Epidemiology of oral cancer in South and South-East Asia: Incidence and mortality.

INTRODUCTION: This study provides an epidemiological description of cancer in the lip, oral cavity, and oropharynx in the South and South-East Asia region. METHODS: The number of new cases and deaths was extracted from the GLOBOCAN 2020 and the CI5 series. We present age-standardized incidence and mortality rates per 100,000 inhabitants. To assess temporal trends, we estimated the annual percent change. RESULTS: The incidence rates (ASR) for lip and oral cavity cancer in South and South-East Asia were highest in Taiwan (30.2), Sri Lanka (16.5), India (14.8), and Pakistan (13.2) among males. For oropharyngeal cancer, the highest rates were found in Taiwan (4.7), Bangladesh, Sri Lanka, and India (4.3, 2.9, and 2.6, respectively). Incidence rates were consistently higher in males compared to females. Overall, trends in lip and oral cavity cancer incidence were either stable or decreasing in most of the populations evaluated. In India, an increase in rates among males contrasted with a decline among females over the study period. CONCLUSION: Incidence and mortality rates of oral cavity cancer in South and South-East Asia are among the highest globally. Our results suggest an optimistic trend of reduction in oral cavity rates in the region, despite an increase in rates among Indian males.

Epidemiology and management of oral cavity squamous cell carcinoma in Ireland.

INTRODUCTION: The epidemiology and management of oral cavity cancer have changed considerably in recent decades. This study examines epidemiological and management trends in oral cavity squamous cell carcinoma (OCSCC). METHODS: A retrospective cohort study of data from the National Cancer Registry of Ireland between 1994 and 2014. RESULTS: A total of 2725 patients were identified. The most common subsites were the tongue (34 %, n = 1025), lip (19 %, n = 575), floor of mouth (FOM) (18 %, n = 550), and retromolar trigone (RMT) (6 %, n = 189). The incidence of OCSCC remained largely unchanged (3.14 cases/100000/year) during the study period. 5-year disease-specific survival (DSS) was 58.6 % overall, varying between subsites (lip 85 %, RMT 62.9 %, tongue 54.7 %, and FOM 47.3 %). DSS improved over the study period (p = 0.03), in particular for tongue primaries (p = 0.007). Primary surgery significantly improved DSS versus radiotherapy (HR 0.28, p < 0.0001). Survival of T4 disease managed surgically was superior to that of T1 disease managed with radiotherapy. In node positive patients, chemotherapy improved overall survival (HR 0.8 p = 0.038) but not DSS (HR 0.87 p = 0.215). CONCLUSION: Primary surgery remains the standard of care in the management of OCSCC. Prognosis has improved in line with an increase in the use of primary surgery in the same time frame, though the incidence remains unchanged.

Depth of invasion as an independent prognostic factor in early-stage oral cavity squamous cell carcinoma.

PURPOSE: To determine the significance of depth of invasion as a predictor of recurrence and mortality in tongue and non-tongue early-stage oral cavity squamous cell carcinoma patients treated with surgery and no postoperative radiotherapy. MATERIALS AND METHODS: 344 patients with oral cavity squamous cell carcinoma from 2005 to 2022 at a tertiary academic medical center were reviewed. Patients were included if they had newly diagnosed, previously untreated T1-T2N0 disease treated with surgery alone that was observed within a follow-up of 5 years. For each patient, anatomic site of oral cavity squamous cell carcinoma was categorized as either tongue or non-tongue. Cox proportional hazards regression analyses were performed to determine the association of depth of invasion with recurrence and mortality, with anatomic site, smoking status, and age at biopsy as covariates. Model assumptions were tested by statistical and graphical evaluation using Schoenfeld residuals. RESULTS: Of 108 patients with T1-T2N0 disease, 78 (72.2 %) had tongue disease, and 30 (27.8 %) had non-tongue disease. Median follow-up was 18.2 months (range, 0.01-58.2 months). In the Cox proportional hazards models, with adjustment for anatomic site and other covariates, depth of invasion positively predicted recurrence (HR 1.16, 95 % CI: 1.01-1.32, p = 0.034) and death (HR 1.42, 95 % CI: 1.11-1.83, p = 0.006). CONCLUSIONS: Depth of invasion is an independent predictor of recurrence and death across early-stage tongue and non-tongue squamous cell carcinoma. Therefore, depth of invasion may indicate a need for more aggressive treatment than surgery alone, such as postoperative radiotherapy, even in the absence of other adverse features on pathology within the early-stage population.

