Proposal for a Two-Tier Re-classification of Stage IV/M1 domain of Renal Cell Carcinoma into M1 (“Oligometastatic”) and M2 (“Polymetastatic”) subdomains: Analysis of the Registry for Metastatic Renal Cell Carcinoma (REMARCC)

Purpose

We hypothesized that two-tier re-classification of the “M” (metastasis) domain of the Tumor-Node-Metastasis (TNM) staging of Renal Cell Carcinoma (RCC) may improve staging accuracy than the current monolithic classification, as advancements in the understanding of tumor biology have led to increased recognition of the heterogeneous potential of metastatic RCC (mRCC).

Methods

Multicenter retrospective analysis of patients from the REMARCC (REgistry of MetAstatic RCC) database. Patients were stratified by number of metastases into two groups, M1 (≤3, “Oligometastatic”) and M2 (>3, “Polymetastatic”). Primary outcome was overall survival (OS). Secondary outcomes were cancer-specific survival (CSS). Cox-regression and Kaplan-Meier (KMA) analysis were utilized for outcomes, and receiver operating characteristic analysis (ROC) was utilized to assess diagnostic accuracy compared to current “M” staging.

Results

429 patients were stratified into proposed M1 and M2 groups (M1 = 286/M2 = 143; median follow-up 19.2 months). Cox-regression revealed M2 classification as an independent risk factor for worsened all-cause mortality (HR=1.67, p=0.001) and cancer-specific mortality (HR=1.74, p<0.001). Comparing M1-oligometastatic vs. M2-polymetastatic groups, KMA revealed significantly higher 5-year OS (36% vs. 21%, p<0.001) and 5-year CSS (39% vs. 17%, p<0.001). ROC analyses comparing OS and CSS, for M1/M2 reclassification versus unitary M designation currently in use demonstrated improved c-index for OS (M1/M2 0.635 vs. unitary M 0.500) and CSS (M1/M2 0.627 vs. unitary M 0.500).

Conclusion

Subclassification of Stage “M” domain of mRCC into two clinical substage categories based on metastatic burden corresponds to distinctive tumor groups whose oncological potential varies significantly and result in improved predictive capability compared to current staging.

Predictive factors for recurrence and outcomes in T1a renal cell carcinoma: Analysis of the INMARC (International Marker Consortium for Renal Cancer) database

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Background: Stage migration in renal cell carcinoma (RCC) has led to an increasing proportion of diagnoses at earlier clinical tumor stage and has rendered the phenomenon of the ‘small renal mass’ as a dominant presenting clinical paradigm. While thought of as being low risk, emerging knowledge about heterogeneity of RCC histologies and consequent impact on prognosis, in addition to awareness of impact of functional decline and demographic drivers on outcomes led us to further explore outcomes and predictive factors in T1a RCC patients treated with surgical resection. Methods: The INMARC database was queried for patients with small renal masses (≤ 4 cm) who underwent surgery via partial or radical nephrectomy and who presented without nodal or distant metastases. Patients were stratified into two groups based on having recurrence (distant or loco-regional) or not. Primary outcome was overall survival (OS). Multivariable analyses (MVA) were performed to analyze clinicopathological variables associated with recurrence and identify predictors of recurrence, cancer-specific mortality (CSM), and all-cause mortality (ACM). Kaplan-Meier analyses (KMA) were performed to compare recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS) between histology types clear cell, chromophobe, papillary, and “other.” Results: We analyzed 1,878 cT1aN0M0 RCC patients; 101 (5.4%) developed recurrence (median follow up 53.6 months; median time to recurrence 19.3 months); 51.1% developed distant recurrence, 35.6% had loco-regional recurrence, and 13.9% experienced distant and loco-regional recurrence. MVA demonstrated age (HR=1.02, p=0.02), sex (HR=1.71, p=0.045), diabetes (HR=1.94, p=0.006), high/unclassified grade (HR=2.82-4.40, p<0.001-0.007), papillary (HR=0.37, p=0.013) and other (HR=2.51, p=0.019) RCC as predictive factors for recurrence. MVA identified high/unclassified grade (HR=3.17-6.22, p=0.002-0.003) and papillary RCC (HR=0.12, p=0.036) as predictive factors for CSM. MVA for ACM demonstrated age (HR=1.03, p<0.001), non-Caucasian race (HR=0.85, p<0.001), high grade (HR=1.42, p=0.024), recurrence (HR=1.86, p=0.003), and GFR<45 (HR=2.89, p<0.001) to be independent risk factors. KMA comparing Clear Cell, Papillary, Chromophobe and Other RCC revealed significant differences for 5-year CSS (97.8% vs. 99.3% vs. 98.5% vs. 87.0%, p=0.018) and 5-year RFS (92.4% vs. 96.0% vs. 97.8% vs. 81.7%, p<0.001), but not 5-year OS (89.4% vs. 85.2% vs. 93.2% vs. 73.7%, p=0.34). Conclusions: We noted differential outcomes in T1a RCC based on histology and grade for recurrence and CSM, while renal functional decline in addition to pathological factors and recurrence were predictive for ACM. These findings suggest consideration to refine management and post treatment surveillance strategies in T1a RCC.

