Evidence for a causal association between human papillomavirus and a subset of head and neck cancers

BACKGROUND

High-risk human papillomaviruses (HPVs) are etiologic agents for anogenital tract cancers and have been detected in head and neck squamous cell carcinomas (HNSCCs). We investigated, retrospectively, an etiologic role for HPVs in a large series of patients with HNSCC.

METHODS

Tumor tissues from 253 patients with newly diagnosed or recurrent HNSCC were tested for the presence of HPV genome by use of polymerase chain reaction (PCR)-based assays, Southern blot hybridization, and in situ hybridization. The viral E6 coding region was sequenced to confirm the presence of tumor-specific viral isolates. Exons 5-9 of the TP53 gene were sequenced from 166 specimens. The hazard of death from HNSCC in patients with and without HPV-positive tumors was determined by proportional hazards regression analysis.

RESULTS

HPV was detected in 62 (25%) of 253 cases (95% confidence interval [CI] = 19%-30%). High-risk, tumorigenic type HPV16 was identified in 90% of the HPV-positive tumors. HPV16 was localized specifically by in situ hybridization within the nuclei of cancer cells in preinvasive, invasive, and lymph node disease. Southern blot hybridization patterns were consistent with viral integration. Poor tumor grade (odds ratio [OR] = 2.4; 95% CI = 1.2- 4.9) and oropharyngeal site (OR = 6.2; 95% CI = 3.1-12.1) independently increased the probability of HPV presence. As compared with HPV-negative oropharyngeal cancers, HPV-positive oropharyngeal cancers were less likely to occur among moderate to heavy drinkers (OR = 0.17; 95% CI = 0.05-0.61) and smokers (OR = 0.16; 95% CI = 0.02-1.4), had a characteristic basaloid morphology (OR = 18.7; 95% CI = 2.1-167), were less likely to have TP53 mutations (OR = 0.06; 95% CI = 0.01-0. 36), and had improved disease-specific survival (hazard ratio [HR] = 0.26; 95% CI = 0.07-0.98). After adjustment for the presence of lymph node disease (HR = 2.3; 95% CI = 1.4- 3.8), heavy alcohol consumption (HR = 2.6; 95% CI = 1.4-4.7), and age greater than 60 years old (HR = 1.4; 95% CI = 0.8-2.3), all patients with HPV-positive tumors had a 59% reduction in risk of death from cancer when compared with HPV-negative HNSCC patients (HR = 0.41; 95% CI = 0.20-0.88).

CONCLUSIONS

These data extend recent molecular and epidemiologic studies and strongly suggest that HPV-positive oropharyngeal cancers comprise a distinct molecular, clinical, and pathologic disease entity that is likely causally associated with HPV infection and that has a markedly improved prognosis.

Head and neck cancer

Most head and neck cancers are squamous cell carcinomas that develop in the upper aerodigestive epithelium after exposure to carcinogens such as tobacco and alcohol. Human papillomavirus has also been strongly implicated as a causative agent in a subset of these cancers. The complex anatomy and vital physiological role of the tumour-involved structures dictate that the goals of treatment are not only to improve survival outcomes but also to preserve organ function. Major improvements have been accomplished in surgical techniques and radiotherapy delivery. Moreover, systemic therapy including chemotherapy and molecularly targeted agents--namely, the epidermal growth factor receptor inhibitors--has been successfully integrated into potentially curative treatment of locally advanced squamous-cell carcinoma of the head and neck. In deciding which treatment strategy would be suitable for an individual patient, important considerations include expected functional outcomes, ability to tolerate treatment, and comorbid illnesses. The collaboration of many specialties is the key for optimum assessment and decision making. We review the epidemiology, molecular pathogenesis, diagnosis and staging, and the latest multimodal management of squamous cell carcinoma of the head and neck.

Interaction between tobacco and alcohol use and the risk of head and neck cancer: pooled analysis in the International Head and Neck Cancer Epidemiology Consortium

BACKGROUND

The magnitude of risk conferred by the interaction between tobacco and alcohol use on the risk of head and neck cancers is not clear because studies have used various methods to quantify the excess head and neck cancer burden.

