Treatment of spinal metastases in renal cell carcinoma: A critical review

Knockdown of LMNA inhibits Akt/β-catenin-mediated cell invasion and migration in clear cell renal cell carcinoma cells

The LMNA gene encoding lamin A/C is amplified in some clear cell renal cell carcinoma (ccRCC) samples. Our data showed that depletion of the tumor suppressor PBRM1 can upregulate lamin A/C levels, and lamin A/C could interact with PBRM1. However, the role of lamin A/C in ccRCC is not yet fully understood. Our functional assays showed that although the proliferation ability was slightly impaired after LMNA depletion, the migration and invasion of ccRCC cells were significantly inhibited. This suppression was accompanied by a reduction in MMP2, MMP9, AKT/p-AKT, and Wnt/β-catenin protein levels. Our data therefore suggest that lamin A/C, as an interaction partner of the tumor suppressor PBRM1, plays a crucial role in tumor invasion and metastasis in ccRCC.

Clear Cell Renal Cell Carcinoma Spinal Metastases: Which Factors Matter to the Overall Survival? A 10-Year Experience of a High-Volume Tumor Spine Center

Clear cell renal cell carcinoma (ccRCC) usually spreads in the spinal region causing instability or spinal cord compression leading to neurological deficits. Therefore, surgical treatment is required for improving the outcome of patients. The aim of this study is to identify which prognostic factors could affect overall survival in patients affected by ccRCC. Methods: Retrospective cohort study of patients with ccRCC spinal metastases, surgically treated from November 2009 to April 2019. Demographic and clinical data were collected. The Kaplan−Meier method was used to estimate overall survival, and the log-rank test was used to evaluate differences in survival among potentially prognostic factors. Results: A total of 69 patients were surgically treated and followed up for a median period of 65 months. The average age at the time of surgery was 62.6 years old. The median overall survival (OS) was 34.7 months (95% CI 20.8−51.9) and 5-year OS was 31.2% (95% CI 19.2−44.1). A high Tokuhashi score (p = 0.0217), the presence of visceral metastases (p < 0.001), other bone metastases (p = 0.02012) and the kind of surgical treatment (p = 0.0395) are the main prognostic factors that influence the OS. Moreover, 3-year progression-free survival (PFS) was analyzed: the median PFS was 53.1 months and the % 3-year PFS was 62.9% (45.2−76.3). In the multivariate analysis, only pre-operative radiation therapy had a significant impact on 3-year PFS (95% CI 0.929−12.994, p = 0.0643). Conclusion: The results of this study suggest that the absence of visceral metastases and an aggressive surgery as en-bloc, when feasible, could prolong the survival rate and improve quality of life for patients.

The Emerging Role of Radiation Therapy in Renal Cell Carcinoma

Advancements in radiation delivery technology have made it feasible to treat tumors with ablative radiation doses via stereotactic ablative radiation therapy (SAbR) at locations that were previously not possible. Renal cell cancer (RCC) was initially thought to be radioresistant, even considered toxic, in the era of conventional protracted course radiation. However, SAbR has been demonstrated to be safe and effective in providing local control to both primary and metastatic RCC by using ablative radiation doses. SAbR can be integrated with other local and systemic therapies to provide optimal management of RCC patients. We will discuss the rationale and available evidence for the integration and sequencing of SAbR with local and systemic therapies for RCC.

PBRM1 deficiency oncogenic addiction is associated with activated AKT–mTOR signalling and aerobic glycolysis in clear cell renal cell carcinoma cells

The PBRM1 (PB1) gene which encodes the specific subunit BAF180 of the PBAF SWI/SNF complex, is highly mutated (~ 40%) in clear cell renal cell carcinoma (ccRCC). However, its functions and impact on cell signalling are still not fully understood. Aerobic glycolysis, also known as the ‘Warburg Effect’, is a hallmark of cancer, whether PB1 is involved in this metabolic shift in clear cell renal cell carcinoma remains unclear. Here, with established stable knockdown PB1 cell lines, we performed functional assays to access the effects on 786‐O and SN12C cells. Based on the RNA‐seq data, we selected some genes encoding key glycolytic enzymes, including PFKP, ENO1, PKM and LDHA, and examined the expression levels. The AKT–mTOR signalling pathway activity and expression of HIF1α were also analysed. Our data demonstrate that PB1 deficiency promotes the proliferation, migration, Xenograft growth of 786‐O and SN12C cells. Notably, knockdown of PB1 activates AKT–mTOR signalling and increases the expression of key glycolytic enzymes at both mRNA and protein levels. Furthermore, we provide evidence that deficient PB1 and hypoxic conditions exert a synergistic effect on HIF 1α expression and lactate production. Thus, our study provides novel insights into the roles of tumour suppressor PB1 and suggests that the AKT–mTOR signalling pathway, as well as glycolysis, is a potential drug target for ccRCC patients with deficient PB1.

