Inflammatory Tongue Conditions and Risk of Oral Tongue Cancer Among the US Elderly Individuals

Abstract

Purpose: The incidence of oral tongue cancers has increased since the 1980s among US men and women for unknown reasons. We investigated associations of inflammatory tongue conditions with risk of cancers of the oral tongue, other oral cavity, and oropharynx among the US elderly individuals (age 65 years or older).

Methods: We conducted a case-control study (2,534 oral tongue cancers, 6,832 other oral cavity cancers, 9,373 oropharyngeal cancers, and 200,000 controls) within the SEER-Medicare data set (1992-2013). Medicare records were used to identify patients with clinically diagnosed inflammatory tongue conditions (glossitis, benign migratory glossitis, median rhomboid glossitis, atrophic glossitis, glossodynia, other specified conditions [eg, atrophy and hypertrophy], and other unspecified conditions) and oral precancer (leukoplakia/erythroplakia). Only conditions preceding cancer/control selection by >12 months were included.

Results: The prevalence of inflammatory tongue conditions was significantly higher in patients with tongue cancer than controls (6.0% v 0.6%; odds ratios [ORs], adjusted for age, sex, race, Medicare utilization, and precancer, 5.8 [95% CI, 4.7 to 7.2]). This overall association primarily arose from glossitis, 5.6 (95% CI, 4.4 to 7.2); other specified conditions, 9.1 (95% CI, 5.5 to 15.2); and other unspecified conditions, 13.7 (95% CI, 8.0 to 23.7). These associations remained strongly elevated >5 years preceding tongue cancer (arguing against reverse causation), for conditions diagnosed by a specialist (arguing against misclassification), and among patients who received an oral biopsy (arguing against missed cancer). During 2013, an estimated 1 in 11 patients with oral tongue cancer had a preceding diagnosis of inflammatory tongue conditions. Associations of inflammatory tongue conditions were relatively weak for other oral cavity cancers (ORs, 1.8 [95% CI, 1.5 to 2.3]) and oropharyngeal cancer (OR, 1.3 [95% CI, 1.0 to 1.6]) and were observed only closest to cancer diagnosis.

Conclusion: Inflammatory tongue conditions were associated with strongly increased risks of oral tongue cancers and preceded cancer diagnosis by several years, underscoring the need for increased clinical surveillance among patients with such apparently benign diagnoses.

FIG 1.

Associations of inflammatory tongue conditions with the risk of oral tongue cancer, separately by site of cancer. This figure shows the association of inflammatory tongue conditions (combined), glossitis, other specified tongue conditions, and other unspecified tongue conditions with the risk of oral tongue cancer separately by site of cancer (dorsal, lateral, ventral, and anterior two third NOS). The results are based on binary logistic regression models. Separate models for each exposure were adjusted for age, sex, race, No. of medical visits (continuous, on the basis of NCH records) between entry and 1 year before cancer/control selection, and oral precancer. The results are shown on a log (natural) scale. NCH, National Claims History; NOS, not otherwise specified; OR, odds ratio.

FIG 2.

Associations of inflammatory tongue conditions and oral precancer with the risk of oral tongue cancer, stratified by stage at cancer diagnosis. This figure shows the ORs and 95% CIs for the association of inflammatory tongue conditions (combined), glossitis, other specified tongue conditions, and other unspecified tongue conditions with the risk of oral tongue cancer stratified by stage at cancer diagnosis (SEER historic stage: localized, regional, and distant). Associations are also shown for oral precancer (leukoplakia/erythroplakia). The results are based on multinomial logistic regression models with controls (reference category), localized, regional, distant, and unstaged cancer as the outcome. Separate models for each exposure were adjusted for age, sex, race, No. of medical visits (continuous, on the basis of NCH records) between entry and 1 year before cancer/control selection, and oral precancer. The results are shown on a log (natural) scale. NCH, National Claims History; OR, odds ratio.

FIG A1.

Prevalence of inflammatory tongue conditions by calendar time in controls and patients with oral tongue cancer. (A) Shown for controls and (B) oral tongue cancer cases are crude prevalence of inflammatory tongue conditions in each calendar year and modeled prevalence of such conditions in each year. Modeled prevalence was estimated in binary logistic regression models with inflammatory tongue conditions as the outcome and calendar year as a linear predictor, with adjustment for age, sex, and race. Mean of the model predicted probability in each calendar year is shown.