Outcomes of complete metastasectomy in metastatic renal cell carcinoma patients: The Canadian Kidney Cancer information system experience

BACKGROUND

Surgical resection of metastasis can be integrated in the management of metastatic renal cell carcinoma (mRCC) as it can contribute to delay disease progression and improve survival.

OBJECTIVE

This study assessed the impact of complete metastasectomy in mRCC patients using real-world pan-Canadian data.

DESIGN, SETTING AND PARTICIPANTS

The Canadian Kidney Cancer information system (CKCis) database was used to select patients who were diagnosed with mRCC between January 2011 and April 2019. To minimize selection bias, each patient having received a complete metastasectomy was matched with up to 4 patients not treated with metastasectomy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Overall survival (OS) was calculated from the date of metastasectomy or selection, to death from any cause. A Cox proportional hazards model was used to assess the impact of the metastasectomy while adjusting for potential confounding variables.

RESULTS

A total of 229 patients undergoing complete metastasectomy were matched with 803 patients not treated with metastasectomy. After matching, baseline characteristics were well balanced between groups. After 12 months, the proportion of patients that were still alive was 96.0% and 89.8% in the complete metastasectomy and its matched group, respectively; the 5-year OS were 63.2% and 51.4%, respectively. Multivariate analysis performed in the matched cohort revealed that patients who underwent complete metastasectomy had a lower risk of mortality compared to patients who did not undergo metastasectomy (hazard ratio: 0.41, 95% confidence interval:0.27-0.63).

CONCLUSION

Our study found that patients who underwent complete metastasectomy have a longer overall survival and a longer time to initiation of targeted therapy compared to patients not receiving metastasectomy. These findings should support aggressive resection of metastasis in selected patients.

Determining generalizability of the Canadian Kidney Cancer information system (CKCis) to the entire Canadian kidney cancer population

INTRODUCTION

The Canadian Kidney Cancer information system (CKCis) has prospectively collected data on patients with renal tumors since January 1, 2011 from 16 sites within 14 academic centers in six provinces. Canadian kidney cancer experts have used CKCis data to address several research questions. The goal of this study was to determine if the CKCis cohort is representative of the entire Canadian kidney cancer population, specifically regarding demographic and geographic distributions.

METHODS

The CKCis prospective cohort was analyzed up to December 31, 2018. Baseline demographics and tumor characteristics were analyzed, including location of patients' residence at the time of CKCis entry. Geographic data is presented by province, rural vs. urban via postal code information (2^nd digit=0) and by Canadian urban boundary files. To determine the proportion of renal cell carcinoma (RCC) patients that CKCis captures, CKCis accruals were compared to projected Canadian Cancer Society RCC incidence in 2016-2017 and the incidence from the 2016 Canadian Cancer Registry. To determine if the CKCis baseline data is representative, it was compared to registry data and other published data when registry data was not available.

RESULTS

This CKCis cohort includes 10 298 eligible patients: 66.6% male, median age 62.6 years; 14.6% had metastatic disease at the time of diagnosis and 70.4% had clear-cell carcinomas. The CKCis cohort captures about 1250 patients per year, which represents approximately 20% of the total kidney cancer incidence. The proportion of patients captured per province did vary from 13-43%. Rural patients make up 17% of patients, with some baseline differences between rural and urban patients. There appears to be no major differences between CKCis patient demographics and disease characteristics compared to national data sources. Canadian heat maps detailing patient location are presented.

CONCLUSIONS

CKCis contains prospective data on >10 000 Canadian kidney cancer patients, making it a valuable resource for kidney cancer research. The baseline demographic and geographic data do appear to include a broad cross-section of patients and seem to be highly representative of the Canadian kidney cancer population. Moving forward, future projects will include determining if CKCis cancer outcomes are also representative of the entire Canadian kidney cancer population and studying variations across provinces and within rural vs. urban areas.

Outcomes of patients with metastatic renal cell carcinoma (mRCC) treated with first-line Immuno-oncology (IO) agents who do not meet eligibility criteria for clinical trials

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Background: IO combination therapies [including IOIO and IO/vascular endothelial growth factor inhibitor (IOVE) combinations] in mRCC have been approved based on registration clinical trials that have strict eligibility criteria. The clinical outcomes of trial ineligible patients who are treated with first-line IOIO or IOVE combinations are unknown. Methods: Metastatic RCC patients treated with first-line IOIO or IOVE were retrospectively deemed ineligible for clinical trials (according to commonly used inclusion/exclusion criteria in IO trials) if they had a Karnofsky performance status (KPS) < 70%, no clear-cell component, brain metastases, hemoglobin (Hb) < 9 g/dL, eGFR < 40 mL/min, platelet count of < 100,000/mm3, and/or neutrophil count < 1500/mm3. Time to treatment failure (TTF) and overall survival (OS) were calculated from time of starting first-line IO therapy. Results: Overall, 26% (155/592) of patients in the International mRCC Database Consortium (IMDC) were deemed ineligible for clinical trials by the above criteria. Baseline characteristics are listed in Table. The reasons for ineligibility were: no clear-cell component (34%, 53/155), Hb < 9g/dL (28%, 44/155), eGFR < 40 mL/min (19%, 30/155), brain metastases (19%, 29/155), KPS < 70% (14%, 21/155), platelet < 100,000/mm3 (3%, 4/155) and neutrophil count < 1500/mm3 (0%, 0/155). Between ineligible versus eligible patients, the response rate, median TTF and median OS of first-line IOIO or IOVE was 34% vs 46% (p = 0.02), 4.2 vs 9.7 months (p < 0.01), and 25.3 vs 44.4 months (p < 0.01), respectively. When adjusted by the IMDC prognostic categories, the HR for death between trial ineligible and trial eligible patients was 1.50 (95% CI 1.05-2.14). Conclusions: The number of patients that are ineligible for clinical trials is substantial and their outcomes are inferior. These data may guide patient counselling and specific trials addressing the unmet needs of protocol ineligible patients are warranted. [Table: see text]

