The Cleveland Clinic experience with papillary (chromophil) renal cell carcinoma: clinical outcome with histopathological correlation.

OBJECTIVES: A review of the Cleveland Clinic experience with papillary (chromophil) renal cell carcinoma (PRCC) is performed with emphasis on correlation of histopathologic features with prognosis.

METHODS: Retrospective chart review was performed on 99 patients (85 male, 14 female) identified as having papillary renal cell carcinoma. All patients underwent renal surgery (partial or radical nephrectomy) at The Cleveland Clinic Foundation. Review of archival pathologic material was performed on all patients, and the reviewing pathologist was blinded to previous pathology reports. The reviewing pathologist evaluated tumor size, nuclear grade, TNM stage, tumor vascularity, multifocality, degree of papillary histology, macrophage infiltration, and presence of adenomata. Disease free survival data were generated via Kaplan-Meier estimates. Statistical significance was evaluated by the log rank test.

RESULTS: Ninety-four (81 male, 13 female) of the original 99 patients were included in the study. Mean follow-up was 28.25 months. Most tumors were organ-confined (T1=24, T2=53, T3a=7, T3b=3, T3c=6). Histologically, most of the tumors were pure papillary histology (54.3%). Multifocality was present in 30 patients (31.9%). Overall cancer-specific survival (CSS) was 93.7% at 1 year, 89.9% at 2 years, and 78.6% at 5 years. Age (P=0.48), sex (P=0.41), tumor size (P=0.15), presence of adenomata (P=0.53), degree of pure papillary histology (P=0.73) and multifocality (P=0.93) did not significantly affect survival. Grade did not significantly affect survival (P=0.67). Low grade (Gr 1 or 2) lesions had a 5 year CSS of 75.7%, and high grade lesions had a 5 year CSS of 83.8%. Stage significantly impacted survival (P=0.017). T1-2 lesions had a 5 year CSS of 82.3%, T3a lesions 100%, T3b/T3c 66.7%. Patients with N1-2 disease (N=5) had 1 year CSS of 33.3%, and 2 year CSS of 0%. Extranodal metastases were associated with poor prognosis; 5 year CSS was 12.5% in M1 patients.

CONCLUSIONS: Papillary renal cell carcinoma has a propensity to be both low grade and low stage with a less aggressive clinical course. The strongest predictor for cancer-specific survival is tumor stage. Due to the high incidence of multifocality, nephron-sparing surgery is often necessary. It is suggested that genetic differences between PRCC and other RCC variants may be exploited in the future for surgical decision making.