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SEER Inquiry System - Report
Produced: 01/07/2026 3:34 PM
Question 20210014
Inquiry Details
References:
Solid Tumor Rules. Lung; December 2020 Update
Question:
Solid Tumor Rules (2018, 2021)/Multiple Primaries--Lung: How many primaries should be reported for a 4/2019 diagnosis of left upper lobe (LUL) adenosquamous carcinoma (left lingula mass biopsy: adenosquamous carcinoma; LUL lung biopsy: pulmonary adenocarcinoma, stated to be a collision tumor and single primary per the Tumor Board), treated with radiation followed by an enlarging LUL mass in 7/2020 found to be squamous cell carcinoma? See Discussion.
Discussion:
The physician stated the prior LUL adenosquamous carcinoma was PD-L1 negative and the LUL squamous cell carcinoma is PD-L1 positive and is calling it a new primary.
5/22-7/3/19 6000x30 IMRT Photons LUL lung Chemo refused Not a Surg candidate
10/01/2019 CT Chest: IMP: In comparison to CT chest 03/06/2019 and PET/CT 03/21/2019, left lingular mass has mildly decreased in size. Left apical anterior and posterior lung lesions more anterior lesion appears slightly increased in size, the other slight decreased in size, with adjacent areas of atelectasis and scarring.
06/23/2020 CT Chest: MP: In comparison to CT chest 10/1/2019, left lingular mass has increased in size concerning for increasing tumor with adjacent thicker focal pleural thickening involving the chest wall, concerning for possible chest wall invasion. Left apical anterior and posterior lung lesions appears more solid in appearance, representing known adeno CA, given that the appearance has changed, is concerning for residual tumor.
07/06/2020 PET: Hypermetabolic lingular mass and peripheral nodularity has increased in size and FDG avidity on the prior PET/CT. Left apical nodular opacity is difficult to separate from fairly uniform mild left apical pleural hypermetabolism which may be treatment related and/or neoplastic.
Answer:
Abstract two primaries: 8560 and 8140 using rule M6. One of the original tumors with adenosquamous now shows only residual SCC following XRT. PD-L-1 is not used to determine multiple primaries. Assuming three tumors (the post-XRT SCC is not a new tumor but residual from one of the adenosquamous tumors) there are two primaries: 8560 and 8140 per M6. For collision tumors, each histology identified in the tumor is used to determine multiple primaries.
