Propensity score analysis exploring the impact of smoking and drinking on the prognosis of patients with oral cancer

Oral cavity cancer in young, non-smoking, and non-drinking patients: A contemporary review

Oral squamous cell carcinoma (OSCC) in non-smoking and non-drinking (NSND) individuals appears to be distinct from the traditional head and neck squamous cell carcinoma (HNSCC). The incidence of this subset is increasing, as are the number of studies examining its characteristics. NSND OSCC individuals tend to be younger (<45 years) compared to traditional HNSCC patients. The proportion of females in the NSND OSCC cohort is also higher. The tongue is the predominantly affected subsite. Studies have revealed several gene mutations and unique epigenomic profiles but no definitive genetic etiology. Transcriptomic analysis has not found any causative viral agents. Other proposed etiologies include chronic dental trauma, microbiome abnormalities, marijuana consumption, and genetic disorders. There are international efforts to determine the relative prognostic outcome of this unique cohort, but no consensus has been reached. Here, we review the incidence, demographics, subsite, possible etiologies, prognosis, and therapy implications of the NSND OSCC cohort.

OSCC in Never-Smokers and Never-Drinkers Is Associated with Increased Expression of Tumor-Infiltrating Lymphocytes and Better Survival

The aim of this study was to investigate the clinical, histopathologic, and immunologic differences of oral squamous cell carcinoma of never-smokers/never-drinkers and smokers/drinkers. Immunohistochemical staining for CD4, CD8, FoxP3, CD1a, and p16 was performed in 131 oral squamous cell carcinomas from smokers/drinkers and never-smokers/never-drinkers. Associations of smoking/drinking status with clinicopathologic data, immunohistochemical antibody expression, and survival were examined. Oral squamous cell carcinoma in never-smokers/never-drinkers was associated with the female gender (p < 0.001). Never-smokers/never-drinkers were older at diagnosis than smokers/drinkers (p < 0.001). Never-smokers/never-drinkers had more tumors in the maxilla, mandible, and tongue (p < 0.001). Pre-existing oral potentially malignant disorders appeared to be more common in never-smokers/never-drinkers (p < 0.001). Perineural invasion was more common in smokers/drinkers (p = 0.039). Never-smoking/never-drinking was associated with better overall survival (p = 0.004) and disease-specific survival (p = 0.029). High CD4+ T cell infiltration was associated with never-smoking/never-drinking (p = 0.008). Never-smokers/never-drinkers also showed increased CD8+ T cell infiltration (p = 0.001) and increased FoxP3+ Treg infiltration (p = 0.023). Furthermore, the total group of tumor-infiltrating lymphocytes was associated with never smoking/never drinking (p = 0.005). To conclude oral squamous cell carcinoma of the never-smokers/never-drinkers appears to be a distinct type of tumor, as it appears to have unique clinical and pathologic features and a more immunogenic microenvironment.

Oral Cavity Squamous Cell Carcinoma Risk Factors: State of the Art

Head and neck (HN) squamous cell carcinomas (SCCs) originate from the epithelial cells of the mucosal linings of the upper aerodigestive tract, which includes the oral cavity, the pharynx, the larynx, and the sinonasal cavities. There are many associated risk factors, including alcohol drinking coupled with tobacco use, which accounts for 70% to 80% of HNSCCs. Human papilloma virus (HPV) is another independent risk factor for oropharyngeal SCC, but it is only a minor contributor to oral cavity SCC (OSCC). Betel quid chewing is also an established risk factor in southeast Asian countries. However, OSCC, and especially oral tongue cancer, incidence has been reported to be increasing in several countries, suggesting risk factors that have not been identified yet. This review summarizes the established risk factors for oral cavity squamous cell carcinomas and examines other undemonstrated risk factors for HNSCC.

No survival benefit in never-smoker never-drinker patients with oral cavity cancer

BACKGROUND

Although strongly associated with tobacco and alcohol use, many oral cavity squamous cell carcinoma (OCSCC) cases occur in patients without exposure to either, known as "never-smoker, never-drinkers" (NSND). We aimed to compare clinical outcomes between NSND and tobacco/alcohol-exposed populations and to define demographic characteristics of NSND.

METHODS

We performed a retrospective, single-institution cohort study of 672 OCSCC patients. Cox models were used to estimate differences in overall survival (OS) and recurrence-free survival (RFS) between NSND and tobacco/alcohol-exposed patients while adjusting for confounders.

