Squamous cell head and neck cancer in nonsmokers

Nonsmoking and Nondrinking Oral Squamous Cell Carcinoma Patients: A Different Entity

Objective

Our goal was to analyze the demographic and pathologic characteristics as well as prognosis in nonsmoking and nondrinking (NSND) oral squamous cell carcinoma (SCC) patients compared with typical oral SCC patients.

Patients and Methods

A total of 353 patients were retrospectively enrolled and divided into two groups: the NSND group and the current smoking/current drinking (CSCD) group. Demographic, pathologic, and molecular data were compared between the two groups. The main research endpoints were locoregional control (LRC) and disease-specific survival (DSS).

Results

In the NSND group, 16.3%, 41.9%, and 53.5% of patients were aged no more than 40 years, were female, and had an educational background of high school or above compared to 3.7%, 6.0%, and 38.2% of patients in the CSCD group, respectively. A total of 15.1% of the NSND patients had SCC of the lower gingiva and floor of the mouth, which was lower than the 35.6% of patients in the CSCD group. CSCD patients were likely to have an advanced disease stage (48.7% vs 32.5%, p=0.042) and poorly differentiated cancer (26.6% vs 16.3%, p=0.042). The NSND patients had a mean Ki-67 index of 24.5%, which was lower than the mean of 35.7% in the CSCD patients. The two groups had no HPV infection and similar p16 expression (4.7% vs 10.1%, p=0.132), but there was higher expression of p53 (38.6% vs 17.4%, p<0.001) and p63 (59.9% vs 29.1%, p<0.001) in the CSCD group. The 5-year LRC rates for NSND patients and CSCD patients were 48% and 38%, respectively, and the difference was significant (p=0.048). The 5-year DSS rates for NSND patients and CSCD patients were 56% and 39%, respectively, and the difference was significant (p=0.047). Further, a Cox model confirmed the independence of smoking and drinking status for affecting LRC and DSS.

Conclusion

NSND oral SCC patients are a different entity. HPV infection has a limited role in carcinogenesis in NSND patients, and p16 expression is associated with worse locoregional control.

Secondhand smoke exposure and oral cancer risk: a systematic review and meta-analysis

OBJECTIVES

Inhalation of secondhand smoke (SHS) causes several diseases, including lung cancer. Tobacco smoking is a known cause of oral cancer; however, it has not been established whether SHS also causes oral cancer . The aim of this study was to evaluate the potential association between SHS exposure and the risk of oral cancer.

METHODS

A systematic review and meta-analysis study (following the PRISMA guidelines) was developed to examine the studies reporting on the associations of SHS and the risk of oral cancer, employing a search strategy on electronic databases (PubMed, Web of Science, Scopus, Cochrane Library, Open Grey, and ProQuest databases for dissertations) until 10 May 2020. Meta-analyses and sensitivity analyses were performed using random-effect models. The protocol was registered in PROSPERO (CRD42020189970).

RESULTS

Following the application of eligibility criteria, five studies were included, comprising a total of 1179 cases and 5798 controls, with 3452 individuals exposed and 3525 individuals not exposed to SHS. An overall OR of 1.51 (95% CI 1.2o to 1.91, p=0.0004) for oral cancer was observed, without significant heterogeneity (I²=0%, p=0.41). The duration of exposure of more than 10 or 15 years increased the risk of oral cancer (OR 2.07, 95% CI 1.54 to 2.79, p<0.00001), compared with non-exposed individuals, without significant heterogeneity (I²=0%, p=0.76).

CONCLUSIONS

This systematic review and meta-analysis supports a causal association between SHS exposure and oral cancer. Our results could provide guidance to public health professionals, researchers, and policymakers to further support effective SHS exposure prevention programs worldwide.

Addiction of tobacco chewing and smoking in the patients of head and neck squamous cell carcinoma: A descriptive epidemiological study in Pakistan

Objective:

The associated risk factors for the majority of patients with head and neck squamous cell carcinoma (HNSCC) are tobacco and betel nut abuse, while there also seems to be a rising proportion of patients who report no history of tobacco or betel nut usage. Therefore, objective of the study was to find out potential risk factors and demographics of HNSCC patients addicted to tobacco and/or betel nut, as well as non-addicted patients.

Methods:

This epidemiological study was conducted in Karachi Institute of Biotechnology and Genetic Engineering (KIBGE), University of Karachi, and Jinnah Postgraduate Medical Centre (JPMC) from January to December 2016. All subjects were participants in an epidemiological study of HNSCC. Demographics and clinical characteristics were obtained for 185 addicted and 26 non-addicted patients.

