Design of an individualised questionnaire to measure the impact of cancer on quality of life: The cancer dependent quality of life (CancerDQoL) questionnaire.

Aim: To design an individualised questionnaire to measure the impact of cancer and its treatments on quality of life (QoL). MATERIALS & METHODS: Design of the Cancer-Dependent Quality of Life (CancerDQoL) questionnaire was based on the Audit of Diabetes Dependent QoL (ADDQoL) questionnaire and related -DQoLs for other conditions. Item selection, face validity and content validity were established through clinician and patient ratings of the importance and relevance of 60 domains from the -DQoL Item Library, and semi-structured interviews with 25 English-speaking participants with a range of cancers attending a cancer centre in Zimbabwe (age range: 25-78 years; 16 women, 9 men). Ten interviews were subsequently conducted with UK English-speaking participants with a range of cancers attending Maggie's Centres in London and Dundee (age range: 40-76; 5 women, 5 men) to adapt the CancerDQoL for UK use.

Results: The first draft of the CancerDQoL contained 25 domain-specific items from the -DQoL Item Library plus four overview items. Zimbabwean participants indicated that cancer negatively impacted on all life domains included, except 'having children'. Weighted impact (impact ratings multiplied by importance) was most negative for 'sex life', 'depend on others' and 'physical capability'. The least negative weighted impact was found for 'having children', 'spiritual/religious life' and 'past medical/self-care'. UK interviews confirmed no new items were required.

Conclusions: Face and content validity of the CancerDQoL is established for an adult sample of English-speaking cancer patients in Zimbabwe and confirmed in an adaptation following UK interviews.