Is pathological upstaging to T3a renal cell carcinoma associated with a similar prognosis to non-upstaged pathologic T3a disease? A multicenter analysis

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Background: Pathological upstaging to T3a disease may occur following radical (RN) or partial nephrectomy (PN) for patients with T1/T2 renal cell carcinoma (RCC). While a number of studies have demonstrated increased risk of T1/T2 upstaging to pT3a compared to initial staging, a comparison of pathologically upstaged T3a RCC and T3a RCC which was not upstaged has not been performed. We sought to compare survival outcomes and predictors of outcomes in patients who underwent surgical therapy for upstaged T3a RCC versus non-upstaged pT3a RCC. Methods: We conducted a retrospective analysis of a multi-institutional dataset of patients who underwent radical (RN) or partial nephrectomy (PN) with final pathologic stage of pT3a. Patients were classified as being upstaged (US) from cT1 or cT2 or non-upstaged (NUS) with cT3a disease. Primary outcome was Overall Survival (OS)/all-cause mortality (ACM). Secondary outcomes were Cancer-Specific Survival (CSS)/Cancer-Specific Mortality (CSM), and Recurrence-Free survival (PFS)/Recurrence. Multivariable Cox regression analysis (MVA) were conducted for predictors of mortality outcomes and Kaplan Meier Analyses (KMA) were conducted to elucidate survival outcomes comparing US and NUS groups. Results: We analyzed 879 patients [US 691 (cT1 389/cT2 302); NUS 188; median follow-up 48 months). NUS had significantly greater tumor size (9.3 vs. US 7.3 cm, p<0.001), but no difference in positive surgical margins (6.9% vs. 3.9%, p=0.16). MVA for ACM revealed RN (HR 4.35, p<0.001), clear-cell RCC (HR 2.38, p<0.001), and positive surgical margin (HR 2.24, p=0.023) were independently associated, while upstaging status was not (p=0.78). MVA for CSM demonstrated age (HR 1.04, p=0.024) and positive margin (HR 5.28, p=0.029) were independently associated, while upstaging status was not (p=0.14). MVA for recurrence revealed positive margin (HR 6.7, p=0.003) and NUS (HR 3.85, p=0.001) to be associated with increased risk. KMA Comparing NUS and US groups, revealed no difference in 5-year OS (57% NUS vs. US 56%, p=0.38), and worsened 5-year CSS (NUS 66% vs. US 75%, p=0.04) and 5-year RFS (NUS 60% vs. US 84%, p<0.001). Conclusions: Pathologic upstaging to T3a RCC was associated with a lower risk of recurrence compared to non-pathologically upstaged T3a RCC; nonetheless in our analysis upstaging status was not independently associated with increased risk of cancer-specific or overall mortality in T3a RCC. Our findings also highlight the importance of complete surgical resection in the setting of T3a disease and should prompt consideration of intensified follow up, aggressive re-salvage resection and use of adjuvant therapy.

Trends and outcomes in localized renal cell carcinoma with sarcomatoid dedifferentiation: Analysis of the National Cancer Database

