Histopathologic and molecular alterations in bronchial epithelium in habitual smokers of marijuana, cocaine, and/or tobacco

Lung cancer in patients who have never smoked - an emerging disease

Lung cancer is the most common cause of cancer-related deaths globally. Although smoking-related lung cancers continue to account for the majority of diagnoses, smoking rates have been decreasing for several decades. Lung cancer in individuals who have never smoked (LCINS) is estimated to be the fifth most common cause of cancer-related deaths worldwide in 2023, preferentially occurring in women and Asian populations. As smoking rates continue to decline, understanding the aetiology and features of this disease, which necessitate unique diagnostic and treatment paradigms, will be imperative. New data have provided important insights into the molecular and genomic characteristics of LCINS, which are distinct from those of smoking-associated lung cancers and directly affect treatment decisions and outcomes. Herein, we review the emerging data regarding the aetiology and features of LCINS, particularly the genetic and environmental underpinnings of this disease as well as their implications for treatment. In addition, we outline the unique diagnostic and therapeutic paradigms of LCINS and discuss future directions in identifying individuals at high risk of this disease for potential screening efforts.

Effects of cannabis smoking on the respiratory system: A state-of-the-art review

The diminished perception of the health risks associated with the consumption of cannabis (marijuana) lead to a progressive increase in its inhalational use in many countries. Cannabis can be smoked through the use of joints, spliffs and blunts, and it can be vaporised with the use of hookah or e-cigarettes. Delta-9 tetrahydrocannabinol (THC) is the main psychoactive component of cannabis smoke but contains numerous other substances. While the recreational use of cannabis smoking has been legalised in several countries, its health consequences have been underestimated and undervalued. The purpose of this review is to critically review the impact of cannabis smoke on the respiratory system. Cannabis smoke irritates the bronchial tree and is strongly associated with symptoms of chronic bronchitis, with histological signs of airway inflammation and remodelling. Altered fungicidal and antibacterial activity of alveolar macrophages, with greater susceptibility to respiratory infections, is also reported. The association with invasive pulmonary aspergillosis in immunocompromised subjects is particularly concerning. Although cannabis has been shown to produce a rapid bronchodilator effect, its chronic use is associated with poor control of asthma by numerous studies. Cannabis smoking also represents a risk factor for the development of bullous lung disease, spontaneous pneumothorax and hypersensitivity pneumonitis. On the other hand, no association with the development of chronic obstructive pulmonary disease was found. Finally, a growing number of studies report an independent association of cannabis smoking with the development of lung cancer. In conclusion, unequivocal evidence established that cannabis smoking is harmful to the respiratory system. Cannabis smoking has a wide range of negative effects on respiratory symptoms in both healthy subjects and patients with chronic lung disease. Given that the most common and cheapest way of assumption of cannabis is by smoking, healthcare providers should be prepared to provide counselling on cannabis smoking cessation and inform the public and decision-makers.

Should oncologists trust cannabinoids?

Cannabis enjoyed a "golden age" as a medicinal product in the late 19th, early 20th century, but the increased risk of overdose and abuse led to its criminalization. However, the 21st century have witnessed a resurgence of interest and a large body of literature regarding the benefits of cannabinoids have emerged. As legalization and decriminalization have spread around the world, cancer patients are increasingly interested in the potential utility of cannabinoids. Although eager to discuss cannabis use with their oncologist, patients often find them to be reluctant, mainly because clinicians are still not convinced by the existing evidence-based data to guide their treatment plans. Physicians should prescribe cannabis only if a careful explanation can be provided and follow up response evaluation ensured, making it mandatory for them to be up to date with the positive and also negative aspects of the cannabis in the case of cancer patients. Consequently, this article aims to bring some clarifications to clinicians regarding the sometimes-confusing various nomenclature under which this plant is mentioned, current legislation and the existing evidence (both preclinical and clinical) for the utility of cannabinoids in cancer patients, for either palliation of the associated symptoms or even the potential antitumor effects that cannabinoids may have.

Marijuana and the Lung: Evolving Understandings

Human beings have used marijuana products for centuries. Relatively recent data showing extensive cannabinoid receptors, particularly in the brain, help to explain the impacts of cannabinoids on symptoms/diseases, such as pain and seizures, with major nervous system components. Marijuana can cause bronchitis, but a moderate body of literature suggests that distal airway/parenchymal lung disease does not occur; marijuana does not cause chronic obstructive pulmonary disease and probably does not cause lung cancer, distinctly different from tobacco. Potentials for cognitive impairment and for damage to the developing brain are contextually important as its beneficial uses are explored.

Endocannabinoid System and the Otolaryngologist

The endocannabinoid system is located throughout the central and peripheral nervous systems, endocrine system, gastrointestinal system, and within inflammatory cells. The use of medical cannabinoids has been gaining traction as a viable treatment option for varying illnesses in recent years. Research is ongoing looking at the effect of cannabinoids for treatment of common otolaryngologic pathologies. This article identifies common otolaryngologic pathologies where cannabinoids may have benefit, discusses potential drawbacks to cannabinoid use, and suggests future directions for research in the application of medical cannabinoids.

Housing characteristics of crack cocaine users in Northeast Brazil, 2011-2013

We compared sociodemographic characteristics, substance use patterns, sexual behavior, use of health services, and criminal records of homeless vs. domiciled users. Data are from the Brazilian National Survey on Crack Use. A discriminant model and correspondence analysis cross-compared characteristics of users according to their housing status. The logistic model revealed associations between "living in the streets" and female gender and intermittent work. "Homelessness" was also associated with the use of tobacco and "oxi" in the previous 30 days, reliance on soup kitchens, low access to public mental health services, and arrests in the previous year. Correspondence analysis highlighted the spatial proximity of the variables as follows: "having traded sex for drugs", "informal work", "age 31 years or older", "access to public mental health services", "problems with law enforcement", and female gender with homeless crack users. People who smoke crack cocaine in Northeast Brazil are seldom studied. Their profiles, stratified according to their housing conditions, show subgroups with specific characteristics. While domiciled users have access to specialized clinics, homeless users basically reported access to free food and harm reduction services.

Inhaled Marijuana and the Lung

Although vaping has recently increased as a mode of inhaling marijuana and has been associated with numerous and sometimes fatal cases of acute severe lung injury, smoking remains the most common method of inhaling marijuana and has been studied more extensively. Smoking marijuana has been shown to produce modest but significant short-term bronchodilation both in healthy subjects and those with asthma. Long-term effects of habitual marijuana smoking include the following: 1) symptoms of chronic bronchitis (increased cough, sputum production and wheezing); 2) modest effects on lung function in cross-sectional studies (no significant decrease in forced expired volume in 1 second [FEV₁) but mild reductions in FEV₁/forced vital capacity ratio [FEV₁/FVC], an increase in FVC and other lung volumes, reductions in specific airway conductance, and variable effects of maximal mid-expiratory flow rates and diffusing capacity; and 3) variable effects on age-related decline in FEV1 in longitudinal studies. Most cohort and case-control studies have failed to show that marijuana smoking is a significant risk-factor for lung cancer despite the presence of pro-carcinogenic components in marijuana smoke, although further study is warranted. The question whether marijuana smoking is associated with asthma is unclear and requires further investigation. Although delta-9 tetrahydrocannabinol (THC), the principal psychoactive component of marijuana, has immunomodulatory properties that hypothetically could increase the risk of pneumonia, the few available studies in marijuana smokers have failed to find an increased risk of pneumonia in immunocompetent users, although effects in immunosuppressed individuals have been variable.

