Prediction of clinically significant recurrence after partial nephrectomy. Data from the Cancer Registry of Norway with more than five years of follow-up.

Objective: To determine recurrence incidence after partial nephrectomy (PN) for renal cell carcinoma and identify predictors for local recurrence (LR) and metastasis.

Material and methods: We retrospectively evaluated a cohort of 524 patients from the Cancer Registry of Norway, who underwent PN between January 2014 and December 2015 and were followed-up for >6 years. Patient demographics and pathological characteristics were correlated with recurrence and progression-free survival using Kaplan-Meier and Cox regression analyses.

Results: Median patient age was 64 years, and the median tumour size was 2.6 cm. A positive surgical margin (PSM) was observed in 11% of the cases, while the LR and metastasis rates were 3.4% and 3.2%, respectively. PSM (hazard ratio [HR], 55.4; 95% confidence interval [CI], 12.55-244.6), tumour number (HR, 45.4; 95% CI, 6.5-316.1) and stage (HR, 33.5; 95% CI, 5.4-205.3) were independent predictors for LR. Undetermined margin status was also a risk factor for LR. Tumour stage (HR, 41.05; 95% CI, 8.52-197.76), tumour necrosis (HR, 1.3; 95% CI, 0.4-4.31) and age (HR, 1.07; 95% CI, 1.01-1.14) were predictors for metastasis.

Conclusions: Both local and distant recurrences after PN were rare, and the pT stage was a common predictor. PSM or indeterminate surgical margin and tumour number were LR predictors, while age at surgery and the presence of tumour necrosis predicted metastasis.