Systematic under-ascertainment of anaplastic large cell lymphoma cases in cancer registries: report from a comprehensive cancer center.

[INTRODUCTION] Breast implant-associated anaplastic large cell lymphoma (ALCL) has been rapidly rising in the US and around the world, leading to a mandated "black-box" label on all silicone- and saline-filled implants by the Food and Drug Administration (FDA). Because regulatory decisions in the US and around the world have been influenced primarily by risk estimates derived from cancer registries, it is important to determine their validity in identifying cases of ALCL.

[METHOD] We reviewed all cases of ALCL submitted to the New York State Cancer Registry from a large comprehensive cancer center in New York City from 2007 to 2019. To determine the possibility of misdiagnosis or under-diagnosis of ALCL cases reported to cancer registries, we accessed the sensitivity and specificity of the ICD-O-3 codes 9714 (ALCL) and 9702 (Mature T-cell lymphoma, not otherwise specified [T-NOS]) to identify pathologically-proven ALCL.

[RESULTS] We reviewed 2286,164 pathology reports from 47,466 unique patients with primary cancers. Twenty-eight cases of histologically-proven ALCL were identified. The sensitivity and specificity of the ICD-O-3 code 9714 (ALCL) were 82% and 100%, respectively. The sensitivity of the combined codes 9714/9702 (ALCL/T-NOS) was 96% and the specificity was 44%.

[CONCLUSION] Previous epidemiological studies that influenced regulatory decisions by the FDA may have systematically underestimated the risk of ALCL by at least 20%. We encourage updated global risk estimates of breast ALCL using methods that ensure adequate case ascertainment.