Prior exposure to medical and dental x-rays related to tumors of the parotid gland

Risk of subsequent primary oral cancer in a cohort of 69,460 5-year survivors of childhood and adolescent cancer in Europe: the PanCareSurFup study

BACKGROUND

Survivors of childhood cancer are at risk of subsequent primary malignant neoplasms (SPNs), but the risk for rarer types of SPNs, such as oral cancer, is uncertain. Previous studies included few oral SPNs, hence large-scale cohorts are required to identify groups at risks.

METHODS

The PanCareSurFup cohort includes 69,460 5-year survivors of childhood cancer across Europe. Risks of oral SPNs were defined by standardised incidence ratios (SIRs), absolute excess risks and cumulative incidence.

RESULTS

One hundred and forty-five oral SPNs (64 salivary gland, 38 tongue, 20 pharynx, 2 lip, and 21 other) were ascertained among 143 survivors. Survivors were at 5-fold risk of an oral SPN (95% CI: 4.4-5.6). Survivors of leukaemia were at greatest risk (SIR = 19.2; 95% CI: 14.6-25.2) followed by bone sarcoma (SIR = 6.4, 95% CI: 3.7-11.0), Hodgkin lymphoma (SIR = 6.2, 95% CI: 3.9-9.9) and soft-tissue sarcoma (SIR = 5.0, 95% CI: 3.0-8.5). Survivors treated with radiotherapy were at 33-fold risk of salivary gland SPNs (95% CI: 25.3-44.5), particularly Hodgkin lymphoma (SIR = 66.2, 95% CI: 43.6-100.5) and leukaemia (SIR = 50.5, 95% CI: 36.1-70.7) survivors. Survivors treated with chemotherapy had a substantially increased risk of a tongue SPN (SIR = 15.9, 95% CI: 10.6-23.7).

CONCLUSIONS

Previous radiotherapy increases the risk of salivary gland SPNs considerably, while chemotherapy increases the risk of tongue SPNs substantially. Awareness of these risks among both health-care professionals and survivors could play a crucial role in detecting oral SPNs early.

Sociocultural adaptation, translation and pre-testing of the Kannada version of Vanderbilt Head and Neck Symptom Survey 2.0

BACKGROUND

Head and neck cancer (HNC) patients often undergo radiation therapy as part of their treatment. However, radiation therapy can have many side effects, including oral toxicities. Evaluating these toxicities is often considered a challenging task for practicing clinicians due to the lack of assessment tools. The objective of this study is to culturally adapt, translate and validate the Vanderbilt Head and Neck Symptom Survey (VHNSS), an instrument designed to assess oral toxicities and changes in oral functioning in HNC patients receiving radiation therapy.

METHODS

The VHNSS 2.0 was first culturally adapted and translated, following which 36 HNC patients undergoing radiation therapy were identified through the incidental sampling method. The translated version of VHNSS 2.0 was then administered to these patients. Internal consistency was assessed using Cronbach's alpha and Mc Donald's Omega. Test-retest reliability was also analyzed.

RESULTS

Items of the translated version of VHNSS 2.0 showed good content validity. The omega values yielded higher reliability coefficients than the Cronbach's alpha coefficient. Test-retest reliability was found to be 0.8, indicating good reliability.

CONCLUSIONS

Results of this study suggest that the translated Kannada version of the VHNSS 2.0 is linguistically equivalent to the original version. Hence, this tool can be considered a valid and reliable patient-reported tool to evaluate oral symptomatology in HNC patients speaking the Kannada language.

Molecular profiling of papillary thyroid carcinomas in healthcare workers exposed to low dose radiation at the workplace

PURPOSE

Exposure to ionizing radiation, especially during childhood, is a well-established risk factor for thyroid cancer. The vast majority of radiation-induced cancers are papillary carcinomas (PTCs). These tumors typically have gene fusions in contrast to point mutations prevalent in sporadic PTCs. The aim of this study was to investigate the molecular profiles of PTC patients with workplace exposure to ionizing radiation.

METHODS

A retrospective review of 543 patients who underwent surgery with diagnosis of PTC was performed. A cohort of nine healthcare specialists previously exposed to radiation sources during their professional practice was selected and analyzed using the ThyroSeq mutation panel for point mutations and gene fusions associated with thyroid cancer.

RESULTS

The molecular analysis of surgical samples of PTCs was informative and revealed genetic alterations in five patients. BRAF V600E was found in four (67%) cases whereas RET/PTC1 fusion in one (17%) and one sample (17%) was wild type for point mutations and fusions. One sample completely failed molecular analysis while two others were negative for genes fusions but failed DNA analysis; these three samples were excluded.

CONCLUSIONS

In this limited cohort of healthcare workers exposed to low dose of ionizing radiation at the workplace and developed PTC, the molecular profiling determined BRAF V600E point mutation as the most common event, arguing against the role of workplace radiation exposure in the etiology of these tumors.

Tumor microenvironment is not an 'innocent bystander' in the resistance to treatment of head and neck cancers (Review)

Head and neck cancers are still one of the most common types of cancer in the world. They rank in the leading sixth place in terms of incidence globally, and the incidence continues to rise. The mortality rates remain at high levels. Pathological subclassification places squamous cell carcinoma of the head and neck (HNSCC) in the first place concerning the histological forms of head and neck cancers; a tumor with extremely aggressive behavior and high mortality rates. The tumor microenvironment is a very complex ecosystem of cellular and non-cellular components, characterized by unique features, that contribute to the appearance of immunosuppression and diminished anticancer immunity, impacting patient prognosis and treatment outcome. Despite many important advances in therapy, resistance to therapy represents a difficult challenge in HNSCC patients. Tumor progression, metastasis, and response to therapy are all influenced by the complex ecosystem represented by the tumor microenvironment and by the interactions between cellular and non-cellular components of this system. Therefore, the tumor microenvironment, in the light of recent data, is not an innocent bystander. In the last few years, there has been a sustained effort to characterize the tumor microenvironment, to identify targets of response and identify other mechanisms of tumor-specific immune responses, or to discover other biomarkers of response. There is an urgent need to understand how to properly select patients, the therapy sequence, and how to use feasible biomarkers that can help to identify the patient who may obtain the most benefit from available therapies.

Tumor microenvironment: an evil nexus promoting aggressive head and neck squamous cell carcinoma and avenue for targeted therapy

Head and neck squamous cell carcinoma (HNSCC) is a very aggressive disease with a poor prognosis for advanced-stage tumors. Recent clinical, genomic, and cellular studies have revealed the highly heterogeneous and immunosuppressive nature of HNSCC. Despite significant advances in multimodal therapeutic interventions, failure to cure and recurrence are common and account for most deaths. It is becoming increasingly apparent that tumor microenvironment (TME) plays a critical role in HNSCC tumorigenesis, promotes the evolution of aggressive tumors and resistance to therapy, and thereby adversely affects the prognosis. A complete understanding of the TME factors, together with the highly complex tumor-stromal interactions, can lead to new therapeutic interventions in HNSCC. Interestingly, different molecular and immune landscapes between HPV^+ve and HPV^-ve (human papillomavirus) HNSCC tumors offer new opportunities for developing individualized, targeted chemoimmunotherapy (CIT) regimen. This review highlights the current understanding of the complexity between HPV^+ve and HPV^-ve HNSCC TME and various tumor-stromal cross-talk modulating processes, including epithelial-mesenchymal transition (EMT), anoikis resistance, angiogenesis, immune surveillance, metastatic niche, therapeutic resistance, and development of an aggressive tumor phenotype. Furthermore, we summarize the recent developments and the rationale behind CIT strategies and their clinical applications in HPV^+ve and HPV^-ve HNSCC.

Public Perception and Viewpoints of Dental Radiograph Prescriptions and Dentists' Safety Protection Practice

Purpose

The exposure of patients to ionizing radiation used in dentistry comes with a subtle risk of a stochastic effect, but there is tremendous benefit obtained from radiographic investigation for diagnosis, management, and monitoring of the treatment offered.

