INTRODUCTION — The number of living cancer survivors is expected to rise within the United States . Compared with population growth, these increases have been attributed mostly to improved diagnostic modalities resulting in early detection of cancer and to the development of more effective and less toxic treatments. This increase in survival rates highlights the importance of caring for cancer survivors.
While smoking rates have continuously decreased over several decades, the overall smoking prevalence in the United States had remained nearly constant for several years, with some decline in the past few years to approximately 14 percent [2,3]. Despite these trends, approximately 50 million and 41 million Americans still use any forms of tobacco or smoke cigarettes, respectively, despite widespread knowledge that smoking and tobacco use causes cancer as well as cardiovascular disease, pulmonary disease, and several other deadly diseases . Cancer patients and survivors who have comorbid psychiatric disorders are also more likely to be addicted to nicotine and face more difficulty quitting similarly to patients without cancer [5,6]; therefore, innovative methods are needed to effectively reduce the impact of such disorders .
The carcinogenic effects of both alcohol and tobacco have been scientifically established. However, although many alcohol users are informed about organ damage caused by alcohol and the dangers and the legal and social consequences of being intoxicated, far fewer recognize the significant cancer risk of heavy alcohol use . In one review, public awareness of the link between alcohol and cancer was known to approximately 25 and 40 percent of the population .
This review discusses the impact on quitting alcohol and smoking in cancer survivors who have completed cancer-directed treatment. Further discussion on alcohol and tobacco in the general population is covered separately. (See "Cigarette smoking and other possible risk factors for lung cancer" and "Benefits and consequences of smoking cessation" and "Overview of cancer prevention", section on 'Tobacco use' and "Overview of the risks and benefits of alcohol consumption".)
Tobacco use — Data suggest that smoking and tobacco use continues to be an issue for cancer survivors, especially among adolescent and young adult (AYA) cancer survivors. The prevalence of smoking and tobacco use differs by patient age, time from diagnosis, type of cancer, cancer prognosis, and treatment received .
Data on the prevalence of tobacco use among cancer survivors come from the annual population-based National Health Interview Survey (NIHS). While prevalence has declined, approximately 13 percent of cancer survivors aged 18 and older were current cigarette smokers in 2019; in addition, the prevalence of tobacco use appears to be higher among AYA cancer survivors . The following is a subset of findings that have been reported based on data from NIHS:
●In an analysis from 2005, almost 20 percent of adult cancer survivors reported being current smokers, with 43 percent of cancer survivors younger than 40 years reporting current smoking .
●In a subsequent analysis (2012 to 2014 NIHS), 33 percent of AYA cancer survivors were smokers compared with 22 percent of adult cancer survivors .
●Smoking among cancer survivors who are 18 years of age or older declined almost by half over 25 years (from 20 percent for cohort 1998 to 2001 to approximately 14 percent in cohort 2013 to 2017) .
●Compared with individuals without a cancer history overall, a lower percentage of those with a cancer history were never-smokers (48 versus 62 percent) or current smokers (14 versus 17 percent).
●The prevalence of current smoking was higher among survivors of smoking-related cancers (around 20 percent) compared with nonsmoking-related cancer survivors (around 10 percent). After cancer diagnosis, smoking-related cancer survivors had higher odds of continued smoking compared with nonsmoking-related cancer survivors (odds ratio [OR], 2.1; 95% CI, 1.12-3.93) .
Although the prevalence of smoking is high among patients with smoking-related cancers at diagnosis, cancer treatment and prognosis may have an influence on lowering the rate of smoking among patients who survive such cancers [16-19]. For example, smoking prevalence is 40 to 60 percent at time of diagnosis among patients with lung or head and neck tumors [16,18,20,21], and approximately 40 percent among patients with any smoking-related cancer (other than lung cancer) . Patients with a cancer site that is clearly attributable to smoking and a favorable prognosis may be more motivated to quit than those with a poor prognosis ; however, the benefits of abstinence from smoking are present regardless of prognosis or stage . In addition, the nature of the cancer treatment required affects the ability to smoke; for example, cancer patients who are hospitalized or undergo surgery will be forced to quit smoking, at least for a short time.
Alcohol consumption — Heavy alcohol use raises the risk of developing cancer in several different sites, including the head and neck, esophagus, colon and rectum, liver, and breast (in females). (See "Overview of the risks and benefits of alcohol consumption", section on 'Cancer'.)
