SEER Inquiry System - Question 20071051 Details

For cases diagnosed 2007 or later:

When there is a single tumor in one lung and a single tumor in the other lung, apply rule M6 and abstract as multiple primaries. Use this rule whenever there is a single tumor in each lung, even when neither tumor is biopsied or resected.

This rule is unique to lung. Our physician advisors emphasized that it is very unlikely that a single tumor in one lung could be metastatic from a single tumor in the opposite lung. Therefore, the default is to abstract as multiple primaries.

The note at M6 means that there must be proof that one tumor is metastatic in order to abstract as a single primary. For example, a biopsy of the tumor proving that it is metastatic. An opinion or belief that one tumor is metastatic is not sufficient. In the absence of proof, use rule M6 and abstract as multiple primaries.

A list of MP/H clarifications will be available. This issue will be included on the list.