Is Methadone Safe for Patients With Opioid Use Disorder and Coronavirus Disease 2019 Infection?

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic has led to not only increase in substance misuse, substance use disorder, and risk of overdose but also lack of access to treatment services. Due to lack of knowledge of the course and impact of COVID-19 and outcomes of it's interactions with existing treatments, the Substance Misuse Service Team initiated a safety improvement project to review the safety of opioid substitution treatment, particularly the safety of methadone. This preliminary retrospective cross-sectional audit of safety improvement intiative underscores the importance of providing treatment services to those with opioid use disorders and that methadone is safe among this population with a high burden of comorbidity, most of which leads to negative outcomes from COVID-19. The outcomes show that patients who have COVID-19 should continue with opioid substitution treatment with methadone. Although treatment with methadone is safe, symptomatic patients should be monitored. In addition, patients who take methadone at home should be educated on the risk of overdose due to, and adverse outcomes from, COVID-19 infection. Patients should monitor themselves using pulse oximeter for any signs of hypoxia.

Cannabis and Lung Health: Does the Bad Outweigh the Good?

Cannabis use is growing, with multiple medical ‘indications’ and approval for recreational use in many countries. This article will review some of the respiratory complications to cannabis use, which include lung function changes, lung destruction, increased risk of lung and head and neck cancer, and others. These are mostly related to smoking, and the co-administration of nicotine makes the risks a bit difficult to measure. However, with many reports of EVALI, electronic vaping-associated lung injury, being related to cannabis coadministration, it appears that the safest administration of cannabis, as far as lung health, is orally.

Pros and Cons of the Cannabinoid System in Cancer: Focus on Hematological Malignancies

The endocannabinoid system (ECS) is a composite cell-signaling system that allows endogenous cannabinoid ligands to control cell functions through the interaction with cannabinoid receptors. Modifications of the ECS might contribute to the pathogenesis of different diseases, including cancers. However, the use of these compounds as antitumor agents remains debatable. Pre-clinical experimental studies have shown that cannabinoids (CBs) might be effective for the treatment of hematological malignancies, such as leukemia and lymphoma. Specifically, CBs may activate programmed cell death mechanisms, thus blocking cancer cell growth, and may modulate both autophagy and angiogenesis. Therefore, CBs may have significant anti-tumor effects in hematologic diseases and may synergistically act with chemotherapeutic agents, possibly also reducing chemoresistance. Moreover, targeting ECS might be considered as a novel approach for the management of graft versus host disease, thus reducing some symptoms such as anorexia, cachexia, fatigue, anxiety, depression, and neuropathic pain. The aim of the present review is to collect the state of the art of CBs effects on hematological tumors, thus focusing on the essential topics that might be useful before moving into the clinical practice.

Cannabis use disorder and the lungs

Cannabis is one of the world's most widely used recreational drugs and the second most commonly smoked substance. Research on cannabis and the lungs has been limited by its illegal status, the variability in strength and size of cannabis cigarettes (joints), and the fact that most cannabis users also smoke tobacco, making the effects difficult to separate. Despite these difficulties, the available evidence indicates that smoking cannabis causes bronchitis and is associated with changes in lung function. The pattern of effects is surprisingly different from that of tobacco. Whereas smoking cannabis appears to increase the risk of severe bronchitis at quite low exposure, there is no convincing evidence that this leads to chronic obstructive pulmonary disease. Instead, cannabis use is associated with increased central airway resistance, lung hyperinflation and higher vital capacity with little evidence of airflow obstruction or impairment of gas transfer. There are numerous reports of severe bullous lung disease and pneumothorax among heavy cannabis users, but convincing epidemiological data of an increased risk of emphysema or alveolar destruction are lacking. An association between cannabis and lung cancer remains unproven, with studies providing conflicting findings.

Consequences of Vitamin A Deficiency: Immunoglobulin Dysregulation, Squamous Cell Metaplasia, Infectious Disease, and Death

Vitamin A is an important regulator of immune protection, but it is often overlooked in studies of infectious disease. Vitamin A binds an array of nuclear receptors (e.g., retinoic acid receptor, peroxisome proliferator-activated receptor, retinoid X receptor) and influences the barrier and immune cells responsible for pathogen control. Children and adults in developed and developing countries are often vitamin A-deficient or insufficient, characteristics associated with poor health outcomes. To gain a better understanding of the protective mechanisms influenced by vitamin A, we examined immune factors and epithelial barriers in vitamin A deficient (VAD) mice, vitamin D deficient (VDD) mice, double deficient (VAD+VDD) mice, and mice on a vitamin-replete diet (controls). Some mice received insults, including intraperitoneal injections with complete and incomplete Freund’s adjuvant (emulsified with PBS alone or with DNA + Fus-1 peptide) or intranasal inoculations with Sendai virus (SeV). Both before and after insults, the VAD and VAD+VDD mice exhibited abnormal serum immunoglobulin isotypes (e.g., elevated IgG2b levels, particularly in males) and cytokine/chemokine patterns (e.g., elevated eotaxin). Even without insult, when the VAD and VAD+VDD mice reached 3–6 months of age, they frequently exhibited opportunistic ascending bacterial urinary tract infections. There were high frequencies of nephropathy (squamous cell hyperplasia of the renal urothelium, renal scarring, and ascending pyelonephritis) and death in the VAD and VAD+VDD mice. When younger VAD mice were infected with SeV, the predominant lesion was squamous cell metaplasia of respiratory epithelium in lungs and bronchioles. Results highlight a critical role for vitamin A in the maintenance of healthy immune responses, epithelial cell integrity, and pathogen control.

[Pulmonary complications in cocaine users]

Cocaine can be responsible for many psychiatric and/or somatic disorders. The aim of this systematic literature review of data was to expose relations between cocaine use and pulmonary complications. Cocaine can be responsible for acute respiratory symptoms (cough, black sputum, hemoptysis, dyspnea, wheezing, chest pain) and for various pulmonary disorders including barotrauma (pneumothorax, pneumomediastinum, subcutaneous emphysema, pneumopericardium), airway damage, asthma, bronchiolitis obliterans with organizing pneumonia, acute pulmonary edema, alveolar hemorrhage, alveolar pneumonia with carbonaceous material, bullous emphysema, acute eosinophilic pneumonia, pulmonary granulomatosis caused by talc or cellulose, interstitial pneumonitis and pulmonary fibrosis, vasculitis, pulmonary hypertension, pulmonary embolism and pulmonary infarction, mycotic pulmonary arterial aneurysms, septic emboli, aspiration pneumonia, community-acquired pneumonia, HIV-related opportunistic infections, latent tuberculosis infection, pulmonary tuberculosis, lung cancer and crack lung. Some of these complications are serious and may have a fatal outcome. Pulmonary function tests, thoracic tomodensitometry, bronchial fibroscopy with bronchoalveolar lavage and lung scintigraphy may be an aid to the diagnosis of these pulmonary compications. Cocaine use must be sought in case of respiratory symptoms in young persons.