Deferred Cytoreductive Nephrectomy in Patients with Newly Diagnosed Metastatic Renal Cell Carcinoma

BACKGROUND

The use of cytoreductive nephrectomy (CN) selectively for patients who show a favorable response to upfront systemic therapy may be an approach to select optimal candidates with metastatic renal cell carcinoma (mRCC) who are most likely to benefit.

OBJECTIVE

We sought to characterize outcomes of deferred CN (dCN) after upfront sunitinib, outcomes relative to sunitinib alone, and outcomes of CN followed by sunitinib.

DESIGN, SETTING, AND PARTICIPANTS

We used the prospectively maintained International mRCC Database Consortium (IMDC) database to identify patients with newly diagnosed mRCC (2006-2018).

INTERVENTION

Sunitinib alone, upfront CN followed by sunitinib, sunitinib followed by dCN.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Outcomes were overall survival (OS) and time to sunitinib treatment failure (TTF). Kaplan-Meier and multivariable Cox regression analyses were performed; dCN was analyzed as a time-varying covariate to account for immortal time bias.

RESULTS AND LIMITATIONS

We evaluated 1541 patients, of whom 651 (42%) received sunitinib alone, 805 (52%) underwent CN followed by sunitinib, and 85 (5.5%) received sunitinib followed by dCN, at a median of 7.8 mo from diagnosis. Median OS periods for patients treated with sunitinib alone, CN followed by sunitinib, and sunitinib followed by dCN were 10, 19, and 46 mo, respectively, while the median TTF values were 4, 8, and 13 mo, respectively. In multivariable regression analyses, sunitinib followed by dCN was significantly associated with improved OS (hazard ratio [HR] = 0.45, 95% confidence interval [CI] 0.33-0.60, p < 0.001) and TTF (HR = 0.62, 95% CI 0.46-0.85, p = 0.003) versus sunitinib alone. Among CN-treated patients, sunitinib followed by dCN was associated with improved OS (HR = 0.52, 95% CI 0.39-0.70, p < 0.001) and TTF (HR = 0.71, 95% CI 0.56-0.90, p = 0.005) compared with upfront CN followed by sunitinib. In various sensitivity analyses, dCN remained significantly associated with improved OS and TTF.

CONCLUSIONS

Patients who received dCN were carefully selected and achieved long OS. With these benchmark outcomes, optimal selection criteria need to be identified and confirmation of the role of dCN in a clinical trial is warranted.

PATIENT SUMMARY

We characterized benchmark survival outcomes for patients with metastatic kidney cancer treated with sunitinib alone, nephrectomy (kidney removal) followed by sunitinib, and sunitinib followed by nephrectomy. Patients who had their nephrectomy after an initial course of sunitinib had prolonged survival.

Edmonton Prostate Interdisciplinary Cancer Clinic (EPICC): Real-world efficacy outcomes of a multidisciplinary clinic for metastatic castration-resistant prostate cancer

36

Background: Multidisciplinary management improves complex treatment decision making in cancer care but its impact for metastatic castration resistant prostate cancer (M1 CRPC) has not been documented. The Edmonton Prostate Interdisciplinary Cancer Clinic (EPICC) is a multidisciplinary specialized clinic focused on the delivery of novel therapeutics (Androgen Receptor Axis Therapy; ARAT) to men with chemotherapy-naïve M1 CRPC. The objective of the current study was to assess the efficacy of ARAT in the EPICC. Methods: The study was a retrospective quality assurance analysis. Eligible patients had a new diagnosis of chemotherapy-naïve M1 CRPC with minimal symptoms. EPICC patients were assessed and treated by a multidisciplinary cancer control team that included nursing oncology, pharmacy oncology and physician oncology (urologic, medical and radiation). Patients were treated in first line with an ARAT (abiraterone (AA) or enzalutamide (EZ)) from October 2017 to March 2018. The main efficacy outcome was overall survival (OS). The Kaplan-Meier method and Cox regression model were used to analyze survival data. Statistical tests were two-sided (p≤0.05). Results: From October 2017 to March 2018, 160 chemotherapy-naïve M1 CRPC patients were assessed in the EPICC. Median age at EPICC admission was 77 years (range, 54-92 years). Median PSA level at EPICC admission was 26.6 ng/mL (range, 0.1-5000 ng/mL). 84 out of 160 (53%) patients had received prior radical local therapy (RLT) with curative intent. 83 (57%) patients were treated with EZ and 64 (43%) patients were treated AA. Median OS for the entire cohort was 23 months. In multivariable analysis, absence of prior RLT (HR 3.6, 95% CI 1.9 to 6.6, p < 0.001), PSA > 20 ng/mL (HR 3.2, 95% CI 1.4 to 7.2, p = 0.004), and higher ECOG performance status (1 vs 0: HR 2.4, 95% CI 1.3 to 4.4, p = 0.005; 2 versus 0: HR 3.5, 95% CI 1.5 to 8.0, p = 0.003; and 3 versus 0: HR 12.7, 95% CI 2.5 to 63.8, p = 0.002) were independently associated with poorer OS. Conclusions: Multidisciplinary management of chemotherapy-naïve M1 CRPC with ARAT is feasible. Real world efficacy of ARAT in EPICC are similar to data reported in phase 3 trials.

