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SEER Inquiry System - Report
Produced: 02/15/2026 2:41 AM
Question 20230012
Inquiry Details
References:
Solid Tumor Rules. Other Sites, 2023 Update
Question:
Solid Tumor Rules/Multiple Primaries--Prostate: How many primaries are accessioned when a 06/2022 diagnosis of prostate adenocarcinoma is followed less than one year later by a 01/2023 diagnosis of small cell carcinoma (SmCC)? See Discussion.
Discussion:
Rule M4 was added to the Other Sites M Rules to address diagnoses of small cell carcinoma following prostate adenocarcinoma, but Rule M4 states the diagnoses must be greater than one year apart.
In this situation, the diagnoses were less than one year apart and one must continue through the M Rules. The next M Rule that applies Rule M19: “Abstract multiple primaries when separate/non-contiguous tumors are on multiple rows in Table 2-21 in the Equivalent Terms and Definitions. Timing is irrelevant.” If one were to STOP at the first rule that applies, one would stop at Rule M19 which confirms the prostatic adenocarcinoma and small cell carcinoma are separate primaries, regardless of timing. If these are not to be accessioned as multiple primaries, does an Exception need to be added to M19?
Answer:
Assuming the smal cell is a seperate tumor, accession two primaries, adenocarcinoma (8140/3) of the prostate and SmCC (8041/3) of the prostate using Rule M19 of the current Other Sites Solid Tumor Rules. As these two tumors are less than a year apart, Rule M4 does not apply; however, Rule 19 does apply as these are two distinct histology types. It takes time for an acinar tumor to transform into the small cell and it is usually triggered by hormone and/or radiation treatment.
