AUA 2018: Self-Reported Quality of Life for Predicting Mortality in Renal Cell Carcinoma

San Francisco, CA ( Historically, the emphasis has been on pathology and clinical variables as the strongest predictors of clinical outcomes. Yet, more recent studies have begun to demonstrate that subjective measures, such as patient quality of life (QOL) and symptoms, may have an impact on outcomes as well. Renal cell carcinoma (RCC) is typically an asymptomatic disease, but in its more advanced stages, can become symptomatic, either due to direct mass effect or due to paraneoplastic syndromes.

In this study, the authors from Johns Hopkins, evaluate the impact of patient reported QOL as a predictor of mortality in RCC patients.  They utilized the Medicare Health Outcomes Survey, a survey of Medicare patients assessing QOL, and linked these patients to the SEER database. They identified patients who completed a QOL questionnaire after the diagnosis of RCC from 1998-2014. The median time from RCC diagnosis to survey varied significantly. 

They externally validated the data using the prospectively maintained DISSRM dataset (Delayed Intervention and Surveillance for Small Renal Masses). All patients were cT1aM0. 

The components of the questionnaire that they focused on were the mental component summary (MCS) and physical component summary (PCS). MCS and PCS scores were classified as high (≥50) or low (<50) based on a population mean score of 50 points. High (designated as “+”) implies better QOL than low (designated as “-“).Patients were classified into four groups: 1) high MCS, high PCS; 2) high MCS, low PCS; 3) low MCS, high PCS; and 4) low MCS, low PCS.

* It is never stated when the surveys were completed in relation to treatment. 

The primary outcome was an association with all-cause mortality (ACM). However, they also completed a competing risks models adjusted for stage, demographics, and comorbidities to evaluate RCC-specific and non-RCC-specific mortality.

They identified 1,494 patients in the SEER analysis with a median age of 73.4 years (IQR 68.8-79.3); median follow-up was 5.6 years (IQR 4.0-8.3). There were 747 deaths (all-cause) and 139 RCC-related deaths. Median time from RCC diagnosis to the survey was 4.4 years (range 1.8-8.3 years). 

71% of the entire cohort was cT1 and only 15% were cT3-4. 3.4% were metastatic RCC.

While the four subgroups were somewhat balanced, there were clear discrepancies:

- Group 3 had a higher proportion of cT1 than the other 3, and less cT3-4
- Each successive group (1->4) had higher rates of metastatic disease
- Each successive group (1->4) had higher rates of cardiovascular risk factors
- Each successive group (1->4) had lower rates of male patients

On multivariable analysis, each additional MCS and PCS point reduced the hazard of ACM by 1.3% (95% CI 0.981-0.993, P< 0.001) and 2.3% (95% CI 0.972-0.985, P< 0.001), respectively. Therefore, patients that had better mental and physical QOL had reduced ACS.

In the competing risks model, the hazard ratio (HR) of RCC mortality in Groups 2, 3, and 4 were 2.71 (95% CI 1.18-6.22, P= 0.02), 4.55 (95% CI 1.57-13.18, P= 0.005), and 3.11 (95% CI 1.35-7.16, P= 0.008), respectively, compared to Group 1. The HR for non-RCC mortality were 1.50 (95% CI 1.16-1.94, P= 0.002), 1.03 (95% CI 0.59-1.78, P= 0.9), and 1.83 (95% CI 1.41-2.38, P< 0.001), respectively, relative to Group 1.

In the DISSRM analysis, there were 474 patients. They validated that including the QOL measures increased the predictive ability of the model. The single best question was one of physical functioning. 

It would appear, based on this analysis, that patients with worse physical and mental self-reported QOL metrics is associated with worse ACM in RCC patients with good accuracy; lower PCS and MCS scores led to higher rates of ACM, even after accounting for differences in disease, demographics, and comorbidity. This carried forward to RCC specific mortality. In non-RCC mortality, however, low physical health was more associated with worse outcomes than poor mental health.

However, this is obviously limited by the fact that this patient-reported. More importantly, the groups were so poorly balanced, the difference likely represents differences in metastatic disease rates, cardiovascular disease, and clinical stage.

Yet, in discussion with the authors, they accept the limitations and merely want to highlight the augment effect of these factors on outcomes – they will never replace clinical nomograms. 

Presented by: Ridwan Alam, Johns Hopkins University, Baltimore, Maryland
Co-Author: Hiten D. Patel, Michael A. Gorin, Michael H. Johnson, Mohamad E. Allaf, Phillip M. Pierorazio

Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, @tchandra_uromd at the 2018 AUA Annual Meeting - May 18 - 21, 2018 – San Francisco, CA USA