Inflammatory cytokines mediating the effect of oral lichen planus on oral cavity cancer risk: a univariable and multivariable mendelian randomization study.

BACKGROUND: While observational studies and experimental data suggest a link between oral lichen planus (OLP) and oral cavity cancer (OCC), the causal relationship and the role of inflammatory cytokines remain unclear. METHODS: This study employed a univariable and multivariable Mendelian Randomization (MR) analysis to investigate the causal relationship between OLP and the risk of OCC. Additionally, the potential role of inflammatory cytokines in modulating this association was explored. Instrumental variables were derived from genetic variants associated with OLP (n = 377,277) identified in Finngen R9 datasets, with 41 inflammatory cytokines as potential mediators, and OCC (n = 4,151) as the outcome variable. Analytical methods including Inverse Variance Weighted (IVW), Weighted Median, MR-Egger, and MR-PRESSO were utilized to assess the causal links among OLP, inflammatory cytokines, and OCC risk. Multivariable MR (MVMR) was then applied to quantify the mediating effects of these cytokines in the relationship between OLP and increased OCC risk. RESULTS: MR analysis provided strong evidence of a causal relationship between OLP (OR = 1.417, 95% CI = 1.167-1.721, p < 0.001) and the risk of OCC. Furthermore, two inflammatory cytokines significantly influenced by OLP, IL-13 (OR = 1.088, 95% CI: 1.007-1.175, P = 0.032) and IL-9 (OR = 1.085, 95% CI: 1.005-1.171, P = 0.037), were identified. Subsequent analysis revealed a significant causal association only between IL-13 (OR = 1.408, 95% CI: 1.147-1.727, P = 0.001) and higher OCC risk, establishing it as a potential mediator. Further, MVMR analysis indicated that IL-13 (OR = 1.437, 95% CI = 1.139-1.815, P = 0.002) mediated the relationship between OLP and OCC, accounting for 8.13% of the mediation. CONCLUSION: This study not only elucidates the potential causal relationship between OLP and the risk of OCC but also highlights the pivotal mediating role of IL-13 in this association.

Causal association between inflammatory bowel disease and 32 site-specific extracolonic cancers: a Mendelian randomization study.

BACKGROUND: The risk of extracolonic cancer is increased in inflammatory bowel disease (IBD) patients, but it is not clear whether there is a causal relationship. We aimed to systematically estimate the causal relationship between IBD and extracolonic cancers. METHODS: Independent genetic variants strongly associated with IBD were extracted as instrumental variables from genome-wide association study (GWAS) conducted by the International IBD Genetics Consortium including 12,882 IBD patients, 5956 Crohn's disease (CD) patients, and 6968 ulcerative colitis (UC) patients. Three sources of cancer GWAS were selected as outcome data. Two-sample Mendelian randomization (MR) analysis was conducted to assess the causal effects of IBD on 32 extracolonic cancers. The meta-analysis was applied to assess the combined causal effect with multiple MR results. RESULTS: IBD, CD, and UC have potential causal associations with oral cavity cancer (IBD: OR = 1.180, 95% CI: 1.059 to 1.316, P = 0.003; CD: OR = 1.112, 95% CI: 1.008 to 1.227, P = 0.034; UC: OR = 1.158, 95% CI: 1.041 to 1.288, P = 0.007). Meta-analysis showed a significant positive causal relationship between IBD and breast cancer (OR = 1.059; 95% CI: 1.033 to 1.086; P < 0.0001) as well as a potential causal relationship between CD and breast cancer (OR = 1.029; 95% CI: 1.002 to 1.055; P = 0.032) based on combining multiple MR results. CONCLUSIONS: This comprehensive MR analysis suggested that genetically predicted IBD, as well as its subtypes, may be a risk factor in the development of oral cavity and breast cancer.

