Can pathology diagnostic services for cancer be stratified and serve global health?

Abstract

BACKGROUND: Before initiating cancer therapy, a diagnostic tumor tissue sample evaluated within a pathology laboratory by a pathologist is essential to confirm the malignancy type and provide key prognostic factors that direct the treatment offered. METHODS: Pathology evaluation includes multiple expensive reagents, complex equipment, and both laboratory and pathologist technical skills. By using breast cancer as an example, at a minimum, key tumor prognostic information required before the initiation of treatment includes subtype, tumor grade, tumor size, lymph node status when possible, and biomarker expression determined by immunohistochemistry for estrogen receptor. The additional determination of biomarker expression of progesterone receptor and human epidermal growth factor receptor (HER2) is the standard of care in high-resource settings, but assays may not be affordable in low-income and middleincome countries. RESULTS: With positive tests, patients are eligible for either tamoxifen (for estrogen receptor-positive/progesterone receptor-positive cancers) or monoclonal antibody therapy (for HER2-positive cancers). For settings in which endocrine therapy and/ or HER2-targeted therapy is unavailable, biomarker studies have no utility, and high-resource setting standards for pathology evaluation and reporting are unachievable. Resource-stratified pathology evaluation guidelines in cancer diagnosis have not been developed, in contrast to excellent comprehensive, resource-stratified clinical guidelines for use in low-income and middle-income countries, and these are long overdue. CONCLUSIONS: The challenges of pathology evaluation in the context of global health are being met by innovative solutions, which may change the face of pathology practice. Cancer 2020;126:2431-2438.

The Breast Health Global Initiative 2018 Global Summit on Improving Breast Healthcare Through Resource‐Stratified Phased Implementation: Methods and overview

“…The format of pathology reporting must follow the established guidelines of the College of American Pathologists (CAP) or other regulatory agencies within each region of the world. There is an urgent need for a resource‐stratified and WHO/CAP–endorsed set of pathology evaluation guidelines to complement the current NCCN resource‐stratified cancer care guidelines and to enable laboratories in lower resource settings to more practically meet stratified CAP/WHO standards appropriate to their resources, in alignment with stratified therapies available to the population they serve 38 …”

“…Systemic radiographic staging is appropriate for patients who have large, lymph node‐positive disease but is not warranted for asymptomatic patients who have smaller, lymph node‐negative breast cancer. In addition, pathologic and immunochemistry characterizations are imperative to determine biologic factors such as grade and the cancer's specific subtype, which drive the selection of effective systemic treatments 38 . The eighth edition of the AJCC Cancer Staging Manual now considers subtype characterization equally or more important than the anatomic extent of disease to determine prognosis and to select systemic management 40 …”

Neurotrophic tyrosine kinase inhibitors: A review of implications for patients, clinicians and healthcare services

“…28 This represents a significant investment by the NHS and an acknowledgment of the significance of immunohistopathology services to current and future cancer services in providing clinicians with comprehensive data around gene expression to inform treatment choice. 30 The scale of investment in immunohistopathology services to provide such comprehensive data may present another barrier in the ability of healthcare systems in developing nations to provide patients with access to targeted therapies to treat genetic mutations which occur with low frequency across multiple tumour types. 16 As previously discussed NTRK mutations occur across multiple cancer types with an estimated frequency of 1% 2 with the implication that comprehensive whole DNA sequencing across all tumour types to identify patients who may benefit from NTRK inhibitors will result in a high number of negative tests.…”

Breast cancer treatment: A phased approach to implementation

“…Effective cancer management pathways can be difficult to follow in low‐ and middle‐income countries (LMICs) because of financial constraints, the unavailability of resources, a lack of trained personnel, and poor infrastructure. Optimal treatment outcomes are dependent on a timely diagnosis, but in many LMICs, prolonged diagnostic delays are common because pathology services are few, overwhelmed, and costly 2 . Despite the critical nature of these essential tests for correct multimodality treatment planning, routine and critical ancillary pathology testing may not be performed because of extra costs that must be covered by the patient.…”