Invasion characteristics of oral tongue cancer: frequency of reporting and effect on survival in a population-based study.

BACKGROUND

The 2000 College of American Pathologists (CAP) guidelines recommend that a characterization of carcinomas of the upper aerodigestive tract, including tongue cancer, should include depth of invasion (DI) and the presence of lymphovascular invasion (LVI) or perineural invasion (PNI).

METHODS

This study included patients who were diagnosed with cancer of the oral tongue, who underwent tumor resection, and who were reported to either the Metropolitan Atlanta and Rural Georgia Surveillance, Epidemiology, and End Results (SEER) registry or the Los Angeles SEER registry. The authors assessed the completeness of pathology reporting with respect to the documentation of PNI or LVI and DI. Generalized estimating equations were used to examine factors that influenced reporting while taking into consideration clustering of observations within the hospitals. Univariate and multivariate survival analyses were conducted to examine the impact of tumor invasion characteristics on mortality while controlling for other prognostic factors.

RESULTS

DI reporting increased from 13% between 1997 and 1999 to 23% between 2000 and 2004 after the CAP issued its recommendations; whereas mode of invasion (the presence of LVI and/or PNI) reporting for the same period increased from 13% to 38%. The observed increase in reporting was most pronounced in the first 2 years (2000 and 2001) and appeared to decline again afterward. Tumor invasion >3 mm in depth and the presence of PNI were among the strongest predictors of survival in multivariate analyses.

CONCLUSIONS

The current results indicated the importance of reporting tumor invasion characteristics for patients diagnosed with cancer of the oral tongue. The findings also underscore the need for continuous monitoring of adherence to the CAP protocol.