RESULTS

NSND represented 25.6% of our cohort and were older, more female, and more economically advantaged. Among NSND, oral tongue tumors dominated in younger patients, while alveolar ridge tumors dominated in elderly patients. Multivariate survival analysis revealed no differences in OS or RFS between NSND and tobacco/alcohol-exposed patients.

CONCLUSION

When adjusted for independent biologic features, clinical outcomes in OCSCC are similar between NSND and tobacco/alcohol-exposed patients.

Epidemiological, Clinical, and Oncological Outcomes of non-Alcohol Drinking and non-Smoking Laryngeal Squamous Cell Carcinoma Patients: A Distinct Entity

Purpose: To explore the discrepancy in clinicopathological and prognostic features between smoking and alcohol drinking (SA) and non-smoking and non-alcohol drinking (NSNA) patients with laryngeal squamous cell carcinoma (LSCC). Methods: This retrospective study including 1735 patients with LSCC was conducted from January 2005 to December 2010, which were categorized into 4 groups, NSNA group, smoking only group, alcohol-drinking only group, and SA group. We compared overall survival (OS) and disease-free survival (DFS) using the Kaplan-Meier method and indicated clinicopathological features by Cox proportional hazards regression models before and after propensity score matching (PSM). Results: A total of 415 patients (23.92%) were identified as NSNA. The SA group was predominantly patients ≤60 years old (46.63%) while the NSNA group was more older (58.07%). NSNA group was more likely to present at earlier disease stage and more female. No significant difference in OS (P = .685) and DFS (P = .976) was found between the 2 groups. In addition to age and recurrence and metastasis being common independent prognostic factors in terms of OS in both groups of patients, NSNA group also exhibited other factors, namely tumor area >3.7 cm² and positive resection margin. For DFS, N + stage, tumor size >3.7 cm², and positive resection margin were prognostic features specific to NSNA group. Conclusion: The outcome is similar in LSCC patients with and without SA. NSNA group shows a distinct profile from that found in SA group. Clinicopathological features from NSNA group should be considered for LSCC management.

The impact of tobacco smoking on survival of patients with oral squamous cell carcinoma: a population-based retrospective study

BACKGROUND

This article aims to evaluate the impact of smoking status, accumulated tobacco exposure (ATE), and smoking cessation on overall- and disease-free survival (OS and DFS) of patients with oral squamous cell carcinoma (OSCC).

MATERIAL AND METHODS

Patients with primary OSCC treated with curative intent between 2000 and 2019 in Copenhagen were included (n = 1808). Kaplan-Meier curves and multivariable Cox regression analyses were performed to compare the survival of patients with different smoking history. Interactions between ATE and (A) tumor subsite and (B) excessive alcohol consumption (EAC) on the survival were evaluated using multivariable Cox regression analyses with interaction terms.

RESULTS

We included 1717 patients with known smoking status (62.8% males, median age: 64 years (IQR: 57-71 years)), who had a 5-year OS of 53.7% (95%CI: 49.8%-57.9%). Based on fully adjusted multivariable Cox regression analyses, significantly elevated hazard ratios (HRs) for OS and DFS were identified for current, but not former smokers, compared to never-smokers. An approximately linear relationship between continuous ATE and survival estimates was identified. ATE analyzed as a categorical variable showed significantly elevated HRs for OS of patients with all categories (0<x ≤ 30, 30<x ≤ 60, and >60 PYs), however only for DFS of patients with >60 PYs, compared to 0 PYs. Furthermore, an unfavorable long-term prognosis was evident after >3.5 (OS) and >2.5 (DFS) years from diagnosis for patients who continued smoking compared to patients with smoking cessation at diagnosis. The survival estimates of patients with different tumor subsite and alcohol consumption differed with increasing ATE.

CONCLUSION

Tobacco smoking (assessed as smoking status and ATE) was associated with inferior survival (OS and DFS) among patients with OSCC. Unfavorable long-term prognosis was significant for patients who continued smoking compared to patients with smoking cessation at diagnosis. The impact of ATE on survival of patients with OSCC may depend on the tumor subsite and/or alcohol consumption.

Molecular drivers of oral cavity squamous cell carcinoma in non-smoking and non-drinking patients: what do we know so far?

Oral cavity squamous cell carcinoma (OCSCC) is one of the most common head and neck cancers worldwide. It is well known that risk factors for OCSCC include tobacco and excess alcohol consumption. However, in recent years, OCSCC incidence has been increasing in patients without these traditional risk factors. The cause of this increase is unclear and various genetic, environmental, and infectious factors have been hypothesized to play a role. Additionally, there are expert opinions that oral cancer in non-smoking, non-drinking (NSND) patients have a distinct phenotype resulting in more aggressive disease presentation and poorer prognosis. In this review, we summarize the current state of knowledge for oral cavity cancer in patients without traditional risk factors.