Second-line VEGF TKI after IO combination therapy: Results from the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC)

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Background: Immuno-Oncology (IO) combinations are standard of care first-line treatment for metastatic renal cell carcinoma (mRCC). Data on therapy with vascular endothelial growth factor (VEGF) tyrosine kinase inhibitors (TKI) post-progression on IO-combination therapy are limited. Methods: Using the IMDC, a retrospective analysis was done on mRCC patients treated with second-line VEGF TKIs after receiving IO combination therapy. Patients received first-line ipilimumab+nivolumab (IOIO) or anti-PD(L)1+anti-VEGF (IOVE). Baseline variables and second-line IMDC risk factors were collected. Overall response rates (ORR), time to treatment failure (TTF) and overall survival (OS) were determined. Multivariable Cox regression analysis was performed. Results: 142 patients were included. 75 patients received IOIO and 67 received IOVE pretreatment. The ORR of 2nd line therapy was 17/46 (37%) and 7/57 (12%) in the IOIO and IOVE pretreated groups, respectively (p<0.01). 2nd-line TTF was 5.4 months (95% CI 4.1-8.3) for the IOIO- and 4.6 months (95% CI 3.7-5.8) for the IOVE-pretreated group (p=0.37). 2nd-line median OS was 17.2 months (95% CI 10.8-35.1) and 11.8 months (95% CI 9.9-21.3) for the prior IOIO and IOVE groups, respectively (p=0.13). The hazard ratio adjusted by IMDC for IOVE vs IOIO pretreatment was 1.22 (95% CI 0.73-2.07, p=0.45) for 2nd line TTF and 1.43 (95% CI 0.74-2.8, p=0.29) for 2nd line OS. Conclusions: VEGF TKIs show activity after combination IO therapy. Response rates are higher in patients treated with VEGF TKIs after first-line IOIO compared to after IOVE. In patients with VEGF TKI after IOIO or IOVE, no difference in OS and TTF was observed.[Table: see text]

Real-world evidence of cabozantinib in metastatic renal-cell carcinoma (mRCC): Results from the Canadian Kidney Cancer Information System (CKCis)

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Background: Cabozantinib is a multitargeted tyrosine kinase inhibitor (TKI) that has demonstrated efficacy in mRCC randomized trials. Less is known about the activity of cabozantinib in patients (pts) exposed to immuno-oncology (IO) agents. We explored the real-world effectiveness of cabozantinib, including in pts who had progressed on IO therapy. Methods: Using CKCis, a prospective Canadian database, pts treated with cabozantinib monotherapy as second-line or later were identified. Baseline clinical and treatment characteristics were collected. Rates of partial response (PR), stable disease (SD), progressive disease (PD) and disease control (DCR, PR+SD) were determined along with median time to treatment failure (mTTF) and median overall survival (mOS). Results: A total of 156 pts were identified. Median age was 62 years (range 21-84), 74% of pts had clear-cell histology, and 54% had > 3 sites of metastases (12% in CNS, 47% in bone). At time of cabozantinib start, 34% had KPS score < 80. Outcomes are described below. Conclusions: The effectiveness of cabozantinib observed in this real-world population was consistent with results from clinical trials. Cabozantinib also appears to provide benefit to mRCC pts who have progressed on prior IO therapy, and should be incorporated into contemporary treatment algorithms. Further follow up is ongoing.[Table: see text]

Impact of early identification of brain metastases in metastatic renal cell carcinoma (mRCC)

620

Background: Up to one-third of patients with mRCC can present with asymptomatic brain metastases (BM). Timely identification of BM allows for the delivery of early local interventions, which may lead to improved patient outcomes. To investigate the potential utility of routine intra-cranial imaging, we compared the outcomes of mRCC patients with asymptomatic versus symptomatic BM. Methods: Using the Canadian Kidney Cancer information system (CKCis) database, we identified mRCC patients diagnosed with BM between 2011 and 2018. This cohort was divided into two groups dependent on the presence or absence of neurological symptoms. Baseline patient demographics, clinico-pathological disease characteristics and survival data were extracted. Statistical analysis was through chi-square tests, analysis of variance and Kaplan-Meier method to characterize survival outcomes. Results: 269 mRCC patients with BM were identified with the majority presenting with symptomatic disease (n=163; 61%). No significant differences in clinico-pathological disease characteristics were identified. Median overall survival (OS) from mRCC diagnosis for asymptomatic patients was 33.4 months (interquartile range, IQR 27.8-64.4) versus 34.5 months (20.4-43.4) for symptomatic patients (p=0.35). Median OS from time of BM diagnosis revealed a trend favoring asymptomatic, as compared to symptomatic, patients [24.5 (17.6-24.9) vs. 13.1 months (9.0-20.6), p=0.06]. Factors associated with worse OS from time of BM diagnosis included presentation with symptomatic BM [hazard ratio, HR (95% CI): 1.40 (1.03-1.90), p=0.034] and International Metastatic Renal Cell Carcinoma Consortium Database (IMDC)-characterized intermediate/poor risk disease [HR (95% CI): 1.47 (1.01-2.13), p=0.045]. Conclusions: Routine intra-cranial imaging may lead to earlier identification of BM in mRCC. However, further investigation as to whether this practice improves survival is warranted.