METHODS

We analyzed individual-level pooled data from 17 European and American case-control studies (11,221 cases and 16,168 controls) participating in the International Head and Neck Cancer Epidemiology consortium. We estimated the multiplicative interaction parameter (psi) and population attributable risks (PAR).

RESULTS

A greater than multiplicative joint effect between ever tobacco and alcohol use was observed for head and neck cancer risk (psi = 2.15; 95% confidence interval, 1.53-3.04). The PAR for tobacco or alcohol was 72% (95% confidence interval, 61-79%) for head and neck cancer, of which 4% was due to alcohol alone, 33% was due to tobacco alone, and 35% was due to tobacco and alcohol combined. The total PAR differed by subsite (64% for oral cavity cancer, 72% for pharyngeal cancer, 89% for laryngeal cancer), by sex (74% for men, 57% for women), by age (33% for cases <45 years, 73% for cases >60 years), and by region (84% in Europe, 51% in North America, 83% in Latin America).

CONCLUSIONS

Our results confirm that the joint effect between tobacco and alcohol use is greater than multiplicative on head and neck cancer risk. However, a substantial proportion of head and neck cancers cannot be attributed to tobacco or alcohol use, particularly for oral cavity cancer and for head and neck cancer among women and among young-onset cases.

Tumors of the brain and nervous system after radiotherapy in childhood

We investigated the relation between radiotherapy in childhood for tinea capitis and the later development of tumors of the brain and nervous system among 10,834 patients treated between 1948 and 1960 in Israel. Benign and malignant tumors were identified from the pathology records of all Israeli hospitals and from Israeli national cancer and death registries. Doses of radiation to the neural tissue were retrospectively estimated for each patient (mean, 1.5 Gy). Sixty neural tumors developed in the patients exposed as children, and the 30-year cumulative risk (+/- SE) was 0.8 +/- 0.2 percent. The incidence of tumors was 1.8 per 10,000 persons per year. The estimated relative risk as compared with that for 10,834 matched general-population controls and 5392 siblings who had not been irradiated was 6.9 (95 percent confidence interval, 4.1 to 11.6) for all tumors and 8.4 (confidence interval, 4.8 to 14.8) when the analysis was restricted to neural tumors of the head and neck. Increased risks were apparent for meningiomas (relative risk, 9.5; n = 19), gliomas (relative risk, 2.6; n = 7), nerve-sheath tumors (relative risk, 18.8; n = 25), and other neural tumors (relative risk, 3.4; n = 9). A strong dose--response relation was found, with the relative risk approaching 20 after estimated doses of approximately 2.5 Gy. Our study confirms that radiation doses on the order of 1 to 2 Gy can significantly increase the risk of neural tumors.

Changes in survival in head and neck cancers in the late 20th and early 21st century: a period analysis

BACKGROUND

Therapy for head and neck cancers has evolved over the past decade, but few detailed analyses of recent developments in survival on the population level have been published.

METHODS

We use period analysis and modeled period analysis to disclose recent trends in survival in patients with head and neck cancer. Data are derived from the Surveillance, Epidemiology, and End Results limited-use database.

RESULTS

A major, statistically significant improvement in survival was observed, with the overall 5-year relative survival rate going from 54.7% in 1992-1996 to 65.9% in 2002-2006. Subgroup analysis showed improvement in cancers of the oral cavity, tongue, tonsils, and nasopharynx, with the greatest improvements observed in tonsillar carcinoma (+22.2 percentage points) and carcinoma of the tongue (+14.4 percentage points). Further analysis of survival for oral cavity, tonsillar, and tongue carcinoma revealed improvements in survival at each stage and across all age groups except for patients aged ≥ 75 years, with the greatest improvement occurring in locally advanced disease and in patients aged 55-64 years for carcinoma of the tongue and tonsils and those aged 15-44 years for oral cavity cancers.