Comparison of time-to-event machine learning models in predicting oral cavity cancer prognosis

BACKGROUND

Applying machine learning to predicting oral cavity cancer prognosis is important in selecting candidates for aggressive treatment following diagnosis. However, models proposed so far have only considered cancer survival as discrete rather than dynamic outcomes.

OBJECTIVES

To compare the model performance of different machine learning-based algorithms that incorporate time-to-event data. These algorithms included DeepSurv, DeepHit, neural net-extended time-dependent cox model (Cox-Time), and random survival forest (RSF).

MATERIALS AND METHODS

Retrospective cohort of 313 oral cavity cancer patients were obtained from electronic health records. Models were trained on patient data following preprocessing. Predictors were based on demographic, clinicopathologic, and treatment information of the cases. Outcomes were the disease-specific and overall survival. Multivariable analyses were conducted to select significant prognostic features associated with tumor prognosis. Two models were generated per algorithm based on all-prognostic features and significant-prognostic features following statistical analysis. Concordance index (c-index) and integrated Brier scores were used as performance evaluators and model stability was assessed using intraclass correlation coefficients (ICC) calculated from these measures obtained from the cross-validation folds.

RESULTS

While all models were satisfactory, better discriminatory performance and calibration was observed for disease-specific than overall survival (mean c-index: 0.85 vs 0.74; mean integrated Brier score: 0.12 vs 0.17). DeepSurv performed best in terms of discrimination for both outcomes (c-indices: 0.76 -0.89) while RSF produced better calibrated survival estimates (integrated Brier score: 0.06 -0.09). Model stability of the algorithms varied with the outcomes as Cox-Time had the best intraclass correlation coefficient (mean ICC: 1.00) for disease-specific survival while DeepSurv was most stable for overall survival prediction (mean ICC: 0.99).

CONCLUSIONS

Machine learning algorithms based on time-to-event outcomes are successful in predicting oral cavity cancer prognosis with DeepSurv and RSF producing the best discriminative performance and calibration.

"Fact or fiction?": Oral cavity cancer in nonsmoking, nonalcohol drinking patients as a distinct entity-Scoping review

Oral cavity cancer is often described as a lifestyle-related malignancy due to its strong associations with habitual factors, including tobacco use, heavy alcohol consumption, and betel nut chewing. However, patients with no genetically predisposing conditions who do not indulge in these risk habits are still being encountered, albeit less commonly. The aim of this review is to summarize contemporaneous reports on these nonsmoking, nonalcohol drinking (NSND) patients. We performed database searching to identify relevant studies from January 1, 2000 to March 31, 2021. Twenty-six articles from 20 studies were included in this study. We found that these individuals were mostly females in their eighth decade with tumors involving the tongue and gingivobuccal mucosa. This review also observed that these patients were likely diagnosed with early stage tumors with overexpression of programmed death-ligand 1 (PD-L1) and increased intensity of tumor infiltrating lymphocytes. Treatment response and disease-specific prognosis were largely comparable between NSND and smoking/drinking patients.

circVAPA promotes the proliferation, migration and invasion of oral cancer cells through the miR-132/HOXA7 axis

Objective

To study the relationship between the circular RNA vesicle-associated membrane protein-associated protein A (circVAPA) and the pathogenesis of oral squamous cell carcinoma.

Methods

The expression of circVAPA was detected by RT-qPCR. In vitro loss-of-function experiments were performed in Cal-27 cells. The malignant phenotype of cells was evaluated by cell counting kit-8, clone formation and transwell assays. Luciferase reporter assays were used to assess the circVAPA/miR-132/homeobox A (HOXA) regulatory axis.

Results

circVAPA expression was significantly increased in oral cancer tissues and cells. The overall survival and progression-free survival of patients with oral cancer who exhibited high circVAPA expression were significantly shorter compared with those with low expression. circVAPA expression was closely related to tumor size, TNM stage and distant metastasis. circVAPA knockdown reduced the proliferation, invasion and migration of Cal-27 cells. MiR-132 was identified as a target of circVAPA in Cal-27 cells. Cotransfection with si-circVAPA and miR-132 inhibitor reversed the inhibitory effect of circVAPA knockdown on cell malignant phenotypes. HOXA7 was further identified as a downstream target of miR-132.

