Until now, the following has been true for metastatic pancreatic cancer: Once the tumour has spread, local treatment such as surgery is usually no longer an option. In recent years, however, studies have suggested that there is a small group of patients with a limited number of metastases (oligometastases) who can benefit from a combination of drug and local therapy. Until now, however, there has been no uniform definition for this situation. Now, for the first time, an international group of experts led by MedUni Vienna has developed such a consensus. The results of the "OligoPanc" project, currently published in the top journal The Lancet Oncology, pave the way for improving specific treatment strategies.

Fifty-five experts from 20 countries and five medical disciplines participated in the structured consensus process. The project was coordinated by Carl-Stephan Leonhardt and Oliver Strobel (both from the Department of General Surgery, MedUni Vienna) and Gerald W. Prager (Department of Medicine I, MedUni Vienna). In a multi-stage, anonymous voting process ("Delphi process") and on the basis of case studies, the members of the group agreed for the first time on key criteria for defining oligometastasis in pancreatic cancer. The consensus was that a maximum of three metastases in a single organ are considered oligometastatic. The liver and lungs were defined as the organs affected. A distinction is made between synchronous oligometastasis, which is already present at the time of initial diagnosis, and metachronous oligometastasis, which only develops during the course of the disease. In the metachronous form, a longer interval between initial diagnosis and the occurrence of metastases is considered a favourable sign for the prognosis.

For the diagnosis of oligometastasis in pancreatic cancer, there is consensus among the expert group on the necessary imaging, in particular contrast-enhanced computed tomography of the chest and abdomen and magnetic resonance imaging of the liver. The diagnosis should always be made by a multidisciplinary tumour board, i.e. a team from various disciplines such as surgery, oncology, radiology and radiotherapy.

Treatment recommendations were developed on the basis of case studies: in the case of oligometastatic pancreatic cancer, the majority of experts recommended local treatment, usually surgery or radiotherapy, in addition to systemic chemotherapy. In cases of synchronous oligometastasis, surgical removal of the primary tumour and metastases was more frequently recommended, while in cases of metachronous metastases, surgical removal or radiation of the metastases was recommended.

"Pancreatic cancer is one of the most aggressive types of cancer and has a high mortality rate," says Oliver Strobel. "With the consensus definition that has now been developed, we can clearly define for the first time which patients can be diagnosed to have an oligometastatic situation. This is an essential prerequisite for specifically identifying those patients who could potentially benefit from local treatment in addition to systemic therapy." In addition, the new uniform definition enables study results on oligometastatic pancreatic cancer to be compared and advances the development of specific treatment strategies.