Preventing adverse events of chemotherapy by educating patients about the nocebo effect (RENNO study) – study protocol of a randomized controlled trial with gastrointestinal cancer patients

Table 1 Schedule for enrolment, interventions and assessments

Time points	Study period
	Allocation	Post-allocation
	t_1pre	t₁	t_1post	t₂	t₃
ENROLMENT
Eligibility screen^a	✓
Informed consent	✓
Randomized assignment	✓
INTERVENTIONS
Nocebo-education group		✓
Attention control group		✓
ASSESSMENTS
Baseline variables
Demographic and medical characteristics	✓
Distress Thermometer	✓
Information coping style	✓		✓
Outcome variables
Side effect number and intensity (GASE)^b				✓	✓
Coping with side effects (GASE-Coping)				✓	✓
Misattribution of symptoms (GASE-Attribution)				✓	✓
Co-medication to treat side effects (yes/no)				✓	✓
Compliance intention	✓		✓	✓	✓
Attitude towards the chemotherapy	✓		✓	✓	✓
Severity of toxicity (CTC)^c	✓			✓	✓
Further variables
Expected side effects (GASE-Expect)	✓		✓
Expected coping with side effects (GASE-Coping Expect)	✓		✓
Expected efficacy of chemotherapy			✓
Relevance of the conversation			✓
Knowledge about the nocebo effect^d			✓	✓	✓
Disease progression				✓	✓

Note. The time points T1-pre and T1-post refer to the intervention whereas the T2 and T3 refer to the chemotherapy (10 days and 12 weeks after the initial chemotherapy). GASE Generic Assessment of Side Effects, CTC Common Toxicity Criteria
^aThe eligibility screening takes place in two steps. In the first step, medical eligibility criteria are checked, whereas in the second step, all further criteria are assessed as part of the health professional-patient communication right before the signing of the informed consent
^bAssessed symptoms include fatigue, nausea, diarrhea, vomiting, headache, shortness of breath, and rash
^cSeverity of toxicity is assessed by the clinician at every cycle
^dKnowledge about the nocebo effect is only assesses in the nocebo education group

ISSN: 1471-2407