Real-world utilization and safety of ipilimumab plus nivolumab (I+N) in metastatic renal cell carcinoma (mRCC) patients: Results from the Canadian Kidney Cancer Information System (CKCis)

633

Background: I+N is now standard of care for first line treatment of intermediate/poor risk mRCC patients (pts). Real world data is vital to understand drug usage, toxicity and outcomes in non-trial pts. This project describes the amount and tolerability of treatment delivered including discontinuation rates, reasons for discontinuation and outcomes from the CKCis database. Methods: Pts in CKCis, a prospective Canadian database from 15 academic centers, who received first line I+N were included. The number of doses of I+N, number of pts who received single-agent nivolumab (N) and duration of single agent N were determined. Reasons for treatment discontinuation, including the rate, type, and grade of toxicities were identified. Efficacy outcomes included time to failure (TTF – time to progression, death, or second line therapy), overall response rate (ORR) and overall survival (OS). Results: The cohort consists of 182 pts. Median age was 63 yrs, 71% had clear cell histology, 11% were on a clinical trial, the IMDC risk distribution was 5% good, 63% intermediate, 32% poor. Median follow up was 8.8 m. All 4 I+N doses were received by 30% of pts of which 78% went on to receive single-agent N. Less than 4 doses of I+N were received by 70% of pts of which 28% went on to receive single-agent N. The median time on single agent N was 5.7 m. In the entire cohort, 21% of patients discontinued therapy due to toxicity. The most common toxicity events were colitis (56% of all events), pneumonitis (19%), and hepatitis (8%). There were no toxicity-related deaths. Median OS has not been reached (22 events to date). Median TTF was 12.4 m. ORR was 32% (5% complete responses). 26% of pts received second line treatment, the most common being sunitinib in 79%. Conclusions: In this real world cohort, the majority of mRCC pts did not receive all 4 doses of I+N, contrasting with clinical trial reporting, yet many of these pts went on to receive single agent N. Discontinuation rates due to toxicity were similar to those reported in CheckMate 214. Further follow up is ongoing and efficacy outcomes analyzed on the basis of treatment quantity/duration will be presented.

High-dose chemotherapy with autologous stem cell transplantation (HDC-ASCT) for relapsed metastatic germ cell tumors (mGCTs): The Alberta experience from 2001 to 2018

406

Background: HDC-ASCT is a standard therapy for patients (pts) with mGCTs whose disease progresses on or after conventional dose chemotherapy. We conducted a retrospective review of HDC-ASCT in pts with relapsed mCGT in Alberta over the past two decades. Methods: Pts with mGCTs who received HDC-ASCT at two provincial referral cancer centers in Alberta, Canada from 2001-2018 were identified. Baseline clinical and treatment characteristics were collected as well as overall survival (OS) and disease-free survival (DFS). Relevant prognostic variables were analyzed. Results: Forty three pts were identified. Median age was 28 years (range 19 – 56). Majority (95%) had non-seminoma histology and testis/retroperitoneal primary (84%). Twenty pts (47%) had poor risk disease as per IGCCC at start of first-line chemotherapy. HDC-ASCT was used as second-line therapy in 65% and 58% received tandem HDC-ASCT. Median follow-up from ASCT was 22 months (range 2 – 181). At last follow-up, 42% of pts are alive without disease, including 3/7 (43%) of pts with primary mediastinal disease. Two-year and 5-year DFS/OS were 44%/51% and 41%/43%, respectively. Median OS and DFS for all pts were 27.9 months (10.2 – NR) and 9.3 months (4.2 – 124), respectively. Conclusions: We found that HDC-ASCT is an effective salvage therapy in mGCT, consistent with existing literature. Pts appeared to benefit regardless of primary site. Though limited by small sample size, we found a numerical difference in DFS and OS between 2nd and 3rd line HDC-ASCT and single vs. tandem ASCT.[Table: see text]

Controversial issues in the management of patients with advanced prostate cancer: Results from a Canadian consensus forum

INTRODUCTION

The management of advanced prostate cancer (PCa) continues to evolve with the emergence of new diagnostic and therapeutic strategies. As a result, there are multiple areas in this landscape with a lack of high-level evidence to guide practice. Consensus initiatives are an approach to establishing practice guidance in areas where evidence is unclear. We conducted a Canadian-based consensus forum to address key controversial areas in the management of advanced PCa.

METHODS

As part of a modified Delphi process, a core scientific group of PCa physicians (n=8) identified controversial areas for discussion and developed an initial set of questions, which were then reviewed and finalized with a larger group of 29 multidisciplinary PCa specialists. The main areas of focus were non-metastatic castration-resistant prostate cancer (nmCRPC), metastatic castration-sensitive prostate cancer (mCSPC), metastatic castration-resistant prostate cancer (mCRPC), oligometastatic prostate cancer, genetic testing in prostate cancer, and imaging in advanced prostate cancer. The predetermined threshold for consensus was set at 74% (agreement from 20 of 27 participating physicians).

