Quality of Life versus Length of Life: Are Cancer Patients' Preferences Stable Over Time?
Background: Balancing treatment-related gains and losses with respect to quality of life (QoL) and length of life (LoL) is common in cancer. Little is known about patient preferences for QoL versus LoL and preference stability in the setting of adjuvant therapy. An appropriate assessment tool could inform both patient and clinician. Objectives: Primary – to describe the distribution and stability of preferences for QoL versus LoL in early cancer, using scores obtained on the Quality Quantity Questionnaire (QQQ). Secondary –to determine concurrent scores on three other questionnaires to inform the interpretation of the QQQ and to test the validity of the QQQ. To examine the association between sociodemographic variables, type of cancer and preferences for QoL versus LoL. To trial the QQQ with non-metastatic cancer patients, and to discuss possible cultural influences in relation to studies from different countries. To further develop the Daily Time Trade Off (TTO) instrument, and to trial it with non-metastatic patients. Design: an observational, prospective, cohort study. Assessment following diagnosis and approximately 4 months later. Setting: Dunedin Hospital, New Zealand. Participants: Baseline - 44 adult patients (70% participation rate) receiving either adjuvant chemotherapy for breast (n=15) or bowel (n=14) cancer, or radiotherapy for prostate (n=15) cancer (mean age, 57 [SD, 12.1] years). 21 men, 23 women. Follow-up – 39 patients (breast n=13, bowel n=11, prostate n=15) (mean age, 56 [SD, 12.0] years). 20 men, 19 women. Measurements: The QQQ questionnaire, supplemented with the Functional Assessment of Cancer Therapy-General (FACT-G), Daily Time Trade-off (TTO), EuroQol (EQ-5D), and a socio-demographic checklist. Results: Primary – at baseline 75% of adjuvant patients did not report a clear preference for QoL versus LoL; 20% preferring LoL (n=9), 5% preferring QoL (n=2). There was a significant association between baseline and follow-up scores (r=0.84, n=39, p<0.001). There was no significant difference in QQQ scores from baseline (mean 15.9, SD 6.3) to follow-up (mean 16.8, SD 5.6), p=0.093. With an estimated increase of 0.95, clinically significant changes could not be ruled out. Exploratory subgroup analyses showed significant positive changes for women (baseline mean 16.4, SD 5.5; follow-up mean 17.9, SD 5.1; p=0.029), and for people with a degree (baseline mean 15.2, SD 6.3; follow-up mean 17.2, SD 6.9; p=0.010). Secondary –No significant associations between socio-demographic variables, type of cancer, and baseline QQQ score. No significant associations between the QQQ and the FACT-G, TTO or EQ-5D. Conclusions: Most adjuvant patients do not express a clear preference for QoL versus LoL. A small minority do, so assuming an individual’s preference is inappropriate. Results indicate good relative and absolute stability of preference using the QQQ, although there may be an increase in preference for QoL for women and people with a degree. Other socio-demographic variables, cancer type and reported QoL may not significantly influence preference. Future studies may favour the Daily TTO over other utility measures, given its acceptability to patients. The reliability and validity of the QQQ have been enhanced by this study.
Advisor: Perez, David; Buckingham, Ken; Gray, Andrew
Degree Name: Master of Health Sciences
Degree Discipline: Medicine
Publisher: University of Otago
Keywords: cancer; quality of life; length of life
Research Type: Thesis