Analysis of features of recurrence after radical nephrectomy in patients with N0M0 renal cell carcinoma

Background. To reduce unnecessary tests for patients with renal cell carcinoma (RCC) at low risk of metastasis, we designed a postoperative surveillance protocol for N0M0 RCC, based on the features of recurrence. Methods. Of 462 N0M0 RCC patients who underwent radical nephrectomy, 180 patients (39%) showed recurrence. We stratified these patients according to pathological T-stage (pT-stage) with consideration given to the pathological grade of malignancy (grade). A surveillance protocol was designed based on calculated disease-free survival rates. Results. The median time until recurrence was 36 months (range, 1 to 228 months), and 78.3% of all patients, recurrence was diagnosed within 5 years. The rate of recurrence increased in accordance with increased pT-stage: pT1a, 9.9% (10/101); pT1b, 29.8% (39/131); pT2, 41.7% (20/48); pT3a, 58.8% (60/102); pT3b, 60.9% (42/69); pT3c, 71.4% (5/7); pT4, 100% (4/4). Significant differences in disease-free survival rates were observed among the patients at all pT-stages, except for pT1b vs pT2, pT2 vs pT3a, pT3a vs pT3b, and pT3c vs pT4. Basically, a 5-year follow-up was conducted, except for the patients with pT1b (grade 1 + 2), pT2 (grade 1 + 2), pT3a (grade 1, 3), and pT3b (grade 1 + 2), who showed recurrence more than 5 years postoperatively. Conclusion. We conclude that our surveillance protocol for N0M0 RCC after nephrectomy, based on pT-stage and grade, is to some extent a reasonable guideline. However, a further survey of prognostic factors for RCC is necessary, because of the difficulty in predicting recurrence in patients with a low pT-stage and because of the presence of patients with late recurrence.