Predictors of surgical approach for the management of renal cell carcinoma: a population-based study from New South Wales

Machine learning models for predicting the onset of chronic kidney disease after surgery in patients with renal cell carcinoma

BACKGROUND

Patients with renal cell carcinoma (RCC) have an elevated risk of chronic kidney disease (CKD) following nephrectomy. Therefore, continuous monitoring and subsequent interventions are necessary. It is recommended to evaluate renal function postoperatively. Therefore, a tool to predict CKD onset is essential for postoperative follow-up and management.

METHODS

We constructed a cohort using data from eight tertiary hospitals from the Korean Renal Cell Carcinoma (KORCC) database. A dataset of 4389 patients with RCC was constructed for analysis from the collected data. Nine machine learning (ML) models were used to classify the occurrence and nonoccurrence of CKD after surgery. The final model was selected based on the area under the receiver operating characteristic (AUROC), and the importance of the variables constituting the model was confirmed using the shapley additive explanation (SHAP) value and Kaplan-Meier survival analyses.

RESULTS

The gradient boost algorithm was the most effective among the various ML models tested. The gradient boost model demonstrated superior performance with an AUROC of 0.826. The SHAP value confirmed that preoperative eGFR, albumin level, and tumor size had a significant impact on the occurrence of CKD after surgery.

CONCLUSIONS

We developed a model to predict CKD onset after surgery in patients with RCC. This predictive model is a quantitative approach to evaluate post-surgical CKD risk in patients with RCC, facilitating improved prognosis through personalized postoperative care.

Variability in surgical management of kidney cancer between urban and rural hospitals in Queensland, Australia: a population-based analysis

Background

International guidelines recommend partial over radical nephrectomy for management of kidney tumours, due to perceived advantages of kidney function preservation. In Queensland, oncological nephrectomy is performed in both metropolitan and rural hospitals. Previous studies have shown that patients from rural areas with kidney tumours are less likely to undergo partial nephrectomy compared with those in major cities. The aim of this study was to investigate patterns of partial nephrectomy according to geographical area, and to identify patient- and health-service-level characteristics associated with partial nephrectomy.

Methods

All 3,799 incident kidney cancer cases in Queensland (Jan 2009 to Dec 2014) were ascertained. Patients aged <18 yrs (n=47), who did not receive surgery (n=988), or had end-stage kidney disease (ESKD) before surgery (n=17) were excluded. The final sample included 2,747 patients. Data were analysed using multivariable logistic regression in order to identify associations with partial nephrectomy.

Results

Of 2,747 patients, 637 (25%) underwent partial nephrectomy. The likelihood of undergoing partial nephrectomy increased with more recent year of surgery (P<0.001) and higher socioeconomic status (P<0.001). The likelihood of undergoing partial nephrectomy decreased for patients managed in lower-volume centres (P=0.004), with increasing age (P<0.001), and hospital location outside of a major city (P<0.001). Overall, the number of nephrectomies, and proportion/number of partial nephrectomies, performed in rural hospitals has increased over the study period.

Conclusions

Our results suggest that, although patients who are managed in major cities are more likely to undergo partial nephrectomy, likelihood of undergoing partial nephrectomy in rural centres is increasing, consistent with international best practice.

A Simple Clinical Tool for Stratifying Risk of Clinically Significant CKD after Nephrectomy: Development and Multinational Validation

BACKGROUND

Clinically significant CKD following surgery for kidney cancer is associated with increased morbidity and mortality, but identifying patients at increased CKD risk remains difficult. Simple methods to stratify risk of clinically significant CKD after nephrectomy are needed.