Results:

Non-addicted patients were more likely to be females (χ2=19.0, p<0.001) and were significantly younger than addicted patients (χ2=21.0, p<0.001). Addicted patients more likely belonged to a lower income group (χ2=14.4, p=0.006) and had a higher proportion of oral cancers (χ2=30.0, p<0.001). Almost all addicted females had oral cancers (97%), whereas more than half of the non-addicted females had oral cancers (53%).

Conclusions:

Addicted patients commonly have oral cavity cancers. This might be due to the habit of chewing tobacco and/or betel nut that addicted patients have. Non-addicted patients are commonly young females. It is likely that no single known factor is responsible for HNSCC in non-addicted patients, and several occupational exposure studies in future may be important to the etiology of non-addicted patients.

The effect of second hand smoke in patients with squamous cell carcinoma of the head and neck

Background

Active tobacco smoking is a well-known risk factor for head and neck malignancy, and strong evidence has associated tobacco as the main carcinogenic factor in squamous cell cancers of this region. Evidence supporting a carcinogenic effect of second-hand smoke (SHS) on head and neck organs in non-smokers was also demonstrated with results consistent with those for active smokers. There is little data on the effects of SHS in patients previously treated for squamous cell carcinomas of the head and neck.

Objective

The purpose of this study was to prospectively evaluate the role of SHS on recurrence and survival in treated head and neck cancer patients.

Methods

We conducted a prospective cohort study to examine the association between self-reported SHS exposure and the risk of recurrence and mortality in patients treated for squamous cell cancers of the head and neck in a longitudinal fashion. Patients filled out an exhaustive smoking questionnaire on presentation and abbreviated questionnaires at each follow-up visit, which occurred every 6 months. Primary outcome measures were recurrence, development of a second primary malignancy, and recurrence-free survival. Chi square analysis was used to assess the association between SHS and the primary outcomes. A multivariate binary logistic regression analysis was applied to determine the independent predictors of recurrence. Cox proportional hazards and Kaplan Meier modeling were employed to assess the possible relationships between SHS exposure and time to develop the primary outcomes.

Results

Untreated new patients with a histologically confirmed diagnosis of first primary SCC of the UADT (defined as cancer of the oral cavity, the oropharynx, the hypopharynx, and the larynx) were recruited. Patients seen at The University of Texas Medical Branch (UTMB) Head and Neck oncology clinic from 1988 to 1996 were considered as cases in this study. One hundred and thirty-five patients were enrolled in the study. The median follow-up time for the sample was 54 months (3.92 years). Complete records were achieved for 92% of patients, thus 124 patients were included in the final analysis. SHS significantly correlated with recurrence and recurrence-free survival. The rate of recurrence was 46% in the group exposed to SHS and 22% in the non-exposed group. Based on multivariate binary logistic regression analysis, SHS exposure was detected as a significant independent predictor for recurrence (HR = 3.00 [95% CI 1.18–7.63]). Kaplan-Meier analysis demonstrated that patients who were not exposed to SHS had a statistically significant longer recurrence-free survival (log-rank P = 0.029). The mean survival for non SHS-exposed patients was 76 [63–89] months versus 54 [45–63] months for those exposed to SHS.

Conclusions

SHS exposure is an independent predictor of recurrence and survival after head and neck cancer treatment. These results support the importance and efforts of reducing smoking at home in in the work-place.

The rising rate of nonsmokers among laryngeal carcinoma patients: Are we facing a new disease?

OBJECTIVES/HYPOTHESIS

Laryngeal squamous cell carcinoma (SCC) is strongly associated with tobacco smoking. With the rising awareness of tobacco's adverse health effects, we have witnessed a global decrease in tobacco use. Nevertheless, laryngeal SCC remains prevalent and includes a subset of patients lacking the traditional risk factors.

STUDY DESIGN

A two-center retrospective cohort.

METHODS

Medical records of patients diagnosed with laryngeal SCC between 2009 and 2016 were reviewed. Data collected included demographics, smoking status, and tumor site. Patients who have never smoked were designated as nonsmokers.