RESULTS

Consensus participants included uro-oncologists (n=13), medical oncologists (n=10), and radiation oncologists (n=4). Of the 64 questions, consensus was reached in 30 questions (n=5 unanimously). Consensus was more common for questions related to biochemical recurrence, sequencing of therapies, and mCRPC.

CONCLUSIONS

A Canadian consensus forum in PCa identified areas of agreement in nearly 50% of questions discussed. Areas of variability may represent opportunities for further research, education, and sharing of best practices. These findings reinforce the value of multidisciplinary consensus initiatives to optimize patient care.

Rapid atrophy of cardiac left ventricular mass in patients with non-small cell carcinoma of the lung

BACKGROUND

Cancer is a systemic catabolic condition affecting skeletal muscle and fat. We aimed to determine whether cardiac atrophy occurs in this condition and assess its association with cardiac function, symptoms, and clinical outcomes.

METHODS

Treatment naïve metastatic non-small cell lung cancer patients (n = 50) were assessed prior to and 4 months after commencement of carboplatin-based palliative chemotherapy. Methods included echocardiography for left ventricular mass (LVM) and LV function [LV ejection fraction, global longitudinal strain (GLS), diastolic function], computed tomography to quantify skeletal muscle and total adipose tissue, Eastern Cooperative Oncology Group Performance Status (ECOG-PS), validated questionnaires for dyspnoea and fatigue, plasma biomarkers, tumour response to therapy, and overall survival.

RESULTS

During 112 ± 6 days, the median change in LVM was -8.9% [95% confidence interval (95% CI) -10.8 to -4.8, P < 0.001]. Quartiles of LVM loss were -20.1%, -12.9%, -4.8%, and +5.5%. Losses of muscle, adipose tissue, and LVM were frequently concurrent; LVM loss > median value was associated with loss of skeletal muscle [odds ratio (OR) = 4.5, 95% CI: 1.4-14.8, P=0.01] and loss of total adipose tissue (OR = 10.0, 95% CI: 2.7-36.7, P < 0.001). LVM loss was associated with decreased GLS (OR = 6.6, 95% CI: 1.9-22.7, P=0.003) but not with LV ejection fraction or diastolic function. In the population overall, plasma levels of C-reactive protein (P=0.008), high sensitivity troponin T (hs-TnT) (P=0.03), and galectin-3 (P=0.02) increased over time, while N-terminal pro B-type natriuretic peptide and hs-cTnI did not change over time. C-reactive protein was the only biomarker associated with LVM loss but at the univariate level only. Independent predictors of LVM loss were prior weight loss (adjusted OR = 10.2, 95% CI: 2.2-46.9, P=0.003) and tumour progression (adjusted OR = 14.6, 95% CI: 1.4-153.9, P=0.02). LVM loss was associated with exacerbations of fatigue (OR = 6.6, 95% CI: 1.9-22.7, P=0.003), dyspnoea (OR = 9.3, 95% CI: 2.4-35.8, P<0.001), and deterioration of performance status (OR = 4.8, 95% CI: 1.3-18.3,P=0.02). Patients with concurrent loss of LVM, skeletal muscle, and fat were more likely to deteriorate in all three symptom domains and to have reduced survival (P=0.05).

CONCLUSIONS

Intense LVM atrophy is associated with non-small cell lung cancer-induced cachexia. Loss of LVM was associated with emerging alterations of GLS, indicating subtle changes in left ventricular function. Longer term studies are needed to assess the full scope of cardiac atrophy and its impact. LVM atrophy arises in conjunction with losses of fat and skeletal muscle and is temporally associated with meaningful declines in performance status, worsening of fatigue, and dyspnoea, as well as poorer tumour response and decreased survival. The specific contribution of LVM atrophy to these outcomes requires further study.

Diabetes and kidney cancer survival in patients undergoing nephrectomy: A Canadian multi-center, propensity score analysis

INTRODUCTION

Diabetes has been associated with worse survival outcomes in various malignancies; however, there are conflicting data in kidney cancer. Determining whether diabetes is associated with survival in kidney cancer may help guide treatment in a comorbid patient population.

METHODS

We used the Canadian Kidney Cancer information system database to identify patients undergoing partial or radical nephrectomy between 1989 and 2017 for localized renal cell carcinoma at 16 institutions across Canada. We derived inverse probability of treatment weights (IPTW) from a propensity score model based on various clinical, surgical, and pathological characteristics. We used Cox proportional hazard models to evaluate the association between diabetes and cancer-specific and overall survival, in the sample weighted by the IPTW.

RESULTS

4828 patients met inclusion criteria, of whom 948 (19.6%) were diabetic. Median follow-up in those without death was 26.6 months (interquartile range 9.7-53.8). Among the entire cohort, 901 deaths were from any cause, and 299 deaths from kidney cancer. Before propensity score methods, diabetics were older, more likely to have comorbidities and clear cell histopathology. After propensity score adjustment, all characteristics were balanced between groups (standardized difference <0.10). IPTW-adjusted Cox proportional hazard models demonstrated no significant association between diabetes and cancer-specific (hazard ratio 1.13, 95% confidence interval 0.78-1.62), or overall survival (hazard ratio 1.14, 95% confidence interval 0.94-1.38).

