Ablative radiation therapy is considered to be an alternative to surgery, providing an effective noninvasive option for local treatment of many types of cancer, but it is unknown whether ablative radiation therapy is effective for pancreatic ductal adenocarcinoma. Surgery provides improved long-term survival for patients with pancreatic ductal carcinoma, with a benefit of avoiding metastatic disease. However, there is a potential risk for postoperative morbidity that could interfere with systemic therapy. Nonoperative options are needed for patients unable to have surgery.
In a single-institution study, Reyngold et al sought to determine whether definitive ablative radiation therapy might offer an effective alternative to surgery in cases of resectable pancreatic ductal adenocarcinoma. The study was published in JAMA Oncology.
Study Details
Researchers evaluated 25 consecutive patients treated at Memorial Sloan Kettering Cancer Center from a prospectively maintained database. All patients had histologically confirmed, resectable pancreatic ductal adenocarcinoma (T1-2N0–1M0) and were treated between June 2016 and December 2022. Due to non–cancer-related comorbidities, these patients were not eligible for surgery.
The median age of patients was 80 years (range = 74–87); 13 patients were male. Karnofsky performance status (KPS) was poor, with 20 patients having a KPS score of 80 or lower.
Patients received ablative radiation therapy in biologically effective doses exceeding 97.5 Gy with computed tomography or magnetic resonance imaging guidance, motion management, and daily or selective adaptation of the dose distribution. Thirteen patients received 75 Gy of radiation therapy in 25 fractions; 9 patients received 67.5 Gy in 15 fractions; 2 patients received 50 Gy in 5 fractions; and 1 patient received 60 Gy in 10 fractions.
Efficacy and Safety
The investigators reported an overall survival rate, the primary endpoint, of 43.7% at 2 years. Further, local progression at 2 years was 43.7% (95% confidence interval [CI] = 27.4%–69.5%) and distant metastasis–free survival was 20.0% (95% CI = 9.1%–43.8%). Grade 3 acute gastrointestinal tract toxic effects were reported in three patients and late grade 3 gastrointestinal tract toxic effects were reported in one patient. No grade 4 or higher events were reported.
Conclusions
The authors concluded, “In this cohort study of patients with surgically resectable pancreatic ductal adenocarcinoma, advanced age, poor [KPS] score, and limited chemotherapy use, [ablative radiation therapy] approaching 100-Gy [biologically effective dose] was associated with durable control of the primary tumor, favorable survival, and few toxic effects. These data provide the basis for a prospective evaluation of a nonoperative approach involving [ablative radiation therapy] in high-risk resectable pancreatic cancer.”
Marsha Reyngold, MD, PhD, of the Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, is the corresponding author of the study.
Disclosure: For full disclosures of all study authors, visit JAMAnetwork.com.