Association Between Marijuana Use and Risk of Cancer: A Systematic Review and Meta-analysis

Importance

Marijuana use is common and growing in the United States amid a trend toward legalization. Exposure to tobacco smoke is a well-described preventable cause of many cancers; the association of marijuana use with the development of cancer is not clear.

Objective

To assess the association of marijuana use with cancer development.

Data Sources

A search of PubMed, Embase, PsycINFO, MEDLINE, and the Cochrane Library was conducted on June 11, 2018, and updated on April 30, 2019. A systematic review and meta-analysis of studies published from January 1, 1973, to April 30, 2019, and references of included studies were performed, with data analyzed from January 2 through October 4, 2019.

Study Selection

English-language studies involving adult marijuana users and reporting cancer development. The search strategy contained the following 2 concepts linked together with the AND operator: marijuana OR marihuana OR tetrahydrocannabinol OR cannabinoid OR cannabis; AND cancer OR malignancy OR carcinoma OR tumor OR neoplasm.

Data Extraction and Synthesis

Two reviewers independently reviewed titles, abstracts, and full-text articles; 3 reviewers independently assessed study characteristics and graded evidence strength by consensus.

Main Outcomes and Measures

Rates of cancer in marijuana users, with ever use defined as at least 1 joint-year exposure (equivalent to 1 joint per day for 1 year), compared with nonusers. Meta-analysis was conducted if there were at least 2 studies of the same design addressing the same cancer without high risk of bias when heterogeneity was low to moderate for the following 4 cancers: lung, head and neck squamous cell carcinoma, oral squamous cell carcinoma, and testicular germ cell tumor (TGCT), with comparisons expressed as odds ratios (ORs) with 95% CIs.

Results

Twenty-five English-language studies (19 case-control, 5 cohort, and 1 cross-sectional) were included; few studies (n = 2) were at low risk of bias. In pooled analysis of case-control studies, ever use of marijuana was not associated with head and neck squamous cell carcinoma or oral cancer. In pooled analysis of 3 case-control studies, more than 10 years of marijuana use (joint-years not reported) was associated with TGCT (OR, 1.36; 95% CI, 1.03-1.81; P = .03; I2 = 0%) and nonseminoma TGCT (OR, 1.85; 95% CI, 1.10-3.11; P = .04; I2 = 0%). Evaluations of ever use generally found no association with cancers, but exposure levels were low and poorly defined. Findings for lung cancer were mixed, confounded by few marijuana-only smokers, poor exposure assessment, and inadequate adjustment; meta-analysis was not performed for several outcomes.

Conclusions and Relevance

Low-strength evidence suggests that smoking marijuana is associated with developing TGCT; its association with other cancers and the consequences of higher levels of use are unclear. Long-term studies in marijuana-only smokers would improve understanding of marijuana's association with lung, oral, and other cancers.

Trial Registration

PROSPERO identifier: CRD42018102457.

Pulmonary effects of inhaled cannabis smoke

Background: The smoke generated from cannabis delivers biologically active cannabinoids and a number of combustion-derived toxins, both of which raise questions regarding the impact of cannabis smoking on lung function, airway inflammation and smoking-related lung disease.Objectives: Review the potential effects of cannabis smoking on respiratory symptoms, lung function, histologic/molecular alterations in the bronchial mucosa, smoking-related changes in alveolar macrophage function and the potential clinical impact of cannabis smoking on chronic obstructive pulmonary disease, lung cancer and pulmonary infections.Methods: Focused literature review.Results: The carcinogens and respiratory toxins in cannabis and tobacco smoke are similar but the smoking topography for cannabis results in higher per-puff exposures to inhaled tar and gases. The frequency of chronic cough, sputum and wheeze and the presence of airway mucosal inflammation, goblet cell and vascular hyperplasia, metaplasia and cellular disorganization are similar between cannabis smokers and tobacco smokers. Cannabis smoke has modest airway bronchodilator properties but of unclear clinical significance. While clear evidence exists for progression to obstructive lung disease and emphysema in chronic tobacco smokers, the effects from habitual cannabis use are less clear. Evidence suggests that alveolar macrophages from cannabis smokers have deficits in cytokine production and antimicrobial activity not present in cells from tobacco smokers.Conclusions: Solid conclusions regarding the respiratory consequences of regular cannabis smoking are difficult to make due to a relative paucity of literature, confounding by concurrent tobacco smoking and reports of conflicting outcomes. Additional well-controlled clinical studies on the pulmonary consequences of habitual cannabis use are needed.

Alcohol, Tobacco, and Marijuana Use during the Initial Transition to College

Objectives

This study aimed to better examine substance use among college students during the acute period of transition between high school and college.

Methods

One week before coming to campus, participants completed an online survey assessing their alcohol, tobacco, and marijuana use. Next, beginning on the first Friday of the semester, they completed a 10-day experience sampling (ES) protocol, receiving one app-based survey each morning assessing recent substance use.

Results

Among students who used any tobacco product prior to college, 70% or more reported alcohol use during ES. Among previous marijuana users, 85.7% reported alcohol use during ES. Baseline alcohol and tobacco use were not associated with subsequent marijuana use.

Conclusions

Substance use prevention should target the transition to college.

Marijuana and head and neck cancer: an epidemiological review

Background

Marijuana is the most widely used illicit substance in Canada. To date, no conclusive study has looked at the epidemiologic basis of marijuana use and head and neck cancer (HNC). Due to the imminent recreational legalization of marijuana in Canada, the epidemiologic relationship between marijuana use and HNC is becoming increasingly important.

Objective

To examine the epidemiologic characteristics of HNC patients who are recreational marijuana users.

Methods

This study was conducted at a single tertiary care centre from 2011 to 2014. Patients were enrolled consecutively at time of diagnosis of malignancy. Data was prospectively collected and included socioeconomic factors, alcohol/tobacco history, tumor characteristics, and treatment modality. Marijuana use was defined as current usage on an at least weekly basis.

Results

Eight hundred seventy-nine patients met inclusion and exclusion criteria. Seventy-four (8.4%) patients were classified as marijuana users. Compared to non-users, marijuana users were less likely to be married (p = 0.048) and had less significant tobacco smoking history (p = 0.004). There were no significant differences between other socioeconomic factors or local and regional disease (p > 0.05). Marijuana users differed in the proportion of cancers stratified by primary site (p < 0.0001), with higher rates of p16+ oropharyngeal cancers, and treatment modality (p < 0.0001), with more use of chemoradiation.

