Smoking and Cystic Fibrosis

Cystic Fibrosis and Cancer: Unraveling the Complex Role of CFTR Gene in Cancer Susceptibility

Cystic fibrosis (CF) is a genetic disorder affecting multiple organs, primarily the lungs and digestive system. Over the years, advancements in medical care and treatments have significantly increased the life expectancy of individuals with CF. However, with this improved longevity, concerns about the potential risk of developing certain types of cancers have arisen. This narrative review aims to explore the relationship between CF, increased life expectancy, and the associated risk for cancers. We discuss the potential mechanisms underlying this risk, including chronic inflammation, immune system dysregulation, and genetic factors. Additionally, we review studies that have examined the incidence and types of cancers seen in CF patients, with a focus on gastrointestinal, breast, and respiratory malignancies. We also explore the impact of CFTR modulator therapies on cancer risk. In the gastrointestinal tract, CF patients have an elevated risk of developing colorectal cancer, pancreatic cancer, and possibly esophageal cancer. The underlying mechanisms contributing to these increased risks are not fully understood, but chronic inflammation, altered gut microbiota, and genetic factors are believed to play a role. Regular surveillance and colonoscopies are recommended for early detection and management of colorectal cancer in CF patients. Understanding the factors contributing to cancer development in CF patients is crucial for implementing appropriate surveillance strategies and improving long-term outcomes. Further research is needed to elucidate the molecular mechanisms involved and develop targeted interventions to mitigate cancer risk in individuals with CF.

Influences of environmental exposures on individuals living with cystic fibrosis

INTRODUCTION

Natural, social, and constructed environments play a critical role in the development and exacerbation of respiratory diseases. However, less is known regarding the influence of these environmental/community risk factors on the health of individuals living with cystic fibrosis (CF), compared to other pulmonary disorders.

AREAS COVERED

Here, we review current knowledge of environmental exposures related to CF, which suggests that environmental/community risk factors do interact with the respiratory tract to affect outcomes. Studies discussed in this review were identified in PubMed between March 2019 and March 2020. Although the limited data available do not suggest that avoiding potentially detrimental exposures other than secondhand smoke could improve outcomes, additional research incorporating novel markers of environmental exposures and community characteristics obtained at localized levels is needed.

EXPERT OPINION

As we outline, some environmental exposures and community characteristics are modifiable; if not by the individual, then by policy. We recommend a variety of strategies to advance understanding of environmental influences on CF disease progression.

An exploration into experiences and attitudes regarding risky health behaviours in an adult cystic fibrosis population

Health risk behaviours (HRBs) are prevalent within the cystic fibrosis (CF) population, and there is a lack of research around what influences their engagement. This research explored beliefs associated with HRBs within an adult CF population using qualitative semi-structured interviews. Participants' beliefs towards their CF and its life impact were investigated to explore reasons for engaging in HRB. A desire for normalcy was evident, often accompanied by engagement in everyday HRB as a method of minimising the illness identity. Evidence of a life-orientated illness perspective was also prevalent, with participants engaging in some risky behaviours for fun. Overall, there was a lack of knowledge on the consequences of HRB, with many participants reporting not being informed of these by clinicians. This research highlights a dilemma between clinical recommendations and personal life strategies undertaken by individuals with CF to support their identity.

The Impact of Secondhand Smoke Exposure on Children with Cystic Fibrosis: A Review

Secondhand smoke exposure (SHSe) has multiple adverse effects on lung function and growth, nutrition, and immune function in children; it is increasingly being recognized as an important modifier of disease severity for children with chronic diseases such as cystic fibrosis (CF). This review examines what is known regarding the prevalence of SHSe in CF, with the majority of reviewed studies utilizing parental-reporting of SHSe without an objective biomarker of exposure. A wide range of SHSe is reported in children with CF, but under-reporting is common in studies involving both reported and measured SHSe. Additionally, the impact of SHSe on respiratory and nutritional health is discussed, with potential decreases in long-term lung function, linear growth, and weight gain noted in CF children with SHSe. Immunologic function in children with CF and SHSe remains unknown. The impact of SHSe on cystic fibrosis transmembrane conductance regulator (CFTR) function is also examined, as reduced CFTR function may be a pathophysiologic consequence of SHSe in CF and could modulate therapeutic interventions. Finally, potential interventions for ongoing SHSe are delineated along with recommended future areas of study.

