ESTxENDS Trial: MN Substudy - Micronuclei in Buccal Epithelium, a Surrogate Measure of Future Cancer Risk, Induced by Electronic Nicotine Delivery Systems (ENDS/Vaporizer/E-cig)

--\> This is a substudy of the main ESTxENDS trial (NCT03589989). Micronuclei in buccal epithelial outcomes should be considered secondary outcomes of the main smoking cessation outcome formulated in NCT03589989.

Cigarette smoking is the leading cause of preventable death in Switzerland and still more than a quarter of the Swiss population smokes cigarettes. Recently, electronic nicotine delivery systems (ENDS; also called vaporizer, e-cigarette or electronic cigarette) have become popular with smokers who want to stop smoking or reduce their exposure to inhaled chemicals since ENDS use appears to be safer than tobacco smoking.

The micronucleus cytologic assay test was originally developed to screen for drug toxicity in bone marrow samples from mammals. The technique identifies micronuclei on smears obtained by oral cavity exfoliation and indicate genomic instability. Buccal MNs may predict cancer risk for the upper aerodigestive tract. The HUman MicroNucleus project on eXfoLiated buccal cells (HUMNXL) found MN counts gradually increased during the progression from normal mucosal to precancerous lesions to carcinoma. MN assessment discriminates between exposure to tobacco smoke in smokers and in non-smokers, and has been tested on a small number of ENDS users.

For the main ESTxENDS trial (NCT03589989), cigarette smokers motivated to quit smoking cigarettes will be included. Participants in the intervention group will receive an ENDS and nicotine-containing e-liquids, which they will be allowed to use ad libitum. Additionally, they will receive smoking cessation counseling. Participants in the control group will receive smoking cessation counseling only. All participants will be followed over a 24-month period. Measures of MN frequency will test the potential effect of ENDS use on cancer-related outcomes, in particular incident of mouth-, lung- and kidney- cancers.


Eligibility Criteria:
Inclusion Criteria:

* Informed Consent as documented by signature
* Persons aged 18 or older
* Currently smoking 5 or more cigarettes a day for at least 12 months
* Willing to try to quit smoking within the next 3 months,
* Persons providing a valid phone number, a valid email address and/or a valid postal address.

Exclusion Criteria:

Known hypersensitivity or allergy to contents of the e-liquid Participation in another study with investigational drug within the 30 days preceding the baseline visit and during the present study where interactions are to be expected

* Women who are pregnant or breast feeding
* Intention to become pregnant during the course of the scheduled study intervention, i.e. within the first 6-months of the study
* Persons having used ENDS regularly in the 3 months preceding the baseline visit
* Persons having used nicotine replacement therapy (NRT) or other medications with demonstrated efficacy as an aid for smoking cessation such as varenicline or bupropion within the 3 months preceding the baseline visit
* Persons who cannot attend the 6- month follow-up visit for any reason
* Cannot understand instructions delivered in person or by phone, or otherwise unable to participate in study procedures