Dose-escalated SBRT for borderline and locally advanced pancreatic cancer. Feasibility, safety and preliminary clinical results of a multicenter study

B Salas; L Ferrera-Alayón; A Espinosa-López; A Vera-Rosas; E Salcedo; A Kannemann; A Alayon; R Chicas-Sett; M LLoret; P C Lara

doi:10.1016/j.ctro.2024.100753

Dose-escalated SBRT for borderline and locally advanced pancreatic cancer. Feasibility, safety and preliminary clinical results of a multicenter study

Clin Transl Radiat Oncol. 2024 Feb 23:45:100753. doi: 10.1016/j.ctro.2024.100753. eCollection 2024 Mar.

Authors

B Salas¹, L Ferrera-Alayón^{1

2}, A Espinosa-López³, A Vera-Rosas¹, E Salcedo¹, A Kannemann¹, A Alayon¹, R Chicas-Sett⁴, M LLoret^{1

2

5}, P C Lara^{5

6

7}

Affiliations

¹ Department of Radiation Oncology University Hospital Dr Negrín Las Palmas de Gran Canaria, Barranco de la Ballena s/n, 35010 Las Palmas de Gran Canaria, Spain.
² Las Palmas de Gran Canaria University (ULPGC) ,C. Juan de Quesada, 30, 35001 Las Palmas de Gran Canaria,Spain.
³ Department of Radiation Oncology, University Hospital Virgen de la Arrixaca, Carretera Madrid-Cartagena, S/N, 30120 El Palmar (Murcia), Spain.
⁴ Department of Radiation Oncology, ASCIRES GRUPO BIOMEDICO, Valencia, Spain.
⁵ Instituto Canario de Investigacion del Cáncer ICIC.
⁶ Canarian Comprehensive Cancer Center, Department of Oncology University Hospital San Roque, C. Dolores de la Rocha, 5, 35001 Las Palmas de Gran Canaria, Spain.
⁷ Fernando Pessoa Canarias University, Calle la Juventud, s/n, 35450 Guía, Las Palmas de Gran Canaria, Spain.

Abstract

Background: Pancreatic Stereotactic Body Radiotherapy (SBRT) allows for the administration of a higher biologically effective doses (BED), that would be essential to achieve durable tumor control. Escalating treatment doses need a very accurate tumor positioning and motion control during radiotherapy.The aim of this study to assess the feasibility and safety of a Simultaneous Integrated Boost (SIB) dose-escalated protocol at 45 Gy, 50 Gy and 55 Gy in 5 consecutive daily fractions, in Border Line Resectable Pancreatic Cancer (BRCP) /Locally Advanced Pancreatic Cancer (LAPC) by means of a standard LINAC platform.

Methods: Patients diagnosed of BRPC/LAPC, candidates for neoadjuvant chemotherapy and SBRT, in four university hospitals of the province of Las Palmas (Canary Islands, Spain) were included in this prospective study. Radiotherapy was administered using standard technology (LINACS) with advanced positioning (Lipiodol® and metallic stent used as fiducial markers) and tumor motion control (4D, DBH, Calypso®). There were 3 planned dose-escalated SIB groups, 45 Gy/5f (9 patients) 50 Gy/5f (9 + 9 patients) and 55 Gy/5f (9 patients). The defined primary end points of the study were the safety and feasibility of the proposed treatment protocol. Secondary endpoints included radiological tumor response after SBRT, local control and survival.

Results: From June 2017 to December 2022, sixty-two patients were initially assessed for eligibility in the study in the four participating centers, and 49 were candidates for chemotherapy (CHT). Forty-one were referred to radiotherapy after CHT and 33 finally were treated by escalated-dose SIB, 45 Gy (9 patients) 50 Gy (16 patients), 55 Gy(8 patients). All patients completed the scheduled treatment and no acute or late severe (≥grade3) gastrointestinal toxicity was observed.Local response was analyzed by CT/MRI two months after the end of SBRT. Ten patients (31,25 %) achieved objective response (2/9:45 Gy, 5/15:50 Gy, 3/8:55 Gy). Follow-up was closed as July 2023. Freedom from local progression at 1-2y were 89,3% (95 %CI:83,4-95,2%) and 66 % (95 %CI:54,6-77,4%) respectively. The 1-2y survival rates were 95,7% (95 %CI:91,4-100 % and 48,6% (95 %CI:37,7-59,5%) respectively.

Conclusion: These promising results should be confirmed by further studies with larger sample size and extended follow-up period.

Keywords: BRPC; Escalated dose; Feasibility; LAPC; SIB; Safety; sbrt.