After the Smoke Clears

Immunotherapy in Head and Neck Cancer: Where Do We Stand?

PURPOSEOF REVIEW

Head and neck cancer (HNC) comprises a group of malignancies, amongst which squamous cell carcinoma accounts for more than 90% of the cases. HNC has been related to tobacco use, alcohol consumption, human papillomavirus, Epstein-Barr virus, air pollution, and previous local radiotherapy. HNC has been associated with substantial morbidity and mortality. This review aims to summarize the recent findings regarding immunotherapy in HNC.

RECENT FINDINGS

The recent introduction of immunotherapy, with the use of programmed death 1 (PD-1) inhibitors pembrolizumab and nivolumab, which have been FDA approved for the treatment of metastatic or recurrent head and neck squamous cell carcinoma, has changed the field in metastatic or recurrent disease. There are many ongoing trials regarding the use of novel immunotherapeutic agents, such as durvalumab, atezolizumab, avelumab, tremelimumab, and monalizumab. In this review, we focus on the therapeutic potential of novel immunotherapy treatment modalities, such as combinations of newer immune-checkpoint inhibitors; the use of tumor vaccines such as human papillomavirus-targeted vaccines; the potential use of oncolytic viruses; as well as the latest advances regarding adoptive cellular immunotherapy. As novel treatment options are still emerging, a more personalized approach to metastatic or recurrent HNC therapy should be followed. Moreover, the role of the microbiome in immunotherapy, the limitations of immunotherapy, and the various diagnostic, prognostic, and predictive biomarkers based on genetics and the tumor microenvironment are synopsized.

Head and neck cancer

Head and neck cancer is the seventh most common type of cancer worldwide and comprise of a diverse group of tumours affecting the upper aerodigestive tract. Although many different histologies exist, the most common is squamous cell carcinoma. Predominant risk factors include tobacco use, alcohol abuse, and oncogenic viruses, including human papillomavirus and Epstein-Barr virus. Head and neck malignancies remain challenging to treat, requiring a multidisciplinary approach, with surgery, radiotherapy, and systemic therapy serving as key components of the treatment of locally advanced disease. Although many treatment principles overlap, treatment is generally site-specific and histology-specific. This Seminar outlines the current understanding of head and neck cancer and focuses on treatment principles, while also discussing future directions to improve the outcomes of patients with these malignancies.

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.

Gastric reflux is an independent risk factor for laryngopharyngeal carcinoma

BACKGROUND

Gastric reflux can reach into the upper airway, inducing cellular damage in the epithelial lining. This condition is believed to be a risk factor for development of laryngopharyngeal squamous cell carcinoma (LPSCC), although the literature is conflicting.

METHODS

To better clarify this relationship, we assessed the association of self-reported heartburn history and medication use among 631 patients with LPSCCs and 1234 control subjects (frequency-matched on age, gender, and town of residence) enrolled as part of a population-based case-control study of head and neck squamous cell carcinoma in the greater Boston area.

RESULTS

After adjusting for age, gender, race, smoking, alcohol consumption, HPV16 seropositivity, education, and body mass index, subjects reporting a history of frequent heartburn and who were neither a heavy smoker nor heavy drinker had a significantly elevated risk of LPSCCs [OR, 1.78; 95% confidence interval (CI), 1.00-3.16]. Among those with a history of heartburn, there was an inverse association between antacid use and LPSCCs relative to those never taking heartburn medication (OR, 0.59; 95% CI, 0.38-0.93) that remained consistent when analyzed by smoking/drinking status, HPV16 status, or by primary tumor site.

CONCLUSIONS

Our data show that gastric reflux is an independent risk factor for squamous cancers of the pharynx and larynx. Further studies are needed to clarify the possible chemopreventive role of antacid use for patients with gastric reflux.

IMPACT

Elucidation of additional risk factors for head and neck cancer can allow for risk stratification and inform surveillance of high-risk patients.