METHODS

To develop a tool for stratifying patients' risk of CKD arising after surgery for kidney cancer, we tested models in a population-based cohort of 699 patients with kidney cancer in Queensland, Australia (2012-2013). We validated these models in a population-based cohort of 423 patients from Victoria, Australia, and in patient cohorts from single centers in Queensland, Scotland, and England. Eligible patients had two functioning kidneys and a preoperative eGFR ≥60 ml/min per 1.73 m². The main outcome was incident eGFR <45 ml/min per 1.73 m² at 12 months postnephrectomy. We used prespecified predictors-age ≥65 years old, diabetes mellitus, preoperative eGFR, and nephrectomy type (partial/radical)-to fit logistic regression models and grouped patients according to degree of risk of clinically significant CKD (negligible, low, moderate, or high risk).

RESULTS

Absolute risks of stage 3b or higher CKD were <2%, 3% to 14%, 21% to 26%, and 46% to 69% across the four strata of negligible, low, moderate, and high risk, respectively. The negative predictive value of the negligible risk category was 98.9% for clinically significant CKD. The c statistic for this score ranged from 0.84 to 0.88 across derivation and validation cohorts.

CONCLUSIONS

Our simple scoring system can reproducibly stratify postnephrectomy CKD risk on the basis of readily available parameters. This clinical tool's quantitative assessment of CKD risk may be weighed against other considerations when planning management of kidney tumors and help inform shared decision making between clinicians and patients.

Changing trends in surgical management of renal tumours from 2000 to 2016: a nationwide study of Medicare claims data

BACKGROUND

Guidelines recommend nephron sparing surgery where possible for patients with T1 renal tumours. The trends of nephron sparing surgery outside the USA are limited, particularly since the introduction of robotic-assisted partial nephrectomy (RAPN). The aim of this study was to describe contemporary surgical management patterns of renal tumours in Australia according to Medicare claims data.

METHODS

Claims data according to the Medicare Benefits Schedule on surgical management of renal tumours in adult Australians between January 2000 and December 2016 was collated. Analysis of absolute number, population-adjusted rate and renal cancer-adjusted rate of interventions according to age and gender were performed, as well as proportion of RAPN.

RESULTS

Between 2000 and 2016, the rate of partial nephrectomy (PN) increased while radical nephrectomy (RN) remained stable (PN: 0.87-4.16, RN: 6.52-6.70 per 100 000 population). Since 2015, PN has become more common than RN in patients aged 25 to 44 years (0.98 versus 0.95 procedures per 100 000 population). Renal cancer-adjusted rate exhibited a trend towards increasing utilization of PN and reduced RN across all age groups. An increase in overall surgical treatment was observed (25%-41%), mainly due to increased treatment of patients older than 75 years. The proportion of RAPN was seen to rapidly increase (4.7% in 2010 to 58% in 2016).

CONCLUSIONS

Treatment utilization for renal masses has markedly changed in Australia according to Medicare claims. PN is increasingly replacing RN in younger patients, and older patients are receiving more surgical treatment. The impact of increased RAPN utilization is yet to be determined.

National Norwegian Practice Patterns for Surgical Treatment of Kidney Cancer Tumors ≤7cm: Adherence to Changes in Guidelines May Improve Overall Survival

BACKGROUND

Guidelines on surgical treatment for kidney cancer (KC) have changed over the last 10 yr. We present population-based data for patients with KC tumors ≤7cm from 2008 to 2013 to investigate whether surgical practice in Norway has changed according to guidelines.

OBJECTIVE

To assess the predictors of treatment and survival after KC surgery.

DESIGN, SETTING, AND PARTICIPANTS

We identified all surgically treated KC patients with tumors ≤7cm without metastasis diagnosed during 2008-2013 (2420 patients) from the Cancer Registry of Norway.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Relationships with outcomes were analyzed using joinpoint regression, multivariate logistic regression, Kaplan-Meier survival estimates, Cox regression, relative survival (RS), and competing-risk analyses.

