Totally implanted venous access ports allow a safe delivery of medication, mainly chemotherapy, but are also used for blood sampling. This last procedure is not always successful, as it appeared from a nurse's survey in different hospitals in Flanders, including the University Hospitals in Leuven, Belgium. In 3 to 29 percent of the attempts, blood withdrawal is impaired or not possible, as an intermittent or permanent fact. This is in line with international literature data where difficulty in blood draw was noted in 6 to 26% of port accessions. Partial or total occlusion leads to discomfort for the patient, delay in therapy, higher costs and extra nursing time.

A new port system with a tangential outlet (Vortex port) was designed and according to the manufacturer, this shape will allow to cleanse the entire reservoir of the port more efficiently and avoid the formation of precipitates of medication or blood that could lead to an obstruction of the device. These precipitates are also regarded as a potential risk factor for infection.

However, only one previously published small randomised study addressed the value of the Vortex port when compared to conventional access devices: Stevens et al. were able to show a reduction in obstruction incidence from 26% to 7% with the use of the Vortex port. The incidence of blood withdrawal problems in our experience with conventional ports in University hospitals Leuven was 8% thus lower than that reported by Stevens, but this remains the most frequent problem faced by care providers and patients.

With this study, the investigators aim to compare the performance of the tangential outlet ports and that of a "conventional" port in order to assess an eventual functional difference.

Inclusion Criteria:

• request of a standard size totally implanted venous port
• patent superior vena cava
• normal clotting tests (PT>40% and platelet count >40000/mm3)

Exclusion Criteria:

• unable to provide written informed consent