A joint team of doctors and researchers from the European Institute of Oncology (IEO), the Istituto Nazionale di Fisica Nucleare (INFN) and Sapienza University of Rome, coordinated by Emilio Bertani of the Digestive System Surgery Unit and Director of the IEO's Neuroendocrine Tumour Surgery Unit and Francesco Ceci Director of the IEO's Nuclear Medicine Unit, demonstrated in a clinical study that the use of a novel 'tumour-seeking' probe improves the effectiveness of surgery for gastrointestinal neuroendocrine tumours (NETs).

The probe under study is an innovative instrument capable of detecting positrons, particles emitted by radiopharmaceuticals such as those commonly used in PET (Positron Emission Tomography) diagnostics. The device, developed by INFN and Sapienza, has demonstrated high sensitivity in detecting tumour cells labelled with a radiopharmaceutical specific to neuroendocrine tumours. This ability makes the probe effective in guiding the surgeon's hand to the exact location of the lesion, no matter how microscopic or in a difficult position. The study carried out at the IEO between May 2022 and April 2023 on 20 patients, showed that the new probe can detect lesions with a sensitivity and specificity of 90%.

Thanks to the use of the probe, surgical operations, whether traditional or robotic, will therefore be more precise and conservative since it will be possible to detect with great precision the presence of tissue to be removed while avoiding unnecessary removal. In summary, the procedure involves the injection of a minimal dose of a radiopharmaceutical specific to neuroendocrine tumours, which selectively targets tumour cells.

Francesco Collamati of the INFN and Riccardo Faccini of Sapienza University of Rome explain: "To date, radio-guided surgery has used gamma-ray probes, which do not work when what you want to detect is close to organs that absorb a lot of radiopharmaceuticals, such as in the abdomen. A probe such as the one we developed, which detects positrons instead of photons, can accurately detect certain forms of cancer in areas of the body where they would otherwise be impossible to detect. Thanks to the collaboration with the IEO, we have been able to validate the probe during surgery for the first time".

Francesco Ceci, Director of the Nuclear Medicine Unit and one of the leading experts in the field, was the first to propose carrying out this trial at the IEO. "My research has always focused on theranostics, the discipline that combines state-of-the-art diagnostics with precision therapies. When I heard about this device, I immediately realised its incredible potential and a fruitful collaboration with Dr Collamati began. The real innovation of this surgical procedure is that the same cancer-specific radiopharmaceutical used in PET diagnostics is administered to the patient during surgery. We first use the PET scan to identify the tumour sites and then use the probe to remove them with great precision. Diagnosis and therapy, the basis of theranostics, this time applied to surgery".

"The IEO is getting closer and closer to the goal of 'precision surgery', capable of removing no more and no less than what is necessary to cure - says Emilio Bertani, surgeon at the Digestive System Surgery Unit and coordinator of the clinical trial - even the most experienced surgeon may, in one out of three cases, leave some residual disease that is not even visible on PET scans because it is located, for example, in the small lymph nodes close to the mesenteric vessels. The beta probe can detect even the smallest presence of tumour cells, and in 80 per cent of cases, the surgeon can remove them without causing excessive damage. The strength of the procedure is that it balances the ability to find the disease with the need to preserve vital tissue for the patient".

"It is important to remember that for neuroendocrine tumours, surgery is the only form of radical treatment", Bertani continues, "but unfortunately up to 30% of laparotomies fail to sterilise the tumour bed and thus control the tumour. Lymph node metastases recur in 10% of cases. The new probe therefore represents great progress and hope in the treatment of NETs although it must be emphasised that what changes the outcome is not so much the technology as the procedure. The probe is only effective if it is in the hands of an experienced surgeon".

"The excellent results obtained on neuroendocrine tumours encourage us to extend the study. A study in prostate cancer is already underway at IEO, and we plan to apply the beta probe procedure to other gastrointestinal tumours and gynaecological cancers as well" Ceci concludes.

Further Information

Riccardo Faccini
Department of Physics
riccardo.faccini@uniroma1.it