CONCLUSIONS

Survival has substantially improved for head and neck cancer patients over the past decade. The greatest improvement was seen in tonsillar and tongue cancers.

Association between cigarette smoking and mutation of the p53 gene in squamous-cell carcinoma of the head and neck

BACKGROUND

Although epidemiologic studies have long associated tobacco and alcohol use with the development of squamous-cell carcinoma of the head and neck, the molecular targets of these carcinogens have yet to be identified. We performed a molecular analysis to determine the pattern of mutations in the p53 gene in neoplasms from patients with squamous-cell carcinoma of the head and neck and a history of tobacco or alcohol use.

METHODS

Sequence analysis of the conserved regions of the p53 gene was performed in tumor samples from 129 patients with primary squamous-cell carcinoma of the head and neck. We then used statistical analysis to identify any patient characteristics associated with mutation of the p53 gene.

RESULTS

We found p53 mutations in 42 percent of the patients (54 of 129). Fifty-eight percent of the patients who smoked cigarettes and used alcohol (37 of 64; 95 percent confidence interval, 45 to 70 percent), 33 percent of the patients who smoked but abstained from alcohol (13 of 39; 95 percent confidence interval, 19 to 50 percent), and 17 percent of the patients who neither smoked nor drank alcohol (4 of 24, 95 percent confidence interval, 5 to 37 percent) had p53 mutations (P = 0.001). (Two patients used alcohol but did not smoke, and neither had a p53 mutation.) Furthermore, 100 percent of the mutations in the patients who neither drank nor smoked occurred at sites containing cytidine phosphate guanosine dinucleotides (potentially representing endogenous mutations) within the p53 gene (5 of 5 mutations; 95 percent confidence interval, 48 to 100 percent), whereas only 23 percent of those in cigarette smokers consisted of such changes (12 of 53 mutations; 95 percent confidence interval, 12 to 36 percent; P = 0.001).

CONCLUSIONS

In our study, a history of tobacco and alcohol use was associated with a high frequency of p53 mutations in patients with squamous-cell carcinoma of the head and neck. Preliminary evidence linked cigarette smoking to p53 mutations at nonendogenous mutation sites. Our findings suggest a role for tobacco in the molecular progression of squamous-cell carcinoma of the head and neck and support the epidemiologic evidence that abstinence from smoking is important to prevent head and neck cancer.

Association of cancer sites with tobacco and alcohol consumption and socioeconomic status of patients: interview study from the Third National Cancer Survey

From personal interviews obtained for 7,518 incident cases of invasive cancer from the population-based Third National Cancer Survey, the quantitative lifetime use of cigarettes, cigars, pipes, unsmoked tobacco, wine, beer, hard liquor, and combined alcohol were recorded, as well as education and family income level. In an initial screening analysis of these data, Mantel-Haenszel 2 X 2 contingency tabulations and multiple regression analyses were used to compare each specific cancer site with controls from other sites to test for associations with the "exposure variables." Significant positive associations with cigarette smoking were found for cancers of the lung, larynx, oral cavity, esophagus, stomach, pancreas, bladder, kidney, and uterine cervix. Other forms of tobacco were associated with cancers of the oral cavity, larynx, lung, and cervix. Consumption of wine, beer, hard liquor, and all combined showed positive associations with neoplasms of the oral cavity larynx, esophagus, colon, rectum, breast, and thyroid gland. College educaton and high income both showed positive associations with cancers of the breast, thyroid gland, uterine corpus, and melanomas in males. These same indicators of high socioeconomic status showed inverse associations with invasive neoplasms of the uterine cervix, lung, lip-tongue, and colon in females. College attendance (but not income) showed an inverse association with stomach cancer and positive association with pancreatic cancer in males. Still other tumor sties showed "suggestive" associations with each of these exposure variables. In the analyses producing these results, age, race, sex, smoking, drinking, education, income, parity, foreign birth, marital status, and geographic location were used as stratification variables separately or in combination when appropriate to assess and control for their potentially confounding affects and to examine results in different strata to assess interaction.

