Benefit from preoperative radiotherapy in rectal cancer treatment: disease-free patients' and oncologists' preferences

Abstract

Preoperative radiotherapy (PRT) in resectable rectal cancer improves local control but increases probability of faecal incontinence and sexual dysfunction. Consensus was reached in 2001 in the Netherlands on a guideline advising PRT to new patients. Purpose was to assess at what benefit oncologists and rectal cancer patients prefer PRT followed by surgery to surgery alone, and how oncologists and patients value various treatment outcomes. Sixty-six disease-free patients and 60 oncologists (surgical, radiation, medical) were interviewed. Minimally desired benefit from PRT (local control) was assessed using the Treatment Tradeoff Method. Importance of survival, local control, faecal incontinence, and sexual dysfunction in determining treatment outcome preferences was assessed using Adaptive Conjoint Analysis. The range of required benefit from PRT varied widely within participant groups. Seventeen percent of patients would choose PRT at a 0% benefit; 11% would not choose PRT for the maximum benefit of 11%. Mean minimally desired benefit excluding these two groups was 4%. For oncologists, the required benefit was 5%. Also, how strongly participants valued treatment outcomes varied widely within groups. Of the four outcomes, participants considered incontinence most often as most important. Relative treatment outcome importance differed between specialties. Patients considered sexual functioning more important than oncologists. Large differences in treatment preferences exist between individual patients and oncologists. Oncologists should adequately inform their patients about the risks and benefits of PRT, and elicit patient preferences regarding treatment outcomes.

Figure 1

Consecutive information (treatment options, side effects, and consequence) presented with the TTM (male patient).

Figure 2

Adaptive conjoint analysis questionnaire.

Figure 3

Cumulative proportion of oncologists (N=58) and patients (N=66) preferring PRT according to minimum percentage of benefit in local control. Numbers of patients do not add up to 100% because of those never preferring PRT.

Figure 4

Individual importance scores (range 0–100) of treatment outcomes in patients and clinicians. M=mean; s.d.=standard deviation; Pt=patient; Clin=clinician. One oncologist and four patients were excluded from the analyses because they valued the worst probability of one of the treatment outcomes highest compared to the other outcome probabilities of that outcome.