This prospective interventional clinical study evaluates the efficacy and safety of combining systemic chemotherapy followed by ablative stereotactic body radiotherapy (SBRT) as first-line treatment in adult patients with locally advanced, inoperable pancreatic cancer.

The study aims to determine the response rate after SBRT delivered following initial chemotherapy, as well as time to disease progression and treatment-related toxicity. Patients receive standard first-line chemotherapy and, in the absence of disease progression, undergo ablative SBRT to the primary tumor, followed by continuation of systemic therapy according to clinical practice.

The study is conducted in Slovenia, with patient enrollment expanded to additional participating clinical centers following an approved amendment.

Pancreatic cancer is a highly aggressive malignancy with poor prognosis. In patients with locally advanced pancreatic cancer (LAPC) who are not candidates for surgical resection, systemic chemotherapy is the standard first-line approach. However, local tumor progression remains a major cause of morbidity and mortality. Stereotactic body radiotherapy (SBRT) enables delivery of high-dose ablative radiation to the primary tumor while minimizing exposure of surrounding organs at risk.

This prospective interventional study investigates a combined treatment strategy consisting of initial systemic chemotherapy followed by ablative SBRT in adult patients with locally advanced, inoperable pancreatic cancer.

Eligible patients receive first-line systemic chemotherapy according to standard clinical practice. Patients without progression after initial chemotherapy are treated with ablative SBRT directed to the primary pancreatic tumor. After completion of SBRT, patients may continue systemic treatment based on clinical evaluation and institutional practice.

The primary objective of the study is to evaluate the response rate following ablative SBRT after initial chemotherapy. Secondary objectives include evaluation of time to disease progression and safety/tolerability of the combined treatment approach, including acute and late treatment-related toxicity.

The study is conducted as a non-randomized prospective clinical trial. Following an approved amendment, additional clinical centers in Slovenia were included to support recruitment and increase the number of enrolled participants.

Inclusion Criteria:

• Adults aged 18 years and older
• Locally advanced, inoperable pancreatic cancer
• Treated with first-line systemic chemotherapy followed by stereotactic body radiotherapy (SBRT) at participating centers
• Ability to provide written informed consent

Exclusion Criteria:

• Metastatic pancreatic cancer
• Prior systemic therapy for locally advanced pancreatic cancer (one or more previous lines of systemic treatment)
• Disease progression after initial chemotherapy prior to SBRT
• Any condition that, in the investigator's opinion, would interfere with study participation or evaluation