Detection and prognostic value of cytokeratin positive tumor cells in bone marrow of patients with renal cell carcinoma.

Purpose: Several investigations indicate the prognostic value of disseminated cytokeratin positive tumor cells in bone marrow of patients with carcinoma of different origin. In this study we evaluated the prognostic significance of epithelial cells in bone marrow of patients with renal cell carcinoma (RCC).

Materials And Methods: Aspiration of bone marrow was performed preoperatively in 335 patients with RCC between 1990 and 1998. A total of 287 patients fulfilled all study inclusion (eg M0 R0 tumor stage) and exclusion (eg second malignancy during followup) criteria for the final analysis. Cytospin preparations were made after density gradient centrifugation of bone marrow samples and incubated with monoclonal antibodies directed against cytokeratin 18 (CK2) and pan-cytokeratin. Staining was performed using the alkaline phosphatase-anti-alkaline phosphatase method and 256 samples were evaluated. RESULTS In 25% (63 of 256) of the patients cytokeratin positive (CK+) cells were detected in bone marrow. Tumor progression (defined as tumor associated death, local recurrence or new metastases) was present in 12% (31 of 256) during the followup period (median 40 months), and 14% (9 of 63) with CK+ cells and 11% (22 of 193) with negative bone marrow status exhibited tumor progression. Survival analysis (log-rank test) showed no significant difference between the CK+ and cytokeratin negative group. The detection of CK+ cells was not an independent prognostic parameter in multivariate analysis (Cox regression model).

Conclusions: These results indicate that the immunocytochemical detection of disseminated cytokeratin positive tumor cells in the bone marrow of patients with RCC has no prognostic significance.