Background: Access to reliable anatomical pathology services remains a major bottleneck for cancer diagnosis in many low- and middle-income countries, particularly in sub-Saharan Africa. In the Democratic Republic of Congo, limited laboratory infrastructure and specialist capacity severely constrain timely and accurate cancer detection, especially in the eastern region where the burden of disease is increasing.
Objective: The objective of this study was to evaluate the infrastructure and diagnostic capacity of pathology laboratories in eastern Democratic Republic of Congo (DRC) in order to inform strategies for strengthening cancer diagnosis in a low-resource setting.
Method: A multi-site study was conducted using a mixed-methods approach to analyse laboratory equipment, human resources and diagnostic performance. Data were collected from February to April 2023 through local pathology laboratories. Laboratory assessments were conducted using a structured evaluation grid adapted from international pathology capacity assessment frameworks. Quantitative data on diagnostic outputs were complemented by key informant interviews with laboratory personnel to capture operational constraints and training needs.
Results: The results show a concentration of laboratories in urban areas covering populations in only three provinces (South Kivu, North Kivu and Haut Katanga), leaving nine provinces without diagnostic coverage and more than 26.8 million people lacking access to pathology services. The analysis revealed major gaps in anatomical pathology services, including the absence of immunohistochemistry outside Panzi Hospital, lack of computerized sample-tracking systems and non-standardized quality control protocols. Human resources are critically limited, with most laboratories operating with a single pathologist and minimal histotechnician support. Histopathology accounted for 73.4% of processed samples, with inflammatory and infectious lesions representing 41.2% of diagnoses. The most frequent malignancies were cervical (16.6%), prostate (14.1%), breast (13.9%) and colorectal cancers (3.0%). Limited cytological analyses and the absence of fine-needle aspiration further compromise diagnostic accuracy.  
Conclusion and implications: Beyond documenting gaps, this study highlights the critical role of regional and international partnerships in supporting diagnostic services and identifies priority areas for capacity strengthening, including decentralization of pathology infrastructure, introduction of basic immunohistochemistry, implementation of quality assurance systems, and continuous training of laboratory personnel. In this context, an ongoing research collaboration with the International Agency for Research on Cancer (IARC) supports diagnostic validation, with the IARC laboratory serving as an international reference center for the verification of colorectal cancer diagnoses generated by laboratories in eastern DRC. These external quality assessment activities, currently in progress, represent an important mechanism for improving diagnostic reliability and strengthening research capacity in the region. Furthermore, the introduction of digital pathology tools (slide scanners), combined with laboratory networking, offers a promising strategy to expand diagnostic coverage, enable remote expertise, and improve equitable access to pathology services for underserved populations in eastern DRC. Strengthening these components through coordinated national and international partnerships is essential to improving cancer diagnosis and equity of care in the DR Congo