Should ipsilateral solitary adrenal involvement in renal cell carcinoma be staged as M1?

In 2009, the TNM classification of malignant tumors was revised, and the renewal of the T2-4 stage in renal cell carcinoma was adopted. To date, however, the staging of ipsilateral solitary adrenal involvement in renal cell carcinoma has not been sufficiently evaluated.

We retrospectively reviewed the adrenal involvement in renal cell carcinoma among 1033 patients admitted to the Department of Urology at Hamamatsu University Hospital, Japan, and affiliated hospitals between 1978 and 2007.

We identified 23 of the 1033 patients (2.2%) with adrenal involvement in renal cell carcinoma. In renal cell carcinoma patients with adrenal involvement, a tendency for a high histological grade of tumor and lower overall survival (P< 0.0001) was observed. Ipsilateral solitary adrenal involvement was detected in 4 of the 23 patients (15%), whereas 2 of the 23 (9%) had direct invasion of the adrenal gland. All tumors in the 14 patients without ipsilateral solitary adrenal involvement and recurrent adrenal tumors were classified as Stage IV. The TNM classification of the four renal cell carcinoma patients with ipsilateral solitary adrenal involvement was determined to be either pT3N0M0 or pT1-3N0M1. Among the four patients with ipsilateral solitary adrenal involvement, three patients had recurrent tumors, despite complete surgical resection. Two of these patients died of metastatic renal cell carcinoma after 2 and 10 years of radical nephrectomy, respectively, whereas one was still alive with cancer 3 years after the initial radical nephrectomy. The fourth had no recurrence of renal cell carcinoma, but did develop synchronous gall bladder cancer (pT2N0M0) and bile duct cancer (pT2N0M0).

Adrenal involvement in primary renal cell carcinoma was observed more frequently in patients with advanced tumor stages. In the TNM classification system, we propose that ipsilateral solitary adrenal involvement in renal cell carcinoma should be staged as M1.