A total of 60 patients were included in the study. Two-thirds of all patients who underwent nephrectomy for suspected renal cell carcinoma were male. The median age was 61.4 years, with the youngest patient being 35 years and the oldest 88 years old. (Table 1). Ten per cent of patients identified as Aboriginal and/or Torres Strait Islander, and 20.0% resided in remote areas within the THHS catchment area (Table 1). Nearly half of the patients undergoing nephrectomy reported a past or current tobacco smoking history, with 30.0% reporting excessive alcohol consumption at the time of surgery. The commonest pre-operative comorbidity was hypertension (43.3%), followed by T2DM (31.7%), CKD (30.0%), cardiovascular disease (26.7%) and lastly, chronic obstructive pulmonary disease (13.3%) (Table 1).

Radical nephrectomies were the most common procedure, accounting for 71.7% of all nephrectomies for suspected RCC at TUH. Roughly two-thirds of nephrectomies were done with a laparoscopic approach (63.3%), with the remaining 36.7% being open nephrectomies (Table 1). The median pre-operative eGFR and serum creatinine were 83.75 mL/min/1.73m2 and 78.49micromol/L, respectively. Pre-operatively, half of the patients were in CKD stage II and 11.6% in CKD stage IIIa-IV. The remaining 13.3% did not have accessible or available pre-operative pathology results (Table 1).

Of the 60 patients included in the study, 59 had RCC. Over two-thirds of histopathology results were clear cell RCCs (68.3%), 15.0% were papillary and 10.0% were chromophobe RCCs. The remaining 6.7% of histopathology results included multifocal RCC with leiomyomatous stroma, multilocular cystic RCC, unclassified RCC and benign anastomosing haemangioma (Table 2). The RCC specimens were graded using the Fuhrman or International Society of Urologic Pathologists/World Health Organisation (ISUP/WHO) grading systems. Both showed similar frequencies, with grade 2 RCC being the most common (25.0% and 23.3% respectively), followed by grade 3 (11.7% and 18.3%, respectively). A majority of RCCs were classified as American Joint Committee on Cancer (AJCC) stage 1 (71.1%) (Table 2).

The median follow-up time was 1186 days (~ 39 months), ranging from 2 to 2857 days. In the 30-day post-operative period, the mean average eGFR was 54.44 mL/min/1.73m2, and the median average serum creatinine was 116.84micomol/L. During this period, a quarter of patients were in CKD stage II (25.0%), with nearly 70% of patients’ renal function falling between the CKD II-IIIb range and 3.3% of patients falling to CKD stage V (Table 2). The distribution of kidney function in this cohort was similar at one- and three years post-nephrectomy. One year post-operatively, the mean average eGFR was 56.44 mL/min/1.73m2, which remained unchanged after three years at 56.51 mL/min/1.73m2 (Table 2). Likewise, with average serum creatinine, the median average levels were 109.50micomol/L and 111.00micromol/L at one and three years, respectively. The distribution of CKD staging after one year was like that observed after 30 days, with 30% of patients having CKD stage Ia and an unchanged number of patients with CKD V (3.3%). At three years, the frequency of CKD V remained the same; however, the number of patients with CKD IIIa halved. This may be explained by the fact that over a quarter of patients were lost to follow-up by this time (26.7%), as the frequency of other CKD stages was similar (Table 2). The median eGFR at the last follow-up was 63.0051 mL/min/1.73m2, with CKD stage II representing the largest proportion of patients at 45.0%. No patients were identified as being in CKD V at the last follow-up (Table 2).

An adverse kidney function outcome was identified in 76.7% of patients who underwent nephrectomy for suspected RCC at TUH. This included any one of the following: Progression of 1 or more CKD stages (75.0%), the one-year NICE composite (43.3%) or new commencement of acute or chronic KRT (6.7%) (Table 2). One patient received a deceased donor kidney transplant, and another was on the kidney transplant waiting list at the time of data collection.

