An Evaluation of Total Internal Motions of Locally Advanced Pancreatic Cancer during SABR Using Calypso® Extracranial Tracking, and Its Possible Clinical Impact on Motion Management.

Hrvoje Kaučić,Dragan Schwarz,Vanda Leipold,Adlan Čehobašić,Hrvoje Šobat,Mihaela Mlinarić,Ivo Pedišić,Domagoj Kosmina,Andreas Mack,Matea Lekić

doi:10.3390/curroncol28060389

Hrvoje Kaučić, Dragan Schwarz + Show 8 more

Open Access

https://doi.org/10.3390/curroncol28060389

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Journal: Current Oncology	Publication Date: Nov 11, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: University of Osijek, University of Rijeka

Abstract

(1) Background: the aims of this study were to determine the total extent of pancreatic cancer’s internal motions, using Calypso® extracranial tracking, and to indicate possible clinical advantages of continuous intrafractional fiducial-based tumor motion tracking during SABR. (2) Methods: thirty-four patients were treated with SABR for LAPC using Calypso® for motion management. Planning MSCTs in FB and DBH, and 4D-CTs were performed. Using data from Calypso® and 4D-CTs, the movements of the lesions in the CC, AP and LR directions, as well as the volumes of the 4D-CT-based ITV and the volumes of the Calypso®-based ITV were compared. (3) Results: significantly larger medians of tumor excursions were found with Calypso® than with 4D-CT: CC: 29 mm (p < 0.001); AP: 14 mm (p < 0.001) and LR: 11 mm (p < 0.039). The median volume of the Calypso®-based ITV was significantly larger than that of the 4D-CT based ITV (p < 0.001). (4) Conclusion: beside known respiratory-induced internal motions, pancreatic cancer seems to have significant additional motions which should be considered during respiratory motion management. Only direct and continuous intrafractional fiducial-based motion tracking seems to provide complete coverage of the target lesion with the prescribed isodose, which could allow for safe tumor dose escalation.

Highlights

Patients with unresectable, locally advanced pancreatic cancer (LAPC) still represent one of the most challenging subset of patients in oncology
Most of the studies published in recent years have reported the data of recorded pancreatic cancer movements or reductions of movements collected during respiratory motion management techniques, such as motion mitigation, deep breath hold gating, respiratory gating, or retrospective 4D-CT planning, or they have reported the data of pancreatic cancer movements recorded using fluoroscopic cone beams during fiducial tracking
Our findings suggest that there is a possibility that the usage of respiratory motion management or mitigation of solely respiratory movements during Stereotactic ablative radiotherapy (SABR) could result in dose undercoverage of peripheral portions of the pancreatic tumor, as they could protrude out of the planning target volume (PTV), at some time during treatment

Summary

Introduction

Locally advanced pancreatic cancer (LAPC) still represent one of the most challenging subset of patients in oncology. Of patients, respectively [2]. A significant proportion of patients with LAPC, especially those with poor performance status, are still treated as patients with distant disease [3]. The addition of radiochemotherapy can be beneficial, but its role in the course of treatment still remains unclear [4]. Stereotactic ablative radiotherapy (SABR) has emerged as an effective and safe form of local treatment for patients with LAPC in recent years, but, similar to chemoirradiation, the value of SABR in terms of prognosis is unclear [4,5,6,7,8]

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