RESULTS AND LIMITATIONS

The mean follow-up was 5.2 yr. There was a 28% increase in the number of patients undergoing surgical treatment over the study period. Joinpoint regression revealed a significant annual increase in partial nephrectomy (PN) and a small reduction in radical nephrectomy (RN). PN increased from 43% to 66% for tumors ≤4cm and from 10% to 18% for tumors of 4.1-7cm. Minimally invasive (MI) RN increased from 53% to 72% and MI PN from 25% to 64%, of which 55% of procedures were performed with robotic assistance in 2013. The geographical distribution of treatment approaches differed significantly. Both PN and MI approaches were more frequent in high-volume hospitals. Cox regression analysis revealed that PN, age, and Fuhrman grade and stage were independent predictors of survival. There were no significant differences in cancer-specific survival (p=0.8). The 5-yr RS for T1a disease was higher after PN than after RN.

CONCLUSIONS

The rate of PN for tumors ≤7cm increased in the 6-yr study period. MI approaches increased for both RN and PN. This treatment shift coincides with the new guideline recommendations in 2010. The possible better survival for patients undergoing PN compared to RN indicates the importance of following evidence-based guidelines.

PATIENT SUMMARY

The use of partial nephrectomy and minimally invasive surgery for kidney cancer tumors increased in Norway from 2008 to 2013 according to population-based data, coinciding with guideline changes. The study illustrate that adherence to guidelines may improve patient outcomes.

Incident Chronic Kidney Disease After Radical Nephrectomy for Renal Cell Carcinoma

BACKGROUND

Chronic kidney disease (CKD) after surgery for kidney cancer is common, and is associated with increased morbidity and mortality. This study aimed to identify factors associated with incident CKD in patients managed with radical nephrectomy.

PATIENTS AND METHODS

All patients diagnosed with renal cell carcinoma between January 2012 and December 2013 were ascertained from state-based cancer registries in Queensland and Victoria. Information on patient, tumor, and health service characteristics was obtained via chart review. Multivariable logistic regression was used to evaluate exposures associated with incident CKD (estimated glomerular filtration rate [eGFR] <60 mL per minute per 1.73 m²) at 12 months after nephrectomy.

RESULTS

Older age (adjusted odds ratio [aOR] per 5-year increase, 1.5; 95% confidence interval [CI], 1.4-1.6), male sex (aOR, 1.4; 95% CI, 1.0-2.0), obese compared with not obese (aOR, 1.8; 95% CI, 1.2-2.7), rural compared with urban place of residence (aOR, 1.8; 95% CI, 1.1-3.0) were associated with a higher risk of incident CKD. Lower preoperative eGFR was also associated with a higher risk of incident CKD. Management in private compared with public hospitals was also associated with a higher risk of CKD (aOR, 1.6; 95% CI, 1.2-2.2). Factors related to tumor size and cancer severity were also associated with worse postoperative kidney function, although it is likely this was a consequence of selection bias.

CONCLUSION

Patient characteristics have the strongest associations with incident CKD after radical nephrectomy. Potential risk factors were reasonably similar to recognized CKD risk factors for the general population. Patients who undergo nephrectomy who have CKD risk factors might benefit from ongoing postoperative screening for deterioration of kidney function.

Chronic kidney cortical damage is associated with baseline kidney function and albuminuria in patients managed with radical nephrectomy for kidney tumours

