Breast cancer: managing long-term treatment, a constant psychological challenge

Breast can­cer affects nearly 2.3 mil­lion new patients world­wide each year, mak­ing it the most com­mon can­cer among women. Once ini­tial treat­ment is com­plete, many must con­tin­ue long-term treat­ment for years, some­times for more than a dec­ade, a pro­cess accom­pan­ied by per­sist­ent side effects and a daily remind­er of the dis­ease. How­ever, nearly half of these patients even­tu­ally stop or space out this treat­ment along the way, res­ult­ing in an increased risk of relapse. This dis­con­tinu­ation reflects a shift in patients’ motiv­a­tion to seek treat­ment. What are the causes of this phenomenon?

Two main clin­ic­al scen­ari­os arise fol­low­ing ini­tial treat­ment. Patients in remis­sion after cur­at­ive treat­ment gen­er­ally need to con­tin­ue oral hor­mone ther­apy (tamox­ifen, aro­mata­se inhib­it­ors) for five to ten years; yet between 30 % and 50 % of them dis­con­tin­ue it before five years have elapsed, with a doc­u­mented risk of relapse. Patients with meta­stat­ic can­cer, on the oth­er hand, often must under­go sev­er­al con­sec­ut­ive courses of tar­geted oral ther­apies, which exposes them to cumu­lat­ive tox­icity and an increased risk of non-adher­ence. Bey­ond the phys­ic­al strain, this long-term treat­ment imposes a daily psy­cho­lo­gic­al toll: per­sist­ent side effects, a con­stant remind­er of the dis­ease, and reper­cus­sions on qual­ity of life and sense of self.

Most exist­ing research into these beha­viours had, until now, focused on adjuvant hor­mone ther­apy in patients in remis­sion. Patients with meta­stat­ic dis­ease were there­fore largely excluded, and it is this gap that our recent study seeks to fill by recruit­ing women in both clin­ic­al situ­ations. The socio-eco­nom­ic (level of edu­ca­tion, employ­ment, fin­an­cial con­straints), clin­ic­al (side effects, com­plex­ity of the care path­way) and rela­tion­al (qual­ity of com­mu­nic­a­tion with the doc­tor) determ­in­ants of non-adher­ence are already well doc­u­mented in the sci­entif­ic lit­er­at­ure. What remained poorly under­stood was the motiv­a­tion­al mech­an­ism link­ing these factors to adher­ence beha­viour over time.

To explore this ques­tion, we drew on self-determ­in­a­tion the­ory. This is a well-estab­lished psy­cho­lo­gic­al frame­work that dis­tin­guishes between two main forms of motiv­a­tion: autonom­ous motiv­a­tion and con­trolled motiv­a­tion. Autonom­ous motiv­a­tion is based on the patient’s com­mit­ment to her own val­ues: she fol­lows her treat­ment because it makes sense to her. Con­trolled motiv­a­tion¹, by con­trast, stems from extern­al pres­sure: the fear of relapse, pres­sure from those around her, or a sense of guilt. This self-determ­in­a­tion the­ory pos­its that sat­is­fac­tion of three fun­da­ment­al psy­cho­lo­gic­al needs is key: a sense of com­pet­ence, a sense of autonomy and a sense of social con­nec­tion. Although already val­id­ated for med­ic­a­tion adher­ence in dia­betes and hyper­ten­sion, this the­or­et­ic­al frame­work had nev­er been empir­ic­ally tested in the con­text of breast cancer.

To test it, adult women with breast can­cer who had com­pleted cur­at­ive treat­ment and had been tak­ing hor­mone ther­apy or oral med­ic­a­tion for at least six months were recruited via the French plat­form Seintinelles, a com­munity of volun­teer patients. Fol­low­ing an ini­tial explor­at­ory phase to val­id­ate the ques­tion­naire with 89 par­ti­cipants, a second phase, involving 412 women, enabled the test­ing of a stat­ist­ic­al mod­el based on self-determination.

The key find­ing of the study is that only autonom­ous motiv­a­tion sig­ni­fic­antly pre­dicts the inten­tion to con­tin­ue treat­ment. Con­trolled motiv­a­tion, on the oth­er hand, showed no sig­ni­fic­ant effect. Many things may prompt a patient to take her tab­let every morn­ing, but only one type of motiv­a­tion makes a dif­fer­ence in the long run: the kind that comes from with­in. ‘I do it because I have to’ holds up for a while, then gives way to men­tal fatigue and the tempta­tion to stop; ‘I choose to do it’ stands the test of time. The use of fear or guilt in pub­lic aware­ness cam­paigns does not guar­an­tee the motiv­a­tion needed to com­mit to treat­ment in the long term.

