SEER Training Modules

Coding CS Tumor Size

This field records the largest dimension, or the diameter of the primary tumor, and is always recorded in millimeters. To convert centimeters to millimeters, multiply the dimension by 10.

The table below shows the allowable values for the 3-digit Tumor Size field in Collaborative Staging, using colon as an example.

Code Description
000 Indicates no mass or no tumor found.
001-998 Exact size in millimeters.
989 989 millimeters or larger.
990 Microscopic focus or foci only; no size of focus is given.
991 Described as less than 1 cm.
992 Described as less than 2 cm.
993 Described as less than 3 cm.
994 Described as less than 4 cm.
995 Described as less than 5 cm.
Site Specific Codes Where Needed
Code Description
998 Familial polyposis (M8220/8221)
999 Unknown; size not stated; not stated in patient record.

Click here to see the General Rules for Coding Tumor Size.