CONCLUSIONS

Our multi-centre study found that diabetes and nondiabetics have similar survival following nephrectomy for kidney cancer.

Renal cell carcinoma in the Canadian Indigenous population

Background

Diagnosis and treatment of renal cell carcinoma (rcc) might be different in Indigenous Canadians than in non-Indigenous Canadians. In this cohort study, we compared rcc presentation and treatments in Indigenous and non-Indigenous Canadians.

Methods

Patients registered in the Canadian Kidney Cancer Information System treated at 16 institutions between 2011 and 2018 were included. Baseline patient, tumour, and treatment characteristics were compared between Indigenous and non-Indigenous Canadians. The primary objective was to determine if differences in rcc stage at diagnosis were evident between the groups. The secondary objective was to determine if treatments and outcomes were different between the groups.

Results

During the study period, 105 of the 4529 registered patients self-identified as Indigenous. Those patients were significantly younger at the time of clinical diagnosis (57.9 ± 11.3 years vs. 62.0 ± 12.1 years, p = 0.0006) and had a family history prevalence of rcc that was double the prevalence in the non-Indigenous patients (14% vs. 7%, p = 0.004). Clinical stage at diagnosis was similar in the two groups (p = 0.61). The disease was metastatic at presentation in 11 Indigenous Canadians (10%) and in 355 non-Indigenous Canadians (8%). Comorbid conditions that could affect the management of rcc-such as obesity, renal disease, diabetes mellitus, and smoking-were more common in Indigenous Canadians (p < 0.05). Indigenous Canadians experienced a lower rate of active surveillance (p = 0.01). Treatments and median time to treatments were similar in the two groups.

Conclusions

Compared with their non-Indigenous counterparts, Indigenous Canadian patients with rcc are diagnosed at an earlier age and at a similar clinical stage. Despite higher baseline comorbid conditions, clinical outcomes are not worse for Indigenous Canadians than for non-Indigenous Canadians.

Active surveillance in metastatic renal cell carcinoma (mRCC): Results from the Canadian Kidney Cancer information system (CKCis)

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Background: Active surveillance (AS) is a commonly used strategy in patients (pts) with low tumor burden or slow growing disease. However, few studies have assessed AS for mRCC compared to immediate treatment. We aimed to assess the outcomes and safety of AS in comparison to immediate systemic treatment for mRCC pts. Methods: Using CKCis, mRCC pts diagnosed between January 1, 2011 and December 31, 2016 were identified. AS strategy was defined as: (1) start of systemic therapy ≥6 months after diagnosis of mRCC; or (2) never receiving systemic therapy for mRCC with an overall survival (OS) ≥1 yr (OS ≥ 1 yr a surrogate to exclude pts not started on treatment due to poor prognosis). Pts starting systemic treatment < 6 months after diagnosis of mRCC were defined as receiving immediate systemic treatment. OS and time until 1st line treatment failure (TTF) between the two cohorts were compared. Results: A total of 863 pts met criteria for AS (cohort A). Of these, 370 started treatment ≥ 6 months after their initial diagnosis (cohort A1) and 493 never received systemic treatment and were alive for ≥1 year (cohort A2). 848 pts received immediate systemic treatment (cohort B). Median age for pts in cohort A and B was 65.1 (19.0-91.5) vs. 62.2 yrs (23.1-87.1) (p < 0.0001). Sex distribution was not statistically different. Pts in cohort A had fewer sites of metastatic disease vs. cohort B ( < 0.0001) and 23% of pts in cohort A had metastasectomy vs. 5% in cohort B (P = < 0.0001). Five-year OS probability was significantly greater for cohort A than for cohort B (70.2% vs. 32.1%; P < 0.0001). After adjusting for IMDC risk criteria and age, both OS (HR 0.46, 0.38-0.56, P < 0.0001) and TTF (HR 0.79, 0.69-0.92, P = 0.0021) were greater in cohort A1 vs. B. For cohort A1 the median time on AS was 14.2 m (range 6 – 71). Conclusions: Based on the largest analysis of AS in mRCC to date, our data suggest that a subset of pts may be safely observed without immediate initiation of systemic therapy. Prospective validation is required in the contemporary immunotherapy era.

Deferred cytoreductive nephrectomy among patients with newly diagnosed metastatic renal cell carcinoma treated initially with sunitinib

4578

Background: While the CARMENA trial prompts more caution with upfront cytoreductive nephrectomy (CN) in patients with metastatic renal cell carcinoma (mRCC), 17% of patients in the sunitinib alone arm underwent deferred CN (dCN). Upfront systemic therapy has been proposed as a potential litmus test to identify patients suitable for CN, but data on outcomes are limited. We sought to characterize outcomes of dCN after upfront sunitinib relative to sunitinib alone. Methods: Patients with newly diagnosed mRCC receiving upfront sunitinib were identified from the International mRCC Database Consortium (IMDC) from 2006-2018. All CNs done after initial sunitinib were included, excluding CNs performed after sunitinib failure. The outcomes were overall survival (OS) and time to treatment failure (TTF). Kaplan Meier and multivariable Cox regression analyses were performed; dCN was analyzed as a time-varying covariate to account for immortal time bias. Results: The cohort included 708 patients of whom 53 (7.5%) underwent dCN at a median of 6.5 months (IQR 3.5,10.5) from diagnosis. Patients in the dCN group were more likely to have better Karnofsky performance status (KPS), intermediate IMDC risk, fewer metastatic sites, and response to upfront sunitinib (Table). There were 604 deaths during a median follow-up of 63 months. Median OS and TTF with dCN were 43.5 and 19.8 months vs. 9.4 and 4.3 months without, respectively. Upon multivariable analysis, dCN remained significantly associated with OS (HR 0.45, 95%CI 0.31-0.65; p < 0.001) but not TTF (HR 0.73, 95%CI 0.52-1.01; p = 0.056). Conclusions: Patients who received dCN were carefully selected and achieved long OS. With these benchmark outcomes, optimal selection criteria need to be identified and confirmation of the role of dCN in a clinical trial is warranted. [Table: see text]