Where does this intrins­ic motiv­a­tion come from? The mod­el reveals a clear chain: feel­ing sup­por­ted (a bond of trust with one’s health­care team) nur­tures the sense of being able to man­age one’s treat­ment on a day-to-day basis, which in turn rein­forces the feel­ing of retain­ing free­dom of choice in the face of the ill­ness, and this, in turn, fuels intrins­ic motiv­a­tion. Everything hinges on how the patient feels, and intrins­ic motiv­a­tion acts as an essen­tial step­ping stone.

Fatigue, joint pain, hot flushes: one might think that it is these side effects that prompt patients to stop treat­ment. The study shows that side effects relate more to the patient’s men­tal health than to their phys­ic­al con­di­tion. Phys­ic­al symp­toms do not dir­ectly affect the inten­tion to con­tin­ue treat­ment: they first take their toll on mor­ale and social life; this dip in mor­ale erodes the sense of com­pet­ence (“I can’t man­age it any more”), and it is this loss of self-con­fid­ence that weak­ens autonom­ous motiv­a­tion, and sub­sequently the inten­tion to con­tin­ue. It is not the pain itself that causes patients to stop treat­ment; it is what the pain does, silently, to their self-confidence.

Where­as many pre­vi­ous stud­ies viewed side effects as a dir­ect bar­ri­er, our study iden­ti­fies their psy­cho­lo­gic­al bur­den as the true inter­me­di­ary mech­an­ism. Identi­fy­ing and address­ing this psy­cho­lo­gic­al impact as early as pos­sible there­fore not only safe­guards phys­ic­al well-being, but also the entire motiv­a­tion­al mech­an­ism that under­pins adherence.

One might think that, in the case of more advanced ill­ness, it is neces­sary to insist, to press the point, and to emphas­ise the urgency. The study shows the oppos­ite. Among patients who have received three or more lines of treat­ment (and are there­fore in more vul­ner­able situ­ations), the free­dom to choose becomes the almost exclus­ive driver of motiv­a­tion. This gives rise to a clin­ic­al para­dox: when the stakes seem high­er, health­care pro­fes­sion­als might be temp­ted to adopt a more dir­ect­ive approach to com­mu­nic­a­tion, yet this proves to be less effect­ive. The heav­ier the bur­den, the more the patient needs to feel in con­trol of her own choices, rather than being told what to do.

And of all the con­tex­tu­al factors tested, the actions and beha­viour of the onco­lo­gist proved to be the most decis­ive. Being informed, feel­ing listened to, and being able to par­ti­cip­ate in decisions: these exper­i­ences strongly foster a sense of being sup­por­ted, which has a knock-on effect on autonom­ous motiv­a­tion and the inten­tion to under­go treat­ment. This find­ing con­firms what pre­vi­ous research had sug­ges­ted more gen­er­ally: the qual­ity of the doctor–patient rela­tion­ship mat­ters. But the study spe­cifies how it works: a doc­tor who helps their patient to choose, rather than simply obey, sets in motion the whole chain of events that ulti­mately leads to genu­inely autonom­ous motiv­a­tion. Com­mu­nic­a­tion that sup­ports the patient’s autonomy should there­fore be regarded as a med­ic­al skill in its own right, rather than merely an addi­tion­al rela­tion­al element.

A final find­ing con­cerns loved ones. A wor­ried part­ner, or a fam­ily that insists, makes the patient feel guilty or keeps a close eye on them, all start out with good inten­tions. How­ever, when per­ceived as pres­sure, this atten­tion mod­estly but sig­ni­fic­antly reduces patients’ sense of autonomy, and their intrins­ic motiv­a­tion weak­ens. The sup­port that truly helps is that which leaves the ini­ti­at­ive with the patient; this calls on health­care teams to guide loved ones so that their involve­ment rein­forces the sense of choice rather than under­min­ing it.

As the first empir­ic­al test of self-determ­in­a­tion the­ory applied to treat­ment adher­ence in breast can­cer, this study ulti­mately iden­ti­fies three prac­tic­al strategies: com­mu­nic­a­tion that allows for choice; a focus on emo­tion­al well-being rather than solely on clin­ic­al out­comes; and sup­port for loved ones to provide assist­ance without exert­ing pres­sure. Over time, remind­ers of the risks are no longer suf­fi­cient to motiv­ate patients. Stick­ing to treat­ment is a choice that is renewed every day: what helps patients per­severe is feel­ing that they are act­ive par­ti­cipants in their treat­ment, rather than simply endur­ing it.