Aim

The aim of this study was to assess the viewpoint of the population concerning the prescriptions and practices in dentistry associated with dental radiographs and the safe use of ionizing radiation in dental clinics.

Patients and Methods

Validated and pretested structured self-administered questionnaires with 11 items were used. An electronic version of the questionnaire was created using Google Forms and distributed online through social media outlets. A total of 437 patients completed the questionnaire which contains questions about their demographic data and their perception of the practice of dentistry regarding hazard from dental radiographs. The collected data were analyzed statistically.

Results

Up to 88.6% of the study participants underwent dental radiography for various dental treatments. A majority of them relied on the dentist for the type of requested radiograph, 40% of them reported that dentist never explained the hazards associated with radiography. More than half of the participants (55%) never or hardly ever asked about safety measures before undergoing radiography. Most of the participants approved of radiography and never refrained.

Conclusion

There is a spectrum of perceptions by the population. Continuous patient education is recommended to enhance awareness regarding this matter. Community perception assists in correcting wrong beliefs and ensuring improvement.

Molecular and Cellular Modelling of Salivary Gland Tumors Open New Landscapes in Diagnosis and Treatment

Salivary gland tumors are neoplasms affecting the major and minor salivary glands of the oral cavity. Their complex pathological appearance and overlapping morphological features between subtypes, pose major challenges in the identification, classification, and staging of the tumor. Recently developed techniques of three-dimensional culture and organotypic modelling provide useful platforms for the clinical and biological characterization of these malignancies. Additionally, new advances in genetic and molecular screenings allow precise diagnosis and monitoring of tumor progression. Finally, novel therapeutic tools with increased efficiency and accuracy are emerging. In this review, we summarize the most common salivary gland neoplasms and provide an overview of the state-of-the-art tools to model, diagnose, and treat salivary gland tumors.

Trends in Estimated Thyroid, Salivary Gland, Brain, and Eye Lens Doses From Intraoral Dental Radiography Over Seven Decades (1940 TO 2009)

The purpose of this study is to support retrospective dose estimation for epidemiological studies by providing estimates of historical absorbed organ doses to the brain, lens of the eye, salivary glands, and thyroid from intraoral dental radiographic examinations performed from 1940 to 2009. We simulated organ doses to an adult over 10 y time periods from 1940 to 2009, based on commonly used sets of x-ray machine settings collected from the literature. Simulations to estimate organ dose were performed using personal computer x-ray Monte Carlo software. Overall, organ doses were less than 1 mGy for a single intraoral radiograph for all decades. From 1940 to 2009, doses to the brain, eye lens, salivary glands, and thyroid decreased by 86, 96, 95, and 89%, respectively. Of these four organs, the salivary glands received the highest doses, with values decreasing from about 0.23 mGy in the 1940s to 0.025 mGy in the 2000s for a single intraoral radiograph. Based on simulations using collected historical data on x-ray technical parameters, improvements in technology and optimization of the technical settings used to perform intraoral dental radiography have resulted in a decrease in absorbed dose to the brain, eye lens, salivary glands, and thyroid over the period from 1940 to 2009.

Dental X-Rays and the Risk of Thyroid Cancer and Meningioma: A Systematic Review and Meta-Analysis of Current Epidemiological Evidence

Background: Exposure to moderate-to-high doses of ionizing radiation is the only established environmental risk factor for thyroid cancer and brain and central nervous system tumors. Considering the high lifetime prevalence and frequency of exposure to dental X-rays, the most common source of diagnostic radiation exposure in the general population, even a small associated increase in cancer risk would be of considerable public health importance. With the objective to inform clinical practice and guidelines, we synthesized the current epidemiological evidence on the association between dental X-rays and the risk of thyroid cancer, meningioma, and other cancers of the head and neck region. Methods: The Medline, Embase, and Web of Science databases were searched to identify eligible studies. Summary odds ratio/relative risk estimates and confidence intervals were extracted, and pooled risk ratios (RRs) for each cancer were calculated using random effects meta-analysis. Results: The literature search identified 5537 publications; of these, 26 studies including 10,868 cancer patients were included in the synthesis. The random effects meta-analyses, based on seven studies of thyroid cancer (six case/control, one cohort) and eight studies of meningioma (all case/control), showed that multiple (or repeated) exposures to dental X-rays were significantly associated with an increased risk of thyroid cancer (pooled RR = 1.87 [95% confidence interval, CI 1.11-3.15]) and meningioma (pooled RR = 1.53 [CI 1.26-1.85]). There was no association with glioma, and there were too few studies of other cancers of the head and neck region to conduct a meaningful meta-analysis. Conclusions: Based on a meta-analysis of retrospective case/control studies, these findings provide some support to the hypothesis that multiple (or repeated) exposures to dental X-rays may be associated with an increased risk of thyroid cancer and meningioma. These studies did not include individual organ doses and ages at exposure, and are subject to recall bias and other limitations. Furthermore, the thyroid exposure has decreased dramatically over time from the use of thyroid shields and improved technology/equipment. Prospective studies, based on dental X-ray records and patient follow-up, are needed to test the hypothesis further and clarify the possible cancer risk associated with dental radiography, as although the risk at the individual level, particularly with improved technology/equipment, is likely to be very low, the proportion of the population exposed is high. Considering that about one-third of the general population in developed countries is routinely exposed to one or more dental X-rays per year, these findings manifest the need to reduce diagnostic radiation exposure as much as possible.

A comprehensive review of the literature on the biological effects from dental X-ray exposures

PURPOSE

Routine dental X-rays are among the most common sources of ionizing radiation exposure for healthy individuals globally, with 300 examinations/1000 individuals/year as documented by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) global survey of medical radiation usage and exposure. Furthermore, in the United States of America, an increased use of dental radiography is evident. However, with the shift from using film to digital image receptors, the dose of radiation per routine examination has decreased. Despite this, there remains public concern of dental X-rays. This continuing concern highlights the need to review the literature on biological and health effects related to exposure, from dental X-rays.

MATERIAL AND METHODS

This report presents studies investigating biological and health effects related to exposures using dental X-rays in patients and provides a critical evaluation. Relevant studies specific to dental X-rays are reviewed from 1970 and onward with the bulk data in this field resulting from epidemiological and biomonitoring studies.

RESULTS

While, most epidemiological studies suggest a possible correlation between head/neck related tumors and exposure to dental X-rays, evidence for causation is lacking. Biomonitoring studies suggest that exposure to low-level radiation such as that of dental radiography may not be a factor in inducing long-term chromosomal damage, but may result in localized cytotoxicity in the irradiated region of the mouth, with no long-term harm.

CONCLUSIONS

In general, the total number of studies is low and the majority of the data has been generated from poorly designed experiments. This review will highlight shortcomings that could influence outcomes and provide a more balanced interpretation that could impact the public perception and the level of public concern on the health effects resulting from dental X-rays.

Health effects from exposure to dental diagnostic X-ray

The purpose of this review is to summarize the results of studies on of the association between exposure to dental X-rays and health risk. To perform the systematic review, We searched the PUBMED, EMBASE, and MEDLINE databases for papers published before December 15, 2016. A total of 2 158 studies, excluding duplicate studies, were found. Two reviewers independently evaluated the eligibility of each study. The final 21 studies were selected after application of exclusion criteria. In terms of health outcomes, there were 10 studies about brain tumors, 5 about thyroid cancer, 3 about tumors of head and neck areas, and 3 related to systemic health. In brain tumor studies, the association between dental X-ray exposure and meningioma was statistically significant in 5 of the 7 studies. In 4 of the 5 thyroid-related studies, there was a significant correlation with dental diagnostic X-rays. In studies on head and neck areas, tumors included laryngeal, parotid gland, and salivary gland cancers. There was also a statistically significant correlation between full-mouth X-rays and salivary gland cancer, but not parotid gland cancer. Health outcomes such as leukemia, low birth weight, cataracts, and thumb carcinomas were also reported. In a few studies examining health effects related to dental X-ray exposure, possibly increased risks of meningioma and thyroid cancer were suggested. More studies with a large population and prospective design are needed to elaborate these associations further.