Human papillomavirus-associated head and neck cancer is a distinct epidemiologic, clinical, and molecular entity

There is currently sufficient evidence to conclude that human papillomavirus (HPV) plays a role in the pathogenesis of a distinct subset of head and neck squamous cell cancers (HNSCC), particularly tonsillar cancers. There is a strong and consistent association between high-risk HPV types, specifically HPV16, a known human carcinogen, and these distinctive oropharyngeal cancers with molecular characteristics indicative of viral oncogene function. Risk for HPV-HNSCC is increased by certain sexual behaviors after consideration of alcohol and tobacco exposure, consistent with an extensive literature that has established HPV infection as a sexually transmitted disease. Furthermore, exposure to HPV16 has been associated with increased risk for subsequent development of oropharyngeal cancer. Prophylactic and therapeutic vaccines targeted against the viral capsid components and oncoproteins will provide the ultimate evidence for a role for HPV in HNSCC, if demonstrated to be effective in the prevention or therapy of this disease. It is time for clinician scientists to translate knowledge of this newly recognized disease entity into potential applications for the prevention, detection, and treatment of HPV-HNSCC.

Profiling early head and neck cancer

Head and neck squamous-cell carcinoma (HNSCC) is the sixth most common cancer worldwide and, disappointingly, survival rates are not improving. Moreover, HNSCC has a severe impact on the quality of life of patients and survivors, and the significant morbidity subsequent to treatment often mandates long-term multidisciplinary care, which places significant financial pressures on the treating institution. Therefore, prevention and early diagnosis of high-risk pre-malignant lesions are high priorities for reducing deaths due to head and neck cancer. Recent advances have begun to elucidate the different aetiologies of HNSCCs in relation to previous pre-malignancies and to identify which pre-malignant lesions are likely to progress to malignancy.

Smoking tobacco, oral snuff, and alcohol in the etiology of squamous cell carcinoma of the head and neck: a population-based case-referent study in Sweden

BACKGROUND

This case-referent study was conducted to elucidate the role of selected exogenous agents in the etiology of head and neck cancer. The factors studied were tobacco smoking, alcohol intake, the use of moist oral snuff, dietary factors, occupational exposures, and oral hygiene. In this first report, the authors discuss the impact of tobacco smoking, the use of oral snuff, and alcohol consumption.

METHODS

The study base was approximately 2 million person-years at risk and consisted of Swedish males age 40-79 years living in 2 geographic regions during the years 1988-1990. A total of 605 cases were identified in the base, and 756 controls were selected by stratified random sampling from population registries covering the base.

RESULTS

Among those who were tobacco smokers at the time of the study, the relative risk of head and neck cancer was 6.5% (95% confidence interval, 4.4-9.5%). After cessation of smoking, the risk gradually declined, and no excess risk was found after 20 years. The relative risk associated with alcohol consumption of 50 grams or more per day versus less than 10 grams per day was 5.5% (95% confidence interval, 3.1-9.6%). An almost multiplicative effect was found for tobacco smoking and alcohol consumption.

CONCLUSIONS

Tobacco smoking and alcohol intake had a strong interactive effect on the risk of squamous cell carcinoma of the head and neck. Moderate alcohol intake (10-19 grams per day) had little or no effect among nonsmokers. No increased risk was found for the use of Swedish oral snuff.

The epidemiology and risk factors of head and neck cancer: a focus on human papillomavirus

Head and neck cancer was the eighth leading cause of cancer death worldwide in 2000. Although the incidence of head and neck squamous cell carcinoma (HNSCC) in the United States is relatively low, survival is poor and has not improved for several decades. While tobacco and alcohol are the primary risk factors for HNSCC development, epidemiological studies report a strong association with human papillomavirus (HPV) in a subset of HNSCC. More than 95% of cervical squamous cell carcinomas are linked to persistent HPV infection; evidence demonstrates that HPV is a necessary carcinogen. Not all HPV-positive HNSCC express the viral oncogenes (E6 and E7), which suggests that HPV may function as a carcinogen in a smaller proportion of HNSCC. This review presents our current understanding of the relationship between HPV and HNSCC, and describes future research directions that may lead to a better understanding of the involvement of HPV in head and neck cancer.