Clinical outcomes and failure patterns after postoperative radiotherapy for oral cavity squamous cell carcinoma.

PURPOSE: This study aimed to assess recurrence patterns and identify the optimal dose and target volumes of postoperative radiotherapy (PORT) in patients with oral cavity squamous cell carcinoma (OSCC). METHODS: Data of 111 patients who received PORT for OSCC between January 2010 and April 2020 were retrospectively reviewed. The median age was 68 years (range 19-88). PORT was administered as initial treatment to 63 patients and as salvage treatment for recurrent tumors to 48 patients. The median prescribed dose was 60 Gy (range 50-66) administered in 30 fractions (range 25-33). RESULTS: Median follow-up time was 73 months (range 24-147). Overall survival (OS), progression-free survival (PFS), local control (LC), and locoregional control (LRC) at 3 years were 55.6%, 45.6%, 74.6%, and 63.1%, respectively. There were no significant differences in OS, PFS, LC, and LRC between the initially diagnosed and postoperative recurrent cases. Of 22 patients (20%) who developed regional nodal recurrences, 17 (15%) and 11 (10%) had in-field and out-of-field recurrences, respectively. Of 105 patients who received irradiation to the primary tumor bed, 24 (23%) developed recurrence at the primary site. The PFS and LC rates were significantly worse in patients receiving ≤ 56 Gy to the primary site than those receiving > 56 Gy (p = 0.016 and p = 0.032, respectively). CONCLUSION: PORT was effective for postoperative recurrences as well as for initially diagnosed oral cavity cancer. Doses greater than 56 Gy to the primary site may be required in PORT for OSCC.

Proactive Swallowing Rehabilitation in Patients with Recurrent Oral Cancer Receiving Salvage Treatment: Long-Term Swallowing-Related Outcomes.

The present study aimed to evaluate the impact of proactive swallowing rehabilitation on swallowing function and quality of life in patients with recurrent oral cancer in the first 2 years after salvage treatment. Consecutive adult patients with recurrent oral cancer who received salvage surgery and free flap reconstruction were recruited prospectively, to whom proactive swallowing rehabilitation was provided. Body weight (BW); fiberoptic endoscopic evaluation of swallowing (FEES), functional oral intake scale (FOIS), and diet level; 10-item eating assessment tool (EAT-10), and MD Anderson Dysphagia Inventory (MDADI); and adherence at baseline, 1, 3, 6, 12, 18 and 24 months were evaluated. A total of 50 patients were included during May 2018 to July 2020. Compared to the baseline, significant deterioration in BW, FOIS, and MDADI was noted at one month. However, a trend of recovery was observed in BW and FOIS from one month, and in MDADI from three months. All patients were free of tube feeding at 18-24 months and tolerated diet with special preparations or compensation. Safe swallowing could be achieved in approximately 80% participants after 12 months of diet modification or compensatory maneuvers. Proactive swallowing therapy was feasible in patients with recurrent oral cancer receiving salvage treatment. Although this patient population might have pre-existing dysphagia from previous treatments, rehabilitation could facilitate safe per oral intake and maintain adequate nutrition with adaptive maneuvers or compensatory strategies. Patients who underwent proactive swallowing rehabilitation had better recovery in the functional oral intake level.

Seasonality of head and neck cancers.

PURPOSE: The purpose of this study is to investigate if the season of diagnosis is associated with patient, tumor, and treatment characteristics within head and neck cancer. MATERIALS AND METHODS: 1406 patients with a diagnosis of head and neck cancer (HNC) were identified from a HNC database (1996-2019). Patients were classified as receiving a diagnosis in the winter, spring, summer, or fall by calendar definition. Proportions and chi-squared analysis compared patient, tumor, and treatment factors for all diagnoses. Data was subdivided and analyzed based on the primary site. RESULTS: From this cohort, 23 %, 27 %, 25 %, and 25 % of HNC patients were diagnosed in winter, spring, summer, and fall respectively with no statistically significant difference between seasons of diagnosis. When subdivided by primary site, oral cavity cancer was significantly more likely to be diagnosed in spring, salivary gland cancer was more likely to be diagnosed in winter and summer (p = 0.03 and p = 0.01 respectively). No other demographic, clinicopathologic, or management characteristics were associated with the season of diagnosis (p > 0.05 for all). CONCLUSIONS: Diagnosis of head and neck cancer does not follow a seasonal pattern. Diagnosis of oral cavity and salivary gland cancer showed a seasonal pattern. The majority of patient, tumor and management characteristics were not associated with the.