RESULTS

The study included 330 patients with laryngeal SCC, of whom 75 (22.7%) were nonsmokers; this rate was relatively similar for each of the two institutions independently (21.9% and 25%). There were 285 patients with glottic SCC and 45 with supraglottic SCC. All nonsmoking patients in this cohort had glottic SCC, representing 26.3% (75/285) of the glottic SCC cases. The rate of female patients was significantly higher among nonsmokers. Of the patients with glottic SCC, females represented 25.3% (19/75) of the nonsmokers compared with 12.4% (26/210) of the smokers (P = .008). Mean age at diagnosis was 60.2 ± 17.5 years for nonsmoking glottic SCC patients and 63.6 ± 12.4 years for smokers (P = .280). However, nonsmokers demonstrated a distinct age distribution pattern. Nonsmoking females with glottic SCC demonstrated a bimodal age distribution pattern; 73.7% (14/19) were age <40 years or >75 years at diagnosis.

CONCLUSIONS

The rate of laryngeal SCC in nonsmokers is higher than what has previously been reported, representing a growing proportion, and may suggest a shift in etiology. Knowing that laryngeal SCC in nonsmokers predominantly affects the glottis, and that females and age extremities are more vulnerable, the traditional screening paradigm should be revised.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:E108-E115, 2020.

Epidemiological evidence on environmental tobacco smoke and cancers other than lung or breast

We reviewed 87 epidemiological studies relating environmental tobacco smoke (ETS) exposure to risk of cancer other than lung or breast in never smoking adults. This updates a 2002 review which also considered breast cancer. Meta-analysis showed no significant relationship with ETS for nasopharynx cancer, head and neck cancer, various digestive cancers (stomach, rectum, colorectal, liver, pancreas), or cancers of endometrium, ovary, bladder and brain. For some cancers (including oesophagus, colon, gall bladder and lymphoma) more limited data did not suggest a relationship. An increased cervix cancer risk (RR 1.58, 95%CI 1.29-1.93, n = 17 independent estimates), reducing to 1.29 (95%CI 1.01-1.65) after restriction to five estimates adjusting for HPV infection or sexual activity suggests a causal relationship, as do associations with nasosinus cancer observed in 2002 (no new studies since), and less so kidney cancer (RR 1.33, 95%CI 1.04-1.70, n = 6). A weaker association with total cancer (RR 1.13, 95%CI 1.03-1.35, n = 19) based on heterogeneous data is inconclusive. Inadequate confounder control, recall bias, publication bias, and occasional reports of implausibly large RRs in individual studies contribute to our conclusion that the epidemiological evidence does not convincingly demonstrate that ETS exposure causes any of the cancers studied.

HPV prevalence and p16INKa overexpression in non-smoking non-drinking oral cavity cancer patients

OBJECTIVE

Our aim was to compare HPV and p16INK4a (p16) expression and their influence on survival and prognosis in oral cavity squamous cell cancer (OCSCC), between non-smokers and non-drinkers (NSND) and smokers and drinkers (SD).

SUBJECTS AND METHODS

Patients with OCSCC treated with surgery from 2000 to 2010 were included in the study. Patients who did not smoke at all or smoked less than 10 pack per years and did not drink alcohol on a daily basis were considered the NSND group. An equal number of SD were the control group. HPV presence was determined from paraffin-embedded blocks investigated by PCR analysis. p16 expression was evaluated with immunohistochemistry.

RESULTS

The NSND group were mostly younger or older female patients with tongue or gingival cancers. p16 expression was significantly more frequent in NSND patients (27% vs 10%). Patients with stronger p16 expression had significantly worse survival, especially for tongue cancers (P = 0.026). In Cox multivariate analysis, both HPV and p16 expression carried a negative prognosis for NSND patients (P = 0.0351 and P = 0.0260).

CONCLUSIONS

NSND are a specific population of OCSCC patients. In contrast to oropharyngeal cancer, HPV and p16 expression in OCSCC are negative predictive factors, especially in NSND patients.

Squamous cell carcinoma of the oral cavity often overexpresses p16 but is rarely driven by human papillomavirus

OBJECTIVE

Human papillomavirus (HPV) is a causal and prognostic factor for oropharyngeal cancer, but its role in squamous cell carcinoma of the oral cavity (SCCOC) is unclear. We sought to clarify HPV's role in SCCOC.

MATERIALS AND METHODS

Patients with newly diagnosed SCCOC (N=460) were prospectively recruited, treated, and followed at one institution. p16/HPV status was determined by p16 immunohistochemistry (IHC) (N=210), PCR-based HPV 16/18 E6/7 DNA testing (N=403), and/or HPV in situ hybridization (ISH) (N=178). Kaplan-Meier curves and log-rank tests were used to compare survival by p16/HPV status.