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Background: Sarcomatoid dedifferentiation in Renal Cell Carcinoma (sRCC) is well known to be a subtype with poor prognosis with a high rate of synchronous metastases at presentation. Nonetheless, outcomes in a contemporary cohort of patients with localized sRCC are not well characterized in a population-based study. We sought to determine the clinical characteristics, temporal trends in prevalence, and survival outcomes in patients with localized sarcomatoid RCC. Methods: From 2004-2019, all 440,230 cases of RCC in patients ≥18 years were extracted from the National Cancer Database; of these, 3.3% (14,713) had sarcomatoid dedifferentiation. Trend analyses were conducted using Cochran-Armitage test of trend. Multivariable Cox Proportional-Hazards regression was used to determine the impact of clinical and pathologic characteristics on all cause mortality (ACM) in patients with non-metastatic sRCC. Actuarial Overall Survival (OS) was computed with Kaplan-Meier analysis (KMA), with sub-analysis performed for patients with AJCC Prognostic Stages I-III (Stage). Clear cell was reference histology for all analyses. Holm adjustment for multiple comparisons was applied when necessary. Results: Sarcomatoid dedifferentiation increased from 1.9% in 2004 to 4.1% in 2019, average annual percentage change (AAPC) 0.060 (p<0.001). sRCC with synchronous metastasis decreased from 48.7% in 2004 to 38.7% in 2019, AAPC -0.028 (p<0.001). Of all sRCC, 39.3% had synchronous metastasis to lung, 17.9% to bone, 5.3% to liver, 2.2% to brain, 35.3% to >1 site. On Cox regression for non-metastatic sRCC, ACM was associated with age (HR 1.02, p<0.001), Charlson comorbidity (HR 1.21, p<0.001), tumor size (HR 1.04, p<0.001), cN1 (HR 1.01, p<0.001), collecting duct (HR 2.33, p=0.002), medullary (HR 4.75, p=0.031), and RCC unspecified (HR 1.46, p<0.001) histology, tumor grade (HR 1.30, p<0.001); and inversely with partial (HR 0.19, p<0.001) and radical (HR 0.32, p<0.001) nephrectomy. In non-metastatic sRCC, 5-year OS was 52.9%. Substratification showed 5-year OS of 72.9% for Stage I, 60.4% Stage II, and 40.9% for Stage III sRCC (p<0.001). Conclusions: The findings constitute the largest retrospective characterization of localized RCC with sarcomatoid dedifferentiation; sRCC has increased in prevalence, while patients presenting with synchronous metastases have decreased. Despite the latter trend, outcomes in patients with localized sRCC are poor and associated with patient comorbidity, stage, and associated histological findings. While partial and radical nephrectomy was associated with improved outcomes, these findings must be interpreted with caution and are likely secondary to significant selection bias. Future studies investigating the underlying biology driving increased sarcomatoid dedifferentiation despite generalized downward stage migration in RCC are requisite.

Preoperative c-reactive protein and risk of major complications and mortality outcomes in patients undergoing surgery for renal cell carcinoma

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Background: C-reactive protein (CRP) has been demonstrated to be an independent predictor of survival outcomes in renal cell carcinoma (RCC). The use of biomarkers to predict post-surgical complications is not well studied. We sought to investigate predictive factors for major complications following surgery for RCC and delineate their impact on mortality outcomes. Methods: We performed a two-center retrospective analysis of patients who underwent partial (PN) and radical nephrectomy (RN) for RCC. Patients who had complications within 30 days after surgery were identified and the complications were scored using the Clavien-Dindo classification system. Patients were grouped based on whether they experienced 30-day major (Clavien ≥3) complications and whether they had elevated preoperative CRP defined as >5mg/L. Primary outcome was non-cancer mortality (NCM), with secondary outcomes being all-cause (ACM) and cancer-specific (CSM) mortality. Multivariable analyses (MVA) were conducted to evaluate predictors for Clavien ≥3 complications, NCM, CSM, and ACM. Kaplan-Meier analyses (KMA) were performed to compare overall survival (OS), noncancer-specific survival (NCS), and cancer-specific survival (CSS) between patients with non-elevated and elevated preoperative CRP and between patients without and with 30-day Clavien ≥3 complications. Results: A total of 2,234 patients were analyzed [116 (5.2%) experienced Clavien ≥3 complications; median follow up 44 months]. MVA revealed that coronary artery disease (OR 2.37, p=0.005), elevated CRP (OR 2.25, p=0.004), PN (OR 2.79, p<0.001), and open surgical approach (OR 1.74, p=0.049) were predictive of Clavien ≥3 complications. Additionally, MVA demonstrated that elevated CRP was an independent predictor of NCM (HR 2.50, p=0.009), CSM (HR 5.51, p<0.001) and ACM (HR 4.04, p<0.001), while presence of 30-day Clavien ≥3 complications was independently associated with worsened NCM (HR 3.05, p=0.042) but not CSM or ACM. KMA comparing non-elevated and elevated preoperative CRP revealed significant differences for 5-year OS (96.0% vs. 66.8%, p<0.001), 5-year CSS (98.2% vs. 75.6%, p<0.001), and 5-year NCS (97.6% vs. 87.7%, p<0.001). KMA comparing patients without and with 30-day Clavien ≥3 complications revealed significant differences for 5-year OS (87.3% vs. 80.7%, p=0.015) and 5-year NCS (95.6% vs. 87.0%, p<0.001), but not 5-year CSS (91.3% vs. 88.9%, p=0.601). Conclusions: In patients undergoing surgical resection for RCC, elevated preoperative CRP was an independent risk factor for development of 30-day Clavien ≥3 complications, while elevated CRP and development of Clavien ≥3 complications were associated with worsened NCM. Our findings suggest an interplay between major complications and NCM in patients who undergo surgery for RCC, with elevated preoperative CRP being a predictor for both.

