The five-year survival rate for U.S. patients with cancer of the base of the tongue or tonsils doubled between 1980 and 2002, according to a new study in Cancer Causes & Control (January 2012, Vol. 23:1, pp. 153-164).
In addition, patients with human papillomavirus (HPV)-related cancers had greater survival rates than those with other oral cancers, and survival was greater for male patients than females regardless of age, according to the study authors, from the New York Eye and Ear Infirmary, the University of Utah School of Medicine, and the University of California, Los Angeles School of Public Health. However, patients with subsequent multiple cancers showed no overall survival improvement.
The incidence rates of tongue and tonsil cancers have increased significantly in recent decades in the U.S., particularly among younger patients, the researchers noted. At the same time, a number of studies have shown a strong association between HPV infection and tongue and tonsil cancers.
For this study, they used data from the Surveillance, Epidemiology, and End Results (SEER) 1973-2006 registry system to examine changes in survival rates among patients with base of tongue, tonsil, and other tongue cancers in recent decades. The study included 10,704 patients with squamous tongue or tonsil cancer who were at least 20 years old.
The researchers separated the patients into those with one primary cancer and those with subsequent multiple cancers, then compared trends using three nonoverlapped periods: 1980-1982, 1990-1992, and 2000-2002. The first group included those with only one primary base of tongue, tonsil, or other tongue cancer, while the other consisted of those with subsequent primary cancers after an initial diagnosis of base of tongue, tonsil, or other tongue cancer.
Some 9,187 patients had one primary base of tongue, tonsil, or other tongue cancer, including 2,619 who were diagnosed with base of tongue cancer, 3,225 with tonsil cancer, and 3,343 with cancer in other sites of the tongue. Another 1,517 had subsequent multiple cancers, including 450 who were previously diagnosed with base of tongue cancer, 514 with tonsil cancer, and 553 with other tongue cancer.
Overall survival rates
After analyzing the data, the researchers found that the five-year overall survival rates for base of tongue cancer rose from 24.7% in the 1980s to 50.5% by 2002 (p < 0.001). For patients with tonsil cancer, the survival rate increased from 28.2% to 60.0% (p < 0.001). Patients with other tongue cancers experienced survival rate increases from 36.3% to 52.4% (p < 0.001) in the same 20-year period.
Compared with patients with one primary cancer, however, survival rates for patients with multiple tumors in the base of tongue, tonsil, or other tongue sites dropped significantly, the study authors noted.
Most notably, the five-year cancer-specific survival rates went up by 222.4% (17.4% in 1980 versus 56.1% in 2002) for the base of tongue cancer, 292.3% (16.8% in 1980 versus 65.9% in 2002) for tonsil cancer, and 95% (29.9% in 1980 versus 58.3% in 2002) for other tongue cancers.
Younger patients had much better survival rates, and young men's survival doubled during the 20-year period, the researchers found. Five-year overall survival rates among female patients ages 20 to 59 years old increased by 71.3% (p < 0.001) and 27% (p = 0.03) for women age 60 and older. In contrast, survival rates increased by 152.1% (p < 0.001) for males ages 20 to 59 and 101.0% (p < 0.001) for men age 60 and older, they noted.
Screening and early treatment key
Survival was similar between patients who received surgery alone or those who had radiation therapy, the study authors found.
"A possibility for the improved survival trends is the effects of early oral screening and early diagnosis and early treatment of oral cancer," they wrote.
They also speculated that cancers of the tongue and tonsil may be diagnosed more easily and earlier during oral screening, thus increasing survival.
Patients with regional stage tumors also showed improved survival, the researchers found.
The strong association between HPV infection and base of tongue and tonsil cancers probably played a part in the improved survival of both cancers, they noted. This could be related to the nature of the epithelium of the base of the tongue and the tonsil since HPV infection is close to lymphoid tissue, they wrote.
"Survival has significantly improved from the 1980s to the 2000s among patients with base of tongue or tonsil cancer, as well as among patients with other tongue cancer," the researchers concluded. "Because of the reported strong association of HPV infection with base of tongue and tonsil cancers in incidence and in prognosis, we suspect that the time-dependent improvement may be related with increased HPV infection among patients."