Cigarette smoking and mechanisms of susceptibility to infections of the respiratory tract and other organ systems

The predisposition of cigarette smokers for development of oral and respiratory infections caused by microbial pathogens is well recognised, with those infected with the human immunodeficiency virus (HIV) at particularly high risk. Smoking cigarettes has a suppressive effect on the protective functions of airway epithelium, alveolar macrophages, dendritic cells, natural killer (NK) cells and adaptive immune mechanisms, in the setting of chronic systemic activation of neutrophils. Cigarette smoke also has a direct effect on microbial pathogens to promote the likelihood of infective disease, specifically promotion of microbial virulence and antibiotic resistance. In addition to interactions between smoking and HIV infection, a number of specific infections/clinical syndromes have been associated epidemiologically with cigarette smoking, including those of the upper and lower respiratory tract, gastrointestinal tract, central nervous and other organ systems. Smoking cessation benefits patients in many ways, including reduction of the risk of infectious disease.

Personal attitudes, perceived social norms, and health-risk behavior among female adolescents with chronic medical conditions

To examine whether perceived peer/parent norms or personal beliefs about adolescent substance use influence substance use among female adolescents with chronic medical conditions. Sixty-eight females reported on substance use, personal beliefs, and perceived peer/parent norms. Personal beliefs and perceived peer/parent norms were associated with adolescent's current and future substance use. Although perceived peer norms accounted for variance in current substance use, only personal beliefs accounted for variance in future alcohol use. Targeting perceived peer norms may be effective for intervention efforts among adolescents endorsing current substance use, whereas alcohol use prevention efforts should target personal beliefs.

Smoking prevention and cessation programme in cystic fibrosis: integrating an environmental health approach

BACKGROUND

There have been several studies assessing the epidemiology and effects of tobacco smoke in the cystic fibrosis (CF) population, but few address the efforts of smoking cessation interventions. Our objective is to present one tobacco prevention and cessation programme targeting patients with CF in the Mediterranean region of Murcia (Spain).

METHODS

All registered patients in the Regional CF unit (n=105) in 2008 were included in a cross-sectional and prospective uncontrolled study of tobacco use and exposure in CF patients using a baseline and 1-year follow-up. Target population includes both patients and other family members living at home. The study included an initial telephone questionnaire, measurement of lung function, urinary cotinine levels, and several telephone counselling calls and/or personalised smoking cessation services.

RESULTS

Of the 97 contacted patients, 59.8% (n=58) were exposed to environmental tobacco smoke (ETS), 12.4% (n=12) had smoked at one time, and 14.3% (n=8) of patients over the age of 15 actively smoked. The mean age was 31.13 (range: 19-45). Of the non-smokers (n=89), 56.2% reported ETS and 26.9% live with at least one smoker at home. 49.2% had urinary cotinine levels >10 ng/ml. The correlation found between patients' cotinine levels and their reported tobacco exposure was (0.77, p<0.0001). Active smoking by mothers during pregnancy was associated with significantly lower lung function in young CF patients (-0.385, p=0.04). At the 1-year follow-up, 13 individuals made attempts to stop smoking, 6 of which are now ex-smokers (12.5% of all smokers).

CONCLUSIONS

Smoking during pregnancy adversely affects lung function in individuals with CF. Tobacco prevention and cessation programmes are an effective and vital component for CF disease management. The trained professionals in prevention and smoking cessation services could provide patients with adequate follow-up, integrating an environmental health approach into CF patients' healthcare.

Pneumothorax in cystic fibrosis

PURPOSE OF REVIEW

Cystic fibrosis (CF) is a complex genetic disease affecting many organs, although 85% of the mortality is a result of lung disease. The natural history of the lung disease consists of early and persistent infection, an exaggerated inflammatory response, structural airway changes (i.e. bronchiectasis), and progressive airways obstruction, ultimately resulting in respiratory failure. As airways disease worsens, there is an increased likelihood of respiratory complications, such as pneumothorax, that may be serious. This review describes our current understanding of the pathogenesis of pneumothorax in CF and its treatment.

RECENT FINDINGS

The CF Foundation Pulmonary Therapies Committee recently published their recommendations for the treatment of hemoptysis and pneumothorax. As insufficient data exist from which a systematic review of the literature could be used to develop guidelines, the recommendations were derived from a formalized expert panel consensus process.

SUMMARY

We now have recommendations on specific care of the patient with CF who has a pneumothorax.