Multiple studies show that despite a cancer diagnosis, many cancer survivors continue to consume alcohol. As examples:
●Of over 10,000 respondents who were a part of the British Childhood Cancer Survivor study, the proportion who :
•Admitted to drinking alcohol – 77 percent
•Drank above weekly recommendations – 24 percent
•Consumed potentially harmful amounts – 4 percent
●Another study compared the frequency of alcohol use among almost 1050 young adult cancer survivors with figures from a representative general population survey . Compared with controls, survivors were almost:
•Two times more likely to consume alcohol frequently (odds ratio [OR] 1.7, 95% CI 1.3-2.1)
•Three times more likely to binge drink (OR 2.9, 95% CI 2.3-3.8)
In addition, studies show that advanced cancer patients have a high prevalence of alcohol use. For example, one study concluded that the prevalence of current alcohol use in cancer patients was 18 percent . A separate study that included over 280 patients with head and neck cancer reported that 45 percent of these patients continued to consume alcohol 12 months after diagnosis, with over 20 percent of those who continued to drink classified as problem drinkers .
Impact of smoking on outcomes after cancer diagnosis — Although most data come from retrospective studies, smoking appears to have a deleterious impact on cancer treatment . The 2014 Surgeon General's report concluded that a causal relationship exists between smoking at diagnosis and both all-cause and cancer-specific mortality, as well as increased risk of disease progression and tobacco-related second primary cancers. The evidence reviewed strongly suggests that continued smoking increases the risk of cancer recurrence, poor treatment response, and treatment-related toxicities [29,30]. On the other hand, quitting smoking even at the time of diagnosis reduces the risk of dying by approximately 30 to 40 percent [30,31], improves physiological and psychological functioning [32-34], and has benefits that may equal and may even exceed those of the best cancer treatments available .
Several studies have demonstrated the harmful effect of continued smoking on cancer treatment in cancers of the head and neck [36-43], oropharynx , lung [45,46], prostate [47,48], and breast . As an example, one study reported that cancer patients who were smokers had a significantly higher symptom burden than nonsmokers, both during and six months following treatment . As another example, relapse rates in lung or head and neck cancer patients 12 months after surgery were markedly higher in patients who were still smoking the week before surgery (60 percent) versus those who were abstinent during the week before surgery (13 percent) . Finally, in another study, patients with prostate cancer (which is not a known smoking-related cancer) who continued to smoke during treatment were at an increased risk for toxicity, recurrence, metastasis, and mortality compared with nonsmokers .
The effect of continuing to smoke for cancer survivors is similarly harmful:
●In one review that included 10 studies, people who continued to smoke after a diagnosis of early-stage lung cancer almost doubled their risk of dying .
●In another study that included 611 patients with small cell lung cancer, the risk of all second cancers (mostly non-small cell cancers of the lung) was increased by 3.5 times in smokers (relative risk [RR] 3.5, 95% CI 2.8-4.3) . Compared with never-smokers, the risk of a second lung cancer among patients who received chest radiation was significantly increased (RR 13, 95% CI 9.4-17).
In addition, several studies show that cancer survivors who were former smokers/recent quitters or current smokers scored lower on quality of life indices and had worse health and social functioning than survivors who had never smoked [45,54-56].
Smoking prior to a diagnosis of cancer is also associated with an increased risk of subsequent (second) cancer risk among cancer survivors. An analysis of five cohort studies of cancer (stage I lung, bladder, kidney, and head and neck) survivors who were current smokers prior to the diagnosis of their first cancer diagnosis found a 3 to 8 percent increase in five-year cumulative risks of subsequent smoking-associated cancers, compared with never-smokers . (See "Overview of cancer survivorship care for primary care and oncology providers", section on 'Risk of subsequent primary cancer'.)
Impact of alcohol on outcomes after cancer diagnosis — Data also suggest that alcohol intake (especially moderate to heavy use) increases cancer-related mortality. This was shown in a 2013 meta-analysis that concluded all-cancer mortality was highest in participants who regularly consumed 50 or more grams of alcohol . Curiously, this report also had the following observations:
●There is a J-shaped curve for all-cancer mortality; patients who drank <12.5 grams of alcohol per day had the lowest mortality.
●The mortality associated with alcohol was predominantly in males. Males who consumed up to 12.8 grams of ethanol daily had the lowest mortality rate. However, those who drank ≥28.7 grams per day had a statistically significant increase in their cancer mortality rate.