Oral cancer screening knowledge and practices among dental professionals at the University of Toronto.

INTRODUCTION: Opportunistic oral cancer screening during visits to the dentist is a non-invasive and accessible option for detection of pre-malignant lesions and early-stage malignancies. The objective of this study was to investigate the knowledge, practices, and attitudes towards oral cancer screening among dentists. METHODS: A 42-item survey was sent to 650 dental professionals affiliated with the University of Toronto. Data regarding training/practice characteristics, knowledge of oral cavity cancer, current screening practices, attitudes towards screening, and remuneration were collected. RESULTS: Ninety-one dentists responded. Most obtained their dental degree from Canada (71.4%) and were practicing in large urban centers (87.9%). Most dentists correctly identified the oral tongue (87.8%) and floor of mouth (80%) as the two of most common sites of oral cavity cancer but only 56% correctly identified the most common presentation. 91% performed intra/extra oral examinations at every patient visit. Only 9.9% of dentists discussed the risk factors of oral cancer and 33% were not familiar with resources for smoking cessation and alcohol abuse. International medical graduates were more likely to discuss risk factor management than Canadian medical graduates (p < 0.01). Over 80% of dentists referred to a specialist when a suspected lesion was found. The greatest barrier for oral cancer screening was lack of time. Almost all dentists (98.8%) reported that their screening practices do not differ depending on the patient's insurance status and 63.8% reported compensation would not influence their decision to perform oral examinations. CONCLUSION: Most dentists have a good knowledge of the presentation and risk factors associated with oral cavity cancer. Most dentists perform screening with every patient, with no influence from compensation and insurance status. Dentists are therefore an excellent first contact for oral cavity cancer screening for the general public and for high-risk populations.

HPV and RAD51 as Prognostic Factors for Survival in Inoperable Oral and Oropharyngeal Cancer in Patients Unfit for Chemotherapy Treated with Hyperfractionated Radiotherapy.

INTRODUCTION: The incidence of advanced oral cavity and oropharyngeal cancers is generally high. Treatment outcomes for patients, especially those unfit for comprehensive cancer treatment, are unsatisfactory. Therefore, the search for factors to predict response to treatment and increase overall survival is underway. OBJECTIVE: This study aimed to analyze the presence of 32 HPV genotypes in tumor samples of 34 patients and the effect of HPV status and RAD51 on overall survival. METHOD: Tumor samples of 34 patients with locally advanced oropharyngeal or oral cavity cancer treated with accelerated radiotherapy in monotherapy were analyzed using reverse hybridization and immunohistochemistry for the presence of HPV and RAD51. Its effect on overall survival was examined. RESULTS: Only two types of HPV were identified-HPV 16 (dominant) and HPV 66 (two samples). The HPV positivity was associated with a borderline insignificant improvement in 2-year (p = 0.083), 5-year (p = 0.159), and overall survival (p = 0.083). Similarly, the RAD51 overexpression was associated with borderline insignificant improvement in 2-year (p = 0.083) and 5-year (p = 0.159) survival. CONCLUSION: We found no statistically significant differences but detected trends toward improvement in the survival of HPV-positive and RAD51 overexpressing patients unfit for surgical treatment or chemotherapy treated with hyperfractionated radiotherapy. The trends, however, indicate that in a larger group of patients, the effects of these two parameters would likely be statistically significant.

Trends in mortality rates for oral and oropharyngeal cancer in Spain, 1979-2018.