EUROSCAN, a randomized trial of vitamin A and N-acetylcysteine in patients with head and neck cancer or lung cancer. For the EUropean Organization for Research and Treatment of Cancer Head and Neck and Lung Cancer Cooperative Groups

BACKGROUND

Preclinical evidence suggests that retinoids and antioxidants may prevent or delay the occurrence of cancer in the upper or lower airways, but such effects have not been reliably established in clinical studies. To assess the chemopreventive effects of vitamin A (retinyl palmitate) and N-acetylcysteine, we conducted a large randomized intervention study in patients with head and neck cancer or with lung cancer, most of whom had a history of smoking.

METHODS

From June 1988 through July 1994, a total of 2592 patients (60% with head and neck cancer and 40% with lung cancer) were randomly assigned to receive 1) retinyl palmitate (300000 IU daily for 1 year followed by 150000 IU for a 2(nd) year), 2) N-acetylcysteine (600 mg daily for 2 years), 3) both compounds, or 4) no intervention. All statistical tests were two-sided.

RESULTS

Of the patients, 93.5% had smoked tobacco at sometime in their lives (and 25% continued to smoke after cancer diagnosis). After a median follow-up of 49 months, 916 patients were reported with an event (recurrence, second primary tumor, or death). No statistically significant difference was observed in overall survival or event-free survival between patients who received retinyl palmitate and patients who did not. Similarly, no difference was seen in overall survival or event-free survival between patients who received N-acetylcysteine and patients who did not. There was a lower incidence of second primary tumors in the no intervention arm, but the difference was not statistically significant.

CONCLUSION

A 2-year supplementation of retinyl palmitate and/or N-acetylcysteine resulted in no benefit-in terms of survival, event-free survival, or second primary tumors-for patients with head and neck cancer or with lung cancer, most of whom were previous or current smokers.

TGF-β and NF-κB signal pathway cross-talk is mediated through TAK1 and SMAD7 in a subset of head and neck cancers

Transforming growth factor-beta (TGF-β) has a dual role in epithelial malignancies, including head and neck squamous cell carcinoma (HNSCC). Attenuation of canonical TGF-β signaling enhances de novo tumor development, whereas TGF-β overexpression and signaling paradoxically promotes malignant progression. We recently observed that TGF-β-induced growth arrest response is attenuated, in association with aberrant activation of nuclear factor-κB (NF-κB), a transcription factor, which promotes malignant progression in HNSCC. However, what role cross-talk between components of the TGF-β and NF-κB pathways plays in altered activation of these pathways has not been established. Here, we show TGF-β receptor II and TGF-β-activated kinase 1 (TAK1) are predominantly expressed in a subset of HNSCC tumors with nuclear activation of NF-κB family member RELA (p65). Further, TGF-β1 treatment induced sequential phosphorylation of TAK1, IKK, IκBα and RELA in human HNSCC lines. TAK1 enhances TGF-β-induced NF-κB activation, as TAK1 siRNA knockdown decreased TGF-β1-induced phosphorylation of IKK, IκB and RELA, degradation of IκBα, RELA nuclear translocation and DNA binding, and NF-κB-induced reporter and target gene transcription. Functionally, TAK1 siRNA inhibited cell proliferation, migration and invasion. Celastrol, a TAK1 inhibitor and anti-inflammatory compound used in traditional Chinese medicine, also decreased TGF-β1-induced phosphorylation of TAK1 and RELA, and suppressed basal, TGF-β1- and tumor necrosis factor-alpha (TNF-α)-induced NF-κB reporter gene activity. Celastrol also inhibited cell proliferation, while increasing sub-G0 DNA fragmentation and Annexin V markers of apoptosis. Furthermore, TGF-β and RELA activation promoted SMAD7 expression. In turn, SMAD7 preferentially suppressed TGF-β-induced SMAD and NF-κB reporters when compared with constitutive or TNF-α-induced NF-κB reporter gene activation. Thus, cross-talk by TGF-β via TAK1 and NF-κB promotes the malignant phenotype of HNSCC. Moreover, NF-κB may contribute to the downstream attenuation of canonical TGF-β signaling through increased SMAD7 expression. Celastrol highlights the therapeutic potential of agents targeting TAK1 as a key node in this pro-oncogenic TGF-β-NF-κB signal pathway.

