#1: Solid Tumor Rules (2018)
#2: Multiple primaries
Source 1: 2018 Solid Tumor Rules
Notes: Lung; July 2019 Update
Solid Tumor Rules/Multiple primaries--Lung: How many primaries should be accessioned for the following patient scenario?
1) 09/2014 Left upper lobe (LUL), unifocal, localized acinar adenocarcinoma (8550/3) treated with lobectomy.
2) 04/2016 Right lower lobe (RLL), unifocal, localized acinar adenocarcinoma (8550/3) treated with wedge resection.
3) 04/2019 (within 3 years, but masked full date) Left lower lobe (LLL), unifocal, non-small cell carcinoma (8046/3) with brain metastasis. See Discussion.
Rule M4 does not seem to apply because Note 1 defines clinically disease free to mean no evidence of recurrence in the same lung on follow-up. Patient had been disease free in the left lung after 09/2014 diagnosis. The 04/2019 diagnosis was in a different lung than the 4/2016 diagnosis.
The next applicable rule is either M11 or M14 depending on how we should compare the new 2019 tumor: to the most recent prior tumor in 2016 or to both prior tumors.
Abstract three primary tumors according to the 2018 Solid Tumor Rules as follows :
2014: LUL, single primary using M2
2016: RLL, multiple primary; abstract second primary using M11 (different lung)
2019: LLL, multiple primary after reapplying rules using M4 when comparing to the same lung in 2014. Abstract this tumor as it has been more than three years and it appears the patient had no clinical evidence of disease in the left lung until 2019.