OBJECTIVE: To analyse mortality rate trends in Spain for oral cavity and oropharyngeal cancer (OCOPC) from 1979 to 2018, evaluating differences between oral cavity cancer (OCC) and oropharyngeal cancer (OPC). MATERIALS AND METHODS: Death certificates and mid-year population data were collected from the Spanish National Statistics Institute. Age-standardized mortality rates were calculated using the direct method. Joinpoint regressions were used to identify significant changes in mortality trends. Independent effects of age, period and cohort (APC) were estimated. RESULTS: A total of 52,057 deaths were registered from OCOPC, 38,988 from OCC and 13,069 from OPC between 1979 and 2018. While OCC mortality rates declined, OCOPC rates increased slightly and OPC significantly. OCC and OPC mortality reached their highest values between 1979 and 1992, when OCC rates began to decrease in males and OPC levelled off until 2018. Lip cancer suffered the highest drop. APC models showed a mortality increase in males and females from 40 to 45 and 50 to 55 years of age, respectively. CONCLUSIONS: Favourable OCC mortality trends was plausibly influenced by decreased tobacco/alcohol consumption, while OPC rise was probably associated with increased human papillomavirus infection. The importance of closely monitoring these cancers by age group, sex and location, and continuing with preventive measures against known risk factors, is highlighted.

Oral cavity squamous cell carcinomas in patients with no identified risk factors: Feeling like an outsider.

OBJECTIVES: Head and neck squamous cell carcinomas (HNSCCs) mainly affect smokers and drinkers. However, oral cavity squamous cell cancers (OCSCCs) are increasingly affecting patients with no identified risk factors (NIRFs). This study aimed at characterising their experience of the disease. METHODS: Qualitative study based on semi-structured interviews of 20 survivors of OCSCC with NIRF. Methods used in grounded theory approach were applied. RESULTS: Patients with NIRF had a similar experience to that of patients with risk factors regarding treatments. The absence of identified causes led to stigma and led the patients to distance themselves, both from the stereotypic HNSCC cancer patient and the identity as a cancer patient. Furthermore, having no identified risk factors seemed to reinforce the fear of recurrence. CONCLUSION: This study is the first to address key gaps in knowledge regarding patients with NIRF having survived OCSCC. Their experience is similar to that of patients with orphan diseases. Owing to confrontation with other patients and the repeated questions of caregivers about tobacco/alcohol consumption, these patients felt stigmatised during their treatment. OCSCC patients with NIRF may benefit from guidance and support on how to engage in prevention.

Prevalence of submandibular gland involvement in neck dissection specimens of patients with oral cavity carcinoma.

INTRODUCTION: The submandibular gland is commonly removed during neck dissection in patients with head and neck cancer. The patient experiences various complications due to the removal of the submandibular gland. Therefore, the necessity of submandibular gland removal should be evaluated. This study aimed to was to determine the frequency of submandibular gland (SMG) involvement in patients with oral cavity squamous cell carcinoma (SCC). METHODS: In this retrospective study, medical records of patients with oral cavity cancer who were referred to Amir Alam Hospital between 2015 and 2020 were reviewed. Patient data includes surgical report, histopathology report (tumor size, number of lymph nodes involved, and SMG tumor involvement), Tumor Location, History of Smoking, History of Opium, and Alcohol consumption was extracted from patients' medical records and statistically analyzed using SPSS software version 20. RESULTS: Of the total 60 patients, 24 (40%) were female and 36 (60%) were male. Smoking was reported in 55% of patients with a mean of 4.11 pack-year. Alcohol and opium use was observed in 18.3% and 26% of patients. The majority of patients (78.3%) had tongue cancer. More than half of the patients (53.3%) reported tumors of 2 cm or smaller, and 16.7% of patients had tumors larger than 4 cm. The majority of patients (80.3%) did not have cervical lymph node metastasis, 13.1% had 1-2 involved lymph nodes and 4.9% had 3 to 6 involved lymph nodes and there were no cases of metastasis to more than 6 lymph nodes. Finally, no individual had submandibular gland involvement, ie 100% of patients had no submandibular gland metastasis. CONCLUSION: The results confirmed that SMG involvement is very rare in patients with oral SCC and therefore it is not necessary to remove the gland as part of treatment. Preservation of the submandibular gland prevents complications related to the removal of this gland and reduces morbidity and increases the quality of life of patients after surgery.

