Aim Accurate and reliable patient information plays a crucial role in the multidisciplinary treatment of malignancies helping to ensure compliance of the patients and their relatives with often long-lasting and stressful treatment. The English version of the online encyclopaedia Wikipedia has been recently reported to be the prominent source of online health information. However, there is little information concerning the quality of information found in Wikipedia.

Method We therefore created a questionnaire concerning of 20 questions asking for scope, completeness and accuracy of information found on osteosarcoma. Three independent observers tested the English version of Wikipedia as well as the patient version and the health professional version of the website of the National Cancer Institute. Answers (scores 0-3) were verified with authoritative resources and international guidelines.

Results The professional version of the NCI scored best with 50 of 60 possible points (mean 2.5 ± 0.83 SD per question), compared to the patient version of the NCI with 40 points (mean 2 ± 1.38 SD) and to the Wikipedia site with 33 points (mean 1.65 ± 1.39 SD). Only the difference between the NCI professional version and Wikipedia was significant (p=0.039).

Conclusion Our study shows that the quality of osteosarcoma-related information found in English Wikipedia is good but inferior to the patient information provided by the National Cancer Institute. Especially in multidisciplinary treated tumours like osteosarcoma accurate and complete information found on Wikipedia might influence patients' compliance with treatment.

Therefore national agencies for cancer research like the NCI and international organizations on cancer treatment should check and actualize this website on a regular basis.