# Longitudinal Analysis of Oral Potentially Malignant Disorder Conversion to Malignancy

## TL;DR

A 25-year study tracks how oral conditions linked to cancer risk develop into malignancies over time.

## Contribution

A longitudinal analysis of over 1500 patients reveals malignant conversion rates and the need for long-term surveillance of oral potentially malignant disorders.

## Key findings

- 4.69% of patients with oral potentially malignant disorders developed cancer over a 10-year period.
- Tongue cancers were the most common type of malignancy observed.
- Some malignant conversions occurred after a 5-year surveillance period, suggesting the need for long-term monitoring.

## Abstract

Oral potentially malignant disorders (OPMDs) are local and systemic conditions that can result in oral malignancies. We have had an OPMD surveillance program for 25 years covering over 30% of our state's population. More recent electronic health record search techniques have allowed us to analyze over 1500 patients in over a 10‐year period, approximately 20% of total referrals.

Electronic health record (EHR) information was queried for 24 International Classification of Disease (ICD) 9 and 10 codes to generate a de‐identified data set. Charts within this data set were cross‐referenced against 79 ICD9/10 codes corresponding to oral and oropharyngeal cancers. The time course of conversion and frequencies of precancerous and cancerous lesions was assessed.

Of 4496 unique patients seen, 1535 patient records met inclusion criteria. Seventy two patients showed cancerous conversion (4.69%), with 55 (3.58%) before 5 years, and 17 (1.11%) after a 5‐year surveillance period. Leukoplakia and OLP patients constituted 34.7% of conversions, though other lesions/diseases of the tongue/oral mucosa showed conversion. Tongue cancers were the most represented carcinomas, followed by carcinomas of the oropharynx.

We discovered overall rates of malignant conversion within the broad range reported in the world literature (0%–60%). Importantly, this living data set can be repeatedly queried over time to discover significant malignant conversions, potentially over decades. With significant conversions occurring after 5 years, OPMD conditions likely require longer‐term surveillance like colon, breast, or other cancers.

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