When peo­ple think about the health risks of al­co­hol, liv­er dis­ease and ad­dic­tion of­ten come to mind. Far few­er are aware that al­co­hol is a proven cause of can­cer. De­spite strong sci­en­tif­ic ev­i­dence, pub­lic aware­ness of this link re­mains sur­pris­ing­ly low, and al­co­hol con­tin­ues to be wide­ly per­ceived as a rel­a­tive­ly harm­less part of every­day life.

Al­co­hol is clas­si­fied as a Group 1 car­cino­gen by the In­ter­na­tion­al Agency for Re­search on Can­cer—the same cat­e­go­ry as to­bac­co and as­bestos. This means there is clear and con­vinc­ing ev­i­dence that it caus­es can­cer in hu­mans.

All al­co­holic drinks, in­clud­ing red and white wine, beer and liquor, are linked with can­cer. The more you drink, the high­er your can­cer risk. This, as well, is tak­en straight from the Cen­tres for Dis­ease Con­trol and Pre­ven­tion web­site, which al­so de­tails the types of can­cers that al­co­hol put you at an in­creased risk of—mouth, throat, oe­soph­a­gus, colon, rec­tum and breast.

Yet sur­veys con­sis­tent­ly show that many peo­ple are un­aware of these as­so­ci­a­tions, par­tic­u­lar­ly the link with breast and bow­el can­cer. One rea­son for this lack of aware­ness is how cul­tur­al­ly nor­malised al­co­hol is. Drink­ing is of­ten as­so­ci­at­ed with re­lax­ation, cel­e­bra­tion, and so­cial con­nec­tion.

Un­like smok­ing, which has be­come in­creas­ing­ly stig­ma­tised due to pub­lic health cam­paigns, al­co­hol is fre­quent­ly mar­ket­ed as part of a healthy or as­pi­ra­tional lifestyle. Mes­sages about mod­er­a­tion are com­mon, but clear in­for­ma­tion about can­cer risk is not.

The bi­o­log­i­cal mech­a­nisms link­ing al­co­hol to can­cer are well un­der­stood. When al­co­hol is bro­ken down in the body, it is con­vert­ed in­to ac­etalde­hyde, a tox­ic chem­i­cal that can dam­age DNA and in­ter­fere with the body’s abil­i­ty to re­pair that dam­age. Al­co­hol al­so in­creas­es in­flam­ma­tion, al­ters hor­mone lev­els—par­tic­u­lar­ly oe­stro­gen—and makes it eas­i­er for oth­er car­cino­gens, such as those in to­bac­co smoke, to en­ter cells. In breast tis­sue, even small in­creas­es in oe­stro­gen lev­els can raise can­cer risk, which helps ex­plain why breast can­cer risk ris­es with al­co­hol in­take.

Im­por­tant­ly, there is no com­plete­ly safe lev­el of al­co­hol con­sump­tion when it comes to can­cer risk. While the risk in­creas­es with high­er in­take, stud­ies show that even low lev­els of drink­ing are as­so­ci­at­ed with a mea­sur­able in­crease in cer­tain can­cers, es­pe­cial­ly breast can­cer. This does not mean that every­one who drinks will de­vel­op can­cer, but it does mean that al­co­hol con­tributes to risk in a dose-de­pen­dent way.

The gap be­tween sci­en­tif­ic ev­i­dence and pub­lic un­der­stand­ing has re­al con­se­quences. Many peo­ple who make healthy choic­es—such as ex­er­cis­ing reg­u­lar­ly, main­tain­ing a bal­anced di­et, and not smok­ing—may un­know­ing­ly in­crease their can­cer risk through reg­u­lar al­co­hol con­sump­tion. Women, in par­tic­u­lar, are of­ten un­aware that al­co­hol is one of the few mod­i­fi­able risk fac­tors for breast can­cer.

A ‘mod­i­fi­able risk fac­tor’ means that you can change or mod­i­fy your be­hav­iour in or­der to re­duce your risk. The same can al­so be said for smok­ing and obe­si­ty—both es­tab­lished and ma­jor risk fac­tors for can­cer as well.

Health­care pro­fes­sion­als have an im­por­tant role to play, but con­ver­sa­tions about al­co­hol can be dif­fi­cult. Drink­ing habits are per­son­al, so­cial­ly em­bed­ded, and some­times sen­si­tive. As a re­sult, al­co­hol use may not be dis­cussed rou­tine­ly in clin­i­cal set­tings un­less it is clear­ly ex­ces­sive. This leaves a missed op­por­tu­ni­ty for ed­u­ca­tion and pre­ven­tion.

Pub­lic health ex­perts in­creas­ing­ly ar­gue that clear­er la­belling, bet­ter ed­u­ca­tion, and hon­est mes­sag­ing are need­ed. Just as warn­ing la­bels and cam­paigns trans­formed an un­der­stand­ing of to­bac­co, sim­i­lar ef­forts could help peo­ple make more in­formed de­ci­sions about al­co­hol. The goal is not pro­hi­bi­tion or fear, but trans­paren­cy—en­sur­ing peo­ple un­der­stand the risks as well as the so­cial norms.

Aware­ness does not re­quire ab­sti­nence, but it does re­quire hon­esty. Al­co­hol is not risk-free, and its link to can­cer is re­al, mea­sur­able, and pre­ventable. As an on­col­o­gist, I can safe­ly say that can­cer pre­ven­tion is not on­ly about dra­mat­ic in­ter­ven­tions; it is of­ten about small, every­day de­ci­sions. Recog­nis­ing al­co­hol as a can­cer risk fac­tor is a cru­cial step to­ward re­duc­ing pre­ventable can­cers—and one that de­serves far more at­ten­tion than it cur­rent­ly re­ceives.