Flexible lymph node detector successful in prostate cancer patients

Ten patients with prostate cancer have undergone robot-assisted laparoscopic surgery involving the removal of tumours and suspect lymph nodes. The surgery was performed at Antoni van Leeuwenhoek hospital. The surgeon detected the lymph nodes using the DROP-IN gamma probe developed by the researchers. An initial test in February had already demonstrated that the detector accurately tracks down lymph nodes labelled with radioactivity and fluorescence prior to surgery. Tests conducted in a larger group of patients have now confirmed this result.

Operating the probe with a surgical robot's arm

The researchers say that the flexible gamma probe has several advantages. During laparoscopic surgery, surgical instruments are inserted in the patient through tiny openings. The 'old-fashioned' gamma probe is a long, rigid stick, whereas the new DROP-IN probe consists of a small detector attached to a flexible cable. It can therefore detect signals in all directions.

In addition, it is now possible to insert other surgical instruments into the same opening used for the DROP-IN gamma probe. The old-style gamma probe blocks the entire opening. The rigid nature of the old probe also means that it must be operated by a surgical assistant at the surgeon's instruction. Now, the surgical assistant inserts the DROP-IN gamma probe into the patient and the surgeon takes over operating the probe with the surgical robot's arm.

nternational validation and refinement

How will the researchers proceed? "We've recently begun working with a number of major prostate cancer clinics to validate the technology at various treatment centres. During these studies, we'll be using the DROP-IN gamma probe to treat prostate cancer patients with lymph node metastases," says Fijs van Leeuwen, head of the Interventional Molecular Imaging Laboratory in the LUMC's Radiology Department. An individual Vici grant awarded by the Netherlands Organisation for Scientific Research (NWO) will simultaneously allow the researchers to refine the DROP-IN gamma probe technology.

The article 'Robot-assisted laparoscopic surgery using DROP-In radioguidance - first-in-human translation' can be found on the website of the European Journal of Nuclear Medicine and Molecular Imaging.