Impact of Using Corticosteroid Prophylaxis to Prevent Tumor Flare Reactions During ¹⁷⁷Lu-DOTATATE Treatment in...

Since ¹⁷⁷Lu-DOTATATE was approved for patients with somatostatin receptor (SSTR)-positive gastroenteropancreatic neuroendocrine tumors (NETs), tumor flare reactions including increased pain and small bowel obstruction (SBO) have been reported. Retrospective reviews report some success in using corticosteroids for treatment and prophylaxis of tumor flare reactions from ¹⁷⁷Lu-DOTATATE. Given that corticosteroids are used in practice to help prevent tumor flare reactions based on limited evidence, we aimed to assess if this practice was efficacious in our patient population.

In this retrospective and single-institution study, we identified adult patients with NETs who were treated with ¹⁷⁷Lu-DOTATATE between 1 October 2019 and 31 December 2024; these patients received corticosteroids as prophylaxis for flare reactions due to high burden of disease, significant peritoneal or mesenteric disease, or disease involvement of critical structures as determined by the treating provider. Variables including demographics, diagnosis, treatment history, steroid dosing, and outcomes were collected within a RedCAP database.

Forty-six patients were identified as having received corticosteroid prophylaxis to prevent a tumor flare reaction due to ¹⁷⁷Lu-DOTATATE. Patients had a median age of 66, and 50% were female. The primary disease site was the small intestine (72%) followed by the pancreas (9%). The majority of patients had World Health Organization (WHO) grade 1 (41%) or WHO grade 2 (35%) diseases. Most patients (83%) received corticosteroids prior to the initiation of ¹⁷⁷Lu-DOTATATE, while 17% of patients received corticosteroids due to having a previous tumor flare after ¹⁷⁷Lu-DOTATATE administration. Despite corticosteroid prophylaxis, 28% of patients still experienced a tumor flare event, with three patients experiencing multiple tumor flare events. Small bowel obstructions occurred in 7% of patients and increased abdominal pain in 22% of patients. Adverse events (AEs) due to corticosteroids occurred in 28% of patients.

Short-course corticosteroid prophylaxis to prevent tumor flare reactions in high-risk patients with neuroendocrine tumors treated with ¹⁷⁷Lu-DOTATATE did not appear to decrease the incidence of tumor flare reactions compared to previously reported numbers. Randomized, placebo-controlled trials looking at the use of corticosteroids to prevent tumor flare reactions in patients treated with ¹⁷⁷Lu-DOTATATE are needed to fully elucidate the safety and efficacy of corticosteroids used in this setting and to determine the impact on treatment outcomes.