Abstract
Theoretically, tumor sizes can be expressed with the number of tumor cells, which in turn can be expressed with the number of times of cell division. The number of times of cell division was mathematically expressed as a function of the diameter of a tumor. A corresponding table of tumor diameters and numbers of times of cell division was created for clinical use. With this table, it is possible to determine the time of onset of a metastasis if one has the dates and sizes of a given tumor at different times. Such an analysis was useful to understand three cases of malignant melanoma with an unusual clinical course. The table is also useful to decide the desirable follow-up time prospectively. Theoretically, patients should be examined with in one-tenth of the length of the follow-up times used thus far.[Skin Cancer (Japan) 2015 ; 30 : 113-119]
