In this study, we investigated patient’s individual comprehension and satisfaction of current informed consent procedures. We could clearly demonstrate in our series that age and a lower education level have an impact on patients’ comprehension, which in turn correlates with individual satisfaction. Prior studies already indicated that patients' understanding decreases significantly with increasing age and a lower level of school education (Casarett et al. 2003; Sanchini et al. 2013; Sherlock and Brownie 2014), which is in line with our findings. In contrast to other studies, gender did not influence the understanding of the consent process in our current study (Wagner et al. 2019).
When evaluating the effectiveness of an informed consent process a distinction between subjective and objective understanding is critical (Joffe et al. 2001). While the subjective feeling of having been well informed was high in this current survey, this did not result in a high degree of objective understanding. As an example, a substantial proportion of patients was not able to properly answer the question about their individual diagnosis or their distinct treatment aims. Some patients only mentioned the generic term "cancer" at this point, others did not answer the question at all, which illustrates a lack of understanding.
Some authors claim that the spelling style of informed consent material is too complex and often exceed patients' reading comprehension (Larson et al. 2015). In our survey, we could in part find the same observation, as 13.5% of patients stated that the text contained many incomprehensible words and 34% experienced partial difficulties in understanding. The observed discrepancy between reported subjective satisfaction and difficulties in comprehension can be explained with the effect of social desirability. Older series have demonstrated a higher rate of difficulties, which in turn may reflect improvements in the comprehensibility of current materials.
Data indicate that patients often do not read the consent material at all (D’Souza et al. 2015), which applies for 11% of patients in this survey. About 40% of patients needed a maximum of 15 min to read the informed consent form, which—in light of the volume, complexity and scope—raises skepticism about complete understanding.
Most patients were satisfied with the timing of the informed consent talk before therapy initiation. Those who were dissatisfied either consented on the very same day of therapy start or more than 2 weeks before, indicating that too short and too long intervals between the informed consent talk and therapy start do not meet patients' needs. Overall, most patients indicated that their doctor took enough time to explain everything. In contrast, patients whose conversation only took up to 10 min were only 50% satisfied.
About one third of the patients stated that they consented only verbally, which is questionable since handing out a copy of the signed informed consent form to the patient is a standard procedure. Thus, it can be assumed that not all patients perceive the informed consent talk as their main informative talk. To avoid this misconception, doctors should introduce the purpose of the talk right at the beginning, e.g. by emphasizing that both oral and written informed consent will take place in the next 30 min.
Only few patients had a sense of reverence (and thus restraint) towards the doctor as described in the literature (Hall et al. 2012). Group-specific differences were found regarding school education: patients with low school education were more likely to feel obligated (12.5%) than patients with high school (8%) or intermediate school education (4.5%). Whereas a few decades ago a paternalistic attitude regarding therapy decisions prevailed, patients today are aware of their right to self-determination and freedom of choice (Krishnan and Kasthuri 2007).
Patients were generally satisfied with the information provided, also during the follow-up. However, retrospectively, dissatisfaction was noted regarding information about alternative therapies: 40% stated that they did not feel well informed in this regard. Comparing this to the first survey, it is striking that initially only 29% of the patients stated that information on alternative therapies was important to them. Thus, a change in the need for information during cancer treatment can be assumed, especially for those who do not respond to cancer therapy. A central insight of this survey is that even if there is no alternative therapy option, this information should also be communicated to improve patient satisfaction. 30% of patients were only partially or not satisfied with the display of opportunities and risks of the planned therapy. To discuss risk, van de Water et al. suggest that clinicians should not only use words when describing risks but at least also use some form of numbers or visualization (van de Water et al. 2020).
Still, the influence of emotions should not be underestimated here. According to Visser et al. patients often cannot remember relevant topics of their informed consent talk due to fear, agitation or pain.(D'Souza et al. 2015; Sariturk et al. 2017; Visser et al. 2017). This is of pivotal relevance when the doctor must break bad news as e.g. the lack of curative treatment options. Although in this survey most patients knew their treatment goal after the informed consent talk, for 20% of the patients it was not or only partially clear. Strikingly, most of them had a palliative therapy goal.
To objectify the level of patient understanding in future projects, the use of validated questionnaires as the EORTC QLQ-INFO25 questionnaire is promising (Arraras et al. 2011). To increase patients satisfaction and the level of understanding during the informed consent process, potential new techniques as conducting structured interviews, using “feedback techniques” or audiovisual tools such as tablets with PowerPoint presentations containing the most relevant information should be considered (Sanchini 2013; Glaser et al. 2020). So called "patient coaches", as sometimes established in clinical trials, could help to provide information instead of the doctor. Handing out additional informative material to optimize patient understanding seems less important, since only 60% of patients read the written material completely.
Finally, with increasing demographic aging, informed consent forms need to be adapted in terms of readability. An optimized, age-adapted version should have a larger font size and stronger contrasts, as well as simpler and more concise language (Spellecy et al. 2018; Glaser et al. 2020)—not only for elderly patients. The impact of these features on patients’ satisfaction and understanding of the informed consent process have to be evaluated in future trials.