Does the onset of bone metastasis in sunitinib-treated renal cell carcinoma patients impact the overall survival?

Evolving cancer-niche interactions and therapeutic targets during bone metastasis

Many cancer types metastasize to bone. This propensity may be a product of genetic traits of the primary tumour in some cancers. Upon arrival, cancer cells establish interactions with various bone-resident cells during the process of colonization. These interactions, to a large degree, dictate cancer cell fates at multiple steps of the metastatic cascade, from single cells to overt metastases. The bone microenvironment may even influence cancer cells to subsequently spread to multiple other organs. Therefore, it is imperative to spatiotemporally delineate the evolving cancer-bone crosstalk during bone colonization. In this Review, we provide a summary of the bone microenvironment and its impact on bone metastasis. On the basis of the microscopic anatomy, we tentatively define a roadmap of the journey of cancer cells through bone relative to various microenvironment components, including the potential of bone to function as a launch pad for secondary metastasis. Finally, we examine common and distinct features of bone metastasis from various cancer types. Our goal is to stimulate future studies leading to the development of a broader scope of potent therapies.

[Synchronous oligometastatic renal cell carcinoma-what is the role of surgery?]

BACKGROUND

Long-term remission can be achieved by surgery in patients with metastatic renal cell carcinoma (mRCC), without chronic toxicity due to systemic treatment. Data on metastasectomy are mostly based on observations of metachronous metastasis. However, it is unclear whether patients with synchronous oligometastasis may also benefit from surgery alone as an alternative to highly effective systemic treatment combined with resection of the primary tumor.

MATERIALS AND METHODS

The authors performed an unstructured literature search in PubMed including systematic reviews and meta-analyses. Results are discussed in regard of the current data and clinical practice.

RESULTS AND DISCUSSION

Although there is no uniform definition for oligometastasis in mRCC, cytoreductive nephrectomy in selected patients seems to be mandatory before metastasectomy is performed in primary oligometastatic RCC. In particular, in those patients with oligometastasis of the lung, bone, central nervous system, liver, adrenal gland, and thyroid, metastasectomy appears to be an important therapeutic option. Ultimately, among the therapeutic options, surgery is also an important therapeutic approach in primary oligometastatic mRCC. A balanced consideration between surgery, other local therapies, and modern systemic treatment demands interdisciplinary decision-making that takes into account the patients' preference.

Does Bone-targeted Therapy Benefit Patients with Metastatic Renal Cell Carcinoma?

INTRODUCTION: In metastatic renal cell carcinoma (mRCC), the bone is the second most common site of metastasis and is associated with increased morbidity and poorer quality of life. Bone-targeted therapies (BTTs) such as denosumab and zoledronic acid may prevent skeletal-related events (SREs). However, the benefit of BTTs in combination with tyrosine kinase inhibitors (TKIs) remains unclear. METHODS: We performed a retrospective chart review at the Urologic Cancer Centre for Research and Innovation. Patients with mRCC were included if they had bone metastases treated with TKIs between 2010 and 2017. Our primary outcome was overall survival (OS), defined as the time elapsed from clinical diagnosis of mRCC to death, and modelled using the Kaplan–Meier method. Secondary outcomes included the median time to SRE and the analysis of prognostic factors of OS using Cox proportional hazards regression. RESULTS: In total, 230 patients with mRCC were identified; of which, 46 had bone metastases treated with TKIs and were included in the study (TKI-only, n = 37; TKI + BTT, n = 9). In the TKI + BTT cohort, patients received either denosumab (n = 5) or zoledronic acid (n = 4). At the time of analysis, 63% of patients were deceased. We observed an OS trend favouring the TKI + BTT cohort (13.8 months [95% confidence interval {CI}: 12.3–15.2] vs. 29.6 months [95% CI: 7.2–51.9], hazard ratio [HR]: 1.66 (95% CI: 0.62–4.45), P = 0.31). When patients in the TKI + BTT cohort were stratified by type of therapy (denosumab or zoledronic acid), the median time to SRE was similar between the groups (4.2 months [95% CI: 2.28–6.14] vs. 2.2 months [95% CI: not available], P = 0.71]. On univariate or multivariate analysis, it was found that age, gender, comorbidities, International metastatic RCC database consortium (IMDC) prognostic group and pathologic tumour grade were not significant predictors of worse OS. Pathologic stage 3 or 4 was an independent predictor of worse OS (HR: 5.8, 95% CI: 1.41–24.03, P = 0.015). CONCLUSION: BTTs may have a continued role in the era of targeted therapy and immunotherapy. Further prospective data are required to validate our findings.

An interdisciplinary consensus on the management of bone metastases from renal cell carcinoma

Bone is a major site of haematogenous tumour cell spread in renal cell carcinoma (RCC), and most patients with RCC will develop painful and functionally disabling bone metastases at advanced disease stages. The prognosis of these patients is generally poor and the treatment is, therefore, aimed at palliation. However, RCC-associated bone metastases can be curable in select patients. Current data support a multimodal management strategy that includes wide resection of lesions, radiotherapy, systemic therapy, and other local treatment options, which can improve quality of life and survival. Nevertheless, the optimal approach for metastatic bone disease in RCC has not yet been defined and practical recommendations are rare. To improve the management and outcomes of patients with RCC and bone metastases, the International Kidney Cancer Coalition and the interdisciplinary working group on renal tumours of the German Cancer Society convened a meeting of experts with a global perspective to perform an unstructured review and elaborate on current treatment strategies on the basis of published data and expertise. The panel formulated recommendations for the diagnosis and treatment of patients with RCC and metastasis to the bone. Furthermore, the experts summarized current challenges and unmet patient needs that should be addressed in the future.

In this Expert Consensus, Grünwald et al. summarize their recommendations for the diagnosis and treatment of patients with renal cell carcinoma and metastasis to the bone. They also outline current challenges and unmet patient needs that should be addressed in the future.