Motivation to smoking cessation in head and neck cancer and dysplasia patients in confrontation with the attitudes of otorhinolaryngologists in delivering anti-smoking therapies.

OBJECTIVES: The aim of the study was to determine the influence of oral, oropharyngeal, laryngeal and hypopharyngeal dysplasia and cancer diagnosis on motivation to smoking cessation in patients. Consecutively, we assessed the competence of ENT specialists in counseling anti-smoking therapies. METHODS: Questionnaire of expected support, Schneider motivation test and Fagerström Test for Nicotine Dependence (FTND) were administered to 50 smoking patients. The online survey was collected from 152 ENT doctors. RESULTS: Mean FTND score was 4.58 and Heaviness of Smoking Index (HSI) was 3.1. Patients with oral cavity and oropharyngeal cancer showed the greatest dependence to nicotine 7.67 and 5.25, respectively, and with hypopharyngeal cancer had the lowest 3.5, (p = 0.039). The ranges of HSI were significantly higher for younger patients (p = 0.036). 35 patients were adequately motivated to quit smoking, and their mean age was statistically higher (p = 0.05). Self-reported motivation to smoking cessation was 76%. Of 152 surveyed doctors, only 39% declared knowledge of the diagnostic and therapeutic cessation interventions. 75% showed interest in the training programs.

The changing face of Irish head and neck cancer epidemiology: 20 years of data.

BACKGROUND: Head and neck cancer (HNC) is associated with significant morbidity and mortality, especially when high stage disease is present. The epidemiology and prognosis of HNC has changed considerably over the last 20 years. AIMS: This study aimed to examine the epidemiological trends in HNC patients over a prolonged period in Ireland. METHODS: We conducted a retrospective cohort study using 20 years of cancer registry data provided by the National Cancer Registry of Ireland. Baseline characteristics and survival statistics were thereby generated. RESULTS: 10,148 patients were identified. There is a growing population of young (< 50 years) and very old (> 85 years) HNC patients; 48.15% of the population was elderly (> 65 years). Oral cavity (29.8%) and laryngeal cancer (28.1%) remain the most prevalent subsites, though oral cavity cancer prevalence declined from 35.9% in 1994 to 27.5% in 2014. Oropharyngeal cancer prevalence increased from 13.6 to 22.2% over the same period. Overall 5-year survival has improved significantly to 56.8% in 2010 but there remains a disparity between the elderly and adult cohorts (42.0% vs 60.7%). 5-year survival for hypopharyngeal and oropharyngeal cancers has improved from 11.8% and 33.3% to 22.2% and 44.8%, respectively, while laryngeal and oral cavity cancer survival remains approximately stable at 58.7% and 61.5%, respectively. CONCLUSION: HNC survival in Ireland has improved in line with increasing recognition of the value of multidisciplinary assessment, subspecialisation in cancer care, and targeted therapies based on tumour subsites. Survival in the elderly cohort remains poor despite increasing recognition of the challenges such cases pose.

Estimated projection of oral cavity and oropharyngeal cancer deaths in Spain to 2044.

