#1: Solid Tumor Rules (2018, 2021)
#2: Multiple primaries
Source 1: 2018 Solid Tumor Rules
Notes: Other Sites, Updated 9/11/2018; for cases dx'd 2007 and later
Solid Tumor Rules (2018)/Multiple primaries--Liver: When does a hepatocellular carcinoma (HCC) recurrence in the same area of the liver get accessioned as a new tumor following TACE/Y90/RFA? If there is a new HCC in the same area as previously treated but it is stated to be recurrent and/or progressive disease, is that evidence of a disease-free interval? If the tumor area is stated to be LR-TR and non-viable, but then a new HCC in that area is diagnosed, does that count as a disease-free interval? See Discussion.
Example 1: 5/2013 diagnosis of HCC in segment 4B (single tumor), treated with microwave ablation in 7/2013. CT scan in 11/2017 with new 23mm hypodensity in liver segment 4 suspicious for recurrent disease. Clinical assessment in 1/2018: New enlarging lesion in liver most consistent with progression of HCC. Treated with RFA in 2/2018. Is the 2018 occurrence a new primary as imaging stated this was a new lesion?
Example 2: 7/2017 diagnosis of HCC in right liver; 2.5 cm lesion in segment 5/6 with a couple of satellites and 12mm lesion in segment 6, treated with Y90 radioembolization. Follow-up note in 11/2017: complete response of treated cluster of lesions in segment 5/6 and lesion in segment 6, increase in size of caudate lesion not amenable for treatment (this lesion was stated to be indeterminate on 7/2017 imaging). Caudate lesion finally stated as LI-RADS5 on 3/2018 imaging and was treated with chemoembolization 6/2018. 7/2018 and 10/2018 Follow-up imaging states LR-TR nonviable lesion in caudate lobe. 8/2019 CT shows caudate lobe with arterial enhancement, new compared to prior imaging, LR-TR viable. MD note states patient has small local HCC recurrence in segment 1 (caudate lobe) with plan to repeat TACE. Is this 8/2019 HCC a new primary as the patient was disease free for greater than 1 year, or is it the same tumor and a single primary?
Both examples are multiple primaries.
Example 1: The 2018 lesion is a new tumor. Abstract multiple primaries based on 2018 Other Sites Solid Tumor Rules, Rule M10, when tumors are diagnosed more than one year apart.
Example 2: 2017 diagnosis showed complete response to treatment. 2019 lesion is a new primary based on timing.
The General Instructions of the Solid Tumor Rules instruct: Do not use a physician’s statement to decide whether the patient has a recurrence of a previous cancer or a new primary. Each scenario should be evaluated separately using the rules as a guide.