In Reply

We thank Prof Mroczkowski for his comments on our article (1). They show that patient reported outcomes (PROs) and their use in reflecting outcome quality meet with interest. They also make it obvious/clear once again that no established routines exists as yet for many aspects of practical use and interpretation. Current attempts to canonize what is known regarding PROs mostly consider aspects of monitoring/treatment planning for individual patients (2).

Firstly, let us rectify/clarify several issues. The comment that the timing of the initial questionnaire is inconsistent is not appropriate. The initial survey took place before the treatment was started (neoadjuvant treatment or surgery), as described in our article (1). The (implicit) demand by Prof Mroczkowski that all survey participants need to be questioned at exactly the same time (for example, seven days before their surgery) is unrealistic. Furthermore, the article did not aim to show “optimization options” or the advantages of “treatment in a certified center.” For the former, different designs are required. The latter was shown by the WiZen Study (3). Our objective was, rather, the comparison of outcome quality between centers—which was met.

The other issues raised by Prof Mroczkowski regard primarily methodological aspects, which were actually discussed in the article—for example, the option of additional differentiated analyses, the high proportion of missing data in the ASA classification in a dataset that was otherwise mostly complete, or the multitude of scores in the established questionnaires of the European Organization for the Research and Treatment of Cancer (EORTC) (cue: pain/abdominal pain) and their interpretation. Prof Mroczkowski’s comments underline important issues touched on in the discussion, but they do not cast doubt on the results of our study.