Epidemiology and Demographics of the Head and Neck Cancer Population

Head and neck malignancies comprise a heterogeneous group of malignancies that cause significant morbidity to those affected. These malignancies are associated with specific risk factors and exposures, some of which impact prognosis. The most common risk factors for developing head and neck cancers are tobacco and alcohol use. Marijuana and e-cigarettes, occupational exposures, and use of topical substances have also been linked to head and neck cancers. Human papilloma virus has been associated with oropharyngeal cancer. Such measures as oral hygiene, screening, smoking cessation, and vaccination are measures taken to decrease the incidence and morbidity of head and neck cancers.

Risk factors for salivary gland cancers in France: Results from a case-control study, the ICARE study

OBJECTIVES

Epidemiological studies on the risk factors for salivary gland cancers (SGC) are rare, concern a small sample size, and show inconsistent results. The aim of the present work was to analyze several risk factors for SGC, using the data from the ICARE study, a multicenter, population-based case-control study.

MATERIALS AND METHODS

Data from 73 SGC cases and 3555 controls were collected using a standardized questionnaire on lifestyle habits, personal and family medical history, and lifetime occupational history. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional logistic regressions.

RESULTS

Tobacco use and alcohol consumption were not associated with the risk of SGC. A history of head and neck cancer or that of cervicofacial radiotherapy was associated with a higher risk of SGC (OR = 17.06, 95% CI: 4.34-67.05, and OR = 31.74, 2.48-405.25, respectively). Significantly increased risks were observed for some occupations: waiter (OR = 2.94, 1.11-7.78), charworker (OR = 3.02, 1.38-6.60), electrical and electronic equipment assembler (OR = 7.16, 2.02-25.38), plumber (OR = 3.95, 1.33-11.67), electric arc welder (OR = 6.15, 1.76-21.48), sheet-metal worker (OR = 2.89, 1.01-8.32), building painter (OR = 3.42, 1.01-11.49), and material handling equipment operator (OR = 5.05, 1.71-14.84). Results for industries were consistent with those observed for occupations.

CONCLUSION

Our results showed that a history of head and neck cancer, cervicofacial radiotherapy, and several occupations and industries, were associated with an increased risk of SGC. Further studies with larger sample sizes are indicated to confirm our results.

Utility of Transfacial Dental Ultrasonography in Evaluation of Cystic Jaw Lesions

OBJECTIVES

Plain radiography has been widely used in dentistry. Because of the variability of the quality of equipment, radiographic technique, accuracy of interpretation, and radiation risk to the patients, the field is ripe for the introduction of other newer diagnostic modalities. In this report, we demonstrate the utility of ultrasonography in the diagnostic workup of cystic or cystlike lesions of the jaw.

METHODS

We used a transfacial ultrasonographic scanning approach to examine 32 patients with clinical or radiographic presentation of a jaw cyst. Computed tomography and histopathologic analysis were used as the reference standards to confirm the findings.

RESULTS

Ultrasonography could establish the presence or absence of a lesion, erosion of the buccal cortical plate, and identification of associated soft tissue involvement in all cases (sensitivity and specificity, 100% and 100%, respectively; area under the receiver operating characteristic curve, 1.0; P < .001).

CONCLUSIONS

Our observations revealed the usefulness of ultrasonography and demonstrated its potential value when introduced as a routine office-based imaging method for dentistry.

Thyroid Cancer Induction: Nitrates as Independent Risk Factors or Risk Modulators after Radiation Exposure, with a Focus on the Chernobyl Accident

In recent decades, differentiated thyroid cancer (DTC) incidence has been increasing worldwide. The important contributions to this phenomenon of "overdiagnosis" driven by wider use of improved ultrasound systems are amply documented, notwithstanding the "real" carcinogenic effects of ionizing radiation, e.g., from the Chernobyl accident or health care interventions. Less well understood is the role of nitrates - as environmental pollutants, in diet, and in medication - in thyroid carcinogenesis. Increasing exposure to nitrates is associated with rising incidence of esophageal, stomach, bladder, and colon cancers. Recent data suggest that in agricultural areas with higher mean nitrate levels in groundwater, DTC risk is also elevated. Our work in Belarus after Chernobyl has shown that children in districts with high nitrate concentrations in drinking water had significantly higher thyroid cancer incidence after irradiation than did their counterparts in areas with lower nitrate concentrations. Notwithstanding thyroid shielding, increasing use of computed tomography and dental X-rays heightens radiation exposure of the salivary glands in the general population, especially in children and adolescents. When nitrate intake is increased, salivary gland irradiation may potentially result in carcinogenic elevations in plasma nitric oxide concentrations. In conclusion, excess nitrate intake seems to be an independent risk factor for DTC. Additionally, we hypothesize from our data that high nitrate levels modulate the carcinogenic effect of radiation on the thyroid. Cohort studies, case-control studies, or both, are needed to quantify the effects of nitrates on DTC risk in the presence or absence of radiation exposure, e.g., that associated with diagnostic or therapeutic health care interventions.

The rising incidence of major salivary gland cancer in the United States

We performed a population-based historical cohort study using the Surveillance, Epidemiology, and End Results (SEER) database to determine trends in the incidence of major salivary gland cancer and to evaluate the effect of sex, tumor size, histology, primary site, and extent of disease. Participants were men and women with major salivary gland cancer, diagnosed 1973-2009. The incidence of major salivary gland cancer increased from 10.4 per 1,000,000 in 1973 to 16 per 1,000,000 in 2009 (annual percent change [APC] 0.99; 95% confidence interval [CI] 0.78 to 1.20; p < 0.05). The incidence of parotid cancers increased (APC 1.13; 95% CI 0.88 to 1.39; p < 0.05) and paralleled the increase in major salivary gland cancer overall. There was an increase in the incidence of tumors measuring 0 to 2.0 cm (APC 1.99; 95% CI 0.61 to 3.38; p < 0.05), but no change in tumors measuring 2.1 to 4.0 cm (APC 1.02; 95% CI -0.46 to 2.52; p > 0.05) and tumors measuring > 4 cm (APC -0.52; 95% CI -1.72 to 0.69; p > 0.05). There was an increase in the incidence of regional (APC 0.77; 95% CI 0.32 to 1.23; p < 0.05) and distant (APC 2.43; 95% CI 1.43 to 3.45; p < 0.05) disease, but not localized disease (APC 0.35; 95% CI 0 to 0.71; p > 0.05). We conclude that the incidence of major salivary gland cancer is increasing, especially small parotid tumors. The incidence of tumors with regional and distant metastasis is also increasing. These findings highlight the need for further research on the etiology of salivary gland cancer, which may reveal opportunities for further public health efforts aimed at prevention.

Heterogeneous impact of smoking on major salivary gland cancer according to histopathological subtype: A case-control study

BACKGROUND

Major salivary gland cancers (M-SGCs) are rare, and have distinct heterogeneous histopathological subtypes. To the authors' knowledge, no consistent evidence of an association between cigarette smoking and the risk of M-SGCs has appeared to date. Furthermore, evidence of potential heterogeneity in the impact of smoking on histopathological subtypes is scarce, despite the fact that the histopathological subtypes of M-SGC exhibit different genetic features.

METHODS

The authors conducted a case-control study to investigate the association between smoking and M-SGC by histopathological subtype. Cases were 81 patients with M-SGCs and the controls were 810 age-matched and sex-matched first-visit outpatients without cancer treated at Aichi Cancer Center Hospital from 1988 to 2005. Odds ratios (OR) and 95% confidence intervals (95% CI) were assessed by conditional logistic regression analysis with adjustment for potential confounders.

