Modifications to Pathology practice during COVID-19

Breast Pathology perspective

Dr. Sharon Nofech Mozes MD, Associate professor LMP, Sunnybrook Health Sciences Centre 

As hospitals are setting up measures to prepare to provide medical care to patients in the midst of COVID19 pandemic, substantial considerations had to be applied to the care provided to cancer patients.

The goal is to minimize exposure of cancer patients to COVID-19 without compromising or minimizing impact on oncologic outcomes.

Mitigation strategies to practice social distancing have been established in cancer centres.

Moreover, the necessity to free up hospital beds and other resources has a substantial effect on operating room availability for breast surgeries leading to unprecedented effort to prioritize cases based on risk scale and presence of alternative approaches to enable delayed surgeries.

In principal, whenever a reasonable alternative to the standard of care of primary surgical treatment exists, patients will be assigned to the alternative approach. 

From the perspective of breast pathology service Breast Group at Sunnybrook Health Sciences Centre have modified two points in our routine practice. 

1. As a result of delaying surgeries for noninvasive cancer, we instated reflex testing for hormone receptors (estrogen and progesterone receptors) when ductal carcinoma in situ or pleomorphic lobular carcinoma in situ are diagnosed on core needle biopsy. These results would assist in consideration of presurgical/ neoadjuvant endocrine therapy while monitoring the lesion by breast imaging every 3-6 months. 
2. Patients with ER+/HER2- T1b-cN0 or T2N0 or T3N0 Grade 2-3 will be considered for neoadjuvant endocrine therapy for 3- 6 months. Neoadjuvant chemotherapy may be offered if Oncotype DX recurrence score is high (or intermediate high). Limited data emerging from a phase II trial suggest that both pretreatment and post-treatment Recurrence Scores were significantly associated with disease-free survival after neoadjuvant endocrine therapies. In addition, high Oncotype DX Recurrence Score was associated with pCR after neoadjuvant chemotherapy in a retrospective analysis of the National Cancer Database  of T1-T3 mostly N0 cohort of ER-positive, HER2-negative breast cancer patients;  however the Recurrence Score has not been largely validated in this settings. Furthermore, the standard specimen to use for testing Oncotype DX is breast resection, whereas now we are faced with requests to sending blocks from breast core biopsies for testing. The assay is generally feasible (in about 85% of cases) if there is at least one core with 2 mm contiguous invasive carcinoma, and the pathologist should keep this in mind before selecting the optimal block. In addition, if more than one block with tumor is available from a biopsy procedure, pathologists should preserve the tissue from one of the blocks by avoiding any unnecessary ancillary immunohistochemical stains as long as the diagnosis is not compromised. 

In the proceeding months as neoadjuvant endocrine therapy would to be offered in ER+/HER2- 1-2 early invasive breast carcinoma  and ER+ carcinoma in situ, breast pathologists are expected to examine more resection specimens post neoadjuvant endocrine therapy. 

Resources and references

COVID-19 Supplemental Clinical Guidance for patients with Cancer. Ontario Health, Cancer care Ontario. March 29, 2020. 

Changes in Recurrence Score by neoadjuvant endocrine therapy of breast cancer and their prognostic implication. ESMO Open. 2019 Feb 27;4(1):e000476. doi: 10.1136/esmoopen-2018-000476. eCollection 2019. 

Oncotype DX® Recurrence Score as a Predictor of Response to Neoadjuvant Chemotherapy. Ann Surg Oncol. 2019 Feb;26(2):366-371. doi: 10.1245/s10434-018-07107-8. Epub 2018 Dec 12. 

Utilization of the 21-Gene Recurrence Score in a Diverse Breast Cancer Patient Population: Development of a Clinicopathologic Model to Predict High-Risk Scores and Response to Neoadjuvant Chemotherapy. Ann Surg Oncol. 2018 Jul;25(7):1921-1927. doi: 10.1245/s10434-018-6440-7. Epub 2018 Apr 20. 

The Centre for Addiction and Mental Health (CAMH) 

Guidelines for Medicolegal Autopsies during COVID19 (PDF) - Dr Michael Pollanen, March 2020 - Office of the Chief Coroner/Ontario Forensic Pathology Service (OCC/OFPS)