Screening for Cancers of the Head and Neck

Oral Microbial Species and Virulence Factors Associated with Oral Squamous Cell Carcinoma

The human microbiome has been the focus of numerous research efforts to elucidate the pathogenesis of human diseases including cancer. Oral cancer mortality is high when compared with other cancers, as diagnosis often occurs during late stages. Its prevalence has increased in the USA over the past decade and accounts for over 40,000 new cancer patients each year. Additionally, oral cancer pathogenesis is not fully understood and is likely multifactorial. To unravel the relationships that are associated with the oral microbiome and their virulence factors, we used 16S rDNA and metagenomic sequencing to characterize the microbial composition and functional content in oral squamous cell carcinoma (OSCC) tumor tissue, non-tumor tissue, and saliva from 18 OSCC patients. Results indicate a higher number of bacteria belonging to the Fusobacteria, Bacteroidetes, and Firmicutes phyla associated with tumor tissue when compared with all other sample types. Additionally, saliva metaproteomics revealed a significant increase of Prevotella in five OSCC subjects, while Corynebacterium was mostly associated with ten healthy subjects. Lastly, we determined that there are adhesion and virulence factors associated with Streptococcus gordonii as well as from known oral pathogens belonging to the Fusobacterium genera found mostly in OSCC tissues. From these results, we propose that not only will the methods utilized in this study drastically improve OSCC diagnostics, but the organisms and specific virulence factors from the phyla detected in tumor tissue may be excellent biomarkers for characterizing disease progression.

Demographics and efficacy of head and neck cancer screening

OBJECTIVE

This study was designed to 1) describe the demographics and 2) determine the efficacy of a head and neck cancer screening program to optimize future programs.

STUDY DESIGN

Database analysis plus chart review.

SETTING

Tertiary care academic medical center.

SUBJECTS AND METHODS

After Institutional Review Board approval, we reviewed our 14-year experience (1996-2009) conducting a free annual head and neck cancer screening clinic. Available demographic and clinical data, as well as clinical outcomes, were analyzed for all participants (n = 761). The primary outcome was the presence of a finding suspicious for head and neck cancer on screening evaluation.

RESULTS

Five percent of participants had findings suspicious for head and neck cancer on screening evaluation, and malignant or premalignant lesions were confirmed in one percent of participants. Lack of insurance (P = 0.05), tobacco use (P < 0.001), male gender (P = 0.03), separated marital status (P = 0.03), and younger age (P = 0.04) were the significant demographic predictors of a lesion suspicious for malignancy. Patients complaining of a neck mass (P < 0.001) or oral pain (P < 0.001) were significantly more likely to have findings suspicious of malignancy. A high percentage (40%) was diagnosed with benign otolaryngologic pathologies on screening evaluation.

CONCLUSION

A minority of patients presenting to a head and neck cancer screening clinic will have a suspicious lesion identified. Given these findings, to achieve maximal potential benefit, future head and neck cancer screening clinics should target patients with identifiable risk factors and take full advantage of opportunities for education and prevention.

Salivary markers for oral cancer detection

Oral cancer refers to all malignancies that arise in the oral cavity, lips and pharynx, with 90% of all oral cancers being oral squamous cell carcinoma. Despite the recent treatment advances, oral cancer is reported as having one of the highest mortality ratios amongst other malignancies and this can much be attributed to the late diagnosis of the disease. Saliva has long been tested as a valuable tool for drug monitoring and the diagnosis systemic diseases among which oral cancer. The new emerging technologies in molecular biology have enabled the discovery of new molecular markers (DNA, RNA and protein markers) for oral cancer diagnosis and surveillance which are discussed in the current review.

Screening programmes for the early detection and prevention of oral cancer

BACKGROUND

Screening programmes for major cancers, such as breast and cervical cancer have effectively decreased the mortality rate and helped to reduce the incidence of these cancers. Although oral cancer is a global health problem with increasing incidence and mortality rates, no national population-based screening programmes for oral cancer have been implemented. To date there is debate on whether to employ screening methods for oral cancer in the daily routine work of health providers.

OBJECTIVES

To assess the effectiveness of current screening methods in decreasing oral cancer mortality.

SEARCH STRATEGY

Electronic databases (MEDLINE, CANCERLIT, EMBASE, the Cochrane Central Register of Controlled Trials; 1966 to July 2005, The Cochrane Library - Issue 3, 2005), bibliographies, handsearching of specific journals and contact authors were used to identify published and unpublished data.

SELECTION CRITERIA

Randomised controlled trials of screening for oral cancer or precursor oral lesions using visual examination, toluidine blue, fluorescence imaging or brush biopsy.

DATA COLLECTION AND ANALYSIS

The search found 112 citations and these have been reviewed. One randomised controlled trial of screening strategies for oral cancer was identified as meeting the review's inclusion criteria. Validity assessment, data extraction and statistics evaluation were undertaken by two independent review authors.