RESULTS

Smoking was found to be associated with a significantly increased risk of M-SGC overall, with an OR of 3.45 (95% CI, 1.58-7.51; P =.001) for heavy smokers compared with never-smokers. A significant dose-response relationship was observed (P for trend, .001). When stratified by histological subtype, no obvious impact of smoking was observed among patients with mucoepidermoid carcinoma (MEC). In contrast, smoking demonstrated a significantly increased risk of M-SGCs other than MEC, with an OR of 5.15 (95% CI, 2.06-12.87; P<.001) for heavy smokers compared with never-smokers. The authors observed possible heterogeneity with regard to the impact of smoking on risk between MEC and M-SGCs other than MEC (P for heterogeneity, .052).

CONCLUSIONS

The results of the current study demonstrate a significant positive association between cigarette smoking and the risk of M-SGC overall. However, the impact of smoking appeared to be limited to M-SGCs other than MEC. Cancer 2018;124:118-24. © 2017 American Cancer Society.

How Does Patient Radiation Exposure Compare With Low-dose O-arm Versus Fluoroscopy for Pedicle Screw Placement in Idiopathic Scoliosis?

BACKGROUND

Intraoperative C-arm fluoroscopy and low-dose O-arm are both reasonable means to assist in screw placement for idiopathic scoliosis surgery. Both using pediatric low-dose O-arm settings and minimizing the number of radiographs during C-arm fluoroscopy guidance decrease patient radiation exposure and its deleterious biological effect that may be associated with cancer risk. We hypothesized that the radiation dose for C-arm-guided fluoroscopy is no less than low-dose O-arm scanning for placement of pedicle screws.

METHODS

A multicenter matched-control cohort study of 28 patients in total was conducted. Fourteen patients who underwent O-arm-guided pedicle screw insertion for spinal fusion surgery in 1 institution were matched to another 14 patients who underwent C-arm fluoroscopy guidance in the other institution in terms of the age of surgery, body weight, and number of imaged spine levels. The total effective dose was compared. A low-dose pediatric protocol was used for all O-arm scans with an effective dose of 0.65 mSv per scan. The effective dose of C-arm fluoroscopy was determined using anthropomorphic phantoms that represented the thoracic and lumbar spine in anteroposterior and lateral views, respectively. The clinical outcome and complications of all patients were documented.

RESULTS

The mean total effective dose for the O-arm group was approximately 4 times higher than that of the C-arm group (P<0.0001). The effective dose for the C-arm patients had high variability based on fluoroscopy time and did not correlate with the number of imaged spine levels or body weight. The effective dose of 1 low-dose pediatric O-arm scan approximated 85 seconds of the C-arm fluoroscopy time. All patients had satisfactory clinical outcomes without major complications that required returning to the operating room.

CONCLUSIONS

Radiation exposure required for O-arm scans can be higher than that required for C-arm fluoroscopy, but it depends on fluoroscopy time. Inclusion of more medical centers and surgeons will better account for the variability of C-arm dose due to distinct patient characteristics, surgeon's preference, and individual institution's protocol.

LEVEL OF EVIDENCE

Level III-case-control study.

A Case-Control Study of Risk Factors for Salivary Gland Cancer in Canada

Aim. To assess the effect of various lifestyle risk factors on the risk of salivary gland cancer in Canada using data from a population-based case-control study. Methods. Data from a population-based case-control study of 132 incident cases of salivary gland cancer and 3076 population controls were collected through self-administered questionnaire and analysed using unconditional logistic regression. Results. Four or more servings/week of processed meat product was associated with an adjusted odds ratio (OR) and corresponding 95% confidence interval (CI) of 1.62 (1.02–2.58). Nonsignificantly increased ORs were also related to obesity, >7 drinks/week of alcohol consumption, and occupational exposure to radiation. Furthermore, nonsignificantly decreased ORs were found to be associated with high education level (>12 years) (OR = 0.65), high consumption of spinach/squash (OR = 0.62) and all vegetables/vegetable juices (OR = 0.75), and >30 sessions/month of recreational physical activity (OR = 0.78). Conclusions. This study suggests positive associations with consumption of processed meat, smoking, obesity, alcohol drinking, and occupational exposure to radiation as well as negative associations with higher education, consumption of spinach/squash, and physical activity, which suggest a role of lifestyle factors in the etiology of salivary gland cancer. However, these findings were based on small number of cases and were nonsignificant. Further larger studies are warranted to confirm our findings.

Risk Communication Strategies: Lessons Learned from Previous Disasters with a Focus on the Fukushima Radiation Accident

PURPOSE OF THE REVIEW

It has been difficult to both mitigate the health consequences and effectively provide health risk information to the public affected by the Fukushima radiological disaster. Often, there are contrasting public health ethics within these activities which complicate risk communication. Although no risk communication strategy is perfect in such disasters, the ethical principles of risk communication provide good practical guidance.

FINDINGS

These discussions will be made in the context of similar lessons learned after radiation exposures in Goiania, Brazil, in 1987; the Chernobyl nuclear power plant accident, Ukraine, in 1986; and the attack at the World Trade Center, New York, USA, in 2001. Neither of the two strategies is perfect nor fatally flawed. Yet, this discussion and lessons from prior events should assist decision makers with navigating difficult risk communication strategies in similar environmental health disasters.

Minor Salivary Gland Changes in Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma - A Histopathological Study

INTRODUCTION

The most common etiology for Oral Squamous Cell Carcinoma (OSCC) is tobacco and tobacco related products which cause nuclear damage to the keratinocytes. The chemical carcinogens not only affect the lining of oral epithelium but also affect the lining epithelium of the excretory ducts of the salivary glands. Thus, there is a possibility of epithelial dysplasia of the salivary duct epithelium which may lead to potential malignant transformation.

AIM

The study was performed to see the changes in the minor salivary glands and excretory ducts in cases of oral epithelial dysplasia and OSCC.

MATERIALS AND METHODS

A total of 278 archival cases of mild, moderate and severe epithelial dysplasia, carcinoma in situ, OSCC including verrucous carcinoma were histopathologically evaluated to observe changes in the excretory ducts and the minor salivary glands.

RESULTS

In the study there were 56.5% males and 43.5% females. The age group that was most commonly affected in both the sexes was 50-60 yr old. Buccal mucosa was the most common site of involvement. Ductal changes observed in the excretory duct include simple hyperplasia, metaplastic changes such as mucous, oncocytic & squamous, and infiltration of inflammatory cells and malignant cells. Acinar changes observed were degeneration, squamous metaplasia, myoepithelial cell proliferation and inflammatory cell infiltration. Both the excretory ducts and ducts within the gland showed dysplasia.

CONCLUSION

According to observations in our study it is suggested that histopathological interpretation for oral mucosal lesions especially oral epithelial dysplasias and OSCC should also include changes related to salivary gland tissue to provide a better treatment plan and prevent recurrence of the malignant tumours.

Switching to a Pediatric Dose O-Arm Protocol in Spine Surgery Significantly Reduced Patient Radiation Exposure

BACKGROUND

Intraoperative computed tomography and image-guided navigation improve the accuracy of screw placement. Radiation exposure to the patient remains a primary drawback. The objective of the present study was to compare the total intraoperative radiation dose and assess the resultant image quality for O-arm-assisted pedicle screw insertion, among 3 protocols: default (manufacturer recommended), institutional (reduced dose utilized in our institution), and pediatric (new protocol with lowest dose).

METHODS

Thirty-seven consecutive patients under the age of 18 years underwent posterior instrumentation of the spine and underwent an intraoperative O-arm scan. Techniques (kV and mAs) for default and institutional dose settings were manually adjusted based on spinal level and body weight. Pediatric dose techniques were 80 kV/80 mAs with no adjustment for level or weight. The number of scans repeated because of inadequate imaging was assessed, and the mean estimated effective dose between the 3 protocols was compared.

