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Produced: 10/21/2025 7:42 AM
Question 20190061
Inquiry Details
References:
Solid Tumor Rules. Breast, updated July 2019
Question:
Solid Tumor Rules (2018)/Multiple primaries--Breast: How many primaries should be reported for a diagnosis of ductal carcinoma in situ (DCIS) on core biopsy of the right breast in 2016 with all treatment refused, followed by a 2019 large right breast mass ulcerating the skin and clinical diagnosis of invasive breast cancer (patient again refused all treatment)? See Discussion.
Discussion:
The patient was never treated for the 2016 diagnosis, so the 2019 diagnosis is the same tumor that has progressed. Prior SINQ 20091096 for a similar case type cited multiple primaries per the 2007 Multiple Primaries/Histology Rules, Rule M8, the same rule as the current Solid Tumor rule M17, because this is to be reported as an incidence case.
However, it seems like Solid Tumor Rule M3 would apply because a single tumor is a single primary, and behavior of the 2016 primary would then be updated from /2 to /3. It is unclear how one would advance to the Multiple Tumors module and apply M17 because there is really only a single tumor in this case.
Answer:
Since the first diagnosis is in situ, and the later diagnosis is invasive, the 2019 diagnosis is a new primary even though it may be the same non-treated tumor.
For cases diagnosed 2018 and later, abstract multiple primaries according to the 2018 Breast Solid Tumor Rules, Rule M17 that states
Abstract multiple primaries when an invasive tumor occurs more than 60 days after an in situ tumor in the same breast.
Note 1: The rules are hierarchical. Only use this rule when none of the previous rules apply.
Note 2: Abstract both the invasive and in situ tumors.
Note 3: Abstract as multiple primaries even if physician states the invasive tumor is disease recurrence or progression.
Note 4: This rule is based on long-term epidemiologic studies of recurrence intervals. The specialty medical experts (SMEs) reviewed and approved these rules. Many of the SMEs were also authors, co-authors, or editors of the AJCC Staging Manual.