Head and neck cancer in the betel quid chewing area: recent advances in molecular carcinogenesis

Head and neck cancer (HNC) is one of the 10 most frequent cancers worldwide, with an estimated over 500,000 new cases being diagnosed annually. The overall 5-year survival rate in patients with HNC is one of the lowest among common malignant neoplasms and has not significantly changed during the last two decades. Oral cavity squamous cell carcinoma (OSCC) shares part of HNC and has been reported to be increasing in the betel quid chewing area in recent years. During 2006, OSCC has become the sixth most common type of cancer in Taiwan, and it is also the fourth most common type of cancer among men. It follows that this type of cancer wreaks a high social and personal cost. Environmental carcinogens such as betel quid chewing, tobacco smoking and alcohol drinking have been identified as major risk factors for head and neck cancer. There is growing interest in understanding the relationship between genetic susceptibility and the prevalent environmental carcinogens for HNC prevention. Within this review, we discuss the molecular and cellular aspects of HNC carcinogenesis in Taiwan, an endemic betel quid chewing area. Knowledge of molecular carcinogenesis of HNC may provide critical clues for diagnosis, prognosis, individualization of therapy and molecular therapeutics.

Role of the aryl hydrocarbon receptor in carcinogenesis and potential as a drug target

The aryl hydrocarbon receptor (AHR) is highly expressed in multiple organs and tissues, and there is increasing evidence that the AHR plays an important role in cellular homeostasis and disease. The AHR is expressed in multiple tumor types, in cancer cell lines, and in tumors from animal models, and the function of the AHR has been determined by RNA interference, overexpression, and inhibition studies. With few exceptions, knockdown of the AHR resulted in decreased proliferation and/or invasion and migration of cancer cell lines, and in vivo studies in mice overexpressing the constitutively active AHR exhibited enhanced stomach and liver cancers, suggesting a pro-oncogenic role for the AHR. In contrast, loss of the AHR in transgenic mice that spontaneously develop colonic tumors and in carcinogen-induced liver tumors resulted in increased carcinogenesis, suggesting that the receptor may exhibit antitumorigenic activity prior to tumor formation. AHR ligands also either enhanced or inhibited tumorigenesis, and these effects were highly tumor specific, demonstrating that selective AHR modulators that exhibit agonist or antagonist activities represent an important new class of anticancer agents that can be directed against multiple tumors.

Human papillomavirus in oral exfoliated cells and risk of head and neck cancer

BACKGROUND

Human papillomavirus (HPV) has been associated with the development of head and neck cancers. In this study, we investigated whether the risk factors for head and neck cancer in relation to HPV infection are different from those in the absence of HPV infection and whether HPV detected in oral exfoliated cells is an independent predictor of head and neck cancer risk.

METHODS

We conducted a case-control study in 201 head and neck cancer case patients and 333 control subjects, frequency matched for age and sex. Oral exfoliated cells and tumor tissue were evaluated for HPV using polymerase chain reaction and DNA sequencing to type HPV. Logistic regression was used to calculate odds ratios (ORs) for head and neck cancer with HPV infection and 95% confidence intervals (CIs), adjusted for age, tobacco use, and alcohol consumption.

