The effects of illness beliefs and chemotherapy impact on quality of life in Japanese and Dutch patients with breast or lung cancer.

BACKGROUND

Responses to diagnosis and treatment of cancer are mediated by a patient's illness perceptions. Such perceptions, though different among individuals, may be culturally dependent, and act upon health related quality of life (HRQOL). Over time, individual patients show different types of response trajectories. Four issues were investigated: (I) country and disease differences in illness beliefs between Japanese and Dutch patients with lung or breast cancer; (II) country and disease differences in HRQOL in early chemotherapy; (III) individual, country, and disease differences among HRQOL trajectories; (IV) the impact of illness beliefs on HRQOL trajectories.

METHODS

A total of 89 Japanese and Dutch patients with lung or breast cancer cooperated immediately before, one week after, and eight weeks after the start of chemotherapy. Data included the EORTC QLQ-C30 quality of life (QL) questionnaire and the Brief Illness Perception Questionnaire (B-IPQ). EORTC QLQ-C30 scales were summarized by two dimensions: generalized quality of life (GENQOL) and psychological well-being (PSYQOL).

RESULTS

(I) Japanese patients had higher means on B-IPQ's concern and time line than Dutch patients. Japanese lung cancer patients had a higher mean on treatment control than all other patients; (II) no differences between country and cancer type occurred on the two HRQOL dimensions. First assessment HRQOL differed significantly from the second and third assessments without differences between the latter two. Between the first two assessments, a decrease in GENQOL occurred, together with an improvement in PSYQOL; (III) individual differences dominated the trajectories; (IV) negative beliefs usually coincided with lower scores on GENQOL and PSYQOL. Patients initially lower on PSYQOL generally showed larger improvement.

CONCLUSIONS

Individual differences in HRQOL dominate differences between culture and cancer type, and illness beliefs influence HRQOL changes in individual patients. Clinical application is possible through influencing the patient's illness beliefs to create an optimal starting position for chemotherapy.