[An in vitro sensitivity assay for anti-cancer agents by measuring the inhibition rate of DNA synthesis (3H-thymidine uptake of cancer cells). II. Clinical study of 110 cases of breast cancer].

The sensitivity of cancer cells to anti-cancer agents (ACA) was assessed in 110 cases of breast cancer (87 primary cases and 23 recurrent cases). The cancer cells were cultured with ACAs: Mitomycin C (MMC), Adriamycin (ADR), 5-Fluorouracil (5-FU), Cytosine Arabinoside (Ara-C), Carboquone (CQ), Nimustine Hydrochloride (ACNU), Cis-platinum Diammine Dichloride (CPDD) or Vincristine (VCR) for 3 days and their sensitivity was estimated by the inhibition rate (I.R.) of DNA synthesis (3H-thymidine uptake) of cancer cells. The DNA synthesis was higher in recurrent cases than in primary cases. The primary cases showed high sensitivity to ADR or CQ, and the recurrent cases showed high sensitivity to ADR. Histologically, papillotubular or medullary tubular carcinoma showed high sensitivity to CQ, and scirrhous carcinoma showed high sensitivity to ADR, CQ or 5-FU. The sensitivities of medullary tubular or scirrhous carcinoma to ADR, 5-FU and CQ in patients with stage III and IV were lower than those in patients with stages I and II. No difference of ACA sensitivity was observed between estrogen receptor (+) and (-) cases. All recurrent cases were treated with 5-FU or its derivatives. The 50% survival period in the 5-FU high sensitivity (I.R. greater than 80%) group was 7.0 months and that of the low sensitivity (I.R. less than 80%) group 3.0 months, respectively.