RESULTS

Sixty-eight scans were performed in 37 consecutive patients with mean age of 14 years and mean weight of 55 kg. For reference, the effective radiation dose of a chest x-ray is approximately 0.10 mSv. Use of the default protocol resulted in higher mean effective dose per scan of 4.65 mSv, whereas institutional protocol resulted in 2.37 mSv. The pediatric protocol reduced the mean dose to 0.65 mSv. The total effective dose per surgery was: 1.17 mSv (pediatric), 3.83 mSv (institutional), and 12.79 mSv (default) (P<0.0001 each). All scans lead to satisfactory image quality except in 1 patient >100 kg with stainless steel implants. There were no neurological or other implant-related complications. The pediatric protocol resulted in satisfactory image quality with the lowest total radiation dose, only 1/10 of that of the default protocol.

CONCLUSIONS

We successfully switched to a pediatric low-dose O-arm protocol in clinical practice, reducing the dose to <1/4 of the mean annual natural background radiation. This may allow use of intraoperative computed tomography and navigation for pedicle screw placement without excessive radiation exposure to young patients.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Pediatric salivary gland carcinomas: Diagnostic and therapeutic management

OBJECTIVES/HYPOTHESIS

To analyze clinical presentations, treatment modalities, and evolution of pediatric cases of salivary gland carcinomas to standardize care for these rare diseases.

STUDY DESIGN

Multicentric, retrospective study.

METHODS

We included in this retrospective study all children and adolescents (aged ≤18 years) treated from 1992 to 2012 in six pediatric centers in Paris, France. Pathological tumor specimens of these cases were reviewed.

RESULTS

Forty-three children were included (sex ratio male/female = 19/24, median age = 13 years). The parotid gland was the most common (37 cases) location for tumors. Histological subtypes were mucoepidermoid carcinomas (n = 20), acinic cell carcinomas (n = 14), and other (n = 9). Initial fine-needle aspiration was performed in 15 cases (33%), and was concordant to final diagnosis in three cases (20%). Primary surgery was performed in 42 patients, leading to a complete microscopic resection in 80%. Associated lymph node dissection was performed in 28 patients (homolateral: 27, bilateral: 1) and showed lymph node metastases in only two patients. One patient had distant metastases. Adjuvant irradiation was delivered to 11 patients (median: 60 Gy; range: 50-65) and chemotherapy in five cases. After a median follow-up of 5 years, six tumors relapsed, but no deaths occurred.

CONCLUSIONS

Childhood salivary gland carcinomas have a good prognosis despite possible recurrences. Treatment is mainly based on surgery, with simultaneous node dissection in cases of clinical or radiologic node enlargement. Radiation therapy seems to be restricted to inoperable high-grade tumors or after recurrence.

LEVEL OF EVIDENCE

4 Laryngoscope, 127:140-147, 2017.

Absorbed organ and effective doses from digital intra-oral and panoramic radiography applying the ICRP 103 recommendations for effective dose estimations

OBJECTIVE

During dental radiography, the salivary and thyroid glands are at radiation risk. In 2007, the International Commission on Radiological Protection (ICRP) updated the methodology for determining the effective dose, and the salivary glands were assigned tissue-specific weighting factors for the first time. The aims of this study were to determine the absorbed dose to the organs and to calculate, applying the ICRP publication 103 tissue-weighting factors, the effective doses delivered during digital intraoral and panoramic radiography.

METHODS

Thermoluminescent dosemeter measurements were performed on an anthropomorphic head and neck phantom. The organ-absorbed doses were measured at 30 locations, representing different radiosensitive organs in the head and neck, and the effective dose was calculated according to the ICRP recommendations.

RESULTS

The salivary glands and the oral mucosa received the highest absorbed doses from both intraoral and panoramic radiography. The effective dose from a full-mouth intraoral examination was 15 μSv and for panoramic radiography, the effective dose was in the range of 19-75 μSv, depending on the panoramic equipment used.

CONCLUSION

The effective dose from a full-mouth intraoral examination is lower and that from panoramic radiography is higher than previously reported. Clinicians should be aware of the higher effective dose delivered during panoramic radiography and the risk-benefit profile of this technique must be assessed for the individual patient.

ADVANCES IN KNOWLEDGE

The effective dose of radiation from panoramic radiography is higher than previously reported and there is large variability in the delivered radiation dosage among the different types of equipment used.

Epidemiological characteristics of a Spanish cohort of patients diagnosed with squamous cell carcinoma of head and neck: distribution of risk factors by tumor location

PURPOSE

Head and neck cancer is a highly heterogeneous disease comprising a large number of tumors located in the cervicofacial area. This study aimed to determine the epidemiological characteristics of squamous-cell carcinomas of the head and neck in the Spanish population, and the distribution of risk factors based on tumor locations.

METHODS/PATIENTS

A cohort of 459 patients (75 oral cavity, 167 oro-/hypopharyngeal and 217 laryngeal cancers) recruited in 19 hospitals participating in the Spanish head and neck cancer cooperative group were included over 3 years (2012-2014). Epidemiological parameters and risk factors were obtained from a self-administered questionnaire, and tumor characteristics were obtained from clinical records. Multivariate multinomial logistic regression was used to assess factors associated with tumor location.

RESULTS

Most patients were males (88.4 %), smokers (95 %) and drinkers (76.5 %). Relative to laryngeal cancer, pharyngeal cancer and oral cancer were more common in women than men (OR 3.58, p = 0.003 and 4.33, p = 0.001, respectively); pharyngeal cancer was more associated with rural environment (OR 1.81, p = 0.007) and weekly alcohol intake (10-140 g: OR 2.53, p = 0.012; 141-280 g: OR 2.47, p = 0.023; >280 g: OR 3.20, p = 0.001) and less associated with pack-years of smoking (21-40 packs: OR 0.46, p = 0.045; 41-70 packs: OR 0.43, p = 0.023; ≥71 packs: OR 3.20, p = 0.015).

CONCLUSIONS

The distribution of these tumors differs between the sexes, with a higher proportion of oral cavity and pharyngeal tumors in women than in men. Oro-/hypopharyngeal cancers were more strongly associated with rural areas and with alcohol consumption, although less strongly associated with smoking than laryngeal tumors.

Optimization of exposure in panoramic radiography while maintaining image quality using adaptive filtering

Objective The purpose of the present study was to investigate the potential of using advanced external adaptive image processing for maintaining image quality while reducing exposure in dental panoramic storage phosphor plate (SPP) radiography. Materials and methods Thirty-seven SPP radiographs of a skull phantom were acquired using a Scanora panoramic X-ray machine with various tube load, tube voltage, SPP sensitivity and filtration settings. The radiographs were processed using General Operator Processor (GOP) technology. Fifteen dentists, all within the dental radiology field, compared the structural image quality of each radiograph with a reference image on a 5-point rating scale in a visual grading characteristics (VGC) study. The reference image was acquired with the acquisition parameters commonly used in daily operation (70 kVp, 150 mAs and sensitivity class 200) and processed using the standard process parameters supplied by the modality vendor. Results All GOP-processed images with similar (or higher) dose as the reference image resulted in higher image quality than the reference. All GOP-processed images with similar image quality as the reference image were acquired at a lower dose than the reference. This indicates that the external image processing improved the image quality compared with the standard processing. Regarding acquisition parameters, no strong dependency of the image quality on the radiation quality was seen and the image quality was mainly affected by the dose. Conclusions The present study indicates that advanced external adaptive image processing may be beneficial in panoramic radiography for increasing the image quality of SPP radiographs or for reducing the exposure while maintaining image quality.

