Critically Appraised Topic: Genetic Testing and Smoking Cessation

Critically Appraised Topic:

Genetic Testing and Smoking Cessation

Kara Bodmer

University of Mary

Common Health Problems of the Maturing Adult

NUR 568

CRITICALLY APPRAISED TOPIC 3

Critically Appraised Topic: Genetic Testing and Smoking Cessation

Author: Kara Bodmer, DNP-s

Date: August 1, 2016

Clinical Scenario: M.M. is a forty-year old man who has a 20-pack year smoking history and presents today for an annual exam. During the health history interview, the provider finds out that M.M.’s mother died of breast cancer at 40, and his father died of prostate cancer at the age of 50. The patient recently underwent genetic testing and found out he has several gene mutations linked to cancer. While discussing health maintenance items, M.M. expresses concern regarding his smoking behavior related to his family history and states to the provider, “I really think I should quit smoking so I can be around for awhile.”

PICO Question: Among adult smokers, does awareness of a genetic risk factor for certain cancers lead to higher rates of smoking cessation, compared to those who do not undergo genetic testing?

Articles:

De Viron, S., Van der Heyden, J., Ambrosino, E., Arbyn, M., Brand, A., & Van Oyen, H. (2012). Impact of genetic notification on smoking cessation: system review and pooled analysis. PLOS One (7)7, e40230-e40230

Julian-Reynier, C., Resseguier, N., Bouhnik, A-D., Eisinger, F., Lasset, C., Fourme, E., & Nogues, C. (2015). Cigarrette smoking in women after BRCA1/2 genetic test disclosure: a 5-year follow-up study of the GENESPO PS cohort. Genetics in Medicine (17)2, 117-123. Doi: 10.1038/gim.2014.82

Summary and Appraisal of Key Evidence of Article One

De Viron et al (2012) completed a systematic review and pooled analysis. The goal of the review was to determine if the genetic-notification of smoking related diseases influenced smoking cessation rates. The authors also sought to determine if genetic notification was correlated with an intention to quit smoking. The only studies that were included for the meta-analysis required actual notification a genetic risk factor verses being made aware of a potential genetic risk factor. Ultimately, eight randomized trials were used for the meta-analysis. In order to accurately assess the outcome of smoking cessation, smoking cessation rates were collected at the follow-up intervals identified by the studies. Confirmation of smoking cessation was either by evaluating the amount of nicotine in salivary fluid or by verbal report. The genes of interest that were tested for the respective studies were linked to cancer risk and included CYP2D6, GSTMI, L-myc, and NQOI. The results of the studies were collectively analyzed using a pooled analysis. The data from the eight studies was compiled using a pooled analysis. Short-term follow-up was defined as two to six months after the studies were completed. Long-term cessation was characterized as the time interval between six to twelve months. The results of the meta-analysis did show some benefit between genetic notification and the short-term time frame. Participants, who were notified of genetic risk factors, had significantly higher rates of smoking cessation within the first six-months. De Viron et al (2012) also determined that patients, who received genetic notification, experienced increased feelings of anxiety and depression.

The level of evidence assigned to this study is level 1 and serves as a strength for the study. The results are valid; four of the studies used for the study were randomized-controlled trials, which help to minimize selection bias. However, the size of the study was relatively small with only eight studies meeting the qualifications. Another limitation includes how participants were evaluated for smoking cessation. The individuals could either undergo testing or use a self-reported measure. In addition, the researchers did not take into account individual variables such as demographics, income, and education level, which may have influenced a participant’s willingness to quit. The term smoking cessation was not clearly defined throughout the study and can be classified as an additional limitation.

Summary and Appraisal of Key Evidence of Article Two

Julian-Reyneier et al (2015) authored a retrospective study as part of an ongoing Gene Etude Prospective Seine Ovaire (GENESPO) project to determine if there was an association between women who underwent genetic testing for BRCA1/2 and smoking cessation. The genetic mutation of BRCA 1 and BRCA 2 has been linked to many cancers, including breast cancer and ovarian cancer. The goal of the research study is to “measure the smoking habits of cancer-free women who applied for genetic testing because a BRCA1/2 mutation had been identified within their family.” (Julian-Reynier et al., 2015, p. 117). The sample consisted of 621cancer-free women, who had the BRCA ½ mutation or had a family history of BRCA1/2. Prior to starting the study, the participants underwent genetic testing. In order to effectively measure genetic notification and smoking habits, the participants were followed for an interval of time before genetic disclosure. Following disclosure, the participants were then divided into two main groups: cancer-free BRCA ½ mutation carriers and high-risk non-carriers. The participants were surveyed for five years after genetic disclosure to analyze lifestyle factors including tobacco use. The data for the study was collected through questionnaires inquiring about tobacco use. The ZIP regression model was utilized to analyze the data over time and to determine patterns such as the number of cigarettes smoked prior to genetic disclosure compared to after disclosure. The study concluded no differences in the prevalence of smoking between mutation carriers and non-carriers after genetic disclosure. However, the amount of cigarettes consumed by the BRCA ½ mutation carriers decreased significantly (P= 0.04) after genetic disclosure (Julian-Reynier et al., 2012).

Article two is assigned a level II evidence rating. The results of the study are valid. One of the biggest strengths of the article is the sample size. A limitation to the study was how the data was extracted. Questionnaires provided only subjective information. Participants may not been have honest with their smoking status, which may have lead to falsification of the results. The study design may have lead to selection bias, thus a weakness of the study.

Clinical Bottom Line and Implications for Practice:

Although the meta-analysis was rated high in level of evidence, only eight studies were utilized for review. Therefore, it may be not be feasible to generate the information gained to a broader population of individuals. Further research should be conducted before incorporating the learned information into clinical practice. In order to eliminate bias, future studies that assess smoking cessation rates may need to use a more valid method to measure smoking cessation. Additionally, knowledge of a genetic predisposition for certain cancers can be very devastating. Providers must acknowledge the patient’s concerns and offer psychosocial support.

Individuals who are aware of genetic tendencies for certain cancers may be motivated to be make certain lifestyle changes, including smoking cessation. The available literature on the subject concludes that having the knowledge of a genetic risk for a cancer-related disease may lead to lower smoking cessation rates on a short-term basis. Therefore, providers may need to pursue more traditional avenues to assist the patient in achieving long term success with smoking cessation. For this matter and due to the sensitive nature on the subject, health care professionals should not rely completely on genetic testing awareness as a motivator to quit smoking.

References

Discussion Participation Questions

1. The research from this CAT Topic sought to determine if awareness of a genetic risk factor for cancer lead to higher rates of smoking cessation, but is there a genetic predisposition to smoking? What research is available regarding gene alteration to CYP2A6 and smoking?

2. What role does the neurotransmitter Dopamine have in nicotine addiction?

3. What are some tobacco cessation programs or treatment options that can be offered to patients who have undergone genetic testing for certain cancers or chronic diseases and are ready to quit smoking?

4. What educational materials and/or resources available to primary care providers who wish to gain a better understanding of genetic testing for clinical practice?

5. According to De Viron et al (2012), individuals who are aware of genetic risk factors for smoking-related diseases are more likely to experience feelings of anxiety and depression. As primary care providers, what services are available for support?

References