Conclusion

circVAPA is highly expressed in oral cancer, and its abnormal expression might affect the proliferation, invasion and migration of oral cancer cells by modulating the miR-132/HOXA7 signaling axis.

Prognostic value of non-smoking, non-alcohol drinking status in oral cavity cancer

OBJECTIVES

To compare the treatment response and prognosis of oral cavity cancer between non-smoking and non-alcohol-drinking (NSND) patients and smoking and alcohol-drinking (SD) patients.

METHODS

A total of 313 consecutively treated patients from 2000 to 2019 were included. Demographic, clinicopathologic, treatment, and prognosis information were obtained. Relapse-free survival (RFS), disease-specific survival (DSS), and overall survival (OS) were compared between NSND and SD groups using Kaplan-Meier plots, log-rank test, and multivariate Cox regression analysis.

RESULTS

Sample prevalence of NSND patients was 54.6%. These patients were predominantly females in their eighth decade with lower prevalence of floor of the mouth cancers compared to SD patients (1.8% vs 14.8%). No difference in the RFS and DSS between both groups was found following multivariable analysis; however, NSND patients had better OS (HR (95% CI) - 0.47 (0.29-0.75); p = 0.002). Extracapsular extension was associated with significantly poorer OS, DSS, and RFS in this oral cavity cancer cohort.

CONCLUSION

Treatment response and disease-specific prognosis are comparable between NSND and SD patients with oral cavity cancer. However, NSND patients have better OS.

CLINICAL RELEVANCE

This study shows that oral cavity cancer in NSND is not less or more aggressive compared to SD patients. Although better survival is expected for NSND than SD patients, this is likely due to the reduced incidence of other chronic diseases in the NSND group.

Prognostic value of preoperative lymphocyte-to-monocyte ratio in oral cancer patients and establishment of a dynamic nomogram

OBJECTIVE

To assess the association of preoperative lymphocyte-to-monocyte ratio (LMR) and overall survival (OS) in patients with oral cancer and develop a dynamic nomogram for individualized survival prediction.

METHOD

The prognostic value of LMR was evaluated in a large-scale cohort with 651 postoperative patients with oral cancer between January 2010 and December 2017. Propensity score-matched (PSM) analysis and inverse probability of treatment weighting (IPTW) analysis were performed to further verify the prognostic value of LMR. A dynamic nomogram was then developed based on the LMR and clinicopathological features, and its predictive performance and clinical utility were evaluated.

RESULTS

A high LMR was significantly associated with better OS of patients with oral cancer (HR = 0.65; 95% CI = 0.44-0.98). The similar association was also observed in the PSM and IPTW analyses. Moreover, compared with TNM staging system, the dynamic nomogram based on the LMR exhibited more excellent predictive performance (0.72 versus 0.64, p < .001), with calibration curves (1,000 bootstrap resamples) suggesting good match between the actual and predicted probabilities. Decision curve analyses (DCAs) showed a more significant positive net benefit in the practical ranges of threshold probabilities using the dynamic nomogram.

CONCLUSION

Preoperative LMR may serve as an easily accessible and non-invasive prognostic biomarker for predicting the prognosis of patients with oral cancer. A dynamic nomogram based on the LMR may show more convenience in survival prediction for patients with oral cancer. Further future studies are warranted to confirm our findings.

Tobacco Products, Periodontal Health and Education Level: Cohort Study from Sweden

Background: The aim of this study is to investigate if using tobacco products (including snuff, smoking tobacco and dual-using) associates with periodontal health, education level and mortality in a Swedish cohort, hypothesizing that tobacco products affect periodontal health, associate with lower education and increase the risk of death. Method: Study cohort of 1080 subjects aged 31–40 years (528 men, 552 women) was clinically examined and interviewed in 1985 and followed for mortality until 2015. Subjects were classified into two groups: “tobacco users” and “non-users”. Associations between periodontal health parameters, tobacco products, education level and age of death were analysed. SPSS was used for analyses. Results: Tobacco products, as well as education level associated, with poor periodontal health. Tobacco users and lower education was linked to higher plaque-, calculus- and gingival-index scores than non-users (p < 0.001). They also had significantly higher prevalence of deep periodontal pockets (≥5 mm) (p < 0.001 and 0.010, respectively), missing teeth (p = 0.010 and 0.003, respectively) and lower education level (p < 0.001) compared with non-users. However, tobacco product users did not die significantly earlier than non-users. Conclusion: Tobacco products had a negative impact on periodontal health. Tobacco product users were less educated. However, using tobacco products may not cause premature death.