs.

CONCLUSION

Neurosurgery is still a cornerstone in the treatment of symptomatic BM RCC. Among the numerous advantages of neurosurgical intervention, the most important is represented by the quick reversal of neurological manifestations, which in most cases can be life-saving.

Factors affecting local control of bone metastases from radioresistant tumors treated with palliative external beam radiotherapy

BACKGROUND

This study aimed to evaluate the factors that affect the local control (LC) of bone metastases from radioresistant carcinomas (renal cell carcinoma, hepatocellular carcinoma [HCC], and colorectal carcinoma [CRC]) treated with palliative external-beam radiotherapy (EBRT).

METHODS AND MATERIALS

Between January 2010 and December 2020, 211 bone metastases in 134 patients were treated with EBRT in two hospitals (a cancer center and university hospital). Based on follow-up CT, these cases were reviewed retrospectively to evaluate LC at the EBRT site.

RESULTS

The median EBRT dose (BED10) was 39.0 Gy (range, 14.4-66.3 Gy). The median follow-up time of the imaging studies was 6 months (range, 1-107 months). The 0.5-year overall survival and LC rates of the EBRT sites were 73% and 73%, respectively. Multivariate analysis revealed that the primary sites (HCC/CRC), low EBRT dose (BED10) (≤ 39.0 Gy), and non-administration of post-EBRT bone modifying agents (BMAs) and/or antineoplastic agents (ATs) were statistically significant factors that negatively affected the LC of EBRT sites. In the absence of BMAs or ATs, the EBRT dose (BED10) escalation from 39.0 Gy improved the LC of EBRT sites. Based on ATs administration, the LC of EBRT sites was significantly affected by tyrosine kinase inhibitors and/or immune checkpoint inhibitors.

CONCLUSIONS

Dose escalation improves LC in bone metastases from radioresistant carcinomas. Higher EBRT doses are needed to treat patients for whom few effective systemic therapies remain available.

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.

The Efficacy and Safety of Transarterial Chemoembolization Plus Iodine 125 Seed Implantation in the Treatment of Hepatocellular Carcinoma With Oligometastases: A Case Series Reports

Background

Patients with different primary tumor oligometastases can obtain survival benefits from external radiotherapy. The study was conducted to explore the efficacy and safety of transarterial chemoembolization (TACE) plus iodine 125 seed (TACE-I) implantation for hepatocellular carcinoma (HCC) oligometastases.

Methods

187 patients who received TACE-I in our institution were retrospectively reviewed from January 2014 to December 2018. Thirty-two patients were included in the analysis. The primary endpoints of the study were overall survival (OS) and progression-free survival (PFS). The secondary endpoints of the study were tumor response and PFS of the metastatic sites.

Results

The median OS (mOS) of patients was 18 months, and the median PFS (mPFS) was 7 months. The objective response rate (ORR) and disease control rate (DCR) of patients three months after receiving TACE-I were 34.4% and 71.9%, respectively. The ORR and DCR of patients for metastatic sites were 50% and 81.3%, respectively. The mPFS of patients for metastatic sites was 14 months. The univariable and multivariable regression analyses indicated that the ECOG score was an independent predictor for mOS and mPFS. The number of iodine seeds and ECOG scores were independent predictors for mPFS for metastatic sites. After patients received TACE-I, the most common adverse events were abdominal pain, fever, and appetite. The adverse events of patients were relieved after receiving symptomatic treatments.

Conclusion

Iodine 125 seed implantation may be an effective and safe treatment for patients with hepatocellular carcinoma with oligometastasis, thereby providing a new selective option for these patients.

Stereotactic Body Radiation Therapy in Patients with Oligometastatic Disease: Clinical State of the Art and Perspectives

Stereotactic body radiation therapy (SBRT) is a form of radiation therapy (RT) in which a small number of high doses of radiation are delivered to a target volume using highly sophisticated equipment. Stereotactic body radiation therapy is crucial in two cancer stages: early primary cancer and oligometastatic disease, with the goal of inducing complete cancer remission in both. This treatment method is commonly used to treat a variety of disease types. Over the years, a growing body of clinical evidence on the use of SBRT for the treatment of primary and metastatic tumors has accumulated, with efficacy and safety demonstrated in randomized clinical trials. This article will review the technical and clinical aspects of SBRT according to disease type and clinical indication.

[Imaging of oligometastatic disease in selected urologic cancers]

BACKGROUND

Local treatment of the primary or metastatic sites in urologic malignancies is promising when compared to systemic therapy alone, leading to the definition of a potentially curative oligometastatic state.

OBJECTIVES

Comparison of imaging modalities regarding local and metastatic tumor sites in urologic cancers.

METHODS

Review of comparative trials addressing quality criteria of imaging modalities.

RESULTS

Depending on primary tumor and metastatic site, conventional imaging modalities such as computer tomography (CT) and bone scintigraphy still represent the standard of care in Germany. Due to superior quality criteria, hybrid-imaging techniques were widely adopted for oncological staging and particular due to the new PSMA-ligand (PSMA-PET/CT) in prostate cancer imaging. The development of new radioisotopes as well as their clinical application remains a focus of current research.

CONCLUSIONS

High-quality diagnostic imaging modalities lay the groundwork for a precise definition of an oligometastatic state. By enabling treatment of the entire tumor burden, a delay of systemic therapy, longer progression-free survival, or even curative treatment may become achievable.