Self-assessed health-related quality of life in men who have completed radiotherapy for prostate cancer: Instrument validation and its relation to patient-assessed bother of symptoms
H. Wang et al., Self-assessed health-related quality of life in men who have completed radiotherapy for prostate cancer: Instrument validation and its relation to patient-assessed bother of symptoms, INT J CANC, 90(3), 2000, pp. 163-172
The purpose of this study was to develop a psychometrically reliable and va
lid questionnaire to assess the disease-specific dimensions of health-relat
ed quality of life (HRQOL) in the urinary function (UF), bowel function (BF
), and sexual function (SF) domains of prostate cancer (PCa) patients treat
ed with radiation therapy. Patients were given a six-page questionnaire usi
ng Likert-type questions assessing three HRQOL dimensions during their foll
ow-up visits after completing radiotherapy. Scales created from an earlier
study were utilized and tested for reliability and validity. In addition, w
e assessed the relationship between these dimensions and the degree to whic
h a decreased HRQOL increases the degree to which patients feel bothered ab
out their symptoms. There are two scales within each dimension: BF, Urgency
and Daily Living; UF, Urgency and Weakness of Stream; SF, Interest/Satisfa
ction and Impotence. Internal-consistency reliability coefficients (Cronbac
h's alpha) for the proposed scales range from 0.48 to 0.92, and all item-sc
ale correlations and divergence correlations validate the use of the scales
, ranging from 0.49 to 0.89. The validity of these scales is also confirmed
by the rising median scores with rising reported levels of patient-perceiv
ed "bother." The different dimensions have differing quantitative influence
s on patients. We have developed a prostate-specific HRQOL instrument that
is an adequate and suitable tool for measuring HRQOL along three distinct d
imensions for patients who have completed radiotherapy for PCa. Psychometri
c standards for reliability and validity were met for the proposed scales.
Moreover, positive correlations were found between these dimensions and how
bothered patients were by their symptoms, suggesting important relationshi
ps that should be followed in PCa patients after radiotherapy. Certain scal
es have strong influences on patient-perceived "bothersomeness" of symptoms
, such as loss of control of BF, urgency of BF, urgency of urination, and l
evel of interest/satisfaction in sex. Compared to our earlier study on pati
ents being treated with radiotherapy for PCa, this study produced very simi
lar results. With some modification, the same questionnaire could be used f
or both groups of patients, (C) 2000 Wiley-Liss, Inc.