Parental knowledge and attitudes towards dental radiography for children

BACKGROUND

Radiographs are an essential part of most clinical dental examinations and diagnoses. The aim of the study was to assess the knowledge and attitudes of parents towards dental radiographs for their children.

METHODS

A 21-item questionnaire, covering parental level of radiation knowledge and socio-demographics was applied. Sliding scales were used to assess attitude towards dental radiographs.

RESULTS

There were 1467 questionnaires distributed between five primary schools in the Perth (Western Australia) metropolitan area, with 309 surveys (21%) returned for collection. Most parents displayed a low level of knowledge, but had a positive attitude towards dental radiographs. Parents with children who have previously had dental radiographs perceived dental radiographs as 'good', 'useful' and 'pleasant'. A higher level of education and parents with children who have previously had radiographs were significantly associated with a higher level of knowledge about dental radiography. Parents who had higher scores on questions assessing radiation knowledge were more likely to perceive dental radiographs as 'safe' and 'beneficial'.

CONCLUSIONS

Most parents have a positive attitude towards dental radiographs on their children. However, the majority of parents lack knowledge regarding dental radiography, especially regarding the risks involved.

A prospective study of medical diagnostic radiography and risk of thyroid cancer

Although diagnostic x-ray procedures provide important medical benefits, cancer risks associated with their exposure are also possible, but not well characterized. The US Radiologic Technologists Study (1983-2006) is a nationwide, prospective cohort study with extensive questionnaire data on history of personal diagnostic imaging procedures collected prior to cancer diagnosis. We used Cox proportional hazard regressions to estimate thyroid cancer risks related to the number and type of selected procedures. We assessed potential modifying effects of age and calendar year of the first x-ray procedure in each category of procedures. Incident thyroid cancers (n = 251) were diagnosed among 75,494 technologists (1.3 million person-years; mean follow-up = 17 years). Overall, there was no clear evidence of thyroid cancer risk associated with diagnostic x-rays except for dental x-rays. We observed a 13% increase in thyroid cancer risk for every 10 reported dental radiographs (hazard ratio = 1.13, 95% confidence interval: 1.01, 1.26), which was driven by dental x-rays first received before 1970, but we found no evidence that the relationship between dental x-rays and thyroid cancer was associated with childhood or adolescent exposures as would have been anticipated. The lack of association of thyroid cancer with x-ray procedures that expose the thyroid to higher radiation doses than do dental x-rays underscores the need to conduct a detailed radiation exposure assessment to enable quantitative evaluation of risk.

Risk of salivary gland cancer after childhood cancer: a report from the Childhood Cancer Survivor Study

PURPOSE

To evaluate effects of radiation therapy, chemotherapy, cigarette smoking, and alcohol consumption on the risk of second primary salivary gland cancer (SGC) in the Childhood Cancer Survivor Study (CCSS).

METHODS AND MATERIALS

Standardized incidence ratios (SIR) and excess absolute risks (EAR) of SGC in the CCSS were calculated using incidence rates from Surveillance, Epidemiology, and End Results population-based cancer registries. Radiation dose to the salivary glands was estimated based on medical records. Poisson regression was used to assess risks with respect to radiation dose, chemotherapy, smoking, and alcohol consumption.

RESULTS

During the time period of the study, 23 cases of SGC were diagnosed among 14,135 childhood cancer survivors. The mean age at diagnosis of the first primary cancer was 8.3 years, and the mean age at SGC diagnosis was 24.8 years. The incidence of SGC was 39-fold higher in the cohort than in the general population (SIR = 39.4; 95% CI = 25.4-57.8). The EAR was 9.8 per 100,000 person-years. Risk increased linearly with radiation dose (excess relative risk = 0.36/Gy; 95% CI = 0.06-2.5) and remained elevated after 20 years. There was no significant trend of increasing risk with increasing dose of chemotherapeutic agents, pack-years of cigarette smoking, or alcohol intake.

CONCLUSION

Although the cumulative incidence of SGC was low, childhood cancer survivors treated with radiation experienced significantly increased risk for at least 2 decades after exposure, and risk was positively associated with radiation dose. Results underscore the importance of long-term follow up of childhood cancer survivors for the development of new malignancies.

Characteristics and outcome of radiation and chemotherapy-related mucoepidermoid carcinoma of the salivary glands

BACKGROUND

Mucoepidermoid carcinoma (MEC) of the salivary glands has been reported to occur in patients previously treated with chemotherapy and/or radiation. The purpose of our study is to review the patient, tumor, and treatment characteristics of patients who develop a treatment-related MEC.

PROCEDURE

A PubMed search of English language articles was performed using the keywords and MeSH terms: mucoepidermoid, salivary gland, radiation-induced, second malignancy, radiotherapy, and chemotherapy.

RESULTS

The search yielded 23 articles describing 58 patients who received chemotherapy and/or radiotherapy (RT) and subsequently developed MEC. The most common initial diagnoses were acute lymphoblastic leukemia (n = 18), acne (n = 9), and Hodgkin lymphoma (n = 6). Patients were divided into three groups according to chemotherapy and RT treatment: chemotherapy alone (n = 14), RT alone (n = 14), or chemotherapy and RT (n = 30). The parotid gland was the most common site for secondary MEC. Latent time (LT) to development of MEC from initial tumor treatment was significantly shorter in the patients treated with chemotherapy ± RT versus RT alone (7.9 years vs. 27.2 years, P < 0.01). The most common treatment for MEC was surgery alone followed by surgery and postoperative RT. The 2- and 5-year overall survival rates were 98% and 93.4% while the 2- and 5-year locoregional control rates were 97.7% and 92.5%, respectively. There was no difference in survival or locoregional control between groups exposed to RT alone, chemotherapy alone, or chemotherapy with RT for the initial tumor.

CONCLUSION

Radiation and chemotherapy-related MEC has an excellent prognosis.

Second primaries after major salivary gland cancer

OBJECTIVES

To evaluate the risk of second primary cancers in patients with major salivary gland cancer using a large population database and to examine the effects of sex, salivary gland cancer histology, and radiation therapy on the risk of second primaries.

STUDY DESIGN

Population-based study using the Surveillance, Epidemiology, and End Result (SEER) cancer database.

SUBJECT AND METHODS

The subjects were 15,572 men and women ages 15 and above, diagnosed with cancer of the major salivary glands from 1973 to 2006.

RESULTS

There was an increased risk of oral cavity (standardized incidence ratio [SIR] = 3.48, P < .05), salivary (SIR = 9.97, P < .05), lung and bronchus (SIR = 1.60, P < .05), kidney (SIR = 1.68, P < .05), and thyroid (SIR = 2.66, P < .05) cancers. Men had an increased risk of developing kidney cancer (SIR = 1.70, P < .05) compared with women (SIR = 1.64, P > .05). Patients with mucoepidermoid carcinoma had an increased risk of a second salivary gland cancer (SIR = 8.97, P < .05) and thyroid cancer (SIR = 3.97, P < .05). Patients with adenoid cystic carcinoma had an increased risk of oral cavity (SIR = 3.76, P < .05) and nasopharyngeal (SIR = 16.88, P < .05) cancers. Patients with acinar cell carcinoma had an increased risk of salivary (SIR = 31.36, P < .05), kidney (SIR = 2.98, P < .05), and thyroid (SIR = 3.85, P < .05) cancers. Patients who received radiation therapy had a higher incidence of lung and bronchus (SIR = 2.11, P < .05), laryngeal (SIR = 3.08, P < .05), and thyroid (SIR = 2.95, P < .05) cancers compared with patients who did not receive radiation therapy (SIR = 1.18, 0.48, and 2.39, respectively; P > .05). Patients had an increased risk of developing second primaries, even 10 years after diagnosis of primary salivary gland cancer.

CONCLUSIONS

Patients with major salivary gland cancers are at a risk for certain second primary cancers. This highlights the need for long-term surveillance in these patients, not only for recurrence but also for second primary cancers.

