The importance of nonpharmacogenetic factors in endocrine therapy

Systematic adaptation of the adherence improving self-management strategy to support breast cancer survivors' adherence to adjuvant endocrine therapy: An intervention mapping approach

OBJECTIVE

Non-adherence to adjuvant endocrine therapy (AET) for breast cancer leads to increased recurrence and mortality risk and healthcare costs. Evidence on feasible, effective AET adherence interventions is scarce. This paper describes the systematic adaptation of the cost-effective adherence improving self-management strategy (AIMS) for patients with HIV to AET for women after breast cancer treatment.

METHODS

We followed the intervention mapping protocol for adapting interventions by conducting a needs assessment, reviewing target behaviours and determinants, reassessing behaviour change methods and adapting programme content. Therefore, we performed a literature review, consulted behavioural theory and organised nine advisory board meetings with patients and healthcare professionals.

RESULTS

Non-adherence occurs frequently among AET users. Compared to HIV treatment, AET is less effective, and AET side effects are more burdensome. This drives AET treatment discontinuation. However, the key determinants of non-adherence are largely similar to HIV treatment (e.g. motivation, self-regulation and patient-provider relationship); therefore, most strategies in AIMS-HIV also seem suitable for AIMS-AET. Modifications were required, however, regarding supporting patients with coping with side effects and sustaining treatment motivation.

CONCLUSION

AIMS seems to be a suitable framework for adherence self-management across conditions and treatments. Intervention mapping offered a transparent, systematic approach to adapting AIMS-HIV to AET.

Acupuncture in the real world: evaluating a 15-year NADA auricular acupuncture service for breast cancer survivors experiencing hot flushes and night sweats as a consequence of adjuvant hormonal therapies

PURPOSE

While clinical trials provide valuable data about efficacy of interventions, findings often do not translate into clinical settings. We report real world clinical outcomes of a 15-year service offering breast cancer survivors auricular acupuncture to manage hot flushes and night sweats (HFNS) associated with adjuvant hormonal treatments. This service evaluation aims to (1) assess whether usual practice alleviates symptoms in a clinically meaningful way and (2) compare these results with scientific evidence.

METHODS

Data were analysed from 415 referrals to a service offering women eight standardised treatments using the National Acupuncture Detoxification Association (NADA) protocol. Outcome measures administered at baseline, end of treatment (EOT), and 4 and 18 weeks after EOT included hot flush diaries, hot flush rating scale (HFRS) and women's health questionnaire (WHQ).

RESULTS

Over 2285 treatments were given to 300 women; 275 (92.3%) completed all eight treatments. Median daily frequency of HFNS reduced from 9.6 (IQR 7.3) to 5.7 (IQR 5.8) at EOT and 6.3 (IQR 6.5) 18 weeks after EOT. HFRS problem rating showed a clinically meaningful reduction of ≥ 2 points at all measurement points. WHQ showed improvements in several symptoms associated with the menopause. Two adverse events were reported, neither were serious. Results are comparable to published research.

CONCLUSION

This first analysis of a long-term auricular acupuncture service compares favourably with outcomes of other studies for reducing HFNS frequency and associated menopausal symptoms. In day-to-day clinical practice, NADA appears to be a safe effective intervention for breast cancer survivors.

Cytochrome P-450 2D6 (CYP2D6) Genotype and Breast Cancer Recurrence in Tamoxifen-Treated Patients: Evaluating the Importance of Loss of Heterozygosity

Tamoxifen therapy for estrogen receptor-positive breast cancer reduces the risk of recurrence by approximately one-half. Cytochrome P-450 2D6, encoded by the polymorphic cytochrome P-450 2D6 gene (CYP2D6), oxidizes tamoxifen to its most active metabolites. Steady-state concentrations of endoxifen (4-hydroxy-N-desmethyltamoxifen), the most potent antiestrogenic metabolite, are reduced in women whose CYP2D6 genotypes confer poor enzyme function. Thirty-one studies of the association of CYP2D6 genotype with breast cancer survival have yielded heterogeneous results. Some influential studies genotyped DNA from tumor-infiltrated tissues, and their results may have been susceptible to germline genotype misclassification from loss of heterozygosity at the CYP2D6 locus. We systematically reviewed 6 studies of concordance between genotypes obtained from paired nonneoplastic and breast tumor-infiltrated tissues, all of which showed excellent CYP2D6 genotype agreement. We applied these concordance data to a quantitative bias analysis of the subset of the 31 studies that were based on genotypes from tumor-infiltrated tissue to examine whether genotyping errors substantially biased estimates of association. The bias analysis showed negligible bias by discordant genotypes. Summary estimates of association, with or without bias adjustment, indicated no clinically important association between CYP2D6 genotype and breast cancer survival in tamoxifen-treated women.

A randomised trial of the cool pad pillow topper versus standard care for sleep disturbance and hot flushes in women on endocrine therapy for breast cancer

PURPOSE

Quality of life in women receiving adjuvant endocrine therapy for breast cancer (BC) may be impaired by hot flushes and night sweats. The cool pad pillow topper (CPPT) is a commercial product, promoted to improve quality of sleep disrupted by hot flushes. This study aimed to identify if the CPPT reduces severity of sleep disturbance by minimising effects of hot flushes.

