An official website of the United States government
Home
SEER Inquiry System - Report
Produced: 10/07/2026 2:42 PM
Question 20230011
Inquiry Details
References:
#1: Solid Tumor Rules. Other Sites, 2023 Update
#2: WHO Class Male Genital Tumors. 5th edition, online
Question:
Solid Tumor Rules/Multiple Primaries--Prostate: How many primaries are accessioned when a 2023 liver biopsy diagnosed metastatic small cell carcinoma (SmCC) of the prostate following a 2018 radical prostatectomy treated diagnosis of prostatic adenocarcinoma? See Discussion.
Discussion:
SINQs 20190083, 20180088, and 20130221 all indicate diagnoses of prostate adenocarcinoma, followed by a diagnosis of metastatic small cell carcinoma of the prostate are separate primaries because these are distinctly different histologies. Does this logic still apply for 2023 and later since Rule M4 was added to the Other Sites M Rules? Rule M4 states, “Abstract multiple primaries when the patient has a subsequent small cell carcinoma of the prostate more than 1 year following a diagnosis of acinar adenocarcinoma and/or subtype/variant of acinar adenocarcinoma of prostate.”
This patient has a 2018 diagnosis of prostate adenocarcinoma treated with radical prostatectomy, followed by a 2023 diagnosis of metastatic small cell carcinoma of the prostate diagnosed on a liver metastasis core biopsy. Rule M4 does not indicate whether it applies to subsequent biopsy confirmed metastatic tumor only. When a diagnosis of small cell carcinoma follows a diagnosis of prostatic adenocarcinoma, it is almost always confirmed in metastatic sites rather than in the primary site. Does the logic in the referenced SINQs above still apply for Rule M4?
Answer:
Accession two primaries, adenocarcinoma (8140/3) of the prostate and SmCC (8041/3) of the prostate using Rule M4 of the current Other Sites Solid Tumor Rules. The guidance in the aforementioned SINQ entries still applies with the additional criteria of being diagnosed more than one year following the diagnosis of acinar adenocarcinoma, or subtype, of the prostate as stated in Rule M4 of the updated 2023 rules. Small cell carcinomas of the prostate are often diagnosed on follow-up TURP/biopsies; however, if a patient had a previous radical prostatectomy, the small cell carcinoma would be identified in a metstatic site and would still be a new prostate primary. This includes biopsy confirmed metastatic tumors only. It remains important to capture the two distinct histology types.