Metastatic Renal Cell Carcinoma to the Spine: Outcomes and Morbidity: Single-Center Experience

BACKGROUND

Renal cell carcinoma with metastases to the spine (RCCMS) requires a multidisciplinary approach. We reviewed our institutional experience with RCCMS patients undergoing spinal surgery in order to identify factors that may affect clinical outcomes, survival, and complications.

METHODS

Patients with RCCMS who underwent operative intervention from 2007 to 2020 were reviewed retrospectively.

RESULTS

Forty-four patients with the diagnosis of RCCMS were identified. Pain was the most common symptom, and neurologic dysfunction was present in one third of cases. Thoracic spine was the most common location (N = 27), followed by the lumbar (N = 12) and cervical (N = 5) regions. The overall survival from diagnosis of renal cell carcinoma was 25 (2 - 194) months and 8 (0.3 - 92) months after spinal surgery. Gender, age, spinal level, postoperative radiation, and nephrectomy had no bearing on survival. Survival for patients with a Tokuhashi score of 0 - 8, 9 - 11, and 12 - 15 was 6.5 (1.5 - 23.5), 8.9 (0.3 - 91.6), and 23.4 (2.5 - 66) months, respectively (P = 0.03). The postoperative American Spinal Cord Injury Association score of E (hazard ratio 0.109 [95% confidence interval 0.022 - 0.534, P = 0.006) also bore a significant influence on survival. There was a total of 10 complications in 7 of 44 (16%) patients.

CONCLUSIONS

Median postoperative survival of patients with RCCMS was 8 (0.3 - 92) months. Higher Tokuhashi score and ASIA E score at follow-up correlated with improved overall survival. Complication rate was 16%. Spinal surgery in RCCMS is indicated for the preservation of function and prevention of neurologic deterioration. Multimodality therapy with improved chemotherapy and stereotactic spinal radiation is expected to impact quality and length of survival positively.

Outcomes of patients with spinal metastases from renal cell carcinoma treated with conventionally-fractionated external beam radiation therapy

Renal cell carcinoma (RCC) has been traditionally thought to be radioresistant. This retrospective cohort study aims to assess the outcomes of patients with spinal metastases from RCC treated with conventionally-fractionated external beam radiation therapy (cEBRT) in our institution.Patients diagnosed with histologically or radiologically-proven RCC who received palliative cEBRT to spinal metastases, using 3-dimensional conformal technique between 2009 and 2018 were reviewed. Local progression-free survival (PFS), overall survival (OS) and common terminology criteria for adverse events version 4.0-graded toxicity were assessed. Univariable and multivariable Cox proportional hazards regression analyses were performed to evaluate for predictors associated with survivals.Thirty-five eligible patients with forty spinal segments were identified, with a median follow-up of 7 months (range, 0-47). The median equivalent dose in 2 Gy fractions (EQD2) was 32.5 Gy 10 (range, 12-39). Thirty-seven percent of patients underwent surgical intervention. At the time of last follow-up, all but 1 patient had died. Seven patients developed local progression, with the median time to local progression of 10.2 months. The median local PFS and OS were 3.3 and 4.8 months. There was no grade 3 or higher toxicity. A higher radiation dose (equivalent dose to 2 Gy fraction <32.5 Gy 10 vs ≥32.5Gy 10) (hazard ratio [HR], 0.47; 95% confidence interval [CI], 0.17-3.18; P-value (P) = .68) and spinal surgery (HR, 2.35; 95% CI, 0.53-10.29; P = .26) were not significantly associated with local PFS on univariable analysis. Multivariable analysis showed that higher Tokuhashi score (HR, 0.41; 95% CI, 0.19-0.88; P = .02), lower number of spinal segments irradiated (HR, 1.18; 95% CI, 1.01-1.37; P = .04) and use of targeted therapy (HR, 0.41; 95% CI, 0.18-0.96; P = .04) were independent predictors for improved OS.For an unselected group of patients with RCC, there is no significant association between higher radiation dose and improved local control following cEBRT. This may be due to their short survivals. With the use of more effective systemic therapy, including targeted therapy and immunotherapy, survival will likely be prolonged. A tailored-approach is needed to identify patients with good prognosis who may still benefit from aggressive local treatments.

Advantages of Radiation Therapy Simulation with 0.35 Tesla Magnetic Resonance Imaging for Stereotactic Ablation of Spinal Metastases

The hybrid 0.35T magnetic resonance imaging (MRI) and radiation therapy system functions in part as a simulation platform for treatment planning. We have found that the images generated are particularly helpful for planning of stereotactic radiation therapy for spinal metastases. Advantages include the following: (1) Low-field MRI mitigates magnetic susceptibility artifacts caused by spinal hardware. (2) Volumetric pulse sequence provides isotropic images for improved target delineation. (3) Wide-bore MRI in the radiation oncology department allows for easy simulation in treatment position for accurate fusion across imaging modalities. (4) When patients are treated on the MRI and radiation therapy hybrid device, adaptive radiation therapy is available for special situations to avoid mobile organs at risk.