Tumor Tip of the Week 10-31-2025 Who’s the Scariest Sequence of All? HAPPY HALLOWEEN!!

10-31-2025

Scenario: 2025-Diagnosis of simultaneous multiple tumors

• 2-12-2025 Shave biopsy skin right shoulder: Melanoma in situ
• 2-12-2025 Shave biopsy skin left upper back: Invasive Melanoma, Breslow thickness at least 0.8 mm
• Per Solid Tumor Rules Rule M4 Abstract multiple primaries when there are separate, non-contiguous melanomas with different lateralities

Question: Which case would be assigned to Seq 01?

• Melanoma In situ-right shoulder
• Invasive Melanoma-left upper back

Answer: Invasive Melanoma-left upper back- aka- The “Scariest tumor”-the one with the worst prognosis.

SEER/STORE manuals- Assign the lower sequence number to the primary with the worse prognosis when two primaries are diagnosed simultaneously

• Base the prognosis decision on the primary site, histology, and extent of disease for each of the primaries
• If there is no difference in prognosis, the sequence numbers may be assigned in any order