L. Zhang1, B. Cao2, C. Wu2, and J. Wang1; 1Department of Radiation Oncology, First Medical Center of Chinese PLA General Hospital, Beijing, China, 2Chinese PLA Medical School, Beijing, China
Purpose/Objective(s): No studies have reported the use and efficacy of radiotherapy in early-onset pancreatic cancer (EOPC, age = 50 years at diagnosis). Therefore, we report the clinical characteristics and treatment outcomes of a cohort of patients with EOPC who received pancreatic radiotherapy. Materials/
Methods: This study reviewed EOPC patients who received radiotherapy for pancreatic lesions at our institution from 2017 to 2021. Endpoints included overall survival (OS), progression-free survival (PFS), and OS after diagnosis. The Kaplan-Meier method was used to estimate OS, and Cox regression analysis was used to assess prognostic factors. Results: The cohort included 77 patients with EOPC who underwent pancreatic lesions radiotherapy, with 76.6% of males and 57.1% of pancreatic head cancers. According to the staging at the time of radiotherapy, localized, locally advanced, distant metastasis, postoperative regional recurrence, and systemic recurrence accounted for 6.5% (5/77), 31.2% (24/77), 29.9% (23/77), 26.0% (20/77), and 6.5% (5/77) of the cases, respectively. The median tumor volume was 39.7 cm3; the median biologically equivalent dose (BED, a/ß = 10) was 78.6 Gy; and the median time from diagnosis to radiotherapy was 8.3 months. Thirty-three (42.9%) of the patients were treated with intensity-modulated radiotherapy (IMRT) with the planned target volume (PTV) dose of 45-54 Gy and the gross target volume (GTV) dose of 60-65 Gy in 25-30 fractions. Forty-four patients (57.1%) received stereotactic body radiotherapy (SBRT) with the PTV of 37.5-55 Gy delivered in 5-10 fractions. Patients who received surgery, chemotherapy, and no treatment before radiotherapy accounted for 41.6%, 74.0%, and 16.9%, respectively. Patients who received chemotherapy, re-radiotherapy, and no treatment after radiotherapy were 51.9%, 11.7%, and 41.6%, respectively. The median OS (mOS) and mOS after diagnosis were 13.9 months (95% CI: 9.2-18.4 months) and 26.1 (95% CI: 23.1-30.1 months) for the whole group, respectively. The mOS for patients with localized/locally advanced, regional recurrence, and distant metastasis/systemic recurrence were 18.4 months, 16.1 months, and 6.7 months, respectively (p = 0.016). The mPFS for patients with localized/locally advanced and regional recurrence were 10.8 months and 9.2 months, respectively. The mOS for patients who received IMRT and SBRT was 10.4 and 14.1 months (p = 0.15), respectively. There were no Grade 3 or higher treatment-related adverse events. Distant metastasis (HR = 2.63, p = 0.026), adjuvant chemotherapy after radiotherapy (HR = 0.55, p = 0.050), and BED = 80Gy (HR = 2.40, p = 0.016) were independent influences on OS. Conclusion: Radiotherapy can be used in a variety of clinical scenarios in EOPC. A better prognosis can be achieved in patients with inoperable localized, locally advanced and postoperative recurrent EOPC, but the outcome is suboptimal in metastatic patients. Higher BED and adjuvant chemotherapy are associated with a better prognosis.
