Oropharyngeal cancer incidence trends: diminishing racial disparities

Active tobacco smoking and distant metastasis in patients with oropharyngeal cancer

PURPOSE

Distant metastasis is the site of first relapse in approximately one-third of patients with locally advanced oropharyngeal carcinoma, irrespective of human papillomavirus status. Yet the risk factors associated with distant metastasis are not well characterized. We sought to characterize the relationship between smoking status and distant metastasis.

METHODS AND MATERIALS

We evaluated the association between tobacco smoking status and distant metastasis in a retrospective cohort study of 132 patients who underwent definitive radiation therapy and chemotherapy for Stage III-IVA/B oropharyngeal cancer. Information on tobacco smoking was prospectively collected by patient questionnaires and physician notes at the time of diagnosis. Thirty-three percent of the patients were nonsmokers, 51% were former smokers, 16% were active smokers. The cumulative lifetime tobacco smoking in pack-years was 20 (range, 0-150).

RESULTS

With a median follow-up time of 52 months, the overall rate of distant metastasis at 4 years was 8%. Distant metastasis was the most common first site of relapse, occurring in 56% of the patients with recurrences. Active smokers had higher rates of distant metastasis than non-active smokers (including never- and former smokers; 31% vs. 4%, p < 0.001) and former smokers (31% vs. 3%, p < 0.001). There was no statistically significant difference in the risk of distant metastasis for patients with lifetime cumulative pack-years >20 and ≤20 (10% vs. 4%, p = 0.19). In univariate analysis, active smoking (p = 0.0004) and N category (p = 0.009) were predictive of increased risk of distant metastasis. In multivariate analysis, active smoking was the most significant predictive factor for increased risk of distant metastasis (hazard ratio, 12.7, p < 0.0001).

CONCLUSIONS

This study identified a strong association between active smoking and distant metastasis in patients with oropharyngeal cancer.

Streptococci-human papilloma virus interaction with ethanol exposure leads to keratinocyte damage

PURPOSE

Ethanol, human papilloma virus (HPV), and poor oral hygiene are risk factors that have been attributed to oral carcinogenesis. Streptococci sp and HPV infections are common in the head and neck, often associated with sexual activity. Although HPV is linked to head and neck squamous cell carcinoma, it is unclear whether there is a similar role for Streptococci sp. This cell study examines whether Streptococci sp and HPV-16 with exposure to ethyl alcohol (ETOH) can act as cofactors in the malignant transformation of oral keratinocytes.

MATERIALS AND METHODS

ETOH (0.1%-20% vol/vol) was used to investigate Streptococci sp attachment with immortalized E6-expressing HPV/HOK-16B cells, human oral buccal keratinocytes, and foreskin keratinocytes. Streptococci sp (Streptococci mutans [LT11]) and various strains of acetaldehyde (AA) producer and nonproducer Streptococcus salivarius (110-1, 109-2, 101-7, and 107-1) and a lactic acid producer bacterium, Lactobacillus rhamnosus (24-1 and 25-2), were examined for interactions with keratinocytes by use of a green dye (percent of cells with colonies after 24 hours). Carcinogens, AA, malondialdehyde, DNA damage, and proliferation (5'-bromo-2-deoxyuridine) among keratinocytes were also quantified.

RESULTS

AA and malondialdehyde production from permissible Streptococci sp significantly increased with attachment to keratinocytes, whereas L rhamnosus did not significantly attach to keratinocytes. This attachment was associated with enhanced levels of AA adduct formation, proliferation (5'-bromo-2-deoxyuridine incorporation), and enhanced migration through integrin-coated basement membrane by HPV oral keratinocytes, which are characteristics of a malignant phenotype.

CONCLUSIONS

These cell studies suggest that oral Streptococci sp and HPV (HPV-16) cooperate to transform oral keratinocytes after low-level ETOH (1%) exposure. These results appear to suggest a significant clinical interaction, but further validation is warranted.

Trends in incidence of oral and pharyngeal carcinoma in Florida: 1981-2008

OBJECTIVE

While the overall incidence rates of oral and pharyngeal squamous cell carcinoma (SCC) have decreased in the United States, there is evidence of increasing incidence at selected anatomic sites, particularly among younger adults. The objective of this study was to examine trends in incidence rates of oral and pharyngeal cancers in Florida.

METHODS

Using data from the Florida Cancer Data System, we examined the incidence of oral and pharyngeal carcinomas in Florida from 1981 through 2008. Factors of interest included sex, race, and trends over time. Percent change (PC) and annual percent change (APC) were computed to characterize trends over time.