Conclusions

HNC patients who were marijuana users were less likely to be married and smoke tobacco. They have a distinct cancer site prevalence and are more likely to be treated by chemoradiation. Understanding the epidemiological breakdown of marijuana users amongst HNC patients will be a useful adjunct for future studies.

Electronic supplementary material

The online version of this article (10.1186/s40463-018-0319-2) contains supplementary material, which is available to authorized users.

Marijuana Use, Respiratory Symptoms, and Pulmonary Function: A Systematic Review and Meta-analysis

Background

The health effects of smoking marijuana are not well-understood.

Purpose

To examine the association between marijuana use and respiratory symptoms, pulmonary function, and obstructive lung disease among adolescents and adults.

Data Sources

PubMed, Embase, PsycINFO, MEDLINE, and the Cochrane Library from 1 January 1973 to 30 April 2018.

Study Selection

Observational and interventional studies published in English that reported pulmonary outcomes of adolescents and adults who used marijuana.

Data Extraction

Four reviewers independently extracted study characteristics and assessed risk of bias. Three reviewers assessed strength of evidence. Studies of similar design with low or moderate risk of bias and sufficient data were pooled.

Data Synthesis

Twenty-two studies were included. A pooled analysis of 2 prospective studies showed that marijuana use was associated with an increased risk for cough (risk ratio [RR], 2.04 [95% CI, 1.02 to 4.06]) and sputum production (RR, 3.84 [CI, 1.62 to 9.07]). Pooled analysis of cross-sectional studies (1 low and 3 moderate risk of bias) showed that marijuana use was associated with cough (RR, 4.37 [CI, 1.71 to 11.19]), sputum production (RR, 3.40 [CI, 1.99 to 5.79]), wheezing (RR, 2.83 [CI, 1.89 to 4.23]), and dyspnea (RR, 1.56 [CI, 1.33 to 1.83]). Data on pulmonary function and obstructive lung disease were insufficient.

Limitation

Few studies were at low risk of bias, marijuana exposure was limited in the population studied, cohorts were young overall, assessment of marijuana exposure was not uniform, and study designs varied.

Conclusion

Low-strength evidence suggests that smoking marijuana is associated with cough, sputum production, and wheezing. Evidence on the association between marijuana use and obstructive lung disease and pulmonary function is insufficient.

Primary Funding Source

None. (PROSPERO: CRD42017059224).

An Unusual and Fatal Cause of Miliary Nodules on Chest Radiography

Foreign body granulomatosis has many etiologies, including the injection of oral medications intravenously. The insoluble filler materials that are used in the medications can lodge in pulmonary arterioles and capillaries, which can trigger foreign body giant cell reaction, chronic inflammation, thrombosis, and fibrosis, resulting in pulmonary hypertension, progressive shortness of breath, and, potentially, fatal conditions. On imaging, this may present with multiple miliary mottling’s/nodules. The use of a bronchoscopy with biopsy can be an excellent way to establish a diagnosis in appropriate clinical settings. Here, we present a case of a 37-year-old old male found to have multiple miliary densities on imaging due to intravenous use of oral medication.

The epidemiology of lung cancer

The incidence and mortality from lung cancer is decreasing in the US due to decades of public education and tobacco control policies, but are increasing elsewhere in the world related to the commencement of the tobacco epidemic in various countries and populations in the developing world. Individual cigarette smoking is by far the most common risk factor for lung carcinoma; other risks include passive smoke inhalation, residential radon, occupational exposures, infection and genetic susceptibility. The predominant disease burden currently falls on minority populations and socioeconomically disadvantaged people. In the US, the recent legalization of marijuana for recreational use in many states and the rapid growth of commercially available electronic nicotine delivery systems (ENDS) present challenges to public health for which little short term and no long term safety data is available.

Marijuana and Lung Disease

As marijuana smoking prevalence increases in the United States, concern regarding its potential risks to lung health has also risen, given the general similarity in the smoke contents between marijuana and tobacco. Most studies have found a significant association between marijuana smoking and chronic bronchitis symptoms after adjustment for tobacco. Although reports are mixed regarding associations between marijuana smoking and lung function, none have shown a relationship to decrements in FEV₁ and few have found a relationship to a decreased ratio of FEV₁/FVC, possibly related to an association between marijuana and an increased FVC. A few studies have found a modest reduction in specific airway conductance in relation to marijuana, probably reflecting endoscopic evidence of bronchial mucosal edema among habitual marijuana smokers. Diffusing capacity in marijuana smokers has been normal, and two studies of thoracic high-resolution CT scan have not shown any association of marijuana smoking with emphysema. Although bronchial biopsies from habitual marijuana smokers have shown precancerous histopathologic changes, a large cohort study and a pooled analysis of six well-designed case-control studies have not found evidence of a link between marijuana smoking and lung cancer. The immunosuppressive effects of delta-9 tetrahydrocannabinol raise the possibility of an increased risk of pneumonia, but further studies are needed to evaluate this potential risk. Several cases series have demonstrated pneumothoraces/pneumomediastinum and bullous lung disease in marijuana smokers, but these associations require epidemiologic studies for firmer evidence of possible causality.

Correlates and trends in youth co-use of marijuana and tobacco in the United States, 2005-2014

BACKGROUND

Past-month marijuana and tobacco use (co-use) are increasing among U.S. adults, but little is known about the prevalence of co-use among U.S. youth. This study uses nationally representative data to assess the prevalence, correlates, and trends in co-use of marijuana and tobacco, tobacco-only use, and marijuana-only use among U.S. youth.

METHODS

Data came from 176,245 youth ages 12-17 who responded to the National Survey on Drug Use and Health - a nationally representative, household interview survey - between 2005 and 2014. Prevalence, demographics and substance use characteristics from 2013 to 14 were assessed across three groups: past-month users of marijuana and tobacco (co-users), past-month tobacco-only users, and past-month marijuana-only users. Multinomial logistic regression was used to assess demographic correlates of each group. Linear and quadratic trends were assessed from 2005 to 2014 using logistic regression with orthogonal polynomials.

RESULTS

In 2013-14, 5.4% of youth reported past-month co-use of tobacco and marijuana, 2.2% reported marijuana-only use, and 3.9% reported tobacco-only use. Co-use was associated with higher prevalence of past year marijuana dependence (vs. marijuana-only users), and higher past-month risky alcohol and other illicit drug use (vs. both tobacco and marijuana-only use groups). Co-use did not increase significantly between 2005 and 2014; tobacco-only use declined, and marijuana-only use increased.

CONCLUSIONS

Co-use of marijuana and tobacco is more prevalent than tobacco-only or marijuana-only use in U.S. youth. Given changing tobacco and marijuana policies, ongoing surveillance and studies that seek to increase our understanding of co-use behaviors in youth are critical.

