2002 Volume 93 Issue 4 Pages 548-554
(Background) To determine whether the immunosuppressive acidic protein (IAP) could be a useful marker for renal cell carcinoma (RCC), serum IAP levels were compared with clinicopathological features in RCC patients. Furthermore, IAP cutoff level to predict the recurrence was determined using receiver operating characteristics (ROC) curve analysis.
(Patients and Methods) Between January 1994 and December 1998, pretreatment serum IAP was measured in 123 consecutive patients with PCC at Kitasato University Hospital. Ninety-eight patients were received radical surgery and 86 patients were performed as clinically curable renal cell carcinoma (pT1-pT3N0M0). ROC curve analysis was utilized to set the cutoff value of IAP for prediction of cancer recurrence. Significance of prognostic factors in RCC recurrence was analyzed by Cox proportional hazard model.
(Results) The mean age of the 123 patients was 58.6 years (range 33 to 90, median 59). The mean follow-up period was 24.8 months (range 1 to 78, median 26). The median IAP levels were 447ug/ml in stage I, 629ug/ml in stage II, 588ug/ml in stage III and 1, 150ug/ml in stage IV (p<0.05). Tumor size and venous involvement were significantly associated with IAP concentrations (p<0.05). However, tumor grade did not correlate with IAP level. Of 86 patients with clinically curable tumor, 79 patients were disease-free after median follow-up of 27 months. Using ROC curve analysis, IAP cutoff level for prediction of cancer recurrence was set at 620ug/ml. Disease-free survival rate in patients with preoperative TAP levels of 620ug/ml or lower was 98.5% (67/68) at 27 months postoperatively, whereas that in patients with TAP greater than 620ug/ml was 75.0% (12/18). This difference was statistically significant (p<0.05). Results of multivariate analysis revealed that preoperative TAP and pT stage were statistically significant factors for tumor recurrence after radical surgery (p<0.05).
(Conclusions) The present study indicates that preoperative IAP level is a useful prognostic marker in patients with RCC. In particular, patients with clinically curable tumors (pT1-3N0M0), whose preoperative IAP levels greater then 620ug/ml may have high risk for recurrence after radical nephrectomy.
