Poor prognosis associated with thrombocytosis in patients with renal cell carcinoma

Objectives To better define the relationship between platelet count and sur vival using a retrospective analysis in patients with thrombocytosis and me tastatic renal cell carcinoma (RCC), some of whom had a shorter life expect ancy than those with a normal platelet count, Patients and methods The records were reviewed of patients with stage IV RC C who had undergone a variety of adjuvant therapies after nephrectomy betwe en 1972 and 1992, Entry criteria included a tissue diagnosis of RCC, at lea st one platelet count and a complete follow-up until the time of death, Of 350 patients available for review, 259 met the entry criteria. Patients wer e divided into two groups: group 1 included 112 patients whose platelet cou nts remained at <4x10(5)/mu L between the time of nephrectomy and the time of death; group 2 included 147 patients with at least one platelet count of >4 x 10(5)/mu L (mean age in each group 57 years), Results The mean (SD) survival for group 1 was 151 (34) months, compared wi th 92 (18) months for those in group 2. Using the log-rank chi-square test the difference in survival between the groups was significant (P=0.005). Co ntrolling for established prognostic indicators of pathological stage, nucl ear grade and cell type, using Cox's regression technique, the difference i n survival between the groups remained significant (P=0.015). Conclusions These results suggest that patients with metastatic RCC who rec eive adjuvant therapy and have a persistently normal platelet count have a 64% longer life expectancy than those with thrombocytosis. The difference i s highly statistically significant when controlled for nuclear grade, cell type and pathological stage.