Dental x-rays and the risk of thyroid cancer: a case-control study

The thyroid gland is highly susceptible to radiation carcinogenesis and exposure to high-dose ionising radiation is the only established cause of thyroid cancer. Dental radiography, a common source of low-dose diagnostic radiation exposure in the general population, is often overlooked as a radiation hazard to the gland and may be associated with the risk of thyroid cancer. An increased risk of thyroid cancer has been reported in dentists, dental assistants, and x-ray workers; and exposure to dental x-rays has been associated with an increased risk of meningiomas and salivary tumours.

METHODS

To examine whether exposure to dental x-rays was associated with the risk of thyroid cancer, we conducted a population-based case-control interview study among 313 patients with thyroid cancer and a similar number of individually matched (year of birth +/- three years, gender, nationality, district of residence) control subjects in Kuwait.

RESULTS

Conditional logistic regression analysis, adjusted for other upper-body x-rays, showed that exposure to dental x-rays was significantly associated with an increased risk of thyroid cancer (odds ratio = 2.1, 95% confidence interval: 1.4, 3.1) (p=0.001) with a dose-response pattern (p for trend <0.0001). The association did not vary appreciably by age, gender, nationality, level of education, or parity.

DISCUSSION

These findings, based on self-report by cases/controls, provide some support to the hypothesis that exposure to dental x-rays, particularly multiple exposures, may be associated with an increased risk of thyroid cancer; and warrant further study in settings where historical dental x-ray records may be available.

Patient risk related to common dental radiographic examinations: the impact of 2007 International Commission on Radiological Protection recommendations regarding dose calculation

BACKGROUND

In 2007, the International Commission on Radiological Protection (ICRP) revised estimates of the radiosensitivity of tissues including those in the maxillofacial region. The authors conducted a study to reassess patients' risk related to common dental radiographic exposures using the 2007 ICRP recommendations.

METHODS

The authors used a tissue-equivalent head phantom to measure dose. They calculated effective doses by using both 1990 and revised 2007 ICRP recommendations. Effective dose is a calculation that takes into consideration the different sensitivities of organs to long-term effects from ionizing radiation. It is the preferred method for comparing doses between different types of exposures.

RESULTS

Effective doses (per the 2007 ICRP) in microsieverts were as follows: full-mouth radiographs (FMX) with photo-stimulable phosphor (PSP) storage or F-speed film with rectangular collimation, 34.9 microSv; four-image posterior bitewings with PSP or F-speed film with rectangular collimation, 5.0 microSv; FMX using PSP or F-speed film with round collimation, 170.7 microSv; FMX with D-speed film and round collimation, 388 microSv; panoramic Orthophos XG (Sirona Group, Bensheim, Germany) with charge-coupled device (CCD), 14.2 microSv; panoramic ProMax (Planmeca, Helsinki, Finland) with CCD, 24.3 microSv; posteroanterior cephalogram with PSP, 5.1 microSv; and lateral cephalogram with PSP, 5.6 microSv. These values are 32 to 422 percent higher than those determined according to the 1990 ICRP guidelines.

CONCLUSIONS

Although radiographs are an indispensable diagnostic tool, the increased effective doses of common intraoral and extraoral imaging techniques are high enough to warrant reconsideration of means to reduce patients' exposure.

CLINICAL IMPLICATIONS

Clinicians can reduce patients' dose substantively by using digital receptors or F-speed film instead of D-speed film, rectangular collimation instead of round collimation and radiographic selection criteria.

Smoking and risk of parotid gland tumors: a nationwide case-control study

BACKGROUND

Because existing data regarding the relation between smoking and salivary gland tumors are sparse, tobacco is currently not classified as a salivary gland carcinogen. The objective of the current study was to assess the association between smoking and benign and malignant parotid gland tumors (PGTs) in a nationwide study.

METHODS

The sample included 459 patients with incident PGT, aged > or =18 years, who were diagnosed between 2001 and 2003 and a group of 1265 individually matched, population-based controls. Analyses of the risk of PGT associated with various smoking variables were performed by using conditional logistic regression. Data also were stratified by histologic type; statistical significance tests were 2-sided.

RESULTS

Ever smoking cigarettes was associated with an odds ratio (OR) of 1.66 (95% confidence interval [95% CI], 1.31-2.11) for developing a PGT. The risk was strongest for early ages at smoking initiation, and trends of increasing risk were observed with increasing smoking intensity, pack-years, latent period, and smoking duration (P for trend <.001 for each). Analysis by histologic type indicated remarkably high risks for Warthin tumor (OR for ever cigarette smokers: 15.3; 95% CI, 6.1-38.5). For pleomorphic adenomas and malignant tumors, the risks associated with ever smoking were 1.01 (95% CI, 0.75-1.37) and 1.69 (95% CI, 0.81-3.51), respectively.

CONCLUSIONS

Smoking plays an important role in the development of Warthin tumor. Although no association was observed for pleomorphic adenoma, the possible indication of increased risk of malignant tumors requires further investigation in larger studies.

Multiple malignant salivary gland neoplasms: mucoepidermoid carcinoma of palate and adenoid cystic carcinoma of floor of mouth

Salivary gland tumors usually occur as single lesions. To have more than one tumor is unusual. We report a case of an adult male who presented with a mucoepidermoid carcinoma involving the minor salivary glands of the palate at age 57 years, followed by an adenoid cystic carcinoma of the floor of mouth at age 63 years. The patient later succumbed to non-Hodgkin lymphoma at age 72 years. There are 31 acceptable cases of multiple malignant salivary gland neoplasms reported in the world literature. Multiple malignant tumors of the same histologic type are more common than those of different histologic type. Bilateral acinic cell adenocarcinoma was the most frequent combination of multiple salivary gland malignancy, accounting for 14 cases (10 synchronous and four metachronous). All involved the parotid glands bilaterally with the exception of one case that involved parotid and submandibular gland. Polymorphous low-grade adenocarcinoma accounted for three of the four cases of multiple malignant tumors involving minor salivary glands. Individuals with a history of malignancy are at risk for the development of additional malignant tumors and should receive appropriate clinical follow-up.

Solid cancer incidence in atomic bomb survivors: 1958-1998

This is the second general report on radiation effects on the incidence of solid cancers (cancers other than malignancies of the blood or blood-forming organs) among members of the Life Span Study (LSS) cohort of Hiroshima and Nagasaki atomic bomb survivors. The analyses were based on 17,448 first primary cancers (including non-melanoma skin cancer) diagnosed from 1958 through 1998 among 105,427 cohort members with individual dose estimates who were alive and not known to have had cancer prior to 1958. Radiation-associated relative risks and excess rates were considered for all solid cancers as a group, for 19 specific cancer sites or groups of sites, and for five histology groups. Poisson regression methods were used to investigate the magnitude of the radiation-associated risks, the shape of the dose response, how these risks vary with gender, age at exposure, and attained age, and the evidence for inter-site variation in the levels and patterns of the excess risk. For all solid cancers as a group, it was estimated that about 850 (about 11%) of the cases among cohort members with colon doses in excess of 0.005 Gy were associated with atomic bomb radiation exposure. The data were consistent with a linear dose response over the 0- to 2-Gy range, while there was some flattening of the dose response at higher doses. Furthermore, there is a statistically significant dose response when analyses were limited to cohort members with doses of 0.15 Gy or less. The excess risks for all solid cancers as a group and many individual sites exhibit significant variation with gender, attained age, and age at exposure. It was estimated that, at age 70 after exposure at age 30, solid cancer rates increase by about 35% per Gy (90% CI 28%; 43%) for men and 58% per Gy (43%; 69%) for women. For all solid cancers as a group, the excess relative risk (ERR per Gy) decreases by about 17% per decade increase in age at exposure (90% CI 7%; 25%) after allowing for attained-age effects, while the ERR decreased in proportion to attained age to the power 1.65 (90% CI 2.1; 1.2) after allowing for age at exposure. Despite the decline in the ERR with attained age, excess absolute rates appeared to increase throughout the study period, providing further evidence that radiation-associated increases in cancer rates persist throughout life regardless of age at exposure. For all solid cancers as a group, women had somewhat higher excess absolute rates than men (F:M ratio 1.4; 90% CI 1.1; 1.8), but this difference disappears when the analysis was restricted to non-gender-specific cancers. Significant radiation-associated increases in risk were seen for most sites, including oral cavity, esophagus, stomach, colon, liver, lung, non-melanoma skin, breast, ovary, bladder, nervous system and thyroid. Although there was no indication of a statistically significant dose response for cancers of the pancreas, prostate and kidney, the excess relative risks for these sites were also consistent with that for all solid cancers as a group. Dose-response estimates for cancers of the rectum, gallbladder and uterus were not statistically significant, and there were suggestions that the risks for these sites may be lower than those for all solid cancers combined. However, there was emerging evidence from the present data that exposure as a child may increase risks of cancer of the body of the uterus. Elevated risks were seen for all of the five broadly classified histological groups considered, including squamous cell carcinoma, adenocarcinoma, other epithelial cancers, sarcomas and other non-epithelial cancers. Although the data were limited, there was a significant radiation-associated increase in the risk of cancer occurring in adolescence and young adulthood. In view of the persisting increase in solid cancer risks, the LSS should continue to provide important new information on radiation exposure and solid cancer risks for at least another 15 to 20 years.

