Question: 20200050




#1:   Surgery of Primary Site
#2:   Multiple primaries
#3:   Breast


Source 1:   2018 SEER Manual
Notes:   Appendix C Breast Surgery Codes
Source 2:   2018 Solid Tumor Rules
Notes:   Breast; July 2019 Update


Surgery of Primary Site/Multiple primaries--Breast: Should the Surgery of Primary Site for the 2020 diagnosis be coded 51 (Modified radical mastectomy without removal of uninvolved contralateral breast) when a partial mastectomy and axillary lymph node dissection are performed for a 2011 right breast primary and a subsequent 2020 right breast primary is treated with a total mastectomy only? See Discussion.


The patient underwent a partial mastectomy and sentinel lymph node biopsy, followed by an axillary lymph node dissection for the first right breast primary in 2011. The separate 2020 right breast primary was treated with a total mastectomy and removal of one involved axillary lymph node. The operative report only refers to this as a non-sentinel lymph node, with no mention of other axillary findings.

Cumulatively, this patient has undergone a modified radical mastectomy since there were likely no remaining axillary lymph nodes. If the Surgery of Primary Site data item is cumulative, does the order of surgeries matter?

It is unclear whether this question should be directed to SINQ (for coding in a SEER registry) or to CAnswer Forum because both have addressed similar surgery related questions in the past and and there is no guidance regarding this specific situation.


Yes, assign surgery of primary site code 51 for the 2020 diagnosis in this case. Code the cumulative effect of all surgeries to the primary site. This means that for the 2020 primary, code the cumulative effect of the surgery done in 2011 plus the surgery performed in 2020. Use text fields on both abstracts to record the details.


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