RESULTS

p16 expression was detected in 30% of tumors (62/210) and HPV 16/18 E6/7 DNA in 28% (114/403), although correlation between these two assays was poor (r=-0.01). Patients with p16-positive tumors were more likely to be younger and have primary tumors of the oral tongue. Only 4% of tumors (7/171) were positive for HPV by ISH. Comparisons of patients with p16-positive and p16-negative tumors, patients with HPV-positive and HPV-negative tumors by PCR, and patients with HPV-positive and HPV-negative tumors by ISH showed no significant differences in disease-specific or disease-free survival by p16/HPV status. When we applied a more stringent definition of HPV positivity based on a combination of assay results, only 10 of 166 tumors were HPV positive, and there were no significant differences in demographic, exposure, clinical, or survival characteristics between these patients and the 156 HPV-negative patients.

CONCLUSIONS

Very few patients with SCCOC have HPV-driven tumors. SCCOC that overexpresses p16 may be a unique subset deserving of further study.

Childhood passive smoke exposure is associated with adult head and neck cancer

INTRODUCTION

Passive smoke is carcinogenic but its association with head and neck squamous cell carcinoma (HNSCC) is uncertain.

METHODS

We conducted a case-control study of childhood passive smoke exposure (CPSE) and HNSCC in 858 cases and 806 frequency-matched controls using an interviewer-administered questionnaire. Odds ratios (OR) and 95% confidence intervals (CI) were estimated with logistic regression controlling for adult smoking in the total study population, and in never-smokers only (184 cases and 415 controls). CPSE was also studied in oropharyngeal separately from other HNSCC using polytomous logistic regression.

RESULTS

CPSE was associated with HNSCC (OR, 1.28; 95% CI, 1.01-1.63) after controlling for adult smoking and other factors. This association was similar in magnitude, although not statistically significant, among subjects who never smoked as adults (OR, 1.19, 95% CI, 0.80-1.76). CPSE was associated more strongly with oropharyngeal cancer (a HNSCC subtype commonly associated with human papillomavirus (HPV) infection) than with HNSCC at non-oropharyngeal sites (OR, 2.02; 95% CI, 1.01-4.06, N=52 cases vs. OR, 1.04; 95% CI, 0.68-1.60, N=132 cases; P-for-heterogeneity=0.08).

CONCLUSIONS

Data from this large US-based case control study suggest a role for CPSE in HNSCC etiology.

Laryngeal cancer and passive smoking: the neglected factor?

In the present paper we investigate the relationship of environmental tobacco smoke (ETS) exposure to laryngeal cancer. 209 patients who were diagnosed with laryngeal cancer from 2000 to 2009 at the University Hospital of Patras, Western Greece, were reviewed with regard to patient age, disease stage at presentation, tumor differentiation, tobacco product use, alcohol consumption, occupation, and ETS exposure in the working environment. Pearson Chi-square method was used to determine the effect of ETS exposure on cancer stage, TNM classification and tumor differentiation in the dichotomized population (exposed vs. not exposed) and in groups of low, medium and high ETS exposure. ETS exposure in the working environment was found to significantly affect overall disease stage and T stage (p < 0.01) both in the dichotomic analysis and the group analysis. Minor significance was also noted for N stage (p = 0.047) in the exposure group analysis. Our data suggest that occupational ETS exposure presents a contributing risk factor for laryngeal cancer that requires further research to determine its significance.

Active and involuntary tobacco smoking and upper aerodigestive tract cancer risks in a multicenter case-control study

INTRODUCTION

Several important issues for the established association between tobacco smoking and upper aerodigestive tract (UADT) cancer risks include the associations with smoking by cancer subsite, by type of tobacco, and among never alcohol drinkers and the associations with involuntary smoking among nonsmokers. Our aim was to examine these specific issues in a large-scale case-control study in Europe.

METHODS

Analysis was done on 2,103 UADT squamous cell carcinoma cases and 2,221 controls in the Alcohol-Related Cancers and Genetic Susceptibility in Europe project, a multicenter case-control study in 10 European countries. Unconditional logistic regression was done to obtain odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

Compared with never tobacco smoking, current smoking was associated with UADT cancer risks (OR, 6.72; 95% CI, 5.45-8.30 for overall; OR, 5.83; 95% CI, 4.50-7.54 for oral cavity and oropharynx; OR, 12.19; 95% CI, 8.29-17.92 for hypopharynx and larynx; and OR, 4.17; 95% CI, 2.45-7.10 for esophagus). Among never drinkers, dose-response relationships with tobacco smoking pack-years were observed for hypopharyngeal and laryngeal cancers (P(trend) = 0.010) but not for oral cavity and oropharyngeal cancers (P(trend) = 0.282). Among never smokers, ever exposure to involuntary smoking was associated with an increased risk of UADT cancers (OR, 1.60; 95% CI, 1.04-2.46).