Peripheral blood DNA methylation profiles are indicative of head and neck squamous cell carcinoma: an epigenome-wide association study

Head and neck cancer accounts for an estimated 47,560 new cases and 11,480 deaths annually in the United States, the majority of which are squamous cell carcinomas (HNSCC). The overall 5 year survival is approximately 60% and declines with increasing stage at diagnosis, indicating a need for non-invasive tests that facilitate the detection of early disease. DNA methylation is a stable epigenetic modification that is amenable to measurement and readily available in peripheral blood. We used a semi-supervised recursively partitioned mixture model (SS-RPMM) approach to identify novel blood DNA methylation markers of HNSCC using genome-wide methylation array data for peripheral blood samples from 92 HNSCC cases and 92 cancer-free control subjects. To assess the performance of the resultant markers, we constructed receiver operating characteristic (ROC) curves and calculated the corresponding area under the curve (AUC). Cases and controls were best differentiated by a methylation profile of six CpG loci (associated with FGD4, SERPINF1, WDR39, IL27, HYAL2 and PLEKHA6), with an AUC of 0.73 (95% CI: 0.62-0.82). After adjustment for subject age, gender, smoking, alcohol consumption and HPV16 serostatus, the AUC increased to 0.85 (95% CI: 0.76-0.92). We have identified a novel blood-based methylation profile that is indicative of HNSCC with a high degree of accuracy. This profile demonstrates the potential of DNA methylation measured in blood for development of non-invasive applications for detection of head and neck cancer.

Biological evidence for the acute health effects of secondhand smoke exposure

A vast number of studies on the unfavorable effects of secondhand smoke (SHS) exist within the international literature, the majority of which evaluate longitudinal epidemiological data. Although limited, the experimental studies that assess the acute and short-term effects of exposure to SHS are also increasing in number. They include cellular, animal, and human studies that indicate a number of pathophysiological mechanisms through which the deleterious effects of SHS may arise. This current review evaluates the existing biological evidence regarding the acute health effects of SHS exposure. Analyses on the inhaled toxicants and the carcinogenicity of SHS are included as well as in-depth discussions on the evidence for acute SHS-induced respiratory, cardiovascular, metabolic, endocrine and immune effects, and SHS-induced influences on oxygen delivery and exercise. The influence of the length of exposure and the duration of the observed effects is also described. Moreover, recent findings regarding the underlying pathophysiological mechanisms related to SHS are depicted so as to generate models that describe the SHS-induced effects on different systems within the human body. Based on the presented biological evidence, it is concluded that brief, acute, transient exposures to SHS may cause significant adverse effects on several systems of the human body and represent a significant and acute health hazard. Future research directions in this area include research on the concentrations of tobacco smoke constituents in the alveolar milieu following SHS exposure, individual susceptibility to SHS, as well as the effects of SHS on neurobehavioral activity, brain cell development, synaptic development, and function.

Trends in head and neck cancer incidence in relation to smoking prevalence: an emerging epidemic of human papillomavirus-associated cancers?

The trends in head and neck cancer incidence and smoking prevalence are reviewed, discussing where such trends parallel but also how and why they may not. In the U.S., public health efforts at tobacco control and education have successfully reduced the prevalence of cigarette smoking, resulting in a lower incidence of head and neck cancer. Vigilance at preventing tobacco use and encouraging cessation should continue, and expanded efforts should target particular ethnic and socioeconomic groups. However, an unfortunate stagnation has been observed in oropharyngeal cancer incidence and likely reflects a rising attribution of this disease to oncogenic human papillomavirus, in particular type 16 (HPV-16). For the foreseeable future, this trend in oropharyngeal cancer incidence may continue, but with time the effects of vaccination of the adolescent and young adult female population should result in a lower viral prevalence and hopefully a reduced incidence of oropharyngeal cancer. To hasten the reduction of HPV-16 prevalence in the population, widespread vaccination of adolescent and young adult males should also be considered.

