An updated clinical practice guideline from the American Society for Radiation Oncology substantially expands and modernizes recommendations for the use of radiation therapy in pancreatic cancer. Replacing ASTRO’s 2019 pancreatic cancer guideline, the new document incorporates evidence from recently published studies, including several practice-changing randomized trials, and provides expanded guidance on radiation dose escalation, target volumes, adaptive radiation therapy, and the use of radiation across a broader range of clinical settings.

Michael Chuong, M.D., vice chair and medical director of radiation oncology at Baptist Health Cancer Care, co-chaired the multidisciplinary guideline task force. The recommendations cover resectable, borderline resectable, locally advanced, recurrent, metastatic, and palliative disease, while placing greater emphasis on dose escalation and advanced treatment delivery.

Technology Has Changed What Radiation Can Accomplish

One of the guideline’s most consequential changes is a strong recommendation for radiation dose escalation, an approach that was not routinely recommended in the 2019 guideline. Advances in modern technology, including adaptive radiation therapy, allow ablative radiation doses to be delivered more safely in appropriately selected patients. The pancreas is surrounded by radiosensitive organs, especially the stomach and intestines, whose position relative to the tumor frequently changes due to respiration and day-to-day variations in internal anatomy. Historically, these constraints limited the radiation dose that could be delivered safely.

Newer platforms, including magnetic resonance-guided linear accelerators, allow clinicians to clearly visualize the tumor and nearby organs immediately before and during treatment. Online adaptive radiation therapy enables the treatment plan to be modified each day when anatomy changes, while respiratory motion management and continuous image guidance help maintain accuracy during delivery.

“These advances allow us to safely deliver substantially higher radiation doses that can improve clinical outcomes including local tumor control and potentially overall survival for select patients,” Dr. Chuong said. “We can also treat more comprehensively than was possible when the previous guideline was published.”

Prospective Evidence Supporting Ablative Treatment

Among the prospective studies informing the strong recommendation for dose escalation is the international, multi-institutional phase 2 SMART trial, in which Baptist Health Herbert Wertheim Cancer Institute was one of the highest enrolling centers and Dr. Chuong served as a co-principal investigator. The study evaluated 5-fraction stereotactic MR-guided on-table adaptive radiation therapy for patients with borderline resectable or locally advanced pancreatic cancer.

Long-term results from 136 patients showed encouraging survival and limited severe toxicity. Two-year overall survival was 53.6 percent from diagnosis and 40.5 percent from SMART treatment, which are substantially higher compared to historical outcomes after standard dose radiation therapy.

“The ability to deliver ablative doses of radiation increases the probability of long-term tumor control, and may also improve overall survival for some patients,” Dr. Chuong said. “That is especially important for patients with unresectable tumors who are not candidates for or decline surgery.”

Expanding the Treatment Target

The guideline also represents an important change in how clinicians define what should be targeted during treatment. The 2019 guideline recommended targeting the visible tumor without routine elective coverage during stereotactic body radiation therapy. The updated guideline now recommends routine elective coverage of nearby areas at high risk for microscopic disease, including peritumoral margins, extrapancreatic neural pathways, and regional nodal basins.

This recommendation is supported in part by research from Baptist Health Herbert Wertheim Cancer Institute. In a recently published retrospective study, Dr. Chuong and colleagues evaluated patterns of failure among 121 patients with nonmetastatic, inoperable pancreatic ductal adenocarcinoma treated with definitive ablative 5-fraction radiation therapy. As the institution’s elective target volumes evolved to encompass broader regions at risk for microscopic disease, locoregional failures decreased. In fact, no locoregional failures were observed among patients whose treatment included the full “triangle volume,” an area encompassing specific neural pathways and lymph node areas at high risk for microscopic spread.

The finding requires further prospective validation, but it challenges the assumption that smaller treatment volumes are necessarily preferable. Modern radiation planning may make it possible to combine an ablative dose to gross disease with a lower elective dose to surrounding high-risk anatomy without creating unacceptable toxicity.

Applying the Recommendations Beyond Locally Advanced Disease

The updated guideline also addresses radiation therapy indications for isolated locoregional recurrence, reirradiation, oligometastatic disease, oligoprogressive disease, and symptom palliation, settings in which supporting clinical evidence is limited but growing. The guideline conditionally supports definitive local therapy in several of these settings and recognizes emerging approaches such as celiac plexus radiosurgery for pancreatic cancer-related pain. It also addresses a historically understudied population whose tumors are technically resectable but are medically inoperable or decline surgery, recommending definitive chemoradiation or radiation therapy as a local treatment option.

Dr. Chuong emphasized that the strongest evidence for dose escalation and adaptive treatment remains in locally advanced, nonmetastatic pancreatic cancer. Extending these approaches to other pancreatic cancer settings is promising, but the prospective evidence is less mature although future trials are strongly recommended by the task force. Treatment decisions should therefore be individualized through multidisciplinary review, with careful consideration of systemic disease control, prior treatment, patient anatomy, performance status, and the ability to meet organ-at-risk constraints.

For physicians, the guideline signals that radiation therapy in pancreatic cancer should no longer be viewed primarily as a low-dose or palliative modality. In appropriately selected patients, modern radiation therapy can provide a definitive local treatment strategy that complements increasingly effective systemic therapy. The recommendations also underscore the importance of treatment at centers with the advanced imaging, adaptive planning capabilities, and pancreatic cancer expertise needed to deliver these approaches safely.