CONCLUSION

Our results corroborate that tobacco smoking may play a stronger role in the development of hypopharyngeal and laryngeal cancers than that of oral cavity and oropharyngeal cancers among never drinkers and that involuntary smoking is an important risk factor for UADT cancers. Public health interventions to reduce involuntary smoking exposure could help reduce UADT cancer incidence.

Involuntary smoking and head and neck cancer risk: pooled analysis in the International Head and Neck Cancer Epidemiology Consortium

Although active tobacco smoking has been identified as a major risk factor for head and neck cancer, involuntary smoking has not been adequately evaluated because of the relatively low statistical power in previous studies. We took advantage of data pooled in the International Head and Neck Cancer Epidemiology Consortium to evaluate the role of involuntary smoking in head and neck carcinogenesis. Involuntary smoking exposure data were pooled across six case-control studies in Central Europe, Latin America, and the United States. Adjusted odds ratios (OR) and 95% confidence interval (95% CI) were estimated for 542 cases and 2,197 controls who reported never using tobacco, and the heterogeneity among the study-specific ORs was assessed. In addition, stratified analyses were done by subsite. No effect of ever involuntary smoking exposure either at home or at work was observed for head and neck cancer overall. However, long duration of involuntary smoking exposure at home and at work was associated with an increased risk (OR for >15 years at home, 1.60; 95% CI, 1.12-2.28; P(trend) < 0.01; OR for >15 years at work, 1.55; 95% CI, 1.04-2.30; P(trend) = 0.13). The effect of duration of involuntary smoking exposure at home was stronger for pharyngeal and laryngeal cancers than for other subsites. An association between involuntary smoking exposure and the risk of head and neck cancer, particularly pharyngeal and laryngeal cancers, was observed for long duration of exposure. These results are consistent with those for active smoking and suggest that elimination of involuntary smoking exposure might reduce head and neck cancer risk among never smokers.

Laryngeal carcinoma in nonsmoking patients

OBJECTIVES

Smoking is a known risk factor for laryngeal carcinoma. We sought to describe the clinicopathologic characteristics and outcomes of nonsmoking patients with laryngeal carcinoma.

METHODS

Of 1,443 patients treated for laryngeal carcinoma between 1960 and 2006, 55 (3.8%) were nonsmokers: 40 (73%) had never smoked and 15 (27%) had stopped smoking 12 years or more before diagnosis. Patient characteristics and outcomes were reviewed.

RESULTS

The study group consisted of 87% men; the mean age at diagnosis was 67 years. All lesions but one were located in the glottis. The 5-year survival rate for the whole group was 85%. Most tumors were detected early. Of 38 patients (69%) with stage T1 disease, there was no significant difference in prognostic features between those who had never smoked and those who had smoked in the past.

CONCLUSIONS

Fewer than 5% of patients with laryngeal carcinoma were nonsmokers. Like smokers, this subgroup was characterized by a male predominance and an approximate age at diagnosis in the seventh decade. Unlike smokers, nonsmokers show a greater predilection for glottic rather than supraglottic disease. There was no difference in prognosis between smokers and nonsmokers, regardless of whether they had smoked in the past.

Squamous cell carcinoma of the oral tongue: a 25-year, single institution experience

Aim:

To report the characteristics, prognostic factors and treatment outcomes of 102 patients with squamous cell carcinoma of the oral tongue treated and followed up at a single institution over a 25-year period.

Patients and methods:

This retrospective study was carried out by auditing the medical records of 102 patients diagnosed with squamous cell carcinoma of the oral tongue and treated at our institution between 1982 and 2007. Patient follow up ranged from nine to 310 months (median 35 months). Fifty per cent of the patients were treated with surgery followed by a combination of chemotherapy and radiotherapy (43.1 per cent received concurrent chemoradiation and 6.9 per cent received sequential chemotherapy and radiotherapy), whereas 29.4 per cent received surgery followed by adjuvant radiotherapy alone. The remaining patients (20.6 per cent) did not undergo surgery and were treated with definitive radiotherapy with or without chemotherapy.

