"In the majority of patients with hepatic metastases of colorectal cancer, measuring the maximal diameter of the single largest lesion yielded the same treatment-response classification as measuring up to five target lesions. This result suggests that it may be possible to reduce the number of lesions measured in clinical trials."
CT of Colon Cancer Metastases to the Liver Using Modified RECIST Criteria: Determining the Ideal Number of Target Lesions to Measure
Zacharia, Saini, Halpern and Sumner. AJR April 2006; 186:1067-1070
Now wouldn't that make life so much easier?