**5. Buccal mucosa cancer—our perspective**

decrease in the mortality rate of head and neck cancer in France since reaching a peak in the early 1990s and the decline correlated with the reduction in alcohol consumption. Incidence and mortality have been stable in the Nordic countries, the Russian Federation, and the United Kingdom. Mortality rates have been steadily declining in Australia and Hong Kong

The current report highlighted that about 15% of all cancer deaths are related to unhealthy diets, including high intake of red meat, processed meat, and sodium, as well as low intake of fruits and vegetables [20]. Most research is still not consistent about specific nutritional items yet for the cause of cancer geographically [21]. The most current comprehensive review of diet and cancer risks confirms an elevated risk related to red and processed meat but finds less evidence supporting the benefit of the consumption of fruits and vegetables in reducing risk [22]. When well-established risk factors are included in the estimation of cancer, the variations in the strength of the evidence in different studies over time makes the measurement of dietary intake problematic in epidemiological studies. Nearly 5% of cancer deaths worldwide (387,000) would be attributable to dietary risk factors [20]. Ingestion of red meat and processed meat increases the risk of colorectal cancer by an estimate of 43% [21]. Ingestion of red meat and processed meat is generally rising in low- and middle-income countries (LMICs), but is stable in high-income countries (HICs). Another major dietary risk factor is high salt intake, which increases the risk of stomach cancer. Globally, salt intake has declined, and

SAR, China but increasing in Japan and the Republic of Korea [19].

**4. Diet and head and neck cancer**

4 Prevention, Detection and Management of Oral Cancer

**Figure 2.** The mechanism of salivary involvement with diet and cancer.

A buccal mucosa carcinoma is a violent form of head and neck cancer associated with the high rate of locoregional reappearance and poor existence [29]. It is the most common cancer in men and the third most common cancer in women in India [30]. National Cancer Registry Program (India) has stated approximately 13,500 cases of buccal mucosa carcinoma from various Indian cancer registries [31]. Indian Council of Medical Research guideline on buccal mucosa carcinoma management reported that there is the absence of national and international data specifically on buccal mucosa cancer, and very few randomized studies from India on various aspects of buccal mucosa cancer are available [32]. Tumor thickness and other prognostic factors were institutes to be not correct predictors of relapse and most of the studies were not adequately powered to draw a definite conclusion. Patients with head and neck cancer observed by computed tomography, magnetic resonance imaging (MRI), ultrasound-guided fine needle aspiration biopsy, and positron emission tomography (PET) have significant false positive and false negative results, invariably not capable of detecting nodal metastasis [33, 34]. Genetic alterations recognized to date have not been used clinically in the assessment of surgical margins, and no study has developed a gene signature that can accurately predict which patients with buccal cancer are at a higher risk of disease recurrence. Traditional surgical procedures may miss involved lymph nodes due to a limitation in histopathology examinations [35]. Lymph-node metastasis can be predicted by gene expression profiles of primary oral cavity squamous cell carcinomas [36]. Further, markers of prognosis will be validated by qRT-PCR technique. Gene expression profiles of primary tumor and their matched normal mucosa and comparing with different tumor stage and lymph-node status and to identify clinically significant prognostic markers is warranted.

Increase in the incidence of buccal mucosa carcinoma was observed from the hospital registry over the last 15 years [3]. The incidence and cumulative risk of buccal mucosa cancer in Chennai were higher in both sexes among all of the states in India [37]. Currently, there are no markers that can consistently predict malignant progression in oral dysplastic lesions. Recurrent disease after surgery and radiotherapy is hard to salvage because of availability of earlier markers to predict the stage of disease [38]. It was reported that variability in the clinical course of patients remains unexplained and conventional clinicopathological parameters fail to answer all questions. Identification of novel prognostic factors may allow a rational selection of the most appropriate therapeutic options for individual patients [39].

Other risk factors such as arecoline, safrole, and nicotine, which are released in saliva during betel quid chewing plus cigarette smoking, inhibit collagen phagocytosis by fibroblast [52].

Introductory Chapter: Head and Neck Cancer http://dx.doi.org/10.5772/intechopen.86272 7

Majority of head and neck cancers are preceded by a period during which the affected epithelium shows evidence of epithelial dysplasia, although this may not always be clinically apparent [8]. Several studies have exposed great inter- and intra-examiner variability in the assessment of the presence or absence and the grade of oral epithelial dysplasia [53–56], the

Five-year survival with single modality treatment of 19–20% was observed in patients with T3 and T4 stages [57]. Diaz and others had shown that the relapse amount was up to 45% in patients with early stage disease [58], and relapse rate in patients with nodes demanding

Mishra et al. had reported the relation between treatment failure and tumor thickness in a series of 176 patients with early buccal mucosa cancer [59]. Tumor thickness of more than 4 mm was found to be connected with lymph-node metastasis. In another study, tumor thickness of more than 5 mm was linked with nodal metastasis [60]. There are few studies described in the literature that associate the prognostic factors linked with clinical result of

The molecular changes between the tumor subtypes are often accompanied by differences in clinical features, such as statistically robust differences in relapse-free and overall survival [61], and many studies found handfuls of specific genes whose expression is linked with

Using high-throughput analysis of multiple surgical margins and matched oral squamous cell carcinoma to classify deregulated genes with prognostic value for recurrence need to be carried out. Presence of epithelial dysplasia or tumor cells in the surgical resection margins is linked with significant risk (66%) of local recurrence [63]. However, even with histologically normal surgical margins, 10–30% of OSCC patients will still have local recurrence [64]. Gene expression profiling by high-throughput technologies has proven to be valuable tools for prediction of outcome and progression in human malignancies including head and neck

To impact the survival of buccal cancer patients, molecular markers must be identified, which will help target tumors with a propensity for metastatic spread. There are numerous reports on the request of molecular biological markers for the valuation of cancer risk [66]. Molecular changes in oral pre-malignancy and head and neck cancer are influenced by differences in the

Despite having poor clinical risk factors, patients who need chemotherapy will have enormous potential for better individualization of treatment options in breast cancer therapy where the clinical utility of gene signatures are playing a important contribution and proved to reliably identify patients in whom adjuvant chemotherapy is certainly not indicated [68].

ethnic and etiologic characteristics in different parts of the world [67].

kappa values, in general, showing poor to a moderate bargain among examiners.

some form of adjuvant treatment in early disease and high-risk tumors.

**Figure 3** demonstrates the etiopathogenesis of OSCC.

buccal cancer.

prognosis [62].

cancer [65].

Oral tumor thickness and other prognostic factors were found to be not correct predictors of relapse, and most of the study was not adequately powered to drought a definite conclusion. Clinicopathological parameters such as the TNM system, which are generally used as a basis for therapeutic decisions, frequently fail to predict the biologic behavior of the tumors or the patients' outcome [40]. ICMR guideline on buccal mucosa carcinoma highlights that new prognostic factors for buccal mucosa cancer are the very important need to manage it.