Results:

There were 48 men and 54 women. The age at presentation was 19–85 years (median 57 years). The peak incidence was observed between 60 and 70 years. Resection margins were clear in 75 per cent of patients and involved in 25 per cent. Stage I disease was found in 11.8 per cent of patients, stage II in 34.3 per cent, stage III in 22.5 per cent and stage IV in 31.4 per cent. The five-year disease-free survival and overall survival were 65.7 and 72.5 per cent, respectively. Thirty-five patients suffered recurrence after treatment, 74.0 per cent of them at the site of initial cervical nodal involvement. Univariate analysis for overall survival revealed the following as prognostic factors: treatment schedule (surgical vs non-surgical; p < 0.001); age (<60 years vs ≥60 years; p = 0.038); extent of cervical lymph node involvement (p = 0.015); primary tumour stage (p < 0.001); node stage (p = 0.034); and disease stage (p = 0.013). However, on multivariate analysis, only non-surgical treatment (p = 0.001) and advanced disease stage (p = 0.05) were found to have a negative influence on survival.

Conclusions:

Our limited data suggest that, in Iran, squamous cell carcinoma of the oral tongue tends to present at a locally advanced stage, with a high frequency of locoregional failure and a poor outcome. Combined modality therapy should be considered for the majority of patients with squamous cell carcinoma of the tongue.

Current topics in the epidemiology of oral cavity and oropharyngeal cancers

Oral cancer incidence rates rose dramatically during the twentieth century in the United States and Europe, especially among individuals under the age of 60 years. Although influenced by age, sex, and country of origin, incidence trends were most strongly affected by elevated risk among individuals born after approximately 1915. This cohort effect was indicative of strong behavioral influences on oral cancer risk. In this article, associations between oral cancer risk and established behavioral risk factors including alcohol and tobacco use are reviewed. Additionally, possible associations between oral cancer risk and oral hygiene, diet, nutritional status, and sexual behavior as well as the influence of genetic factors on oral cancer risk are considered. Special emphasis is placed on evaluating possible risk differences in individuals above and below the age of 45 and in users and nonusers of alcohol and tobacco.

Squamous cell carcinoma of the head and neck in never smoker–never drinkers: A descriptive epidemiologic study

BACKGROUND

While the attributed risk factors for the vast majority of patients with squamous cell carcinoma of the head and neck (SCCHN) are smoking and alcohol abuse, there appears to be a rising proportion of SCCHN patients who report no significant smoking or drinking history. This study reports the demographic and potential risk factors of a large series of never smoker-never drinker (NSND) patients.

METHODS

All subjects were participants in a prospective epidemiologic study of incident SCCHN. We obtained demographic data, clinical characteristics, and potential etiologic factors for 172 NSND patients and 1131 ever smoker-ever drinker (ESED) patients. RESULTS.: NSND patients were more likely to be female and to present at extremes of age, but overall were significantly younger than ESED patients. NSND patients had a higher proportion of oral cavity and oropharyngeal cancers than ESED patients had. Eleven percent of NSND patients (17% of NSND men) reported regular use of noncigarette tobacco products or marijuana, 41% (45% of NSND women) reported regular environmental exposure to tobacco smoke, 24% (36% of NSND men) reported regular occupational exposures to carcinogens/toxins, and 30% had a history of gastroesophageal reflux disease. More than half the NSND patients with an oropharyngeal primary were serologically positive for human papillomavirus type 16.

CONCLUSION

NSND patients with SCCHN are commonly young women with oral tongue cancer, elderly women with gingival/buccal cancer, or young to middle-aged men with oropharyngeal cancer. While several exposures studied may be important to the etiology of a subset of these cancers in NSND patients, it is likely that no single known factor is responsible for a majority of SCCHN in NSNDs.

Mitochondrial DNA mutations in oral squamous cell carcinoma

It has previously been demonstrated that mitochondrial DNA (mtDNA) mutations within the ND2 gene of histologically normal parotid salivary gland tissue of smokers may be molecular biomarkers for smoking-induced mtDNA damage. Oral squamous cell carcinoma (SCC) is strongly related to cigarette smoking; therefore, we used PCR and direct sequencing to establish whether mtDNA mutations were also present in oral SCC which could be used as additional biomarkers for smoking-associated DNA damage. In addition to searching for mutations in the ND2 gene, the mitochondrial D-Loop was also analysed. Three mutation hotspots were observed in the D-Loop at nt 146, 152 and 186, two of which (nt 146 and 152) have also been implicated in oesophageal SCC, another smoking-related cancer. The mutation hotspot observed at nt 186 has not previously been reported in other tumours. Furthermore, we show that the mutations previously reported within the ND2 gene in normal parotid tissue of smokers were not evident in these samples, but that a mutation hotspot occurs at nucleotide 4917 in oral SCC. We also show that D-Loop mutations occur predominantly in male smokers and female non-smokers and that this association with gender is statistically significant (P = 0.003). We conclude that the mtDNA mutation hotspots found in this study, in particular nt 186, are potential biomarkers for oral SCC. However, owing to gender-specific differences in occurrence in smokers and non-smokers, and a lack of environmental smoking history, in general, it is difficult to associate these mutations with mtDNA damage induced by smoking. If the mutations observed in the subset of male patients are smoking induced, given our previous findings, mutation hotspots in the ND2 gene may be tissue specific suggesting the causative mutagens for mtDNA damage within these tissues are likely to be different.