●For females, consumption of up to 9.1 grams of alcohol daily was associated with the lowest cancer mortality. The increased risk of breast cancer and risk of mortality became significant at 17.4 grams per day and reached a peak at 43.6 grams daily. Interestingly, in the female study population, 75.9 grams or more of daily ethanol intake was associated with less all-cancer mortality, most likely owing to the fact that if a female were to consume such large amounts, her chances of non-cancer mortality were increased significantly when compared with those who did not consume or consumed lower amounts of alcohol.
A subsequent study showed that overall mortality from cancer and other diseases was five times higher in Italian patients who are alcohol-dependent than in Italian patients who did not drink alcohol . This study concluded that being female was a protective factor, as females outlived males at the 5, 10, 15, and 20-year follow-up analyses.
EVALUATION — It is imperative for clinicians working with cancer survivors to systematically screen those survivors for smoking and alcohol use [60,61]. Cancer survivors should be screened for use and dependence (ie, use disorder) using a similar approach to those without a history of cancer, in the absence of a specific diagnostic evaluation tailored for cancer survivors. (See "Clinical assessment of substance use disorders" and "Risky drinking and alcohol use disorder: Epidemiology, pathogenesis, clinical manifestations, course, assessment, and diagnosis", section on 'Screening'.)
Lung cancer screening — The United States Preventive Services Task Force (USPSTF) and other expert groups recommend screening for lung cancer using annual low-dose computed tomography (LDCT) in adults at high risk for lung cancer. The indications for lung cancer screening in cancer survivors is the same as that used for the general population, which are discussed separately. (See "Screening for lung cancer", section on 'Recommendations by expert groups'.)
Cancer survivors with a smoking history may be candidates for lung cancer screening with LDCT of the chest, which is associated with decreased lung cancer mortality and all-cause mortality in the general population . Further studies on lung cancer screening specifically in cancer survivors are needed to understand the unique characteristics of this population, as well as the context within which treatment should be provided .
Screening and co-occurring conditions — To treat a substance use disorder, clinicians must be aware of its presence and be able to make the diagnosis and then offer advice to quit or refer to treatment . While there are no specific demographics, smoking and tobacco use among cancer survivors would be expected to be more frequent in certain populations than in others, as in the general population, including those with [65,66]:
●Low educational attainment – Up to 35 percent of those with less than a high school degree and 45 percent of those with only a GED are smokers. Binge drinking is higher among college graduates, up to 14 percent, in the past 30 days.
●Low socioeconomic status – Around 40 percent of those under the federal poverty level are tobacco users, and around 30 percent report smoking in the past 30 days.
●Psychiatric disorders – Several studies have reported a correlation between smoking and/or excessive alcohol use with psychiatric disorders within the general population [67-77]. As an example, in one observational study of cancer patients, while higher levels of pre-quitting anxiety and fear of recurrence predicted smoking cessation, higher levels of depressive symptoms significantly predicted relapse . In another observational study of cancer survivors, quitting smoking was associated with a decreased fear of disease recurrence . In contrast, among cancer survivors who continue to smoke, fear of recurrence was associated with impaired function and mood. This may explain the propensity of cancer survivors to develop an addiction to substances and having more difficulty quitting . Additionally, the impact of psychiatric comorbidities would be expected to be similarly important among cancer survivors.
TREATMENT APPROACHES — There are limited data on interventions specific to cancer survivors, particularly for issues related to stopping or decreasing smoking and alcohol use. In general, the treatment approaches are similar to those of the general population.
Treatment of smoking — The approach to helping cancer survivors quit smoking is similar to that of the general population. The Centers for Disease Control and Prevention (CDC) has a dedicated page and resources on the topic for health care professionals . The National Comprehensive Cancer Network (NCCN) has dedicated guidelines for smoking cessation in the oncology setting . An overview of the treatment (including pharmacotherapy) for smoking in adults is discussed in detail separately. (See "Overview of smoking cessation management in adults" and "Pharmacotherapy for smoking cessation in adults".)
While little is known about the naturalistic factors that may interfere with cancer patients' and cancer survivors' efforts and ability to quit smoking , evidence suggests that they stand to benefit immensely from comprehensive treatment efforts that lead to tobacco abstinence that are also used in patients without cancer. Such efforts include individualized counseling, pharmacotherapy [84,85], and treatment of psychiatric disorders and other psychosocial stressors.
