Preparing the Laboratory for Neoadjuvant Cancer Immunotherapy: Insights from a Pathology Learning Collaborative

Abstract Introduction/Objective Neoadjuvant immunotherapy (NIT) is an emerging strategy to treat multiple types of early- stage resectable cancers by inducing a systemic anti-tumor immune response and increasing the likelihood of complete pathological response (pCR). The evaluation of pathological response following NIT is challenging and requires specific expertise. Traditional response criteria may be difficult to apply since immunotherapy may lead to unique changes in the tumor bed. Moreover, many laboratories may not feel prepared to evaluate pathologic response following immunotherapy given their lack of experience and the time required to accurately assess specimens and report findings. Methods/Case Report To explore ways to help laboratories prepare for these challenges, the American Society for Clinical Pathology (ASCP) formed an immuno-oncology learning collaborative to engage pathologists from different institutions and subspecialties. The group met over six months to review and discuss the implications of relevant literature, guideline recommendations, and emerging trends such as tumor-specific recommendations (eg, IASLC Neoadjuvant Therapy Pathologic Response Initiative) to pan-tumor immune-related pathologic response criteria (irPRC). ASCP then developed a series of educational resources based on recommendations made by the group. Results (if a Case Study enter NA) Members of the ASCP learning collaborative identified and prioritized several topics to help laboratories prepare and equip their teams to perform pathologic assessment after neoadjuvant immunotherapy in routine clinical practice. These included: definition and classification of pathological response criteria, assessing unique changes in the tumor bed (ie, regression bed), interpreting data from clinical trials, reporting results in routine clinical practice, organizing educational resources, and staffing workload. The group also emphasized the importance of collaborating with oncologists and surgeons and promoting communication about these topics within each institution. Conclusion Based on promising results from neoadjuvant immunotherapy clinical trials, we can expect more FDA approvals for neoadjuvant indications and a growing number of patients receiving this treatment. Pathologists and laboratory professionals need to prepare their institutions for a future where the assessment of pathological response in routine clinical practice will impact treatment decisions following surgical resection.