In vitro chemosensitivity patterns of carcinoma of the lung in human tumor clonogenic assay.

One hundred and sixty-eight different specimens of human carcinoma of the lung were tested for in vitro drug sensitivity using the human tumor clonogenic assay (HTCA) originally described by Hamburger and Salmon. One hundred and twenty-two (73%) specimens grew adequately for chemosensitivity testing. Most tumors were resistant to chemotherapeutic drugs, but in vitro sensitivity, regardless of the type of drugs, varied markedly from specimen to specimen. Although response rates to individual drugs ranged between 9% and 23%, half the specimens tested were sensitive in vitro to at least one drug. A higher in vitro sensitivity rate was observed in small cell lung carcinoma (31%) than in non-small cell lung carcinoma (17%). The frequency of in vitro sensitivity was greater for patients who had received no prior chemotherapy than those who were in relapse. These in vitro results are similar to current clinical experience. There was a significant association between in vitro sensitivity of cells from a primary tumor as compared to its metastases. Overall HTCA appears to be useful in selecting appropriate chemotherapy for individual patients with carcinoma of the lung.