Table 1.

Lowest apparent sizes of spherical metastases of given diameters with step sectioning at given distances

Distance between sections	Metastasis size (diameter in mm)
	2.0	2.1	2.2	2.3	2.4	2.5	2.6	2.7	2.8	2.9	3.0
3 mm	0	0	0	0	0	0	0	0	0	0	0
2.5 mm	0	0	0	0	0	0	0.7	1.0	1.3	1.5	1.7
2 mm	0 (ITC)	0.6	0.9	1.1	1.3	1.5	1.7	1.8	2.0	2.1	2.2
1 mm	1.7	1.8	2.0	2.1	2.2	2.3	2.4	2.5	2.6	2.7	2.8
0.5 mm	1.9	2.0	2.1	2.2	2.3	2.4	2.6	2.7	2.8	2.9	3.0
0.25 mm	2.0	2.1	2.2	2.3	2.4	2.5	2.6	2.7	2.8	2.9	3.0
0.2 mm	2.0	2.1	2.2	2.3	2.4	2.5	2.6	2.7	2.8	2.9	3.0
0.15 mm	2.0	2.1	2.2	2.3	2.4	2.5	2.6	2.7	2.8	2.9	3.0

The cells that are below the stepped line correctly identify the macrometastases in the column headings as such, whereas the cells above this line can identify them as micrometastases or miss them altogether, although by chance they can also find them and categorise them correctly. The value 0 (ITC) suggests that a metastasis with a diameter equal to the distance between the levels could be seen at least as an ITC, because the thickness of the sections is not accounted for in this model; however, this value rounds to 0 in the table. (For details, see Methods and Results sections.)

ITC, isolated tumour cells.