BACKGROUND: Oral cavity cancer (OCC) and oropharyngeal cancer (OPC) are two common malignancies whose mortality is worryingly increasing worldwide. However, few studies have estimated the mortality trends for these cancers in the coming years. This study analysed the mortality rates for OCC and OPC observed between 1980 and 2019 to generate a predictive model for the next 25 years in Spain. METHODS: Mid-year population data and death certificates for the period 1980-2019 were obtained from the Spanish National Institute of Statistics. The Nordpred program (Norwegian Cancer Registry, Oslo, Norway) was used to calculate adjusted mortality rates as well as estimated mortality projections with an age-period-cohort model for the period 2020-2044. RESULTS: The specific mortality rate per 100,000 inhabitants for OCC decreased from 2.36 (1980-1984) to 2.17 (2015-2019) and is expected to decline to 1.68 (2040-2044), particularly in males. For OPC, mortality rates rose from 0.67 (1980-1984) to 1.23 (2015-2019) and are projected to drop to 0.71 (2040-2044). In the group of females > 65 years predictions showed rising mortality rates for both OCC and OPC. The predictive model projects more deaths in females than in males for OCC in the period 2040-2044, while deaths for OPC will decrease in males and gradually increase in females. CONCLUSIONS: Although OCC mortality rates have been found to decrease in males in the last observed decades, there is still room to improve them in females > 65 years in the future by promoting campaigns against smoking and alcohol consumption. OPC mortality will become a growing health problem. Vaccination campaigns for the prevention of human papillomavirus-associated cancers may have a long-term impact on the mortality of these cancers, which should be evaluated in upcoming studies. CLINICAL RELEVANCE: Our findings highlighted the importance of closely monitoring OCC and OPC mortality rates in the coming years by age group and sex, and the need to continue preventive measures against the main known risk factors, such as tobacco, alcohol, and human papillomavirus infection.

Association between smokeless tobacco use and oral cavity cancer risk in women compared with men: a systematic review and meta-analysis.

BACKGROUND: The impact of smokeless tobacco (SLT) use on the risk of oral cavity cancer (OCC) has been confirmed; however, the sex-based difference in this association remains inconclusive. Therefore, this study aimed to estimate the association between SLT use and OCC risk in women and compared it to that in men. METHODS: PubMed, Embase, and Cochrane Library databases were systematically searched for eligible studies from their inception up to August 2020. Studies reporting the effect estimates of SLT use on OCC risk in men and women, were eligible for inclusion. The relative risk ratio (RRR) was applied to calculate the sex-based difference in the relationship between SLT use and OCC risk, and pooled analysis was conducted using a random-effects model with inverse variance weighting. RESULTS: Nineteen studies reporting a total of 6593 OCC cases were included in the final meta-analysis. The pooled relative risk (RR) suggested that SLT use was associated with an increased risk of OCC in both men (RR, 2.94; 95% confidence interval [CI], 2.05-4.20; P < 0.001) and women (RR, 6.39; 95%CI, 3.16-12.93; P < 0.001). Moreover, the SLT-use-related risk of OCC was higher in women than that in men (RRR,1.79; 95%C, 1.21-2.64; P = 0.003). The risk of OCC related to SLT use in women was still significantly higher than that in men (RRR, 1.75; 95%CI, 1.15-2.66; P = 0.008) after excluding indirect comparison results. Finally, a subgroup analysis suggested significant sex-based differences only in individuals who received chewed smokeless products, regardless of the control definition. Pooled analysis of studies with high design quality confirmed the notably higher risk of OCC in women than in men. CONCLUSIONS: This study found that SLT use was associated with a higher risk of OCC in women than in men. Further large-scale prospective cohort studies should be conducted to verify sex-based differences in the association between use of specific smokeless products and OCC risk.

Cell-free DNA and circulating tumor cell kinetics in a pre-clinical head and neck Cancer model undergoing radiation therapy.

BACKGROUND: Monitoring circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs), known as liquid biopsies, continue to be developed as diagnostic and prognostic markers for a wide variety of cancer indications, mainly due to their minimally invasive nature and ability to offer a wide range of phenotypic and genetic information. While liquid biopsies maintain significant promising benefits, there is still limited information regarding the kinetics of ctDNA and CTCs following radiation therapy which remains a vital treatment modality in head and neck cancers. This study aims to describe the kinetics of ctDNA and CTCs following radiation exposure in a preclinical rabbit model with VX2 induced buccal carcinoma. METHODS: Seven rabbits were inoculated with VX2 cells in the buccal mucosa and subjected to radiation. At selected time points, blood sampling was performed to monitor differing levels of ctDNA and CTC. Plasma ctDNA was measured with quantitative PCR for papillomavirus E6 while CTCs were quantified using an immunomagnetic nanoparticles within a microfluidic device. Comparisons of CTC detection with EpCAM compared to multiple surface markers (EGFR, HER2 and PSMA) was evaluated and correlated with the tumor size. RESULTS: Plasma ctDNA reflects the overall tumor burden within the animal model. Analysis of correlations between ctDNA with tumor and lymph node volumes showed a positive correlation (R = 0.452 and R = 0.433 [p < 0.05]), respectively. Over the course of treatment, ctDNA levels declined and quickly becomes undetectable following tumor eradication. While during the course of treatment, ctDNA levels were noted to rise particularly upon initiation of radiation following scheduled treatment breaks. Levels of CTCs were observed to increase 1 week following inoculation of tumor to the primary site. For CTC detection, the use of multiple surface markers showed a greater sensitivity when compared to detection using only EpCAM. Plasma CTC levels remained elevated following radiation therapy which may account for an increased shedding of CTCs following radiation. CONCLUSION: This study demonstrates the utility of ctDNA and CTCs detection in response to radiation treatment in a preclinical head and neck model, allowing for better understanding of liquid biopsy applications in both clinical practice and research development.