RESULTS

A total of 53,648 cases of oral or pharyngeal cancer were identified from 1981 through 2008. Significant increasing trends were observed only for pharyngeal cancers in males, with significant decreasing trends for pharyngeal cancer in females and oral cancer for both sexes. For tonsil and base of tongue cancers, increasing trends were detected for white males only. Further investigation among white males showed that, except for base of tongue cancer in the 20-44 age group, the incidence of both cancers increased across all age groups, with the largest increase for both sites found in the 45-64 age group.

CONCLUSIONS

This study supports the finding of increasing incidence of SCC of the tonsil and base of tongue in males, in contrast to decreasing trends for most oral and pharyngeal carcinomas. However, we observed that this increase occurred in white males only and the most dramatic increase occurred in the 45-64 age group.

The challenges of defining oral cancer: analysis of an ontological approach

An important inconsistency currently exists in the literature on oral cancer. Reviewing this literature, one finds that the term oral cancer is defined and described with great variation. In a search in PubMed, at least 17 different terms were found for titles of papers reporting data on oral cancer. The variability of the terms used for designating anatomic regions and type of malignant neoplasms for reporting oral cancer has hampered the ability of researchers to effectively retrieve information concerning oral cancer. Therefore, it is sometimes extremely difficult to provide meaningful comparisons among various studies of oral cancer. Recently, a new ontological strategy that is rooted in consensus-based controlled vocabularies has been proposed to improve the consistency of data in dental research (Smith et al. in J Am Dent Assoc 141:1173-1175, 2010). In this paper, we analyzed the terminology dilemma on oral cancer and explained the current situation. We proposed a possible solution to the dilemma using an ontology-based approach. The advantages for applying this strategy are also discussed.

Declining oral cancer rates in Sri Lanka: are we winning the war after being at the top of the cancer league table?

OBJECTIVES

To investigate the age-standardized incidence, demography, recent trends and patterns of incidence of oral cancer in Sri Lanka between 1985 and 2005.

MATERIALS AND METHODS

Data on oral and oropharyngeal cancers were obtained from the published hospital-based cancer registry reports in the years 1985, 1990, 1995, 2000, and 2005. The data were analyzed by gender, age (<40 or >40 years), and by site. A linear regression analysis was performed on the age-standardized oral and oropharyngeal cancer incidence rates to examine the trends over a 20-year period.

RESULTS

There was a steady decline in the age-standardized incidence of lip and oral cavity cancers over the past 20 years in both men and women. A significant reduction of 1.9% per year is noted over this period. Contrary to this, cancers of the oropharynx (C09, C10, and C14) showed a slight increase over the same period.

CONCLUSIONS

Reversal of betel quid use and smoking must be considered in accounting for declining trends for oral cancer. Increasing rates of oropharyngeal cancer raises the issue whether risk factors for the oropharynx are different to those of the oral cavity, and this may need further investigation.

Genetic variants of the p53 and p73 genes jointly increase risk of second primary malignancies in patients after index squamous cell carcinoma of the head and neck

BACKGROUND

Because of the structural and biochemical similarities between the antitumor p53 and p73 proteins, the authors hypothesized that individuals who carry high-risk genotypes of p53 codon 72 and p73 G4C14-to-A4T14 polymorphisms have a higher risk of developing second primary malignancy (SPM) after index squamous cell carcinoma of the head and neck (SCCHN).

METHODS

A cohort of 1269 patients with index cases of SCCHN was recruited between May 1995 and January 2007 at The University of Texas MD Anderson Cancer Center and followed for SPM development. Patients were genotyped for p53 codon 72 and p73 G4C14-to-A4T14 polymorphisms. A log-rank test and Cox proportional hazard models were used to compare SPM-free survival and SPM risk among different risk groups with the combined risk genotypes of the 2 polymorphisms.

RESULTS

The data demonstrated that patients with p53 WP + PP and p73 GC/GC genotypes had a worse SPM-free survival and an increased SPM risk compared with the corresponding p53 WW and p73 GC/AT + AT/AT genotypes. After combining the 2 polymorphisms, a borderline significantly or significantly reduced SPM-free survival and increased SPM risk were observed in the medium-risk group (p53 WW and p73 GC/GC or p53 P carriers and p73 AT carriers) and high-risk group (p53 P carriers and p73 GC/GC) compared with low-risk group (p53 WW and p73 AT carriers), respectively.

CONCLUSIONS

The results suggest an increased risk of SPM after index SCCHN with both p53 and p73 polymorphisms individually and in combination.