Table 1

Therapeutic effect of intraductally administered cytotoxic agents on MNU-induced rat mammary tumors. Two weeks after MNU injection, when hyperplasias, MINs, and microscopic carcinomas—but no palpable lesions—were present in the mammary glands, rats were left untreated or were treated with a single intraductal injection of one of the five drugs to all 12 glands. Rats were killed at 22 weeks after the initiation of drug treatment. Time to emergence of tumors was analyzed with the individual gland as the analysis of unit with Cox proportional hazards model, where correlations between observations within the same cluster (rat) were taken into account. Multiple comparisons were adjusted with the Bonferroni procedure. CI, confidence interval; CBD, carboplatin; MTX, methotrexate; ABX, nab-paclitaxel.

Treatment comparisonNumber of tumors at the end of the study per 60 glandsHazard ratio95% CIP
No treatment versus CBD26 versus 310.44.83–22.6<0.0001
MTX (4 mg) versus CBD24 versus 39.624.06–22.8<0.0001
MTX (10 mg) versus CBD25 versus 310.54.09–27.0<0.0001
ABX versus CBD23 versus 39.704.26–22.1<0.0001
No treatment versus MTX (4 mg)26 versus 241.090.67–1.76>0.999
No treatment versus MTX (10 mg)26 versus 250.990.53–1.85>0.999
No treatment versus ABX26 versus 231.080.71–1.64>0.999
MTX (10 mg) versus MTX (4 mg)25 versus 241.090.53–2.27>0.999
MTX (10 mg) versus ABX25 versus 231.080.55–2.16>0.999
ABX versus MTX (4 mg)23 versus 241.010.57–1.78>0.999