After the Smoke Clears

Both environmental and occupational exposures are associated with the development of carcinomas of the upper aerodigestive tract, although most squamous cell carcinomas of the upper aerodigestive tract are related to smoking and drinking. This review discusses environmental and occupational risk factors, other than tobacco and alcohol, for carcinoma of the upper aerodigestive tract and the difficulties encountered when attempts are made to study these environmental and occupational exposures. However, this is not an all-inclusive review; rather, it is designed to give the reader an understanding of the topic, to allow for appropriate counseling of patients, and perhaps to advance public health initiatives.

Descriptive epidemiology and risk factors for head and neck cancer

Although more common in developing countries, over 11,000 deaths will occur in the United States from head and neck cancer in 2004. Squamous cell carcinomas account for the vast majority of cases in the United States and the majority of these are related to exposure to tobacco and alcohol. Newer data suggest a genetic contribution. This group is the focus of primary and secondary preventative efforts.

ANTERIOR TONGUE CANCER: AGE IS NOT A PREDICTOR OF OUTCOME AND SHOULD NOT ALTER TREATMENT

BACKGROUND

Mucosal head and neck cancers usually occur in older males after years of smoking and alcohol abuse. Despite this, approximately 5% of cases occur in young adults. The aetiology remains unclear and the anterior tongue is a prevalent site. Prognosis has been reported as worse in young patients and some have proposed a more aggressive treatment approach.

METHODS

Patients diagnosed with previously untreated anterior tongue squamous cell carcinoma and treated with curative intent were identified. Retrospective and prospective data were collected. Univariate and multivariate analyses were undertaken using Cox regression analysis. The outcome of patients treated with anterior tongue cancer using a cut-off age of 40 years was compared.

RESULTS

Between 1980 and 2000, 106 males and 58 females with anterior tongue squamous cell carcinoma were treated at Westmead Hospital. Median follow up was 47 months (6-210 months). Twenty-two patients (13.4%) were aged </=40 years. Other than age, patient demographics, TNM stage and treatment approach were similar between the two groups. Eighty-one per cent had either a T1 or T2 primary. In total, 139 patients (84.8%) had surgery or surgery and radiotherapy. A total of 56 (34%) patients experienced a recurrent event, with nodal recurrence occurring most often as the first site (n = 33, 59%). Young patients had a higher recurrence rate (45.5% vs 32.4%; P = 0.23). Relapse-free survival at 5 years was 62% versus 81% (P = 0.27). Overall survival at 5 years was 65% versus 67% (P = 0.74).

CONCLUSIONS

In keeping with recently published evidence, young age at diagnosis with anterior tongue cancer did not portend worse outcome. There is therefore currently no strong evidence to support a different treatment approach in young patients.

Expression of cell cycle proteins in head and neck cancer correlates with tumor site rather than tobacco use

Head and neck squamous cell carcinomas of non-smoking patients may result from specific defects in cell cycle control. Expression of p53, pRb, p16(INK4a) and Cyclin D1 was examined by immunohistochemistry of biopsies obtained from 24 non-smoking and 25 smoking patients, both groups representing similar clinical features (tumor site, stage of disease, gender). Expression of p16(INK4a) was restricted to carcinomas of the tonsils (8/24), P=0.0069. In 6/8 p16(INK4a)-positive cases, expression of pRb was absent or reduced. p16 was the only marker showing a significant correlation with a negative smoking history (P=0.0208). Overexpression of Cyclin D1 was frequent in carcinomas of the tongue (6/14) but rare in tonsillar carcinomas (2/24), P=0.0303. Expression of p53 was independent of the smoking history and the tumor site. Our results implicate that there are factors other than tobacco consumption which may influence the development of head and neck cancers at distinct tumor sites.

