Outcomes after high-dose radiation in the management of neuroendocrine neoplasms

• Published in: PloS one Vol. 16; no. 6; p. e0252574
• Main Authors: Chen, Katherine S, Lawhn-Heath, Courtney, Behr, Spencer, Juarez, Roxanna, Whitman, Julia, Paciorek, Alan, Nakakura, Eric K, Fidelman, Nicholas, Feng, Mary Uan-Sian, Bergsland, Emily K, Anwar, Mekhail
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 02-06-2021; Public Library of Science (PLoS)
• Subjects: Adult; Aged; Auroral kilometric radiation; Cancer; Dose-Response Relationship, Radiation; Editing; Electronic mail; Epidemiology; Female; Follow-Up Studies; Health aspects; Hematology; Humans; Male; Medical treatment; Medicine and Health Sciences; Metastasis; Middle Aged; Morbidity; Neoplasm Recurrence, Local - radiotherapy; Neoplasms; Neuroendocrine tumors; Neuroendocrine Tumors - radiotherapy; Oncology; Patients; Radiation; Radiation dosage; Radiation therapy; Radioisotopes; Radiology; Recovery time; Response Evaluation Criteria in Solid Tumors; Retrospective Studies; Surgery; Treatment Outcome; United States; United States > US; San Francisco California; California
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0252574

Neuroendocrine neoplasms (NENs) comprise a rare and heterogenous group of cancers, for which the role of radiation therapy continues to evolve. The purpose of this study is to analyze oncologic outcomes after the use of high-dose radiation in management of NENs at a tertiary hospital.
We performed a retrospective review of patients who received high-dose radiation with intent to cure or provide durable local control (defined as biologically effective dose (BED) ≥40, α/β = 10) for a localized or metastatic NEN from 2006 to 2019. Evaluation of disease status after radiation was performed according to Response Evaluation Criteria in Solid Tumors (RECIST) criteria when possible. Patients were grouped by differentiation (well-differentiated (WD) or poorly-differentiated (PD)) and stage (localized/locally advanced disease (L) or metastatic (M)) in analysis of probabilities of progression after radiation.
45 patients completed a radiation course with BED ≥40 for a NEN (median BED 72). With a median follow-up of 24 months after radiation, the 2-year actuarial rates of local relapse-free survival, new metastasis-free survival, progression-free survival, and overall survival after radiation were 98%, 45%, 41%, and 69%, respectively. 25 patients (56%) developed new metastases after completion of radiation, including 33% (n = 3) of patients with WD-L disease, 44% (n = 8) of WD-M, 77% (n = 10) of PD-L, and 80% (n = 4) of PD-M, with progressively shorter median times to progression (26, 9, 8, and 3 months, respectively; p = 0.093). Of the 25 patients evaluable by RECIST, 68% (n = 17) achieved either a complete or partial best response in the irradiated lesion.
These data suggest that focal, high-dose radiation has a role in the management of selected patients with NENs. Local failure is rare in patients with both well-differentiated and poorly-differentiated disease, although the predominant pattern of failure remains development of new metastases.