Well differentiated (grade 1) clear cell renal carcinoma

Area of Science:

• Urology
• Oncology
• Pathology

Background:

• Clear cell renal carcinoma is a common kidney cancer.
• Well-differentiated oncocytic renal tumors often have a favorable prognosis.
• The clinical course of well-differentiated clear cell renal carcinoma is less understood.

Purpose of the Study:

• To evaluate the clinical course of patients with grade 1 clear cell renal carcinoma.
• To compare the prognosis of clear cell renal tumors with oncocytic renal tumors.

Main Methods:

• Retrospective review of 46 patients with pure grade 1 clear cell renal carcinoma (1950-1980).
• Analysis of tumor size, pathologic stage, and patient outcomes.
• Actuarial survival analysis compared to oncocytic tumors and a control group.

Main Results:

• Most grade 1 clear cell renal carcinomas were incidentally discovered, small (≤6 cm), and early-stage (pathologic stage 1).
• Despite early presentation, 10 patients died of metastatic disease, and 3 had active disease.
• Survival curves indicated a significantly poorer prognosis for clear cell renal tumors compared to oncocytic tumors and controls.

Conclusions:

• Well-differentiated clear cell renal tumors do not always follow an indolent course.
• These tumors can exhibit aggressive behavior similar to malignant carcinomas.
• Treatment strategies should consider the aggressive potential of well-differentiated clear cell renal carcinoma.