Environmental tobacco smoke and cancer of sites other than the lung in adult non-smokers

Evidence from epidemiological studies relating environmental tobacco smoke (ETS) exposure to risk of cancer of sites other than the lung in adult non-smokers is reviewed. Problems common to many studies include small sample size, inadequate control of potential confounding, failure to consider the possibility of misclassification of smoking status, reliance on death certificate diagnosis, use of proxy respondents and the possibility of recall bias. A number of the studies have other obvious weaknesses. Publication bias is known to be a problem, with two very large prospective studies having reported only very limited results. For cancers of the digestive system, bladder and brain, there is little evidence of an association with ETS exposure. Some studies have reported a relationship with cancer of the breast, cervix or nasopharynx, but the overall evidence for these sites is inconsistent and inconclusive, as is that for total cancer incidence. All three studies of nasosinus cancer have reported a statistically significant association with ETS exposure, but they are small, control poorly for potential confounding and have other weaknesses. Taken as a whole, the epidemiological evidence provides little support for the view that ETS causes cancer of any of the sites considered.

Genetic susceptibility--molecular epidemiology of head and neck cancer

In parts of the developing world (South Central Asia in particular), squamous cell carcinoma of the head and neck (SCCHN) is one of the most common malignancies encountered. Although tobacco and alcohol are clearly defined as etiologic factors in these malignancies, clinical observations have suggested that inherited genetic factors put some individuals at increased risk for SCCHN. Emerging data (both phenotypic and genotypic) support this concept of genetic susceptibility to SCCHN and point to differences in DNA repair ability, carcinogen metabolism, and cell cycle control as the systems important to the risk of tobacco-induced malignancies. The ability to identify such high-risk individuals will have major influences on the practice of cancer prevention in the future.

Sharp v Port Kembla RSL Club: establishing causation of laryngeal cancer by environmental tobacco smoke

A New South Wales Supreme Court jury has decided that environmental tobacco smoke (ETS) can cause or materially contribute to the development of laryngeal cancer. Evidence presented that ETS may cause or materially contribute to laryngeal cancer included the molecular genetics of tobacco-smoke-induced carcinogenesis, and two relevant epidemiological studies. The plaintiff's exposure to ETS was established indirectly, on the basis of occupational history involving work as a bar attendant in licensed premises. The jury's decision seems likely to encourage other "passive smoking" cases, and may result in measures to reduce occupational exposure to ETS.

More aggressive behavior of squamous cell carcinoma of the anterior tongue in young women

OBJECTIVE

To review the combined experience from two large medical centers in treating young female patients with anterior tongue cancer to determine the clinical course of this unique subset of patients.

STUDY DESIGN

Retrospective study.

METHODS

Seventeen female patients less than 40 years of age (group A) and 17 older patients, both male and female, greater than 40 years of age (group B) who had treatment for invasive squamous cell carcinoma of the anterior tongue were studied. The charts were reviewed for the clinical staging, treatment, and outcome of each patient. The disease-free survival and recurrence rates were compared between the two cohorts.

RESULTS

The mean disease stage between the groups was II. The survival analysis showed a significant difference between the two groups in recurrences (group A = 65%, group B = 41%; P = .02). Further, of the patients who had recurrence, the young women did so significantly earlier in their disease course than the older patients (group A = 14 mo, group B = 40 mo; P < .05). Although the survival differences did not reach statistical significance (P = .15), the power of the study was low (power = 0.26) resulting in a high-level type II error.

CONCLUSION

These data suggest that young women with squamous cell carcinoma of the anterior tongue have significantly higher rates of recurrent disease and the interval to recurrence is significantly shorter than in older patients. Further investigation is warranted until a statistically significant cohort is accrued; until that time, these patients warrant an aggressive initial treatment and close surveillance for recurrence.

Effects of environmental tobacco smoke on objective measures of voice production

OBJECTIVE

The effects of passive smoking on the voice and laryngeal structures of 20 female passive smokers and 20 age-matched nonsmokers were examined.

METHODS

The voice evaluation consisted of acoustic, aerodynamic, and videostroboscopic analyses.

RESULTS

Three passive smokers displayed mild edema or erythema. Passive smokers had higher mean flow rates and shorter mean maximum phonation times during sustained vowels at comfortable, low-, and high-pitch levels. However, means were only outside normal limits and significantly different from nonsmokers at high pitch. Variables such as the number of years and hours per day subjects were exposed to environmental tobacco smoke were considered.

CONCLUSION

The majority of the variables indicated that vocal fold structure and function were not adversely altered by exposure to passive smoke. Differences between these results and clinical observations are highlighted.