Outpatient specialized care (ASV) is intended to improve interdisciplinary, transsectoral care for patients with rare or complex diseases, especially cancer. Up to now, only very few such specialized care teams have been established. The aim of our study was to evaluate the current state of information and participation as well as reasons for the reluctance of office-based hematologists and oncologists. We conducted a web-based survey amongst office-based hematologists and oncologists in Germany and received responses from 145 institutions comprising more then 350 doctors working there. The questions comprised 22 items concerning the state of information, implementation as well as obstacles to participation and evaluation of the ASV. The majority of the interviewed doctors was well informed about ASV. Only a minority was in principle against this concept. 6% of them had already treated patients within ASV, 8% had completed the preparation, 16% were in the preparation process, 26% were indecisive and 45% had decided not to participate. The main reasons for non-participation or barriers were high expenditure and a lack of benefit for patients, strategic positioning as well as reimbursement. Although implemented more than 5 years ago, ASV plays no relevant role in patient care. The reluctance seems not to be due to information deficits, but rather to obstacles in the participation procedure. Relevant advantages for patient care, interdisciplinary communication or reimbursement are not anticipated. As long as the current low acceptance to participate in ASV is not improved, it cannot unfold its potential.