Cancer Incidence Patterns from First Phnom Penh Population-Based Cancer Registry (PP-PBCR): Cambodia, 2022-2023 
 
Background

PBCR provide the gold-standard data required for national cancer control, yet remain underdeveloped in many low-and-middle-income-countries. To address gaps, Cambodia established its first PBCR in 2023, marking a significant step toward developing a national cancer surveillance system.

Objectives

This study aimed to analyze cancer incidence patterns and data quality from PP-PBCR for the period 2022-2023, and to identify key priorities for strengthening cancer registration in Cambodia.

Methods

Incident cancer cases among PP residents diagnosed during the period were identified through active case finding across major health facilities within the catchment area. Case abstraction followed standardized PBCR procedures.
Tumors were coded according to the International Classification of Diseases for Oncology, Third Edition (ICD-O-3), and data were entered, validated, and managed using CanReg5. Descriptive analyses included computation of crude, age-specific, age-standardized incidence rates (ASRs, standardized to the world population), and cumulative incidence risk.
Data quality was evaluated using standard indicators—morphological verification (MV%), proportion of death-certificate-only (DCO%) cases, checks for internal consistency and duplicate entries.

Results

The PP-PBCR covered an estimated resident population of approximately 2.3 million individuals during the study period. A total of 1,738 incident cancer cases were registered among the residents (59.1% among females; 40.9% among males).
The five most common cancers—breast (13.5%), colorectal and anal (11.0%), cervical (10.6%), liver (9.5%), and thyroid (7.8%)—accounted for approximately 58% of all cases.
Based on age-standardized incidence rates (ASRs) per 100,000 population, the leading cancers among males were liver cancer (ASR 6.2), colorectal and anal cancer (ASR 5.4), and lung cancer. Among females, the leading cancers were breast cancer (ASR 9.3), cervical cancer (ASR 7.8), and colorectal and anal cancer (ASR 3.3). Compared with national estimates from GLOBOCAN 2022, the site-specific ASRs in PP were substantially lower across all major cancer types.
The cumulative risk of developing cancer before age 65 was 2.7% overall (approximately 1 in 38 individuals), with a slightly higher risk among females (2.9%) than males (2.5%). Childhood cancers (age 0–14 years) accounted for 3.9% of all cases, corresponding to an age-standardized incidence rate of 65 per million. The predominant childhood malignancies were leukemia and lymphoma.
Regarding data quality, 92% of cases were MV%, 8% were clinically diagnosed, and no DCO cases were recorded. This reflects reliance on active case finding from medical records during the early implementation. A high proportion of MV% cases and zero DCO percentage may also indicate incomplete capture of cancer deaths occurring outside hospital settings.
Overall, case counts were lower than expected relative to regional benchmarks, suggesting under-ascertainment from selected data sources.

Conclusions

The PP-PBCR demonstrates the feasibility of producing reliable cancer incidence data in a resource-limited setting. While early results highlight under-ascertainment; they also establish a crucial baseline for ongoing improvement. Strengthening institutional capacity, governance, data quality, and the use of findings for policy is essential to ensure the PBCR serves as a foundational platform for evidence-based cancer control planning and integration into national surveillance systems.