Radiation-induced cancer risk from annual computed tomography for patients with cystic fibrosis

RATIONALE

Computed tomography (CT) is being considered as a tool for routine monitoring of lung damage in people with cystic fibrosis. Concern has been raised, however, about the associated risk of radiation-induced cancer.

OBJECTIVES

To estimate the risk of radiation-induced cancer from lung CT for patients with cystic fibrosis, assuming annual monitoring starting at age 2 years.

METHODS

Radiation risk models (derived primarily from the study of Japanese atomic bomb survivors) were used to estimate the excess risk of radiation-induced cancer for the organs that receive measurable doses from lung CT. Two scenarios were considered: median survival to age 36 years (approximate current median survival) and median survival to age 50 years (projected median survival by 2030).

MEASUREMENTS AND MAIN RESULTS

The estimated risk of radiation-induced cancer from annual lung CT was 0.02% for males and 0.07% for females assuming median survival to age 36 years. The estimated risks increased to 0.08% for males and 0.46% for females assuming median survival increases to age 50 years. The risks are higher for females because of the risk of radiation-induced breast cancer (50% of total risk) and higher risk of thyroid cancer.

CONCLUSIONS

The cumulative risk of radiation-induced cancer from repeated lung CT scans for patients with cystic fibrosis is relatively small (less than 0.5%). However, routine monitoring should not be recommended until there is a demonstrated benefit that will outweigh these risks.

Smoking rates and the state of smoking interventions for children and adolescents with chronic illness

Engaging in smoking is particularly risky for children and adolescents with chronic illness whose health status is already compromised because of disease- and treatment-related complications. Yet, some of these youngsters smoke at rates at least comparable to those of their healthy peers. To date, few randomized smoking-prevention and cessation trials have been conducted in children with chronic medical problems. In this review we report on the smoking rates among youngsters with chronic illness, identify specific disease- and treatment-related complications that can be exacerbated by smoking, examine risk factors associated with tobacco use among medically compromised youngsters, and review smoking interventions that have been conducted to date with pediatric populations in the health care setting. The following chronic illnesses are included in this review: asthma, cystic fibrosis, cancer, sickle cell disease, juvenile-onset diabetes, and juvenile rheumatoid arthritis. Objectives for a tobacco-control agenda and recommendations for future tobacco studies in chronically ill pediatric populations are provided. Finally, tobacco counseling strategies are suggested for clinicians who treat these youngsters in their practices.

Pneumothorax in cystic fibrosis

BACKGROUND

Spontaneous pneumothorax is a complication that is commonly reported in patients with cystic fibrosis (CF). An understanding of the pathophysiology of this complication and its consequences is important for the management of patients with CF.

OBJECTIVE

To identify risk factors associated with pneumothorax and to determine the prognosis of CF patients following an episode of pneumothorax.

DESIGN

A retrospective observational cohort study of the National Cystic Fibrosis Patient Registry between the years 1990 and 1999.

PATIENTS

The registry contained data on 28,858 patients with CF who had been followed up over those 10 years at CF centers across the United States.

RESULTS

Pneumothorax occurred with an average annual incidence of 0.64% and in 3.4% of patients overall. There was no increased occurrence by sex, but CF was more prevalent in older patients (mean [+/- SD] age, 21.9 +/- 9.1 years) with more severe pulmonary impairment (nearly 75% of patients with FEV1 of < 40% predicted). The principal risks associated with an increased occurrence of pneumothorax included the presence of Pseudomonas aeruginosa (odds ratio [OR], 2.3), Burkholderia cepacia (OR, 1.8), or Aspergillus (OR, 1.3) in sputum cultures, FEV1 < 30% predicted (OR, 1.5), enteral feeding (OR, 1.7), Medicaid insurance (OR, 1.1), pancreatic insufficiency (OR, 1.4), allergic bronchopulmonary aspergillosis (OR, 1.5), and massive hemoptysis (OR, 1.4). There is an increased morbidity (eg, increased number of hospitalizations and number of days spent in the hospital) and an increased 2-year mortality rate following pneumothorax.

CONCLUSION

Pneumothorax is a serious complication in CF patients, occurring more commonly in older patients with more advanced lung disease. Nearly 1 in 167 patients will experience this complication each year. There is an attributable mortality to the complication and considerable morbidity, resulting in increased health-care utilization and a measurable decline in lung function.