Pathological assessment of tumour beds in breast excisions post-neoadjuvant therapy: a retrospective cohort study

The pathological assessment of breast cancer resection specimens with neoadjuvant therapy (NAT) offers invaluable information for prognosis and further management. At times, these cases are difficult to pathologically evaluate, at least partly due to tumour bed obscuration after NAT. This study aimed to compare time and resource utilization by surgical pathology laboratories when handling breast specimens treated with NAT against those without NAT. We secondarily aimed to identify features associated with tumour bed identifiability at gross assessment.

In this retrospective, single-institution study, we identified 241 breast resection specimens with systemic NAT between 2019 and 2025. A 1:1 non-NAT control group was randomly selected. The NAT cohort had a higher median number of tissue blocks (20.0 versus 13.0, P < 0.001), as well as larger proportions requiring gross resampling (23.7% versus 7.1%, P < 0.001) and pathologist review (16.2% versus 4.6%, P < 0.001) compared with the control. The NAT cohort had a longer median pathology report turnaround time (17.0 days versus 15.0 days, P < 0.001). In NAT cases, pretreatment clinical stage was associated with macroscopic identifiability of the tumour bed.

Breast cancer resection specimens with NAT required significantly more time and laboratory resources than similar specimens without NAT. As NAT becomes more frequent across breast and other cancer types, pathological assessment of the excisional specimens from these patients is expected to become more challenging and time-consuming. By recognizing these trends early, healthcare systems can plan and allocate resources accordingly.