Management algorithms for metastatic prostate cancer

INTRODUCTION

Prostate cancer poses a significant lifetime risk to Canadian men. Treatment for metastatic prostatic cancer (mPCa) is an area of ongoing research with a lack of up-to-date clinical guidance. The multidisciplinary Canadian Genitourinary Research Consortium (GURC) determined that additional guidance focusing on management of mPCa was warranted.

METHODS

The most up-to-date guidelines, consensus statements, and emerging phase 3 trials were identified and used to inform development of algorithms by a multidisciplinary genitourinary oncology panel outlining recommendations for the management of mPCa.

RESULTS

A single pan-Canadian guideline and five national and international guidelines or consensus statements published since 2015 were identified, along with two new phase 3 trials and one additional randomized comparison. Iterative GURC discussions led to the development of two mPCa algorithms: the first addressing management of newly diagnosed metastatic castration-sensitive prostate cancer (mCSPC) patients and the second addressing treatment of patients with metastatic castration-resistant prostate cancer (mCRPC). For newly diagnosed mCSPC patients with high-volume/high-risk disease, either docetaxel or abiraterone acetate and prednisone (AAP) added to androgen-deprivation therapy (ADT) is recommended. The addition of radiotherapy to ADT is suggested for those with low-volume disease and/or AAP to ADT for low-volume or low-risk disease. For first-line mCRPC, androgen receptor-axis-targeted (ARAT) therapy is recommended for most patients, while sequencing with docetaxel, radium-223, ARAT therapy, and/or cabazitaxel is recommended for later lines of therapy.

CONCLUSIONS

Two treatment algorithms were developed for the management of mPC and can be used by multidisciplinary specialist teams to guide treatment.

A Phase II Study of PX-866 in Patients With Recurrent or Metastatic Castration-resistant Prostate Cancer: Canadian Cancer Trials Group Study IND205

BACKGROUND

In PTEN-loss models, the phosphatidylinositol 3-kinase (PI3K)/AKT and androgen receptor signaling pathways cross-regulate by reciprocal feedback whereby inhibition of one activates the other, creating a rationale for co-targeting. We studied the irreversible, pan-isoform inhibitor of Class I PI-3K PX-866 singly (part A) and with abiraterone acetate (AA) in patients on AA with rising prostate-specific antigen (PSA) (part B).

PATIENTS AND METHODS

The primary endpoint was lack of progression at 12 weeks. Exploratory endpoints included changes in circulating tumor cells (CTC), pharmacodynamic studies on platelets (part A), and archival tumor exploration of PTEN as predictor of response (part B).

RESULTS

A total of 43 and 25 patients accrued to parts A and B, respectively. In part A, 14 (33%) patients were progression-free at 12 weeks, with 2 partial objective responses and 1 confirmed PSA response. Favorable CTC conversion (< 5 CTC/7.5 mL) occurred in 6 (24%) of 25 evaluable patients. In part B, 11 of 25 patients had measurable disease. Six (24%) patients were progression-free at 12 weeks. No objective or PSA responses were observed. For all 68 patients, the most common toxicities were diarrhea (53 patients), nausea (36), anorexia (24), fatigue (22), and vomiting (20). Among 17 patients for whom PTEN testing was possible, 3 had PTEN homozygous deletion and 14 had no change. No correlation between PTEN status and response was seen.

CONCLUSIONS

PX-866 had modest single agent activity. Adding AA to PX-866 showed no evidence of resistance reversal. Strategies to combine PI3K inhibition with androgen receptor-targeted therapies could consider initiation earlier, combination with other agents, and/or recruiting a selected population.

Efficacy of targeted therapy (TT) after checkpoint inhibitors (CPI) in metastatic renal cell carcinoma (mRCC): Results from the Canadian Kidney Cancer Information System (CKCis)

