Less Smoking and Drinking Tied to Oral Cancers

Other Factors at Play

Roxanne Nelson

September 18, 2012

September 18, 2012 — The prevalence of smoking and alcohol use has declined over the past few decades in patients with oral cavity cancer, according to a new single-institution study. Because these factors are associated with the disease, it is now considered likely that other causes play a role in the pathogenesis of oral cancer.

Researchers from the Memorial Sloan-Kettering Cancer Center in New York City found that during the past 25 years, there has been a progressive decline in tobacco use in this cancer population at their institution. From 1985 to 1990, 80% of patients treated there used tobacco; from 2005 to 2008, 55% did.

In addition, there was a decline in the daily amount of tobacco used. In the early cohort, 55% of patients smoked more than 1 pack per day, whereas in the late cohort, 30% did (P < .001).

The researchers found that alcohol consumption also declined over the decades, from 80% in the early cohort to 67% in the late cohort (P < .007). In addition, the percentage of patients who consumed more than 3 drinks per day decreased from 23% in the early cohort to only 9% in late cohort (P < .001).

These findings were published in the September issue of the Archives of Otolaryngology — Head & Neck Surgery.

Not Quite That Simple

The worldwide incidence of oral cancer is increasing, explained lead author Ian Ganly, MD, PhD, a surgeon at the Memorial Sloan-Kettering Cancer Center. "In the United States, it is actually decreasing, largely due to the reduction in smoking," he said.

But it is not quite that simple, he noted. The number of cases seen at his institution has doubled over what was seen 25 years ago, he reported. "Our numbers are increasing," Dr. Ganly told Medscape Medical News, "but the patient population is quite different. Before it was largely a smoking/alcohol population; now we see more nonsmokers and nondrinkers with oral cancer than smoker and drinkers," he explained.

The researchers do not know why the demographics have changed. He pointed out that the sex and age distribution and disease staging of their patients is the same, and that survival figures are stable.

However, they are seeing more oral tongue cancer in patients younger than 60 years. For patients younger than 60 years, the percentage of oral and nonoral tongue cancer cases is unchanged, Dr. Ganly said. For those younger than 60 years, the percentage of oral tongue cases is increasing and the percentage of nonoral tongue cancer cases is decreasing, he reported.

Other Causes

A recent study showed that the incidence of oral tongue squamous cell carcinoma increased 28% from 1975 and 2007 in people 18 to 44 years of age, as previously reported by Medscape Medical News (J Clin Oncol. 2011;29:1488-1494). Among white people in this age group, the incidence increased 67%; among white women, the incidence jumped a dramatic 111%.

These data "suggest we are seeing a change in the epidemiology of this disease — mainly in oral tongue cancer," said Dr. Ganly. "There must be another cause for this, but we do not know what it is," he acknowledged.

Studies suggest that human papillomavirus (HPV) might be the driver behind a rising increase of oropharyngeal squamous cell carcinoma. Dr. Ganly notes that a change in the oral microbiome might be another cause. "Clearly, more research is needed to identify what is causing this change," he said.

Changing Trends

Oral cavity cancer is the eighth most frequent cancer in the world, and the traditional causes are smoking and alcohol consumption. However, major cancer registries, such as the Surveillance, Epidemiology and End Results (SEER) database, do not collect information on tobacco and alcohol use in patients with cancer, and the current literature in head and neck cancer has not reported on trends in tobacco and alcohol use among patients with oral cancer, note Dr. Ganly and colleagues.

The scarcity of these data is important, according to the researchers, because recent studies of oropharynx cancer have shown a causal change.

After a review of the medical records of patients with oral cavity cancer from 1985 to 2009, the researchers included data from 1617 patients in their analysis.

To compare trends in alcohol and tobacco use, the patients were divided into 5 different cohorts, according to the date of initial surgery: 274 patients were treated from 1985 to 1990; 250 were treated from 1990 to 1994; 315 were treated from 1995 to 1999; 356 were treated from 2000 to 2004; and 422 were treated from 2005 to 2009.

The median age of patients was 62.5 years (range, 15.0 to 97.0 years), 86.5% were white, and 56.0% were men. The most common cancer subsite was oral tongue (49.0%), and 72.0% had T1 or T2 tumors. During the study period, there were no changes in sex or age distribution, but there was an increase in the percentage of nonwhite patients (9.1% to 16.6%). This change is primarily related to the increase in the number of patients of Asian origin.

The researchers report that over time, there was a small increase in the number of buccal mucosa cancer cases and a reduction in the number of cases of floor of mouth cancer.

When stratified by sex, the decrease in the prevalence of alcohol and tobacco use was larger in women than in men. This decrease was statistically significant for men and women who used tobacco (P < .05) but not for those who used alcohol (P = .06).

The authors have disclosed no relevant financial relationships.

Arch Otolaryngol Head Neck Surg. 2012;138:817-822. Abstract