The impact of comorbidities on survival in oral cancer patients: a population-based, case-control study.

BACKGROUND: Comorbidities have shown to highly influence the outcome and risk of death of head and neck cancer patients. The purpose of this study was to examine the comorbidities among oral cavity squamous cell carcinoma (OSCC) patients, and to investigate the impact of comorbidities on overall survival (OS) and recurrence free survival (RFS). METHODS: Patients diagnosed with OSCC in Eastern Denmark in the period 2000-2014 and treated with curative intend were included. Patients data were linked to the Danish National Patients Register to identify comorbidities based on the Charlson Comorbidity Index (CCI) at the time of diagnosis and five years after diagnosis. Each patient was age-and sex-matched in a 1:10 ratio with an age and sex matched reference group. RESULTS: A total of 1,183 patients and 11,830 controls were included. Overall this study found comorbidities to be more common among OSCC compared to the reference group both at the time of diagnosis and five years after. The 5-year OS among patients with a CCI score of zero, one, two, and three or above was 60%, 44%, 41%, and 40%, respectively. Similarly, the multivariate cox-regression analysis showed that patients with increasing CCI score also had an increasing risk of death compared to patients with no comorbidities. CONCLUSION: OSCC patients had significantly higher comorbidity burden at diagnosis and risk of developing additional comorbidities after diagnosis compared to the reference population. Survival outcomes decreased significantly with higher CCI.

Impact of delay in diagnosis and treatment-initiation on disease stage and survival in oral cavity cancer: a systematic review.

AIM/OBJECTIVES: This study aimed to systematically review the literature on the impact of delay in diagnosis and treatment of oral cavity cancer. METHODS: PubMed and Embase were systematically searched for articles reporting impact of delay in diagnosis and treatment on cancer-stage and survival of oral cavity cancer. Studies comprising at least ten patients, and published since the year 2000, were included. RESULTS: Sixteen studies (n = 45,001, range: 62-18,677 per study, 83% men), from Australia, Asia, Europe, North America and South America, met the inclusion criteria. Eleven studies (n = 1,460) examined delay in diagnosis, while five studies (n = 43,541) reported delay in treatment. Eight of the eleven studies, examining delay in diagnosis (n = 1,220), analyzed the correlation between delay in diagnosis and tumor stage at diagnosis. Three studies found a significant correlation between patient delay and advanced stage at diagnosis (p < 0.05), whereas three other studies did not. The studies reporting a significant correlation were from Asian countries, whereas the three studies that did not find a correlation were from other continents. Studies reporting on professional delay and total diagnostic delay, generally, did not find a significant correlation with advanced cancer at diagnosis. Time to treatment (TTI), defined as time from diagnosis to treatment, was found significantly correlated with survival in three studies (p < 0.01, p < 0.001, p < 0.05), and nonsignificant in two studies. CONCLUSION: A significant correlation between patient delay and advanced stage cancer was reported in Asian studies only, while professional delay and total diagnostic delay were generally found to be non-correlated with advanced stage cancer at diagnosis. TTI was in some studies reported to be correlated with poorer outcome, while other studies did not report a correlation. One study presented that there was no clear advantage in overall survival (OS) for patients treated within 30 days, compared to patients treated between 30 and 44 days.