The median length of stay post-nephrectomy was 4.85 days, with the longest being 12 days. The median length of stay did not differ between laparoscopic and open nephrectomy groups (4.00 days vs 5.00 days, p = 0.349). Eleven patients were admitted to the ICU, with a median length of stay in the ICU of one day. A recurrence of RCC was confirmed in 10.0% of patients, and 15.0% of patients experienced a cardiovascular event post-operatively. Among all patients, 13.3% died of any cause, nearly a third of which were directly attributed to RCC (Table 2).

On average, radical nephrectomy patients were eight years older than partial nephrectomy patients (63.70 years vs 55.41 years, p = 0.016). There were no statistically significant differences in sex, Indigenous status, or remote residence between partial and radical nephrectomy patients (Table 3). Furthermore, there were no differences in the frequency of comorbidities, including smoking and alcohol consumption, between the groups. Overall, radical nephrectomies were strongly associated with poorer kidney function outcomes. Average pre-operative eGFR and serum creatinine were comparable between partial nephrectomy and radical nephrectomy patients (89.40 mL/min/1.73m2 vs 80.0 mL/min/1.73m2, p = 0.100; 75.46micromol/L vs 78.67micromol/L, p = 0.583). However, in the first 30 days post-nephrectomy, the reduction in eGFR among the radical nephrectomy group was more than double that of the partial nephrectomy group (47.69 mL/min/1.73m2 vs 74.70 mL/min/1.73m2, p < 0.001). Likewise, the rise in average serum creatinine post-radical nephrectomy was more than six times post-partial nephrectomy (125.17micromol/L vs 82.67micromol/L, p = 0.001). The difference in average eGFR and serum creatinine between partial nephrectomy and radical nephrectomy patients remained similar, with significantly lower eGFR and high serum creatinine measured among radical nephrectomy patients in the one- (76.83 mL/min/1.73m2 vs 49.16 mL/min/1.73m2p < 0.001; 83.5micomol/L vs 119.82micromol.L, p < 0.001 respectively) and three-year post-operative periods (79.30 mL/min/1.73m2 vs 49.46 mL/min/1.73m2, p < 0.001; 87.03micomol/L vs 120.33micromol/L, p = 0.002, respectively). There were no statistically significant differences in eGFR between the two groups at the last follow-up (67.50 mL/min/1.73m2 vs 63.00 mL/min/1.73m2, p = 0.627). A large majority of the radical nephrectomy patients experienced an adverse renal outcome, nearly double that of partial nephrectomy patients (88.4% vs 47.1%, p = 0.001). Progression in CKD stage was seen in 92.5% of radical nephrectomy cases, compared to 57.1% in the partial nephrectomy group (p = 0.006). No patients in the partial nephrectomy group met the criteria for the NICE composite in the first year post-operatively, whereas 86.7% of patients in the radical nephrectomy group did (p < 0.001). Patients in both partial nephrectomy and radical nephrectomy groups underwent KRT; however, there was no statistically significant difference between them (11.8% vs 4.7%, p = 0.317) (Table 3).

There was no statistically significant difference between partial nephrectomy and radical nephrectomy patients in the length of stay (6.00 days vs 4.00 days, p = 0.085), ICU admission (23.5% vs 26.3%, p = 0.377) or ICU length of stay (1.00 day vs 1.00 day, p = 0.315). Patients who underwent radical nephrectomy were not any less likely to experience RCC recurrence nor any more likely to experience a cardiovascular event post-operatively (5.9% vs 11.6%, p = 0.665; 11.8% vs 16.3%, p = 1.000). There was only one recorded mortality in the radical nephrectomy group, which was not related to the patient’s RCC. There were no differences in all-cause or RCC-related mortality between the two groups (5.9% vs 16.3%, p = 0.420; 0.00% vs 42.9%, p = 1.00, respectively) (Table 3).

A sensitivity subgroup analysis of Indigenous and non-Indigenous, remote, and non-remote patients did not identify any statistically significant differences in clinical characteristics, neoplasm characteristics, or outcomes.