In the Registry Partners November CTR Coding Break, we will review different AJCC M topics such as M category assignment, clinical M components and pathological M components. Criteria for the M category includes the absence of cancer (M0), and involvement of sites/or organs outside of the local tumor area (M1). Negative physical exam is the minimum criteria to qualify for cM0.
pM1 can be coded in the clinical M category when confirmation of microscopic evidence of a distant metastatic site during the diagnostic workup has been performed. There are five microscopic procedures used when categorizing pathological M1 including core biopsy, cytology from FNA, excisional biopsy, incisional biopsy and resection. The lung example shown is coded to pM1 due to the positive cytology from FNA.
Information regarding metastasis to multiple distant sites is reviewed as well under the AJCC 8th Edition Pathological M categorization. Metastases to both sides of a paired organ are considered to be coded as a metastatic site. Remember to read chapter notes as details can vary by site.