Only a few well-designed prospective studies on the treatment of smoking have focused on cancer patients and survivors, with approximately half concentrating on nurse-delivered interventions . As examples:
●One meta-analysis reported that providing a smoking treatment intervention to cancer patients in general did not improve overall abstinence rates, although it was clear that heavy smokers and those in the perioperative period did benefit from this type of intervention . This mixed finding may be due to lack of homogeneity among the pooled studies, as the studies had different treatment intensities, had different measures for smoking and abstinence, and included different cancer sites and cancer patient populations (outpatients only or inpatients only).
●Another report described smoking outcomes from over 3000 smokers (including cancer patients, cancer survivors, and smokers with no cancer history) enrolled in a comprehensive tobacco cessation clinical program . The program included individualized cessation counseling, provision of personalized pharmacotherapy, and integrated assessment and treatment of mental health conditions and other psychosocial stressors . This study reported average abstinence rates of 45, 46, and 44 percent, at the three-, six-, and nine-month follow-ups, respectively. Importantly, these rates did not significantly differ between cancer and non-cancer patients, and only head and neck cancer patients achieved statistically higher abstinence rates.
Treatment for alcohol use — The treatment for alcohol use requires both psychosocial support and pharmacological interventions. (See "Alcohol use disorder: Psychosocial treatment" and "Brief intervention for unhealthy alcohol and other drug use: Efficacy, adverse effects, and administration".)
Although stopping smoking and total abstinence is recommended unequivocally, whether there is a "safe" amount of alcohol one can consume is controversial. In the United States, the CDC and the United States Department of Health and Health Services (HHS) suggest that a limit of two drinks per day (13.7 grams per drink) for males and one drink per day for females is "sensible" or "low-risk" drinking .
However, this recommendation is based on studies that evaluate the short-term effects of alcohol use (eg, social or psychological problems or hospital admissions) and may not account for all the risks and consequences of chronic, long-term exposure. Therefore, many critics have pointed to the limitations of such "sensible drinking" guidelines. It should also be noted that these guidelines do not apply to all subsets of a population. For example, pregnant patients, children, older adults, or those who operate machinery cannot use the "sensible drinking" guidelines to determine whether their level of alcohol consumption is safe.
Cancer survivors ought to be thought of as "a population at risk"; unfortunately, the public perception about the link between alcohol and cancer is low . The American Institute for Cancer Research recommends "not drinking alcohol" for cancer prevention. The American Society of Clinical Oncology (ASCO) published a statement on the importance and the need for cancer treatment providers to educate their patients about the link between alcohol and cancer . While education about the risk is not equivalent to providing treatment, it is a necessary first step. Education can then be followed by screening and referral for those who need treatment.
Treating comorbid psychiatric disorders — For some patients, treatment of comorbid psychiatric disorders may aid in their ability to quit smoking and reduce alcohol intake. Treating such conditions may increase resilience, improve the patient's ability to face cancer, and strengthen their ability to maintain abstinence after quitting tobacco  or further limiting (or stopping) alcohol intake. As reported in one study, patients with low depression scores and patients with early tumor stages were more confident about their ability to quit smoking than were those with higher depression scores and those with more advanced tumor stages . (See "Overview of smoking cessation management in adults", section on 'Psychiatric illness'.)
IMPACT OF REDUCING ALCOHOL USE AND QUITTING SMOKING
Cancer-specific benefits — There are very limited data on the cancer-specific outcomes associated with tobacco abstinence or the reduction or discontinuation of alcohol intake in patients who have been diagnosed with cancer. However, cancer survivors would be expected to benefit from these interventions in ways similar to the general population (ie, those without a history of cancer), including a lower risk of a subsequent (ie, second) primary cancer. In particular, such interventions may lead to a lower risk of a smoking-related malignancy, such as cancers of the oral cavity, oropharynx, nasopharynx, hypopharynx, esophagus, nasal cavity, paranasal sinuses, larynx, lung, uterine cervix, ovary (mucinous histology), urinary bladder, kidney, ureter, and myeloid leukemia . (See "Overview of cancer survivorship care for primary care and oncology providers", section on 'Risk of subsequent primary cancer'.)
General health benefits — Although data are limited for the general benefits of quitting smoking and alcohol use among cancer survivors, it is likely that the adoption of healthy lifestyles, including quitting smoking and "low-risk" and moderate or no alcohol consumption , may result in health benefits similar to those seen in the general population who also adopt these strategies. (See "Approach to treating alcohol use disorder" and "Overview of smoking cessation management in adults".)