The Role of Nicotinamide Adenine Dinucleotide Phosphate Oxidases in Lung Architecture Remodeling

Chronic lung disorders, such as pulmonary artery hypertension (PAH), chronic obstructive pulmonary disease (COPD), asthma and neonatal bronchopulmonary dysplasia (BPD), are characterized by airway and/or vascular remodeling. Despite differences in the pathology, reactive oxygen species (ROS) have been highlighted as a critical contributor to the initiation and development of airway and vascular remodeling. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (Nox) appear to play a pivotal role in lung signaling, leading to marked changes in pulmonary airway and vascular cell phenotypes, including proliferation, hypertrophy and apoptosis. In this review, we summarized the current literature regarding the role of Nox in the airway and vascular remodeling.

Prevalence, correlates, and trends in tobacco use and cessation among current, former, and never adult marijuana users with a history of tobacco use, 2005-2014

BACKGROUND

Approximately 70% of current (past 30-day) adult marijuana users are current tobacco users, which may complicate tobacco cessation. We assessed prevalence and trends in tobacco cessation among adult ever tobacco users, by marijuana use status.

METHODS

Data came from the National Survey on Drug Use and Health, a cross-sectional, nationally representative, household survey of U.S. civilians. Analyses included current, former, and never marijuana users aged≥18 reporting ever tobacco use (cigarette, cigar, chew/snuff). We computed weighted estimates (2013-2014) of current tobacco use, recent tobacco cessation (quit 30days to 12months), and sustained tobacco cessation (quit>12months) and adjusted trends in tobacco use and cessation (2005-2014) by marijuana use status. We also assessed the association between marijuana and tobacco use status.

RESULTS

In 2013-2014, among current adult marijuana users reporting ever tobacco use, 69.1% were current tobacco users (vs. 38.5% of former marijuana users, p<0.0001, and 28.2% of never marijuana users, p<0.0001); 9.1% reported recent tobacco cessation (vs. 8.4% of former marijuana users, p<0.01, and 6.3% of never marijuana users, p<0.001), and 21.8% reported sustained tobacco cessation (vs. 53.1% of former marijuana users, p<0.01, and 65.5% of never marijuana users, p<0.0001). Between 2005 and 2014, current tobacco use declined and sustained tobacco cessation increased among all marijuana use groups.

CONCLUSIONS

Current marijuana users who ever used tobacco had double the prevalence (vs. never-marijuana users) of current tobacco use, and significantly lower sustained abstinence. Interventions addressing tobacco cessation in the context of use of marijuana and other substances may be warranted.

Cytopathological Changes Induced by the Crack Use in Oral Mucosa

AIMS

To evaluate cytological alterations, inflammation, and microbial charge of the oral mucosa epithelium in crack users in in terms of the amount and duration of use.

METHODS

Two hundred thirty four crack users (case group) and 120 non-users (control group) participated in this study. Clinically healthy epithelial cells were collected from the posterior mouth floor, using the conventional exfoliative cytology. Some of the aspects evaluated were as follows: Papanicolaou classification, nuclear area (NA), cytoplasmic area (CA), nuclear/cytoplasmic area ratio (NA/CA), inflammation, microbial charge, keratinization, enucleated superficial cells, and binucleation.

RESULTS

The average time of crack consumption was 9.8 years (±7.1) and the average quantity of use was 13.97 g/week (±18.5). The average NA values and NA/CA ratio were increased and CA values were decreased in the case group compared to those in the controls (p < 0.05). Papanicolaou class II, intense inflammation, and intense microbial charge were more prevalent in the case group than in the controls (p < 0.05). There was a significant association between high quantity of smoked crack rocks per week and increased CA values, absence of keratinization, and presence of enucleated superficial cells (p < 0.05).

CONCLUSION

Crack use seemed to induce inflammatory alterations and early indicators of malignant transformation on the oral mucosa epithelium.

The prominence of smoking-related mortality among individuals with alcohol- or drug-use disorders

INTRODUCTION AND AIMS

Even though individuals with substance-use disorders have a high prevalence of tobacco smoking, surprisingly little is known about smoking-related mortality in these populations. The current retrospective cohort study aims to address this gap.

DESIGN AND METHODS

The study sample included cohorts of individuals hospitalised in California between 1990 and 2005 with alcohol- (n = 509 422), cocaine- (n = 35 276), opioid- (n = 53 172), marijuana- (n = 15 995) or methamphetamine-use (n = 36 717) disorders. Death records were linked to inpatient data. Age-, race- and sex-adjusted standardised mortality ratios (SMR) were generated for 19 smoking-related causes of death.

RESULTS

Smoking-related conditions comprised 49% (79 188/163 191) of total deaths in the alcohol, 40% (1412/3570) in the cocaine, 39% (4285/11 091) in the opioid, 42% (554/1332) in the methamphetamine and 36% (1122/3095) in the marijuana cohorts. The SMRs for all smoking-linked diseases were: alcohol, 3.57 (95% confidence interval [CI] = 3.55 to 3.58); cocaine, 2.40 (95% CI = 2.39 to 2.41); opioid, 4.26 (95% CI = 4.24 to 4.27); marijuana, 3.73 (95% CI = 3.71 to 3.74); and methamphetamine, 2.58 (95% CI = 2.57 to 2.59). The SMRs for almost all of the 19 cause-specific smoking-related outcomes were elevated across cohorts.

DISCUSSION AND CONCLUSIONS

Given the current findings, addressing tobacco smoking among persons with substance-use disorders should be a critical concern, especially given the heavy smoking-related mortality burden and the currently limited attention devoted to smoking in these populations. [Callaghan RC, Gatley JM, Sykes J, Taylor L. The prominence of smoking-related mortality among individuals with alcohol- or drug-use disorders. Drug Alcohol Rev 2018;37:97-105].

Effect of cannabis smoking on lung function and respiratory symptoms: a structured literature review

As cannabis use increases, physicians need to be familiar with the effects of both cannabis and tobacco on the lungs. However, there have been very few long-term studies of cannabis smoking, mostly due to legality issues and the confounding effects of tobacco. It was previously thought that cannabis and tobacco had similar long-term effects as both cause chronic bronchitis. However, recent large studies have shown that, instead of reducing forced expiratory volume in 1 s and forced vital capacity (FVC), marijuana smoking is associated with increased FVC. The cause of this is unclear, but acute bronchodilator and anti-inflammatory effects of cannabis may be relevant. Bullous lung disease, barotrauma and cannabis smoking have been recognised in case reports and small series. More work is needed to address the effects of cannabis on lung function, imaging and histological changes.

