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SEER Inquiry System - Report
Produced: 10/14/2025 6:15 PM
Question 20021165
Inquiry Details
References:
SEER EOD-88, 3rd Ed, 3
Question:
Discussion:
Which size should be used for these examples?
1) Tumor size on a mammogram is smaller than the tumor size on an ultrasound.
2) CT of the lung reveals a 2.5 cm RUL malignancy in June. A biopsy in July confirms a malignancy. A CT is done in August prior to initiating RT which reveals a 3.1 cm RUL nodule.
Answer:
For cases diagnosed 1998-2003:
Generally, code the EOD-Size of Primary Tumor field to the largest size identified in any scan. Use the largest tumor size for most cases. There is no hierarchy for multiple imaging studies, with the exception of the two situations represented in the question examples.
1). Code the size stated on the mammogram, even if that size is smaller than the one specified on the ultrasound. Generally the mammogram size is more accurate for breast cases than ultrasound.
2). Code the EOD-Size of Primary Tumor field to 2.5 cm. In this example, the second scan was the same type as the first. Usually there is not that much of a difference in size between the same tests, unless the tumor has an aggressive histology. The example does not mention the histology. With certain histologies, such as small cell of the lung, a rapid growth in a short amount of time is the normal process. The fact that the size increased that much in a short period of time, using the same type of scan, is an indication of a rapidly growing tumor. It would be better to use the size on the initial scan to code the EOD-Size of Primary Tumor.
