Cochran-Armitage test

A statistically significant increase in hepatocellular carcinomas was seen in male and female mice that were dosed with 590 and 1,179 mg/kg/day hexachloroethane in com oil by gavage for 78 continuous weeks (Weisburger 1977). The incidence of tumors in the exposed mice was greater than that in controls on the basis of both the Fisher Exact test and the Cochran-Armitage test. There were no hepatic tumors in male or female rats with chronic exposure to doses of 10-423 mg/kg/day (NTP 1977, 1989 Weisburger 1977). 

In 1985, the United States Federal Register recommended that the analysis of tumor incidence data be carried out with a Cochran-Armitage (Armitage, 1955 Cochran, 1954) trend test. The test statistic of the Cochran-Armitage test is defined as this term ... 

Cancer. Increased incidences of relatively rare renal tubular cell adenomas and carcinomas were observed in male rats, but the increases were not statistically significant by the Fisher Exact test or the Cochran-Armitage test (NTP 1986). When adjusted for mortality, however, the increased incidences were significantly different from control in the high-dose males when analyzed by the Lifetable test and significant for dose-related trend by the Lifetable and the Incidental Tumor tests. 

In male mice, significant dose-related trends by the Cochran-Armitage test were found for hepatocellular adenoma and carcinoma (combined) and for fibromas, sarcomas, fibrosarcomas, and... 

Groups of 50 male and 50 female C57BL/6 mice were fed diets containing 1.18% or 2.36% acetamide for 12 months. In male mice treated with acetamide, an increase in the incidence of malignant lymphomas was observed (controls, 0/95 low-dose, 7/50 high-dose, 7/46 p = 0.004, Cochran-Armitage test for trend) (Fleischman et al., 1980). 

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