Tumor Tips

Tumor Tip of the Week- 06-16-2023 Prostate cM1a cM1b or cM1c

06-16-2023 Prostate cM1a cM1b or cM1c

Scenario 2023:

Patient diagnosed with Prostate Adenocarcinoma was found to have mets to distant lymph nodes and bones on Scans.

Question:  How would you assign the cM category?

  • M1a Nonregional lymph node(s) 
  • M1b Bone(s) 
  • M1c Other site(s) with or without bone disease 

Answer:  M1b Bone(s) 

Rationale:

AJCC Cancer Staging Manual, Eighth Edition Chapter 58 Prostate

In my opinion, I personally found the instructions and note in the AJCC Cancer Staging Manual a little bit confusing, so I consulted the CAnswer forum for an explanation to help me understand whether to code a cM1b or cM1c.

After researching, this is the rationale behind the choice. The patient had distant lymph node mets which would be a cM1a, then they also had distant bone mets so that would be a cM1b.  So, that is the most advanced category used, we would stop there and assign a cM1b.   The category cM1c would be used for mets to sites other than non-regional nodes or bones, like lung or liver.

CAnswer Forum post

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