●Quitting smoking – Despite limited prospective data, studies suggest that cancer survivors who quit smoking following treatment for their malignancy are likely to benefit as much as (if not more than) those who quit smoking and do not have a history of cancer.
Quitting smoking at the very least appears to have a positive impact on quality of life among cancer survivors. This was shown in a systematic review of medical databases for articles published since the 1980s . Quitting smoking after a diagnosis of cancer was also associated with a better performance status compared with continued smokers.
Some studies also suggest that quitting smoking may impact overall survival in cancer survivors. One analysis aimed to estimate the effects of quitting smoking after a cancer diagnosis using data from the Surveillance, Epidemiology, and End Results (SEER) program in the United States and cancer registry data from New South Wales, Australia . In this study, individuals who continued to smoke eight years after a cancer diagnosis were estimated to have a lower survival compared with nonsmokers, which was seen both in patients from the United States (43 versus 54 percent, respectively) and from Australia (37 versus 49 percent). (See "Benefits and consequences of smoking cessation" and "Benefits and consequences of smoking cessation", section on 'Benefits of smoking cessation'.)
●Reducing or discontinuing alcohol consumption – The data evaluating the impact of interventions to reduce or discontinue alcohol consumption in cancer survivors are even more limited, and no prospective studies have been done to inform the benefits of such an intervention. However, limiting alcohol consumption has other health benefits, which are important for patients after treatment for cancer, as in the general population. These benefits are reviewed separately. (See "Overview of the risks and benefits of alcohol consumption" and "Brief intervention for unhealthy alcohol and other drug use: Efficacy, adverse effects, and administration", section on 'Efficacy'.)
●Smoking and alcohol use among cancer survivors – Although the overall prevalence of current smoking among cancer survivors has declined, smoking and tobacco use continues to be an issue for cancer survivors, especially among adolescent and young adult (AYA) cancer survivors. (See 'Tobacco use' above.)
Despite a cancer diagnosis, many cancer survivors also continue to consume alcohol. (See 'Alcohol consumption' above.)
●Impact of alcohol and smoking on outcomes after cancer diagnosis – Observational studies suggest that smoking appears to have a deleterious impact on cancer treatment and that alcohol intake (especially moderate to heavy use) increases cancer-related mortality. (See 'Impact of smoking on outcomes after cancer diagnosis' above and 'Impact of alcohol on outcomes after cancer diagnosis' above.)
●Evaluation – It is imperative for clinicians working with cancer survivors to screen them for smoking and alcohol use and refer those who are in need for appropriate treatment. The approach to screening should be similar to that used for patients without a history of cancer, in the absence of a specific diagnostic evaluation tailored to cancer survivors. (See 'Evaluation' above.)
●Lung cancer screening – Cancer survivors with a smoking history may be candidates for lung cancer screening with low-dose computed tomography (LDCT) of the chest. (See 'Lung cancer screening' above.)
●Treatment approaches – There are limited data on interventions specific for cancer survivors, particularly for stopping or decreasing smoking and alcohol use. (See 'Treatment approaches' above.)
•Treatment of smoking – The provision of comprehensive tobacco treatment including counseling, medications, and treatment for psychiatric symptoms could result in approximately one-half of patients quitting tobacco, regardless of cancer site or a non-cancer diagnosis. (See 'Treatment of smoking' above.)
•Treatment of alcohol use – The treatment for alcohol use requires psychosocial support and pharmacological interventions. (See 'Treatment for alcohol use' above.)
•Treatment of psychiatric conditions – Treatment of comorbid psychiatric disorders may aid in the ability to quit smoking and reduce alcohol intake. Treating such conditions may increase resilience, improve the patient's ability to face cancer, and strengthen their ability to maintain abstinence after quitting tobacco  or further limiting (or stopping) alcohol intake. (See 'Treating comorbid psychiatric disorders' above.)
●Impact of reducing or discontinuing alcohol use and quitting smoking – There are very limited data on the cancer-specific outcomes associated with smoking cessation or the reduction or discontinuation of alcohol intake in patients who have been diagnosed with cancer. However, cancer survivors would be expected to benefit from these interventions in ways similar to the general population (ie, those without a history of cancer), including a lower risk of a subsequent cancer. (See 'Impact of reducing alcohol use and quitting smoking' above.)
ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Ellen Gritz, PhD, who contributed to previous versions of this topic review.