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Background: While the use of CPI has demonstrated clinical benefit in patients with mRCC, data showing the efficacy of subsequent TT is limited. This real-world analysis evaluated the efficacy of TT post CPI in mRCC patients. Methods: Data was collected and analyzed from CKCis. Patients with mRCC who received TT after CPI were identified and analyzed based on line of therapy. Time to treatment failure (TTF – time from starting first subsequent TT to stopping TT) and overall survival (OS) were calculated. Hazard Ratio (HR) calculations were adjusted for IMDC group and age. Results: 102 patients were treated with TT post CPI (table). Those who received first-line ipilimumab + nivolumab (I/N) versus a vascular endothelial growth factor inhibitor (VEGFi) + CPI combination prior to second-line TT had a median TTF of 8.0 vs 5.2 months (m) (HR=0.43, 95% CI: 0.13-1.44) and median OS of 16.5 m vs not reached (HR=0.76, 95% CI: 0.11-5.24). Patients who received a VEGFi versus a mammalian target of rapamycin inhibitor (mTORi) as third-line TT had a median TTF of 7.6 vs 4.4 m (HR=0.52, 95% CI: 0.24-1.10) and median OS of 21.7 vs 16.2 m (HR=0.41, 95% CI: 0.16-1.08). All third-line TT patients received first-line VEGFi and second-line nivolumab. Of the third-line VEGFi TT patients, 24 received axitinib (TTF 7.1 m, OS 21.7 m) and 22 received cabozantinib (data immature). Conclusions: Activity of TT in mRCC patients after CPI is demonstrated in multiple lines. In second-line, VEGFi TT had numerically better outcomes after I/N than after VEGFi+CPI combination. Efficacy of third-line TT was seen with a trend favoring VEGFi over mTORi. Axitinib in the third-line has notable activity after CPI, while data on cabozantinib and fourth-line TT are maturing. These results support the use of VEGFi after CPI in mRCC patients. [Table: see text]

Hydroxychloroquine is a safe and effective steroid-sparing agent for immune checkpoint inhibitor-induced inflammatory arthritis

Immunotherapy for cancer treatment continues to evolve, and immune checkpoints have proven successful therapeutic targets. With success has come the challenge of managing the commonly associated immune-related toxicities. Arthralgias and arthritis are a common immune-related adverse event (IrAE), well described in the literature (Pardoll Nat Rev Cancer 12:252-264, 2012; Diesendruck and Benhar Drug Resist Updat 30:39-47, 2017; Cappelli et al. Arthritis Care Res 69:1751-1763, 2017; Brahmer et al. J Clin Oncol 36:1714-1768, 2018; Smith and Bass (2017). The optimal management of immune checkpoint inhibitor (ICI)-induced arthritis remains unclear. We describe the first series using hydroxychloroquine as a first-line disease-modifying antirheumatic drug (DMARD) for patients without pre-existing autoimmune disease, who developed arthritis secondary to ICI's. This was a single-center retrospective observational study reporting all patients evaluated by rheumatologists affiliated with the University of Alberta, a large tertiary health care center in Northern Alberta, Canada, deemed to have inflammatory arthritis (IA) following ICIs. We identified 11 patients, without pre-existing autoimmune disease, who developed IA following ICIs. Most patients presented with a symmetrical polyarthritis with both large and small joint involvement. All patients were treated according to the outlined treatment protocol with hydroxychloroquine as a first-line steroid-sparing agent: either as monotherapy or in combination with tapering doses of systemic corticosteroids (3) or intra-articular steroid injections (6). One patient required the addition of methotrexate to control symptoms and none required biologic therapy. There were no reported adverse effects from hydroxychloroquine. Inflammatory arthritis is an important complication of ICIs leading to significant impact on patient quality of life. In our experience, in patients without pre-existing autoimmune disease, hydroxychloroquine is an effective first-line therapy for IA secondary to ICI therapy.

Disparity in public funding of therapies for metastatic castrate-resistant prostate cancer across Canadian provinces

INTRODUCTION

Treatment using abiraterone acetate plus prednisone, enzalutamide, cabazitaxel, and radium-223 (Ra-223) improves overall survival (OS) and quality of life for patients with metastatic castrate-resistant prostate cancer (mCRPC). Despite their proven benefits, access to these therapies is not equal across Canada.

METHODS

We describe provincial differences in access to approved mCRPC therapies. Data sources include the pan-Canadian Oncology Drug Review database, provincial cancer care resources, and correspondence with pharmaceutical companies.

RESULTS

Both androgen receptor-axis-targeted therapies (ARATs), abiraterone acetate plus prednisone and enzalutamide, are funded by provinces in the pre-and post-chemotherapy setting, however, sequential ARAT use is not funded. "Sandwich" therapy, where one ARAT is used pre-chemotherapy and a second is used upon progression on chemotherapy, is funded in six provinces: Ontario (ON), Alberta, New Brunswick, Prince Edward Island (PEI), Nova Scotia (NS), and Newfoundland and Labrador. Ra-223 is funded in five provinces: ON, Quebec (QC), British Columbia (BC), Saskatchewan, and Manitoba to varying degrees; ON allows Ra-223 either pre- or post-chemo (not both); QC allows Ra-223 post-chemo unless chemo is not tolerated; BC allows Ra-223 if other life-prolonging mCRPC therapies have been received or ineligible. Cabazitaxel is funded in all provinces post-docetaxel, except QC and PEI. Cabazitaxel is not funded as fist-line treatment for mCPRC or in combination with other agents. In ON, BC, QC, and PEI, cabazitaxel is not funded after progression on an ARAT in the post-chemotherapy setting.

CONCLUSIONS

While all provinces have access to docetaxel and ARATs, sandwiching sequential ARATs with docetaxel is funded only in select provinces. Ra-223 and cabazitaxel access is not ubiquitous across Canada. Such inequalities in access to life-prolonging therapies could lead to disparities in survival and quality of life among patients with mCRPC. Further research should quantify interprovincial variation in outcomes and cost that may result from variable access.