| - Introduction. A steady increase can be observed in the use of adjuvant chemotherapy in the Netherlands. An extension of the indication generally follows after heated debate about the cost-benefit trade-offs, and an initial unwillingness to treat. Such a process has been seen in node negative breast cancer as well as in Dukes C colon cancer. Although it has been stated repeatedly in the literature that the issue is one in which patient preferences are of utmost importance, given the trade-offs involved, these preferences are not systematically assessed in the process of consensus development. The subsequent implementation of the policy (in guidelines issued by the regional cancer centers) leaves little space for patient preferences either. Patient preferences for adjuvant therapy have been assessed in research settings, and their preferences have been compared to those of oncologists. In general, patients accept chemotherapy at lower levels of benefit than doctors. All these studies involve patients who have had, or who are about to undergo chemotherapy. The psychological processes of consolidation and cognitive dissonance reduction may cause this preference pattern. Preliminary studies at our institution show that patients who are about to undergo, or have undergone, adjuvant treatment would be willing to accept that treatment even without a clear benefit. This implies that what we know about patient preferences is strongly confounded by the mentioned psychological processes. If one truly wishes the patient to decide about his/her treatment, then more knowledge is needed of the considerations that play a role for patients in the decision making process. A nationwide trial is about to start on adjuvant chemotherapy (6 courses of 5 FU/Leucovorin) in operable primary rectal cancer. This trial provides an opportunity, highly appropriate in timing, to study in depth patient preferences and considerations for wanting or not wanting adjuvant therapy, and the processes of consolidation or dissonance reduction. - The purpose of this study is twofold and the study will thus consist of two phases: * To investigate in depth the determinants of patients' preferences and the process of consolidation of these preferences. In this phase an attitude-to-treatment questionnaire will be developed, for use alongside the traditional Treatment Preference instrument in Phase II. * To assess patient preferences for adjuvant chemotherapy and obtain the "minimally required benefit", both in a decision analytic way and through a direct Treatment Preference assessment; and to assess determinants of those preferences and of the discrepancy between the model-derived and the direct preferences. - Plan of investigation. In the first, qualitative phase, 10 patients in each arm of the trial will be interviewed 3 times: before randomization (T1, by telephone), after randomization and before treatment (T2), and 1 month after completing treatment (T3) (or at similar moments in time in the no-chemotherapy arm). The interview will be structured around attitudes to chemotherapy and various determinants of these attitudes and considerations involved in the decision. Interviews will also be held with patients who stop chemotherapy before completion (n=10); and with patients who have a metastasis (n=10). In the second, quantitative study (n=125 in each arm) interviews will be held at T1 and T2, and questionnaires will be mailed at T3, and, additionally, 5 months later (T4) (or at similar moments in time in the no-chemotherapy arm). At T1-T4 attitudes to chemotherapy and preference are assessed, as well as possible determinants thereof. Additionally at T2, patient utilities will be assessed to allow calculation of patients treatment preferences based on a decision model (a QALY-model). A once-only questionnaire will be mailed to all surgeons and internal oncologists involved in the trial, and the attitude of the specialist will be a covariate in the analysis of the patient data. - Relevance for cancer research. The information gained will help the Dutch Colorectal Cancer Group in the development of a national treatment policy for rectal cancer that truly incorporates patient preferences. An ultimate purpose is to obtain more insight into patient preferences and their determinants, which will allow clinicians and patients to decide upon the best treatment, given the patients values. |