RESULTS

Oncogenic, or high-risk (HR), HPV types were detected in oral cells from 22.9% of case patients and 10.8% of control subjects. HPV16 was the most frequently detected type (19% versus 10% of case patients and control subjects, respectively). After adjusting for age, tobacco use, and alcohol consumption, the risk of head and neck cancer was statistically significantly greater in individuals with HPV-HR types (adjusted OR = 2.6, 95% CI = 1.5 to 4.2) but not in individuals with nononcogenic HPV types (adjusted OR = 0.8, 95% CI = 0.4 to 1.7) compared with HPV-negative individuals. Compared with individuals who were HPV-negative and did not use alcohol or tobacco, there was a statistically significant synergistic effect between detection of HPV-HR and heavy alcohol consumption (OR = 18.8, 95% CI = 5.1 to 69.5) but an additive effect between detection of HPV-HR and tobacco use (OR = 5.5, 95% CI = 2.1 to 14.1). HPV-HR types detected in oral exfoliated cells were predictive of HPV-HR types in tumor tissue.

CONCLUSION

Infection of oral exfoliated cells with HPV-HR types is a risk factor for head and neck cancer, independent of alcohol and tobacco use, and acts synergistically with alcohol consumption. HPV testing of an oral rinse may be predictive of an HPV-related head and neck cancer.

Tobacco-related carcinogenesis in head and neck cancer

Head and neck cancer (head and neck squamous cell carcinoma (HNSCC)) is a devastating disease. Patients require intensive treatment that is often disfiguring and debilitating. Those who survive are often left with poor speech articulation, difficulties in chewing and swallowing, and cosmetic disfigurement, as well as loss of taste. Furthermore, given that HNSCC survivors are frequently disabled and unable to return to work, the economic and societal costs associated with HNSCC are massive. HNSCC is one of many cancers that are strongly associated with tobacco use. The risk for HNSCC in smokers is approximately ten times higher than that of never smokers, and 70-80% of new HNSCC diagnoses are associated with tobacco and alcohol use. Tobacco products have been used for centuries; however, it is just within the last 60-70 years that we have developed an understanding of their damaging effects. This relatively recent understanding has created a pathway towards educational and regulatory efforts aimed at reducing tobacco use. Understanding the carcinogenic components of tobacco products and how they lead to HNSCC is critical to regulatory and harm reduction measures. To date, nitrosamines and other carcinogenic agents present in tobacco products have been associated with cancer development. The disruption of DNA structure through DNA adduct formation is felt to be a common mutagenic pathway of many carcinogens. Intense work pertaining to tobacco product constituents, tobacco use, and tobacco regulation has resulted in decreased use in some parts of the world. Still, much work remains as tobacco continues to impart significant harm and contribute to HNSCC development worldwide.

Differences in age, site distribution, and sex between nodular and superficial basal cell carcinoma indicate different types of tumors

Basal cell carcinomas (BCC) are among the most common cancers in white subjects. Etiologic factors include ultraviolet and ionizing radiation, chemical carcinogens, and possibly infection with human papillomaviruses. Because of clinical and histologic differences, differential pathogenetic mechanisms have been suggested for different BCC subtypes. We studied the patient and tumor characteristics of all BCC diagnosed and/or treated at the departments of Dermatology and Plastic Surgery of our hospital between 1985 and 1996, and a review of the literature was carried out. Some important differences between patients with nodular BCC and patients with superficial BCC were observed. The frequency of superficial BCC was higher in females and was seen in younger patients as compared with nodular BCC. The latter occurred mainly in the head/neck region: in males they were seen more frequently on the ears, and in females they were predominantly seen on the eyelids, the lips, and in the neck. Superficial BCC occurred mainly on the trunk, and occurred significantly more often on the trunk in males than in females, where the legs were the most common site. These findings strongly suggest that the superficial subtype is a separate group within the clinical entity of BCC. Furthermore, our findings seem to support the etiologic role of sun exposure in these tumors; however, this role may be different for each subtype. Chronic sun exposure may be an etiologic factor in nodular BCC as compared with intermittent sun exposure in superficial BCC. Other factors, such as differences in site specific host factors and referral bias, may also play a role in the differences found between the subtypes.

Risk of selected subsequent carcinomas in survivors of childhood cancer: a report from the Childhood Cancer Survivor Study

PURPOSE

To determine the risk of subsequent carcinomas other than breast, thyroid, and skin, and to identify factors that influence the risk among survivors of childhood cancer.

