Stereotactic Body Radiotherapy for Extracranial Oligometastatic Pancreatobiliary Cancer.

AIMS: In an oligometastatic disease, stereotactic body radiotherapy (SBRT) is being increasingly used in many different histologies to delay progression. However, by virtue of pancreatobiliary cancers not being as common and more aggressive natural history, data on its usage in pancreatobiliary cancers have been limited. Herein, our study aims to evaluate the outcomes of extracranial SBRT for oligometastatic pancreatobiliary cancers.

MATERIALS AND

METHODS

A retrospective review was conducted on patients with oligometastatic pancreatobiliary cancer treated with extracranial SBRT between 2014 and 2023 at our institution. The analysis examined cumulative incidence of local failure (LF), progression-free survival (PFS), cumulative incidence of starting or changing systemic therapy (SCST), overall survival (OS) and Radiation Therapy Oncology Group-graded treatment-related toxicities. Kaplan-Meier methodology and Cox proportional hazard models were used for survival analysis.

RESULTS

Among the 62 patients (115 lesions) identified, the median follow-up was 13.4 months. By primary location, 71% had pancreatic cancer, 15% had cholangiocarcinoma, and 15% had ampullary cancer. Synchronous and metachronous oligometastatic disease was 37% and 63%, respectively. Eighty-seven percent of patients had 1-2 lesions treated with SBRT. At 12 months, LF, PFS, SCST, and OS was 21.5%, 28.0%, 33.6% and 61.7%, respectively. On multivariable analysis, the only predictor of worse PFS was higher PTV volume. No grade 3-5 toxicities were reported.

CONCLUSION

Similar to other cancers, SBRT appears to be a promising option for those with oligometastatic pancreatobiliary cancer. More research in how to optimise integration of SBRT in a multidisciplinary setting for this challenging disease would be of benefit.