Effects of Marijuana on the Lung and its Defenses against Infection and Cancer

Habitual marijuana use may lead to the following effects on the lung: (1) acute and chronic bronchitis; (2) extensive microscopic abnormalities in the cells lining the bronchial passages, some of which may be pre-malignant; (3) overexpression of molecular markers of progression to lung cancer in bronchial tissue; (4) abnormally increased accumulation of inflammatory cells (alveolar macrophages) in the lung; and (5) impairment in the function of these immune-effector cells (reduced ability to kill micro-organisms and tumour cells) and in their ability to produce protective inflammatory cytokines. Clinically, the major pulmonary consequences that may ensue from regular marijuana use are pulmonary infections and respiratory cancer. Infections of the lung are more likely in marijuana users due to a combination of smoking-related damage to the ciliated cells in the bronchial passages (the lung's first line of defense against inhaled micro-organisms) and marijuana-related impairment in the function of alveolar macrophages (the principal immune cells in the lung responsible for defending it against infection). Patients with pre-existing immune deficits due to AIDS or cancer chemotherapy might be expected to be particularly vulnerable to marijuana-related pulmonary infections. Furthermore, biochemical, cellular, genetic, animal and human studies all suggest that marijuana may be an important risk factor for the development of respiratory cancer. However, proof that habitual use of marijuana does in fact lead to respiratory cancer must await the results of well-designed case-control epidemiologic studies that should now be feasible after the passage of 30 years since the initiation of widespread marijuana use among young individuals in our society in the mid-1960s.

Squamous Metaplasia Is Increased in the Bronchial Epithelium of Smokers with Chronic Obstructive Pulmonary Disease

Aims

To quantify the extent of squamous metaplasia in bronchial biopsies and relate it to the presence of chronic obstructive pulmonary disease (COPD), a smoking-related pathology.

Methods

Bronchial biopsies (n = 15 in each group) from smokers with COPD GOLD stage1 and GOLD stage2, smokers without COPD and healthy non-smokers were stained immunohistochemically with a panel of antibodies that facilitated the identification of pseudostratified epithelium and distinction of squamous metaplasia and squamous epithelium from tangentially cut epithelium. The percentage length of each of these epithelial phenotypes was measured as a percent of total epithelial length using computerised image analysis. Sections were also stained for carcinoembryonic antigen and p53, early markers of carcinogenesis, and Ki67, and the percentage epithelial expression measured.

Results

The extent of squamous metaplasia was significantly increased in both COPD1 and COPD2 compared to healthy smokers and healthy non-smokers. The amount of fully differentiated squamous epithelium was also increased in COPD1 and COPD2 compared to healthy non-smokers, as was the expression of carcinoembryonic antigen. These features correlated with one other.

Conclusion

In subjects with COPD there is a loss of pseudostratified epithelium accompanied by an increase in squamous metaplasia with transition into a fully squamous epithelium and expression of early markers of carcinogenesis.

Damaging Effects of Cannabis Use on the Lungs

Cannabis is the most widely smoked illicit substance in the world. It can be smoked alone in its plant form, marijuana, but it can also be mixed with tobacco. The specific effects of smoking cannabis are difficult to assess accurately and to distinguish from the effects of tobacco; however its use may produce severe consequences. Cannabis smoke affects the lungs similarly to tobacco smoke, causing symptoms such as increased cough, sputum, and hyperinflation. It can also cause serious lung diseases with increasing years of use. Cannabis can weaken the immune system, leading to pneumonia. Smoking cannabis has been further linked with symptoms of chronic bronchitis. Heavy use of cannabis on its own can cause airway obstruction. Based on immuno-histopathological and epidemiological evidence, smoking cannabis poses a potential risk for developing lung cancer. At present, however, the association between smoking cannabis and the development of lung cancer is not decisive.

Cannabis Smoking in 2015: A Concern for Lung Health?

Recent legislative successes allowing expanded access to recreational and medicinal cannabis have been associated with its increased use by the public, despite continued debates regarding its safety within the medical and scientific communities. Despite legislative changes, cannabis is most commonly used by smoking, although alternatives to inhalation have also emerged. Moreover, the composition of commercially available cannabis has dramatically changed in recent years. Therefore, developing sound scientific information regarding its impact on lung health is imperative, particularly because published data conducted prior to widespread legalization are conflicting and inconclusive. In this commentary, we delineate major observations of epidemiologic investigations examining cannabis use and the potential associated development of airways disease and lung cancer to highlight gaps in pulmonary knowledge. Additionally, we review major histopathologic alterations related to smoked cannabis and define specific areas in animal models and human clinical translational investigations that could benefit from additional development. Given that cannabis has an ongoing classification as a schedule I medication, federal funding to support investigations of modern cannabis use in terms of medicinal efficacy and safety profile on lung health have been elusive. It is clear, however, that the effects of inhaled cannabis on lung health remain uncertain and given increasing use patterns, are worthy of further investigation.

Assessing the overlap between tobacco and marijuana: Trends in patterns of co-use of tobacco and marijuana in adults from 2003-2012

BACKGROUND

As marijuana legalization and acceptability increase in the U.S., it is important to understand the potential impact on tobacco use. Accordingly, we assessed prevalence, correlates, and ten-year trends in co-use of marijuana and tobacco among U.S. adults.

METHODS

Data came from 378,459 adults participating in the 2003-2012 National Survey on Drug Use and Health, an annual, cross-sectional, household survey. Data from 2011-2012 were used to compute the most recent prevalence of past 30-day marijuana and tobacco use (co-use). Data from 2003-2012 were used to compute demographic correlates of co-use, overall trends in co-use, and trends by age, race, and sex. We also assessed trends in tobacco use among marijuana users and marijuana use among tobacco users.

RESULTS

From 2011 to 2012, 5.2% of participants were past month co-marijuana and tobacco users, 24.0% were tobacco-only users, and 2.3% were marijuana-only users. From 2003 to 2012, prevalence of co-use increased overall (p<.0001), and among males and females (p<.001, p<.05), those ages 26-34 (p<.001) and 50+years (p<.0001), and Whites (p<.01), Blacks (p<.05), and Hispanics (p<.01); there were no changes among adults 18-25 years. Tobacco use among marijuana users decreased between 2003 and 2012 (from 74.3% to 69.6%, p<.0001), while marijuana use increased among tobacco users (from 14.2% to 17.8, p<.0001).

CONCLUSIONS

Co-use of tobacco and marijuana increased from 2003-2012, with marijuana use increasing among past-month tobacco users and tobacco use declining among past-month marijuana users. Improved surveillance of co-use is needed as marijuana legalization policies expand and become more integrated in communities.

Cannabidiol induces expression of human cytochrome P450 1A1 that is possibly mediated through aryl hydrocarbon receptor signaling in HepG2 cells

AIMS

We herein investigated the inducibility of cytochrome P450 1A1 (CYP1A1) by Δ(9)-tetrahydrocannabinol, cannabidiol (CBD), and cannabinol, three major phytocannabinoids, using human hepatoma HepG2 cells.

MAIN METHODS

The expression of CYP1A1 and the aryl hydrocarbon receptor (AhR) was measured by a quantitative real-time polymerase chain reaction and/or Western blotting.

