08/2022 Breast lump found;
10/2022, US/ Mammo positive for lesion.
10/2022 biopsy returned "invasive ductal carcinoma, Stage 2A, Estrogen positive 80/90%.; Oncology decision, start chemo to shrink tumor as lesion close to pectoral muscle. TC therapy 4-6 rounds, on round every 21 days; Mammoprint was sent out and came back "basal type".
Patient asked oncologist if "basal type" was actually triple negative and oncologist said "don't worry".
10-28 2022 Pt. began TC therapy for 6 treatments.
2-17-2023 was last treatment.
3-23-2023 bilateral mastectomy. Post Chemo tumor was reported as 3mm residual. Pathology then came back as triple negative breast cancer. That specimens was sent for a second opinion. Both the original "core biopsy" and surgical biopsy were sent to Mayo Clinic for a second opinion. Both specimens were triple negative, thus the original read was incorrect. As a result of the above, a second round of chemotherapy was required
Question: What is the morbidity or potential morbidity of this error?
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Do you believe there might have been medical error?
The original pathology was read incorrectly so there is a medical error by the pathologist. the tumor was then sent to Mammoprint which read tumor as basal type which the oncologist did not act on or perform any confirmatory investigation as to why there was a discrepancy between the tumor IHC and the Mammoprint results. this is a medical error on part of the oncologist. the neoadjuvant chemotherapy given would have been a different regimen if it was acknowledged that the tumor was triple negative and not triple positive. Lastly, if the tumor had in fact been "triple positive" the patient was not given herceptin which would have been indicated in the neoadjuvant setting. This is also a medical error on part of oncologist.
Do you believe there might have been causation (i.e. the medical error resulted in an injury)?
Based on results of the Phase III clinical trial KEYNOTE 522, the patient should have received immunotherapy with the neoadjuvant chemotherapy. The regimen the patient should have received pre-op is Taxol/carbo/pembrolizumab x4 cycles followed by adriamycin/pembrolizumab x4 cycles. Following surgery the patient would receive pembro for 9 additional cycles with the option to add additional chemo (oral capecitabine) if pCR was not obtained. All measures of patient outcomes are improved in KEYNOTE 522 with addition of pembrolizumab including rates of pCR (65% vs 51%), EFS (85% vs 77%), and 3 year OS (90 vs 87%).
What makes you a good expert for this case?
I am a medical oncologist at a major cancer institution with over 20 years of specialty experience in breast and gynecological cancers.
How often do you encounter cases similar to this one in your practice?
Treating triple negative and triple positive breast cancer- every day. A case where the initial pathology was read completely incorrectly is rare but I have seen it.
Do you believe there might have been medical error?
Sometimes there could be tumor heterogeneity so final surgical specimen can have different markers than biopsy. But if Mayo Clinic revealed negative er and the site mentioned 80% er it is an error
Do you believe there might have been causation (i.e. the medical error resulted in an injury)?
For upfront triple negative breast cancer, treatment would be different as we would add immunotherapy (pembrolizumab)
What makes you a good expert for this case?
Worked in the field for 10 years and being an active member in the NAPBC accreditation for 2 centers. Besides I am active involved in weekly breast tumor boards and have give talks
How often do you encounter cases similar to this one in your practice?
12-15 cases annually for triple negative breast cancer
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