METHODS

This randomised phase II trial, recruited women with BC, on adjuvant endocrine therapy, experiencing hot flushes and insomnia. Participants were randomised (stratified by baseline sleep efficiency score (SES) and menopausal status) to the intervention arm (CPPT + standard care) or control arm (standard care). Participants completed Hospital Anxiety and Depression Scale and Functional Assessment of Cancer Therapy-Breast (FACT-B) questionnaires and fortnightly sleep/hot flush diaries (where responses were averaged over 2-week periods). The primary endpoint was change in average SES from -2 to 0 weeks to 2 to 4 weeks.

RESULTS

Seventy-four pre- (68.9 %) and post-menopausal (31.1 %) women were recruited. Median age was 49.5 years. Endocrine therapies included tamoxifen (93.2 %). Median SES at weeks 2 to 4 improved in both arms but the increase on the intervention arm was almost twice that on the control arm (p = 0.024). There were significantly greater reductions in hot flushes and HADS depression in the intervention arm (p = 0.09 and p = 0.036, respectively). There were no significant differences in FACT-B or HADS anxiety.

CONCLUSION

This study supports the use of the CPPT as an aid to reduce sleep disturbance and the frequency/severity of hot flushes.

A hard pill to swallow: a qualitative study of women's experiences of adjuvant endocrine therapy for breast cancer

OBJECTIVE

To explore women's experiences of taking adjuvant endocrine therapy as a treatment for breast cancer and how their beliefs about the purpose of the medication, side effects experienced and interactions with health professionals might influence adherence.

DESIGN

Qualitative study using semistructured, one-to-one interviews.

SETTING

2 hospitals from a single health board in Scotland.

PARTICIPANTS

30 women who had been prescribed tamoxifen or aromatase inhibitors (anastrozole or letrozole) and had been taking this medication for 1-5 years.

RESULTS

Women clearly wished to take their adjuvant endocrine therapy medication as prescribed, believing that it offered them protection against breast cancer recurrence. However, some women missed tablets and did not recognise that this could reduce the efficacy of the treatment. Women did not perceive that healthcare professionals were routinely or systematically monitoring their adherence. Side effects were common and impacted greatly on the women's quality of life but did not always cause women to stop taking their medication, or to seek advice about reducing the side effects they experienced. Few were offered the opportunity to discuss the impact of side effects or the potential options available.

CONCLUSIONS

Although most women in this study took adjuvant endocrine therapy as prescribed, many endured a range of side effects, often without seeking help. Advice, support and monitoring for adherence are not routinely offered in conventional follow-up settings. Women deserve more opportunity to discuss the pros, cons and impact of long-term adjuvant endocrine therapy. New service models are needed to support adherence, enhance quality of life and ultimately improve survival. These should ideally be community based, in order to promote self-management in the longer term.

Cohort study of adherence to adjuvant endocrine therapy, breast cancer recurrence and mortality

BACKGROUND

Adjuvant endocrine therapy is recommended for women with oestrogen receptor-positive breast cancer, but many women do not take the medication as directed and they stop treatment before completing the standard 5-year duration.

METHODS

This retrospective cohort study conducted between 1993 and 2008 of all women with incident breast cancer, who are residing in the Tayside region of Scotland, examined adherence to prescribed adjuvant tamoxifen or aromatase inhibitors (AIs). Survival analysis examined the effect of adherence on all-cause mortality, breast cancer death and recurrence, using linked prescribing, cancer registry, clinical cancer audit, hospital discharge and death records.

RESULTS

A total of 3361 women with breast cancer were followed for a median 4.47 years (interquartile range (IQR)=2.04-8.55). The median overall adherence was 90% (IQR=90-100%), but the annual adherence reduced after a longer period from diagnosis. Low adherence of <80% was associated with poorer survival (hazard ratios=1.20; 95% confidence interval=1.03-1.40, P=0.019). There was no significant difference for low adherence over the treatment period and recurrence, or breast cancer death, but patients with high annual adherence for 5 years had better outcomes than those with 3 or less.

CONCLUSION

Low adherence to all adjuvant endocrine therapy for women with breast cancer, whether tamoxifen or AI, increases the risk of death.

Cohort study of adherence to adjuvant endocrine therapy, breast cancer recurrence and mortality

BACKGROUND

Adjuvant endocrine therapy is recommended for women with oestrogen receptor-positive breast cancer, but many women do not take the medication as directed and they stop treatment before completing the standard 5-year duration.

METHODS

This retrospective cohort study conducted between 1993 and 2008 of all women with incident breast cancer, who are residing in the Tayside region of Scotland, examined adherence to prescribed adjuvant tamoxifen or aromatase inhibitors (AIs). Survival analysis examined the effect of adherence on all-cause mortality, breast cancer death and recurrence, using linked prescribing, cancer registry, clinical cancer audit, hospital discharge and death records.

RESULTS

A total of 3361 women with breast cancer were followed for a median 4.47 years (interquartile range (IQR)=2.04-8.55). The median overall adherence was 90% (IQR=90-100%), but the annual adherence reduced after a longer period from diagnosis. Low adherence of <80% was associated with poorer survival (hazard ratios=1.20; 95% confidence interval=1.03-1.40, P=0.019). There was no significant difference for low adherence over the treatment period and recurrence, or breast cancer death, but patients with high annual adherence for 5 years had better outcomes than those with 3 or less.

CONCLUSION

Low adherence to all adjuvant endocrine therapy for women with breast cancer, whether tamoxifen or AI, increases the risk of death.