ABCB1 genetic polymorphism and risk of upper aerodigestive tract cancers among smokers, tobacco chewers and alcoholics in an Indian population

BACKGROUND AND OBJECTIVE

Upper aerodigestive tract (UADT) cancers are associated with the tobacco use and alcohol consumption. Certain toxins and carcinogens causing UADT cancers are found to be substrates of polymorphic ABCB1 gene encoded P-glycoprotein efflux pump. This study investigates the association between ABCB1 gene polymorphism at exon 26 (3435C>T) and risk to UADT cancers in Tamilians, a population of south India.

METHODS

The study included 219 unrelated histopathologically confirmed cases and 210 population-based controls. Genomic DNA was extracted from peripheral leukocytes and genotyped for ABCB1 3435C>T polymorphism by PCR-restriction fragment length polymorphism method.

RESULTS

The multivariate logistic regression analyses demonstrated that the homozygous ABCB1 TT genotype was significantly associated with an overall increased risk for developing UADT cancers [odds ratio (OR): 2.53; 95% confidence interval (CI): 1.28-5.02]. Further, the determination of gene-environment interaction by stratified analyses have revealed a significant interaction between the smoking and homozygous TT genotype [(OR: 7.52; CI: 1.50-37.70) and (OR: 16.89; CI: 3.87-73.79) for 11-20 and >20 pack-years, respectively]. The strongest interaction was observed among the regular tobacco chewers (OR: 45.29; CI: 8.94-130.56) homozygous for TT genotype. No suggestion, however, of an interaction between the genotypes and the alcohol consumption on the multiplicative scale was made.

CONCLUSION

The ABCB1 gene polymorphism at exon 26 (3435C>T) may be one of the risk factors for susceptibility to UADT cancers. Furthermore, the significant interaction among habitual smokers and tobacco chewers, homozygous for TT genotype modulates the risk to UADT cancers in the Tamilian population of south India.

Genetic polymorphisms of glutathione-S-transferase genes (GSTM1, GSTT1 and GSTP1) and upper aerodigestive tract cancer risk among smokers, tobacco chewers and alcoholics in an Indian population

The glutathione-S-transferase (GST) genes are involved in the detoxification of various carcinogens that increase the risk to upper aerodigestive tract (UADT) cancers. In the present study, 408 unrelated histopathologically confirmed cases and 220 population based controls, matched by age and gender, which belonged to the Tamilian population of south India were genotyped for polymorphisms in GSTM1, GSTT1 and GSTP1 using polymerase chain reaction (PCR) based methods. The multivariate logistic regression analyses demonstrated that GSTT1 null genotype was significantly associated with increased risk for UADT cancers (odds ratio (OR) 2.5; 95% confidence intervals (CIs) 1.3-4.7). The combined effects of GST genes have shown that concurrent lack of GSTM1 and GSTT1 had a significantly increased risk (OR 4.6; 95% CI 1.3-15.6), while GSTT1 null genotype along with GSTP1 polymorphic variants further increased the cancer risk (OR 5.3; 95% CI 2.0-13.6). The most remarkable risk was seen among individuals carrying GSTM1 null, GSTT1 null genotypes and GSTP1 polymorphic variants (OR 7.8; 95% CI 1.0-61.0). Tobacco chewers carrying GSTM1 null genotype had an enhanced risk for UADT cancers. An enhanced risk among tobacco chewers and alcoholics (regular) was noted in individuals with GSTT1 null genotype. Similarly, a significant interaction was observed among smokers (>40 pack-year (PY)) and tobacco chewers carrying GSTP1 mutant genotypes. Although the null genotype of GSTT1 is a strong predisposing risk factor for UADT cancers, we conclude that the significant gene-gene and gene-environment interactions of GST genes may confer a substantial risk to UADT cancers in the Tamilian population of south India.

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.