Impact of number of positive lymph nodes on prognostic stratification in renal cell carcinoma: Analysis of the National Cancer Database

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Background: Lymph node positivity in Renal Cell Carcinoma (RCC) is associated with worsened oncologic outcomes. However, the actual prognostic significance of node positivity is poorly understood. Currently, American Joint Committee on Cancer (AJCC) Stage III RCC includes both node-positive pN1 and node-negative pN0 disease. We hypothesize that (1) there is a threshold in number of pathologic node positivity that distinguishes favorable risk from poor risk nodal disease, and (2) current categorization of pN1 can be subdivided into pN1 and pN2 based this threshold. We tested our hypothesis using the National Cancer Database (NCDB). Methods: From 2004-2019, all cases of RCC were queried in patients age ≥18. Patients with pathologic node positive disease and without synchronous metastasis were selected for analysis to minimize confounding from metastatic burden. Multivariable Cox Proportional-Hazards regression tested association between number of pathologically positive lymph nodes and all-cause mortality (ACM), adjusting for clinical and pathologic co-variables. Receiver Operator Characteristic (ROC) Curve analyses employing the concordance probability method evaluated performance of potential cut-points for pN2 node-positivity. Kaplan-Meier analyses (KMA) compared these thresholds against overall survival (OS) in non-metastatic Stage IV RCC. Results: 28,590 patients with above criteria were identified, of which 13.6% had pN1. On multivariable analyses, increased pathologic node positivity was associated with increased hazard of ACM (HR 1.19, 95% Confidence Interval [CI] 1.17-1.20, p<0.001). ROC mapping of all possible lymph node thresholds from ≥2 to ≥10, with stage IV as the highest point, showed comparable concordance probability among these cutoffs 0.26-0.33, AUC=0.656. On KMA, when threshold was set at ≥3, 5-year OS was no longer significantly different from non-metastatic Stage IV RCC as illustrated by overlapping confidence intervals. We designated pN1 as 1-2 pathologic positive nodes, and pN2 as ≥3 pathologic positive nodes. 5-year OS for Stage III pN0 was 69.4% (95% CI 68.4-70.5), for Stage III pN1 was 41.4% (95% CI 39.0-43.8), for Stage III pN2 was 31.8% (95% CI 28.2-35.9%), and for non-metastatic Stage IV was (30.0%, 95% CI 28.2-32.0%). On multivariable analyses, pN2 exhibited 38% greater hazard of ACM (HR 3.31, 95% CI 2.24-2.54, p<0.001) compared to pN1 (HR 2.39, 95% CI 2.24-2.54, p<0.001). Conclusions: These findings represent one of the largest characterizations of impact of positive nodal counts on prognostic stratification in RCC. Pathologic node positivity could be stratified to pN1 and pN2, with pN2 conferring poor prognostic risk comparable to non-metastatic Stage IV pN0 disease. Although further validation studies are warranted, consideration should be given towards stratifying Stage III pN2 patients to a higher risk group.

Age-Related Differences in Oncological Outcomes in Renal Cell Carcinoma: Impact of Functional Conservation as Measured by Postoperative eGFR

INTRODUCTION

We sought to determine whether loss of renal function increases risk of recurrence and metastases in renal cell carcinoma (RCC), and whether this impact was age-related.

MATERIALS AND METHODS

We performed a retrospective analysis of the International Marker Consortium for Renal Cancer (INMARC) registry. Patients were separated into younger (<65 years old) and elder (≥65 years old) age groups, and rates of de novo estimated glomerular filtration rate (eGFR<45 mL/min/1.73m2 [eGFR<45]) were calculated. Multivariable analysis (MVA) was conducted for predictors of progression-free survival (PFS) and all-cause mortality (ACM). Kaplan-Meier Analysis (KMA) was conducted for PFS and overall survival (OS) in younger and elder age groups stratified by functional status.

RESULTS

We analyzed 1805 patients (1113 age<65, 692 age≥65). On MVA in patients <65, de novo eGFR<45 was independently associated with greater risk for worsened progression (HR=1.61, P=.038) and ACM (HR=1.82, P=.018). For patients ≥65, de novo eGFR<45 was not independently associated with progression (P=.736), or ACM (P=.286). Comparing patients with de novo eGFR<45 vs. eGFR ≥45, KMA demonstrated worsened 5-year PFS and OS in patients <65 (PFS: 68% vs. 86%, P<.001; OS: 73% vs. 90%, P<.001), while in patients ≥65, only 5-year OS was worsened (77% vs. 81%, P<.021).

CONCLUSION

Development of de novo eGFR<45 was associated with more profound impact on patients <65 compared to patients ≥65, being an independent risk factor for PFS and ACM. The mechanisms of this phenomenon are unclear but underscore desirability for nephron preservation when safe and feasible in younger patients.