PATIENTS AND METHODS

Subsequent malignant neoplasm history was determined in 13,136 participants (surviving > or = 5 years postmalignancy, diagnosed from 1970 to 1986 at age < 21 years) of the Childhood Cancer Survivor Study to calculate standardized incidence ratios (SIRs), using Surveillance, Epidemiology, and End Results data.

RESULTS

In 71 individuals, 71 carcinomas were diagnosed at a median age of 27 years and a median elapsed time of 15 years in the genitourinary system (35%), head and neck area (32%), gastrointestinal tract (23%), and other sites (10%). Fifty-nine patients (83%) had received radiotherapy, and 42 (59%) developed a second malignant neoplasm in a previous radiotherapy field. Risk was significantly elevated following all childhood diagnoses except CNS neoplasms, and was highest following neuroblastoma (SIR = 24.2) and soft tissue sarcoma (SIR = 6.2). Survivors of neuroblastoma had a 329-fold increased risk of renal cell carcinomas; survivors of Hodgkin's lymphoma had a 4.5-fold increased risk of gastrointestinal carcinomas. Significantly elevated risk of head and neck carcinoma occurred in survivors of soft tissue sarcoma (SIR = 22.6), neuroblastoma (SIR = 20.9), and leukemia (SIR = 20.9).

CONCLUSION

Young survivors of childhood cancers are at increased risk of developing subsequent carcinomas typical of later adulthood, underscoring the importance of long-term follow-up and risk-based screening. Follow-up of the cohort is ongoing to determine lifetime risk and delineate individual characteristics that contribute to risk.

Head and neck cancer: an evolving treatment paradigm

Since the inception of this journal in 1948, the understanding of etiologic factors that contribute to and the treatment of head and neck cancer has evolved dramatically. Advances in surgery, radiation therapy, and chemotherapy have improved locoregional control, survival, and quality of life. The outcomes of these treatment modalities have shifted the focus of curative efforts from radical ablation to preservation and restoration of function. This evolution has been documented in the pages of Cancer for the past 6 decades. This review focuses on the evolution of treatment approaches for head and neck cancer and future directions while recognizing the historic contributions recorded within this journal.

Increased risk of second primary cancers after a diagnosis of melanoma

OBJECTIVE

To quantify the risk of subsequent primary cancers among patients with primary cutaneous malignant melanoma.

DESIGN

Population-based registry study.

SETTING

We evaluated data from 9 cancer registries of the Surveillance, Epidemiology, and End Results program from 1973-2006.

PARTICIPANTS

We included 89 515 patients who survived at least 2 months after their initial melanoma diagnosis.

RESULTS

Of the patients with melanoma, 10 857 (12.1%) developed 1 or more subsequent primary cancers. The overall risk of a subsequent primary cancer increased by 28% (observed to expected [O:E] ratio = 1.28). One quarter of the cancers were subsequent primary melanomas (O:E = 8.61). Women with head and neck melanoma and patients younger than 30 had markedly increased risks (O:E = 13.22 and 13.40, respectively) of developing a subsequent melanoma. Second melanomas were more likely to be thin than were the first of multiple primary melanomas (thickness at diagnosis <1.00 mm, 77.9% vs 70.3%, respectively; P < .001). Melanoma survivors had increased risk of developing several cancers; the most common cancers with elevated risks were breast, prostate, and non-Hodgkin lymphoma (O:E = 1.10, 1.15, and 1.25, respectively).

CONCLUSIONS

Melanoma survivors have an approximately 9-fold increased risk of developing subsequent melanoma compared with the general population. The risk remains elevated more than 20 years after the initial melanoma diagnosis. This increased risk may be owing to behavioral factors, genetic susceptibility, or medical surveillance. Although the percentage of subsequent primary melanomas thicker than 1 mm is lower than for the first of multiple primary melanomas, it is still substantial. Melanoma survivors should remain under surveillance not only for recurrence but also for future primary melanomas and other cancers.