MAIN RESULTS

One 10-year randomised controlled trial has been included (n = 13 clusters: 191,873 participants). There was no difference in the age-standardised oral cancer mortality rates for the screened group (16.4/100,000 person-years) and the control group (20.7/100,000 person-years). Interestingly, a significant 34% reduction in mortality was recorded in high-risk subjects between the intervention cohort (29.9/100,000 person-years) and the control arm (45.4/100,000). However, this study has some methodological weaknesses. Additionally, the study did not provide any information related to costs, quality of life or even harms of screening from false-positive or false-negative findings.

AUTHORS' CONCLUSIONS

Given the limitation of evidence (only one included randomised controlled trial) and the potential methodological weakness of the included study, it is valid to say that there is insufficient evidence to support or refute the use of a visual examination as a method of screening for oral cancer using a visual examination in the general population. Furthermore, no robust evidence exists to suggest that other methods of screening, toluidine blue, fluorescence imaging or brush biopsy, are either beneficial or harmful. Future high quality studies to assess the efficacy, effectiveness and costs of screening are required for the best use of public health resources. In addition, studies to elucidate the natural history of oral cancer, prevention methods and the effectiveness of opportunistic screening in high risk groups are needed. Future studies on improved treatment modalities for oral cancer and precancer are also required.

Screening programmes for the early detection and prevention of oral cancer

BACKGROUND

Although the second half of the last century has generated a rich and complex body of knowledge, the burden of oral cancer is still largely present. As with other cancers, there has been a strong debate whether screening strategies for oral cancer such as visual examination, the use of toluidine blue or newer methods such as brush biopsy or fluorescence imaging are effective in reducing the mortality rate associated with oral cancer.

OBJECTIVES

To assess the effectiveness of current screening methods in decreasing oral cancer mortality.

SEARCH STRATEGY

Electronic databases (MEDLINE, CANCERLIT, EMBASE, the Cochrane Central Register of Controlled Trials; 1966 to September 2002, The Cochrane Library - Issue 2, 2002), bibliographies, handsearching of specific journals and contact authors were used to identify published and unpublished data.

SELECTION CRITERIA

Randomised controlled trials of screening for oral cancer or potentially premalignant oral lesions using visual examination, toluidine blue, fluorescence imaging or brush biopsy.

DATA COLLECTION AND ANALYSIS

The search found 100 citations and these have been reviewed. One randomised controlled trial of screening strategies for oral cancer was identified as meeting the review's inclusion criteria. Validity assessment, data extraction and statistics evaluation have been undertaken by two independent reviewers.

MAIN RESULTS

One ongoing randomised controlled trial has been included (n = 13 clusters: 153,708 eligible subjects, 130,799 included subjects). There was no difference in the age-standardised oral cancer mortality rates for the screened group (21.2/1000,000 person years) and the control group (21.3/100,000 person years). However this study has some methodological weaknesses.

REVIEWER'S CONCLUSIONS

Given the limitation of evidence (only one included randomised controlled trial) and the potential methodological weakness in the included study, it is valid to say that there is no evidence to support or refute the use of a visual examination as a method of screening for oral cancer using a visual examination in the general population. Furthermore, no robust evidence exists to suggest other methods of screening, toluidine blue, fluorescence imaging or brush biopsy, are either beneficial or harmful. Further cost-effective, high quality studies to assess the efficacy and effectiveness of screening are required. In addition, studies to elucidate the natural history of oral cancer, prevention methods and the effectiveness of opportunistic screening in high risk groups are needed.

Comparison of histological grading and large-scale genomic status (DNA ploidy) as prognostic tools in oral dysplasia

Approximately one in ten oral white patches (leukoplakia) are histologically classified as dysplasia, with a well-documented potential for developing into oral squamous cell carcinoma (OSCC). Histological grading in oral dysplasia has limited prognostic value, whereas large-scale genomic status (DNA ploidy, nuclear DNA content) is an early marker of malignant transformation in several tissues. Biopsies from 196 patients with oral leukoplakia histologically typed as dysplasia were investigated. Inter-observer agreement among four experienced pathologists performing a simplified grading was assessed by Cohen's kappa values. For 150 of the 196 cases, it was also possible to assess large-scale genomic status and compare its prognostic impact with that of histological grading. Disease-free survival was estimated by life-table methods, with a mean follow-up time of 103 months (range 4-165 months). The primary considered end-point was the subsequent occurrence of OSCC. For grading of the total of 196 cases, kappa values ranged from 0.17 to 0.33 when three grading groups (mild, moderate, and severe dysplasia) were considered, and from 0.21 to 0.32 when two groups (low grade and high grade) were considered (p=0.41). For the 150 cases in which large-scale genomic status was also assessed, kappa values for the histological grading ranged from 0.21 to 0.33 for three grading groups and from 0.27 to 0.34 for two grading groups (p=0.47). In survival analysis, histological grading was without significant prognostic value for any of the four observers (p 0.14-0.44), in contrast to DNA ploidy (p=0.001). It is concluded that DNA ploidy in oral dysplasia has a practical prognostic value, unlike histological grading of the same lesions.