Salivary tumors in north Jordanians: a descriptive study

OBJECTIVE

To evaluate the types and distribution of tumors of salivary glands in north Jordanians.

STUDY DESIGN

The records of the Department of Pathology at Jordan University of Science and Technology were reviewed for patients who were treated for salivary gland tumors from 1991 to 2002. The tumors were analyzed for age of patient, sex of patient, tumor site, and tumor type.

RESULTS

One hundred two true neoplasms (70% benign and 30% malignant) were found. The most frequent benign and malignant neoplasms found were pleomorphic adenoma (54%) and adenoid cystic carcinoma (13%), respectively. The most common major and minor salivary gland sites were the parotid (51%) and palatal glands (20%), respectively. Although most of major gland tumors were adenomas, carcinomas of the minor glands were only slightly less frequent than adenomas. The most frequent malignant parotid tumors were adenoid cystic carcinoma and mucoepidermoid carcinoma. The most frequent minor salivary gland malignant tumors were palatal adenoid cystic carcinoma. Age ranged from 1 to 94 (mean 40) years, with a male to female ratio of 1:1.2.

CONCLUSION

North Jordanians with salivary gland tumors were found to have similar characteristics with patients of other countries with regard to tumor type, tumor site distribution, and age and sex of patients.

Mobile phone use and risk of parotid gland tumor

Handheld mobile phones were introduced in Denmark and Sweden during the late 1980s. This makes the Danish and Swedish populations suitable for a study aimed at testing the hypothesis that long-term mobile phone use increases the risk of parotid gland tumors. In this population-based case-control study, the authors identified all cases aged 20-69 years diagnosed with parotid gland tumor during 2000-2002 in Denmark and certain parts of Sweden. Controls were randomly selected from the study population base. Detailed information about mobile phone use was collected from 60 cases of malignant parotid gland tumors (85% response rate), 112 benign pleomorphic adenomas (88% response rate), and 681 controls (70% response rate). For regular mobile phone use, regardless of duration, the risk estimates for malignant and benign tumors were 0.7 (95% confidence interval: 0.4, 1.3) and 0.9 (95% confidence interval: 0.5, 1.5), respectively. Similar results were found for more than 10 years' duration of mobile phone use. The risk estimate did not increase, regardless of type of phone and amount of use. The authors conclude that the data do not support the hypothesis that mobile phone use is related to an increased risk of parotid gland tumors.

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.

Radiation exposure to children in intraoral dental radiology

In this study, dose area product (DAP) measurements have been performed aiming at establishing diagnostic reference levels (DRLs) in paediatric intraoral dental radiology. Measurements were carried out at 52 X-ray units for all types of intraoral examinations performed in clinical routine. Not all X-ray units have pre-set child exposure settings with reduced exposure time or in some cases lower tube voltage. Child examinations are carried out using adult exposure settings at these units, which increases the DAP third quartile values by up to 50%. For example, third quartile values for periapical examination ranges from 14.4 to 40.9 mGy cm(2) for child settings and 20.6 to 48.8 mGy cm(2) when the adult settings are included. The results show that there exists a large difference between the patient exposures among different dental facilities. It was also observed that clinics working with faster film type or higher tube voltage are not always associated with lower exposure.

Dosimetry of digital panoramic imaging. Part I: patient exposure

OBJECTIVES

To measure patient radiation dose during panoramic exposure with various panoramic units for digital panoramic imaging.

METHODS

An anthropomorphic phantom was filled with thermoluminescent dosemeters (TLD 100) and exposed with five different digital panoramic units during ten consecutive exposures. Four machines were equipped with a direct digital CCD (charge coupled device) system, whereas one of the units used storage phosphor plates (indirect digital technique). The exposure settings recommended by the different manufacturers for the particular image and patient size were used: tube potential settings ranged between 64 kV and 74 kV, exposure times between 8.2 s and 19.0 s, at fuse current values between 4 mA and 7 mA. The effective radiation dose was calculated with inclusion of the salivary glands.

RESULTS

Effective radiation doses ranged between 4.7 microSv and 14.9 microSv for one exposure. Salivary glands absorbed the most radiation for all panoramic units. When indirect and direct digital panoramic systems were compared, the effective dose of the indirect digital unit (8.1 microSv) could be found within the range of the effective doses for the direct digital units (4.7-14.9 microSv).

CONCLUSIONS

A rather wide range of patient radiation doses can be found for digital panoramic units. There is a tendency for lower effective doses for digital compared with analogue panoramic units, reported in previous studies.

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.

Radiation doses of indirect and direct digital cephalometric radiography

AIM

The aim of this study was to measure organ doses and calculate the effective dose for indirect and direct digital cephalometric exposures.

MATERIAL AND METHODS

Indirect digital cephalometric exposures were made of a Rando phantom head using a Cranex Tome multipurpose unit with storage phosphor plates from Agfa and the direct digital (Charge Coupled Device, CCD) exposures were made with a Proline Ceph CM unit. Exposure settings were 70 kV and 4 mAs for indirect digital exposures. Direct digital exposures were made with 70 kV, 10 mA and a total scanning time of 23 s. TLD700 dosemeters were used to measure organ doses, and the effective doses were calculated with (effective dose(sal)) and without inclusion of the salivary glands. A pilot study was carried out to compare diagnostic image quality of both imaging modalities.

RESULTS

Effective doses were 1.7 microSv for direct digital and 1.6 microSv for indirect digital cephalometric imaging. When salivary glands were included in the calculation, effective doses(sal) were 3.4 microSv and 2.2 microSv respectively. Organ doses were higher for direct digital imaging, except for the thyroid gland, where the organ doses were comparable. Diagnostic image quality of indirect and direct digital cephalometric images seemed comparable.

CONCLUSION

Effective dose and effective dose(sal) were higher for direct digital cephalometric exposure compared with indirect digital exposure. Organ doses were higher for direct digital cephalography. From preliminary data, it may be presumed that diagnostic image quality of indirect and direct digital cephalometric images are comparable.

Bilateral synchronous pleomorphic adenoma diagnosed by fine-needle aspiration

Pleomorphic adenoma is the most common benign neoplasm of the parotid gland. However, bilateral synchronous pleomorphic adenomas occur infrequently. We report a case of bilateral synchronous pleomorphic adenoma involving the parotid gland in a 50-yr-old man diagnosed by fine-needle aspiration biopsy.