This study evaluated the relationship between histological markers of chronic kidney damage in patients undergoing radical nephrectomy for kidney tumours and preoperative kidney function, degree of albuminuria, and changes in glomerular volume. A schema to grade chronic kidney damage could be used to identify patients at risk of developing CKD following nephrectomy. Non-neoplastic cortical tissue was sourced from 150 patients undergoing radical nephrectomy for suspected kidney cancer. This tissue was evaluated for indicators of chronic damage, specifically: glomerulosclerosis, arteriosclerosis, interstitial fibrosis, and tubular atrophy. Glomerular volume was determined using the Weibel and Gomez method. Associations between these parameters and both estimated glomerular filtration rate (eGFR) and albumin-creatinine ratio (ACR) were determined using either a Mann-Whitney U-test or a Kruskal-Wallis ANOVA. Associations between both eGFR and ACR and glomerular volume were assessed using linear regression. eGFR was inversely associated with the degree of glomerulosclerosis (p < 0.001), vascular narrowing (p = 0.002), tubular atrophy (p < 0.001), and interstitial fibrosis (p < 0.001). ACR was associated only with the degree of interstitial fibrosis (p = 0.02) and tubular atrophy (p = 0.02). Glomerular volume was greater for males, diabetics, hypertensive patients, and patients with a greater degree of interstitial fibrosis. Glomerular volume was positively associated with ACR. A schema to grade chronic damage was developed. The proposed schema is associated with baseline clinical indices of kidney function and damage. Longitudinal validation is necessary to determine the prognostic utility of this schema.

Predictors of new-onset chronic kidney disease in patients managed surgically for T1a renal cell carcinoma: An Australian population-based analysis

BACKGROUND

New-onset chronic kidney disease (CKD) following surgical management of kidney tumors is common. This study evaluated risk factors for new-onset CKD after nephrectomy for T1a renal cell carcinoma (RCC) in an Australian population-based cohort.

METHODS

There were 551 RCC patients from the Australian states of Queensland and Victoria included in this study. The primary outcome was new-onset CKD (eGFR <60 mL/min per 1.73 m² ) and the secondary outcome was new-onset moderate-severe CKD (<45 mL/min per 1.73 m² ). Multivariable logistic regression was used to evaluate associations between patient, tumor and health-service characteristics and these outcomes.

RESULTS

Forty percent (219/551) of patients developed new-onset CKD, and 12% (68/551) experienced new-onset moderate-severe CKD. Risk factors for new-onset CKD were age, lower preoperative eGFR, tumor size >20 mm, radical nephrectomy, lower hospital caseloads (<20 cases/year), and rural place of residence. The associations between rural place of residence and low center volume were a consequence of higher radical nephrectomy rates.

CONCLUSION

Risk factors for CKD after nephrectomy generally relate to worse baseline health, or likelihood of undergoing radical nephrectomy. Surgeons in rural centres and hospitals with low caseloads may benefit from formalized integration with specialist centers for continued professional development and case-conferencing, to assist in management decisions.

Cytoreductive nephrectomy for metastatic renal cell carcinoma: inequities in access exist despite improved survival

The use of cytoreductive nephrectomy (CRN) in the targeted therapy era is still debated. We aimed to determine factors associated with reduced use of CRN and determine the effect of CRN on overall survival in patients with metastatic renal cell carcinoma (RCC). All advanced RCC diagnosed between 2001 and 2009 in New South Wales, Australia, were identified from the Central Cancer Registry. Records of treatment and death were electronically linked. Follow-up was to the end of 2011. Multivariable logistic regression analysis was used to determine factors associated with the receipt of CRN. Cox proportional hazards model was used to determine factors associated with survival. A total of 1062 patients were identified with metastatic RCC of whom 289 (27%) received CRN. There was no difference in the use of CRN over the time period of the study. Females (OR 0.68 (95% CI: 0.48-0.96)), unmarried individuals (OR 0.68 (95% CI: 0.48-0.96)), treatment in a nonteaching hospital (OR 0.26 (95% CI: 0.18-0.36)) and individuals without private insurance (OR 0.29 (95% CI: 0.20-0.41)) all had reduced likelihood of receiving CRN. On multivariable analysis, not receiving CRN resulted in a 90% increase in death (HR 1.90 (95% CI: 1.61-2.25)). In addition, increasing age (P < 0.001), increasing Charlson comorbidity status (P = 0.002) and female gender also had a significant independent association with death. Despite a strong association with improved survival, individuals who are elderly, female, have treatment in a nonteaching facility or have no private insurance have a reduced likelihood of receiving CRN.