INACCURACIES IN CERTIFICATION OF NONMELANOMA SKIN-CANCER DEATHS

Nonmelanoma skin cancer is the most common cancer site in the United S tates, yet mortality from this cause is poorly understood. We sought m edical records of the 116 reported deaths during 1979 through 1987 fro m this cause (International Classification of Diseases, 9th version [I CD-9], code 173) among Rhode Island residents to evaluate the accuracy of the reported cause of death. Of the 110 cases for which the cause of death could be classified as correct or incorrect, 59 (54%) were mi sclassified, 49 (83%) of which were mucous-membrane, squamous-cell car cinomas of the head and neck. For most of these, the written death cer tificate diagnosis was squamous-cell carcinoma of the head and neck, w hich was coded 173.4. Other problematic diagnoses were cancer of the h ead and neck and malignant fibrous histiocytoma. In response to a mail ed survey, most health departments replied that squamous-cell carcinom a of the head and neck was coded under rubric 173 and malignant fibrou s histiocytoma was coded under rubric 171, but there was no unanimity. The misclassification of other causes of death to ICD-9 rubric 173 is substantial. The vast majority were coded to rubric 173.4 and were du e to a small number of diagnoses that are recognizable on examination of the death certificate.