KEY FINDINGS

Δ(9)-Tetrahydrocannabinol and CBD concentration-dependently induced the expression of CYP1A1 mRNA, whereas cannabinol showed little or no induction. Among the phytocannabinoids tested, CBD was the most potent inducer of CYP1A1 expression. The induction of CYP1A1 expression by CBD was significantly attenuated by the knockdown of AhR expression with AhR small interfering RNAs. The role of protein tyrosine kinases (PTKs) in the CBD-mediated induction of CYP1A1 was then examined using herbimycin A, a PTK inhibitor. The upregulation of CYP1A1 by CBD was significantly suppressed by herbimycin A as was the induction by omeprazole but not 3-methylcholanthrene. The inducibility of CYP1A1 by CBD-related compounds was examined to clarify the structural requirements for CBD-mediated CYP1A1 induction. Olivetol, which corresponds to the pentylresorcinol moiety of CBD, significantly induced the expression of CYP1A1, whereas d-limonene, CBD-2'-monomethyl ether, and CBD-2',6'-dimethyl ether did not.

SIGNIFICANCE

These results showed that CBD may have induced human CYP1A1 expression through the activation of PTK-dependent AhR signaling, in which two phenolic hydroxyl groups in the pentylresorcinol moiety of CBD may play structurally important roles.

Nuclear changes in oral mucosa of alcoholics and crack cocaine users

The effects of drugs of abuse on oral mucosa are only partly understood. The aims of the present study were to: (1) evaluate the frequency of nuclear changes in normal-appearing oral mucosa of alcoholics and crack cocaine users and (2) assess their association with cell proliferation rate. Oral smears were obtained from the border of the tongue and floor of the mouth of 26 crack cocaine users (24 males and 2 females), 29 alcoholics (17 males and 12 females), and 35 controls (17 males and 18 females). Histological slides were submitted to Feulgen staining to assess the frequency of micronuclei (MN), binucleated cells (BN), broken eggs (BE), and karyorrhexis (KR). A significant increase in the frequency of MN was observed in cells exfoliated from the tongue of crack cocaine users ( p = 0.01), and alcoholics showed a higher frequency of KR in cells obtained from the floor of the mouth ( p = 0.01). Our findings suggest that the use of crack cocaine induces clastogenic effects, whereas alcoholism is associated with higher degrees of keratinization in the floor of the mouth.

Development and first data of a customized short tracheal cannula based on digital data

PURPOSE

At the moment, there is an inadequate margin fit of commercially available stoma buttons. The aim of the present study was to develop a customized short tracheal cannula based on digital data. Furthermore, the applied material has to be evaluated considering germ colonization and appropriate cleaning procedures.

METHODS

Computed tomographies of 53 patients who underwent laryngectomy were surveyed. Based on the digital data, a customized short tracheal cannula was created and manufactured from silicone. The new cannula was incorporated in ten patients and worn for 4 weeks. A clinical examination of an otolaryngologist and subjective assessment of the patients were carried out. Furthermore, microbiological test considering germ colonization was performed.

RESULTS

The customized short tracheal cannula could be incorporated in all patients. The clinical results showed no irritation or mucosal lesions. The subjective individual evaluation by the patients was promising. The proposals for improvement could be considered. The microbiological examination revealed a higher contamination of the silicone compared to the silver cannulas. Both chemical and mechanical decontamination showed sufficient results.

CONCLUSION

A workflow for development and manufacturing of a customized short tracheal cannula from digital data could be established. The cannula is compatible to standard equipment and routine cleaning procedures. Clinical studies are required to evaluate the potential benefit for patients.

Cannabis smoking and lung cancer risk: Pooled analysis in the International Lung Cancer Consortium

To investigate the association between cannabis smoking and lung cancer risk, data on 2,159 lung cancer cases and 2,985 controls were pooled from 6 case-control studies in the US, Canada, UK, and New Zealand within the International Lung Cancer Consortium. Study-specific associations between cannabis smoking and lung cancer were estimated using unconditional logistic regression adjusting for sociodemographic factors, tobacco smoking status and pack-years; odds-ratio estimates were pooled using random effects models. Subgroup analyses were done for sex, histology and tobacco smoking status. The shapes of dose-response associations were examined using restricted cubic spline regression. The overall pooled OR for habitual versus nonhabitual or never users was 0.96 (95% CI: 0.66-1.38). Compared to nonhabitual or never users, the summary OR was 0.88 (95%CI: 0.63-1.24) for individuals who smoked 1 or more joint-equivalents of cannabis per day and 0.94 (95%CI: 0.67-1.32) for those consumed at least 10 joint-years. For adenocarcinoma cases the ORs were 1.73 (95%CI: 0.75-4.00) and 1.74 (95%CI: 0.85-3.55), respectively. However, no association was found for the squamous cell carcinoma based on small numbers. Weak associations between cannabis smoking and lung cancer were observed in never tobacco smokers. Spline modeling indicated a weak positive monotonic association between cumulative cannabis use and lung cancer, but precision was low at high exposure levels. Results from our pooled analyses provide little evidence for an increased risk of lung cancer among habitual or long-term cannabis smokers, although the possibility of potential adverse effect for heavy consumption cannot be excluded.

An epidemiologic review of marijuana and cancer: an update

Marijuana use is legal in two states and additional states are considering legalization. Approximately 18 million Americans are current marijuana users. There is currently no consensus on whether marijuana use is associated with cancer risk. Our objective is to review the epidemiologic studies on this possible association. We identified 34 epidemiologic studies on upper aerodigestive tract cancers (n = 11), lung cancer (n = 6), testicular cancer (n = 3), childhood cancers (n = 6), all cancers (n = 1), anal cancer (n = 1), penile cancer (n = 1), non-Hodgkin lymphoma (n = 2), malignant primary gliomas (n = 1), bladder cancer (n = 1), and Kaposi sarcoma (n = 1). Studies on head and neck cancer reported increased and decreased risks, possibly because there is no association, or because risks differ by human papillomavirus status or geographic differences. The lung cancer studies largely appear not to support an association with marijuana use, possibly because of the smaller amounts of marijuana regularly smoked compared with tobacco. Three testicular cancer case-control studies reported increased risks with marijuana use [summary ORs, 1.56; 95% confidence interval (CI), 1.09-2.23 for higher frequency and 1.50 (95% CI, 1.08-2.09) for ≥10 years]. For other cancer sites, there is still insufficient data to make any conclusions. Considering that marijuana use may change due to legalization, well-designed studies on marijuana use and cancer are warranted.

