Correlation of clonogenic growth with histologic diagnosis after resection of residual tissue following chemotherapy for nonseminomatous testis cancer

Patients who undergo chemotherapy for metastatic nonseminomatous germ cell cancer of the testis often undergo subsequent resection of residual tissue. We performed a retrospective review of 11 consecutive patients who had their resected residual tissue cultured in a soft agar clonogenic assay to determine if there were any biological data that could be obtained in this setting. Twelve assays were performed on the 11 patients. Some colony formation occurred in 10 of the 12 assays, including 4 of 5 assays in which cancer was found and 6 of 7 in which no cancer was found. The rate of colony formation, however, was significantly less for the noncancerous tissues than for the ones with cancer noted (p = 0.019). Three of the patients with cancer are dead, while all of those with benign tissue remain free of disease, with follow-up ranging from three to six years. Our data suggest that clonogenic growth from resected tissue after chemotherapy has the potential to supplement histologic findings, possibly as a predictor of the future biologic behavior of a patient's disease process.