Valuing preferences for treating screen detected ductal carcinoma in situ

Highlights

• This is the first study to value the QoL of active monitoring for breast cancer.

• Screen detected ductal carcinoma in situ (DCIS) may be subject to overdiagnosis and thus overtreatment.

• Women with low-risk DCIS would prefer less invasive treatment in terms of QoL.

• Active monitoring is valued an acceptable alternative to surgery and radiotherapy.

• More research is needed on how to de-escalate and balance the effects of treatment.

Abstract

Background

Mammographic screening reduces breast cancer mortality but may lead to the overdiagnosis and overtreatment of low-risk breast cancers. Conservative management may reduce the potential harm of overtreatment, yet little is known about the impact upon quality of life.

Objectives

To quantify women's preferences for managing low-risk screen detected ductal carcinoma in situ (DCIS), including the acceptability of active monitoring as an alternative treatment.

Methods

Utilities (cardinal measures of quality of life) were elicited from 172 women using visual analogue scales (VASs), standard gambles, and the Euro-Qol-5D-5L questionnaire for seven health states describing treatments for low-risk DCIS. Sociodemographics and breast cancer history were examined as predictors of utility.

Results

Both patients and non-patients valued active monitoring more favourably on average than conventional treatment. Utilities were lowest for DCIS treated with mastectomy (VAS: 0.454) or breast conserving surgery (BCS) with adjuvant radiotherapy (VAS: 0.575). The utility of active monitoring was comparable to BCS alone but was rated more favourably as progression risk was reduced from 40% to 10%. Disutility for active monitoring was likely driven by anxiety around progression, whereas conventional management impacted other dimensions of quality of life. The heterogeneity between individual preferences could not be explained by sociodemographic variables, suggesting that the factors influencing women's preferences are complex.

Conclusions

Active monitoring of low-risk DCIS is likely to be an acceptable alternative for reducing the impact of overdiagnosis and overtreatment in terms of quality of life. Further research is required to determine subgroups more likely to opt for conservative management.

Introduction

Breast cancer screening reduces breast cancer morbidity and mortality [1,2] but may also lead to the overdiagnosis of low-risk disease [3]. Ductal carcinoma in situ (DCIS) is a heterogeneous disease with variable malignant potential [4], but it is not known which patients may be safely left untreated. Standard treatment encompasses surgery, with or without radiotherapy, and endocrine therapy [5]. There is evidence to suggest that active monitoring of low-risk DCIS (defined as low or low-intermediate grade on histopathology) may reduce treatment-related harm from overdiagnosis [6]. Clinical trials comparing conventional treatment to active monitoring are underway [[7], [8], [9]]. However, little is known about the acceptability of active monitoring or how such strategies may impact upon quality of life.

The value of treating DCIS versus active monitoring is dependent on the trade-off in benefits and costs [10,11]. For most women, this is related to the fear and sequalae of progression or recurrence versus the side-effects and morbidity of treatment [12]. To appraise the expected impact of each option on quality of life, utilities are an appropriate outcome measure [13]. Utilities are cardinal measures of quality of life [14], representing the strength of an individuals’ preference for a health state or treatment. They are measured on a scale from 0 to 1, equivalent to being dead and in perfect health, respectively, and are used to measure benefit (quality-adjusted life-years) in economic evaluations informing healthcare decisions [15].

Issues surrounding DCIS management arise from the uncertainty in disease progression. DCIS is not life-threatening but is a risk factor for developing invasive breast cancer [16]. Whilst surgery and radiotherapy may reduce the risk of invasive cancer and need for more invasive treatment if it does not progress, it is unlikely to have significant benefit upon survival [17]. Conversely, many women are exposed to the morbidity and costs of the initial treatment to reduce the risk of recurrence.

The objective of this study was to quantify women's preferences for managing low-risk DCIS identified by screening.