Impact of deviation from guideline recommended treatment on breast cancer survival in Asia

Abstract

Breast cancer survival has improved with significant progress in treatment and disease management. However, compliance with treatment varies. Treatment guidelines for older patients are unclear. We aim to identify predictors of noncompliance with recommended therapy in a large breast cancer population and assess the impact of noncompliance on survival. Our study included 19,241 non-metastatic female breast cancer patients, of whom 3,158 (16%) died within 10 years post-diagnosis (median survival = 5.8 years). We studied the association between treatment noncompliance and factors with logistic regression, and the impact of treatment noncompliance on survival with a flexible parametric survival model framework. The highest proportion of noncompliance was observed for chemotherapy (18%). Predictors of noncompliance with chemotherapy, radiotherapy and endocrine therapy included age, tumor size, nodal involvement and subtype (except radiotherapy). Factors associated with not receiving surgery included age and subtype. Treatment noncompliance was associated with worse overall survival for surgery (HR: 2.26 [1.80-2.83]), chemotherapy (1.25 [1.11-1.41]), radiotherapy (2.28 [1.94-2.69]) and endocrine therapy (1.70 [1.41-2.04]). Worse survival was similarly observed in older patients for whom guidelines generally do not apply. Our results highlight the importance of following appropriate treatment as recommended by current guidelines. Older patients may benefit from similar recommendations. Breast cancer is the leading type of cancer among Asian women, with an increasing number of cases diagnosed every year 1. Between 2003 and 2008, there were more than 2 million women living with breast cancer in SouthEast Asia, where a population of over 650 million women resides 2. As breast cancer is common, the number of lives claimed by the disease is high. On average ~100,000 deaths from breast cancer were recorded every year in the same region 3. With significant progress in treatment and disease management, a growing number of women are surviving breast cancer 4. However, breast cancer survival can vary between countries. While 90% of patients in the United States live at least five years after the cancer is found 5 , the corresponding proportion is lower in SouthEast Asia. In a report by Bhoo-Pathy et al., five-year overall survival rates were estimated to range from 58.5% to 75.8% in SouthEast Asia 6. Several professional organizations and consensus groups exist to translate evidence-based medicine into recommendations for best patient care 7. Examples of providers of such clinical practice guidelines include the

Effects of housing value and medical subsidy on treatment and outcomes of breast cancer patients in Singapore: A retrospective cohort study

“…Our study also revealed associations of lower HI with delays in surgery and reduced compliance to systemic treatment and radiotherapy, all of which is known to adversely affect disease control. [ 22 , 23 ] Patients in lower HI-tiers were also more likely to undergo mastectomy over breast conserving therapy and less likely to undergo breast reconstruction; concurring with observations noted in other studies. [ 24 , 25 ] We speculate that poorer patients may ill-afford the work and family disruption from a lengthy course of adjuvant radiotherapy nor the expense of reconstructive surgery.…”

Invasive breast Cancer treatment in Tanzania: landscape assessment to prepare for implementation of standardized treatment guidelines

“…Overall survival could not be measured directly since many patients’ last visit to the zonal hospital in Mwanza was on their last day of treatment. However, given its strong association with decreased mortality and lower risk of recurrence, adjuvant chemotherapy completion was used as a clinically relevant endpoint in the current study, acknowledging the possibility, although very unlikely in the Lake Region, that a proportion of continued chemotherapy could have been received at another facility [ 2 , 13 , 32 , 33 ]. Despite these inherent limitations in the available data, the assessment process and findings from this study can be used to inform improvements in breast cancer care for future patients, including ongoing interventions as part of a larger organizational study in the region [ 34 ].…”

Receipt of guideline‐concordant care among young adult women with breast cancer

“…Reasons for GDC in YAs included an absence of surgical and/or systemic therapy partially due to treatment refusal. In a study of the impact of GDC on survival in nonmetastatic breast cancer, women younger than 50 years (vs those older than 50 years) had higher odds of not having received recommended surgical or endocrine therapy 25 . A different study of insured women with HR+ breast cancer found that younger women (vs older women) were less likely to adhere to adjuvant endocrine therapy 26 .…”