Lung injury and lung cancer caused by cigarette smoke-induced oxidative stress: Molecular mechanisms and therapeutic opportunities involving the ceramide-generating machinery and epidermal growth factor receptor

Chronic obstructive pulmonary disease (COPD) and lung cancer are frequently caused by tobacco smoking. However, these diseases present opposite phenotypes involving redox signaling at the cellular level. While COPD is characterized by excessive airway epithelial cell death and lung injury, lung cancer is caused by uncontrolled epithelial cell proliferation. Notably, epidemiological studies have demonstrated that lung cancer incidence is significantly higher in patients who have preexisting emphysema/lung injury. However, the molecular link and common cell signaling events underlying lung injury diseases and lung cancer are poorly understood. This review focuses on studies of molecular mechanism(s) underlying smoking-related lung injury (COPD) and lung cancer. Specifically, the role of the ceramide-generating machinery during cigarette smoke-induced oxidative stress leading to both apoptosis and proliferation of lung epithelial cells is emphasized. Over recent years, it has been established that ceramide is a sphingolipid playing a major role in lung epithelia structure/function leading to lung injury in chronic pulmonary diseases. However, new and unexpected findings draw attention to its potential role in lung development, cell proliferation, and tumorigenesis. To address this dichotomy in detail, evidence is presented regarding several protein targets, including Src, p38 mitogen-activated protein kinase, and neutral sphingomyelinase 2, the major sphingomyelinase that controls ceramide generation during oxidative stress. Furthermore, their roles are presented not only in apoptosis and lung injury but also in enhancing cell proliferation, lung cancer development, and resistance to epidermal growth factor receptor-targeted therapy for treating lung cancer.

Marijuana and lung diseases

PURPOSE OF REVIEW

Cannabis sativa (marijuana) is used throughout the world, and its use is increasing. In much of the world, marijuana is illicit. While inhalation of smoke generated by igniting dried components of the plant is the most common way marijuana is used, there is concern over potential adverse lung effects. The purpose of this review is to highlight recent studies that explore the impact upon the respiratory system of inhaling marijuana smoke.

RECENT FINDINGS

Smoking marijuana is associated with chronic bronchitis symptoms and large airway inflammation. Occasional use of marijuana with low cumulative use is not a risk factor for the development of chronic obstructive pulmonary disease. The heavy use of marijuana alone may lead to airflow obstruction. The immuno-histopathologic and epidemiologic evidence in marijuana users suggests biological plausibility of marijuana smoking as a risk for the development of lung cancer; at present, it has been difficult to conclusively link marijuana smoking and cancer development.

SUMMARY

There is unequivocal evidence that habitual or regular marijuana smoking is not harmless. A caution against regular heavy marijuana usage is prudent. The medicinal use of marijuana is likely not harmful to lungs in low cumulative doses, but the dose limit needs to be defined. Recreational use is not the same as medicinal use and should be discouraged.

Legalizing Cannabis: A physician's primer on the pulmonary effects of marijuana

Habitual smoking of marijuana is associated with multiple respiratory symptoms such as cough, sputum production, and wheezing .These symptoms are not significantly different from those exhibited by tobacco smokers. Furthermore, endobronchial biopsies of habitual smokers of marijuana and /or tobacco have shown that both marijuana and cigarette smoking cause significant bronchial mucosal histopathology and that these effects are additive. Although marijuana smokers have minimal changes in pulmonary function studies as compared to tobacco smokers, they may develop bullous disease and spontaneous pneumothoraces. The relationship between marijuana smoking and lung cancer remains unclear due to design limitations of the studies published so far. These findings should warn individuals that marijuana smoking may result in serious short-term and long-term respiratory complications, and habitual marijuana use should be viewed with caution. The medical literature so far does not support routine evaluation by pulmonary function tests or imaging studies; until more definitive data is available, we do not recommend the regular use of these tests in the evaluation of habitual marijuana smokers.

Buccal spectral markers for lung cancer risk stratification

Lung cancer remains the leading cause of cancer deaths in the US with >150,000 deaths per year. In order to more effectively reduce lung cancer mortality, more sophisticated screening paradigms are needed. Previously, our group demonstrated the use of low-coherence enhanced backscattering (LEBS) spectroscopy to detect and quantify the micro/nano-architectural correlates of colorectal and pancreatic field carcinogenesis. In the lung, the buccal (cheek) mucosa has been suggested as an excellent surrogate site in the “field of injury”. We, therefore, wanted to assess whether LEBS could similarly sense the presence of lung. To this end, we applied a fiber-optic LEBS probe to a dataset of 27 smokers without diagnosed lung cancer (controls) and 46 with lung cancer (cases), which was divided into a training and a blinded validation set (32 and 41 subjects, respectively). LEBS readings of the buccal mucosa were taken from the oral cavity applying gentle contact. The diagnostic LEBS marker was notably altered in patients harboring lung cancer compared to smoking controls. The prediction rule developed on training set data provided excellent diagnostics with 94% sensitivity, 80% specificity, and 95% accuracy. Applying the same threshold to the blinded validation set yielded 79% sensitivity and 83% specificity. These results were not confounded by patient demographics or impacted by cancer type or location. Moreover, the prediction rule was robust across all stages of cancer including stage I. We envision the use of LEBS as the first part of a two-step paradigm shift in lung cancer screening in which patients with high LEBS risk markers are funnelled into more invasive screening for confirmation.

Assay of lapatinib in murine models of cigarette smoke carcinogenesis

Lapatinib, a dual tyrosine kinase inhibitor targeting the epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER-2), is prescribed for the treatment of patients with metastatic breast cancer overexpressing HER-2. Involvement of this drug in pulmonary carcinogenesis has been poorly investigated. We used murine models suitable to evaluate cigarette smoke-related molecular and histopathological alterations. A total of 481 Swiss H mice were used. The mice were exposed to mainstream cigarette smoke (MCS) during the first four months of life. After 10 weeks, MCS caused an elevation of bulky DNA adducts, oxidative DNA damage and an extensive downregulation of microRNAs in lung. After four months, an increase in micronucleus frequency was observed in peripheral blood erythrocytes. After 7.5 months, histopathological alterations were detected in the lung, also including benign tumors and malignant tumors, and in the urinary tract. A subchronic toxicity study assessed the non-toxic doses of lapatinib, administered daily with the diet after weaning. After 10 weeks, lapatinib significantly attenuated the MCS-related nucleotide changes and upregulated several low-intensity microRNAs in lung. The drug poorly affected the MCS systemic genotoxicity and had modest protective effects on MCS-induced preneoplastic lesions in lung and kidney, when administered under conditions that temporarily mimicked interventions either in current smokers or ex-smokers. On the other hand, it caused some toxicity to the liver. Thus, on the whole, lapatinib appears to have a low impact in the smoke-related lung carcinogenesis models used, especially in terms of tumorigenic response.

[Cannabis smoking and lung cancer]

Cannabis is the most commonly smoked illicit substance in the world. It can be smoked alone in plant form (marijuana) but it is mainly smoked mixed with tobacco. The combined smoking of cannabis and tobacco is a common-place phenomenon in our society. However, its use is responsible for severe pulmonary consequences. The specific impact of smoking cannabis is difficult to assess precisely and to distinguish from the effect of tobacco. Marijuana smoke contains polycyclic aromatic hydrocarbons and carcinogens at higher concentration than tobacco smoke. Cellular, tissue, animal and human studies, and also epidemiological studies, show that marijuana smoke is a risk factor for lung cancer. Cannabis exposure doubles the risk of developing lung cancer. This should encourage clinicians to identify cannabis use and to offer patients support in quitting.