Complementary medicine in guidelines of the German Guideline Program in Oncology: comparison of the evidence base between complementary and conventional therapy

The German Guideline Program in Oncology (GGPO) comprises guidelines aiming at epidemiology, prevention, diagnosis, treatment and aftercare of different types of cancer. As many patients in Germany use complementary and alternative medicine (CAM), the aim of our study was to assess the information on CAM presented in these guidelines compared to conventional, supportive and psychosocial therapy. We assessed all recommendations and statements from guidelines published from 2010 to 2012 from the program according to level of evidence (LoE) as given in the guideline. We differentiated between conventional cancer treatment, conventional supportive treatment, psychosocial interventions and complementary treatment. A total of 9 guidelines (ovarian, colorectal, pancreatic, gastric, breast, prostate, oral cancer, melanoma and Hodgkin lymphoma) were included in our analysis. The total number of statements is highly diverse, ranging from 35 to 150. Only few statements and recommendations are given regarding supportive, psychosocial or complementary therapy. Regarding conventional treatments, only two guidelines (ovarian and oral cancer) have more than 50 % statements and recommendations on level 1. Considering supportive treatments, the LoE is lower, except the guideline on pancreatic cancer (40 % level 1). In breast cancer, all statements are based on expert consensus. Four guidelines do not include any statement at all. All guidelines beside that on Hodgkin lymphoma include at least one statement or recommendation on psychosocial therapy. Most recommendations are GCP.CAM is discussed in 8 guidelines; LoE is low with GCP statements dominating. There may be different reasons for the low number of statements and recommendations on supportive, psychosocial and CAM therapies. Often, these topics are considered less important, and evidence is assumed as being low. In the GGPO, guidelines focusing on psychosocial and supportive therapy are under development. Thus, cancer-specific guidelines will be able to refer to these guidelines and only include recommendations on psychosocial care and supportive therapy which are specific for the type of cancer. A national guideline on CAM would close the gap of information for physicians and patients. In case of missing or low evidence, a transparent description of this uncertainty would be valuable information to professionals and patients.