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Treatment for estrogen receptor positive (ER+) breast cancer started with tamoxifen (non-steroidal estrogen subcategory) and switched to letrozole (non-steroidal aromatase inhibitor subcategory). Patient being treated with immunotherapy, Avastin (cytostatic agent-antiangiogenesis agent subcategory), and then changed to Atezolizumab (monoclonal antibody subcategory).

Is Atezolizumab a new course of therapy because it is a different subcategory?

Since the peripheral nerves are included in the Malignant CNS schema of the Solid Tumor Rules, neither the differences in subsite nor timing indicate these are separate primaries (Rule M10 indicates a single primary). However, these are separate MPNSTs in different sites and the tumors are not stated to be metastasis. Additionally, these are treated as separate primaries by the managing physician.

While the malignant CNS tumors do not take timing into account, is this correct for these peripheral nerve tumors that are often treated similarly to soft tissue tumors? Should Rule M8 be updated to include tumors in different peripheral nerve subsites?

Patient had a total abdominal hysterectomy-bilateral salpingo-oophorectomy performed in January 2023 with final diagnosis of myxoid and epithelioid leiomyosarcoma.

Diagnosis comment states: The tumor is 15 cm per report. It grows in nests and poorly formed interanastomosing trabeculae and cords that are separated by abundant myxoid background. The cells have an epithelioid morphology with eosinophilic cytoplasm, large nuclei, and very prominent nucleoli. The mitotic activity is overall low ranging from 1 to 3/10 HPFs.

Immunohistochemical stains performed at the outside hospital showed diffuse positivity for SMA, desmin, caldesmon, and PR. They are negative for CD10, claudin-4, calretinin, HBM45, MART1 (rare weakly positive cells), PANCK, and SOX10. This immunohistochemical profile supports a smooth muscle derivation of this neoplasm. As this tumor is extensively myxoid, diagnostic criteria differ from the spindle cell leiomyosarcoma.

Per Solid Tumor Rules Other Sites, Table 16: Uterine Corpus Histologies, Epithelioid Leiomyosarcoma (8891/3) and Myxoid Leiomyosarcoma (8896/3) are both subtypes of Sarcoma, NOS (8800/3).  Per Rule H21, use a combination code when there are multiple specific histologies AND the combination is listed in Table 2 OR there are coding instructions for the combination in the applicable histology Tables 3-21 OR you receive a combination code from Ask A SEER Registrar.  Since there is no combination listed in Table 2 and there is no instruction for the combination in Table 16, how should the histology be coded for this tumor?

While SEER*Rx does indicate infliximab should be coded as biological response modifier (BRM)/Immunotherapy, the manufacturer website for this medication indicates it is given for: Crohn’s disease, ulcerative colitis, rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and plaque psoriasis. In addition, SEER*Rx does not indicate which primary sites this treatment may be given for. If it is indeed cancer directed treatment, can the typical primary sites be added for clarity?

Case example: Patient is diagnosed with colorectal cancer and also has an existing diagnosis of Crohn’s disease; received surgery and FOLFOX6, as well as infliximab. There was no statement of what disease the infliximab was given to treat.  

Patient was diagnosed with a pT1c prostate cancer in 2022. Patient was then treated with radical prostatectomy. No residual disease was found. Would the correct EOD prostate path extension code be 999 based on Note 8 (code 999 when radical prostatectomy is performed, but there is no information on the extension); or, would we use code 300 (confined to prostate) because the data item "...is used to assign pT category for prostate cancer based on radical prostatectomy specimens" and we know it was limited to the prostate because no residual was found?