Inclusion Criteria:

- 18 years of age or older who self-report smoking at least 5 cigarettes (menthol and
non-menthol) per day, on average, for the last 6 months.

- Diagnosed with cancer (all sites) within the past 5 years.

- Karnofsky Score of greater than or equal to 50 or ECOG Performance Status score of
less than or equal to 2 within 6 months of enrollment.

- Able to use varenicline safely, based on a medical evaluation including medical
history and physical examination, and psychiatric evaluation.

- Residing in the geographic area for at least 12 months.

- Women of childbearing potential (based on medical history and physical exam) must
consent to use a medically accepted method of birth control (e.g., condoms and
spermicide, oral contraceptive, Depo-Provera injection, contraceptive patch, tubal
ligation) or abstain from sexual intercourse during the time they are taking study
medication and for at least one month after the medication period ends.

- Able to communicate fluently in English.

- Capable of giving written informed consent, which includes compliance with the
requirements and restrictions listed in the combined consent/HIPAA form.

Exclusion Criteria:

Smoking Behavior

- Current enrollment or plans to enroll in another smoking cessation program in the
next 12 months.

- Regular (daily) use of chewing tobacco, snuff, snus, cigars, cigarillos, or pipes.

- Current use or plans to use nicotine substitutes (gum, patch, lozenge, e-cigarette)
or smoking cessation treatments in the next 12 months.

1. Note: Once participants are found eligible for the study, they are told they
should refrain from using any nicotine replacement therapy (NRT) for the
duration of the study. If a subject reports an isolated (non-daily) instance of
NRT use during the study, they may be permitted to continue.

Alcohol/Drug Exclusion Criteria

- Current diagnosis of substance abuse or dependence.

- Positive urine drug screen (for cocaine, opioids, or methamphetamines) at the Intake
Session (unless taking opiate for pain management).

- Breath Alcohol Concentration (BrAC) assessment greater than or equal to 0.01 at the
Intake Session.

- Current alcohol consumption that exceeds 25 standard alcoholic drinks/week.

Medication Exclusion Criteria

Current use or recent discontinuation (within last 14 days) of the following medications:

- Other smoking cessation medications (e.g. Zyban, Wellbutrin, Wellbutrin SR, Chantix)

a. Note: Once participants are found eligible for the study, they are instructed to
only use the smoking cessation medication provided to them by the study staff. If a
subject reports an isolated (non-daily) instance of using a non-study smoking
cessation medication, the study physician and PI will evaluate the situation and
determine if it is safe for the subject to continue participation.

- Anti-psychotic medications.

- Bipolar Disorder medications.

Medical Exclusion Criteria

- Women who are pregnant, planning a pregnancy within the next 12 months, or lactating.

- History of epilepsy or seizure disorder.

- History of kidney or liver disease, including transplant.

- Uncontrolled hypertension (SBP >160 or DBP >100).

a.Note: If a participant presents with blood pressure greater than 160/100 at
sessions occurring on Week 0 (Pre-Quit) or at any other point during the treatment
period, they will not be provided with/able to continue on medication unless the
study physician grants approval.

- History of heart disease, stroke or MI, unstable angina, abnormal heart rhythms, or
tachycardia (if stable, requires Study Physician approval).

- Abnormal ECG (unless approved by Study Physician).

- Any suicide risk score on MINI, current suicidal ideation on Columbia scale, or
self-reported suicide attempt.

- Current or past diagnosis of psychotic or bipolar disorder, as determined by
self-report & MINI.

- Current diagnosis of unstable and untreated major depression, as determined by
self-report & MINI (eligible if stable for >30 days).

- Previous allergic reaction to varenicline.

General Exclusion Criteria

- Any medical condition or concomitant medication that could compromise subject safety
or treatment, as determined by the Principal Investigator and/or Study Physician.

- Inability to provide informed consent or complete any of the study tasks as
determined by the Principal Investigator and/or Study Physician.