Stereotactic Body Radiosurgery for Pelvic Relapse of Gynecologic Malignancies

Abstract

Clinical management of pelvic relapses from gynecologic malignancies remains challenging. Bulky pelvic relapses often lead to symptomatic cancer-related complications and poor clinical outcomes. Options may be limited by prior surgical, chemotherapeutic, and radiation treatment. Stereotactic body radiosurgery is a novel treatment modality which allows high radiation dose delivery in a non-coplanar fashion with sub-millimeter precision utilizing a linear accelerator mounted on a robotic arm. This study details our clinical experience with stereotactic body radiosurgery for treatment of patients with pelvic relapses of gynecologic malignancies after prior pelvic radiation.

Stereotactic Radiosurgery for Gynecologic Cancer

“…7,8,15 Data question radiobiological effects and mode of cell death resulting from SBRT. Small clinical studies have shown that ablative radiation doses provided by SBRT produce targeted disease control rates exceeding 90%.…”

“…Clinical target volume (CTV) expansion by 0.5 cm, resulting in a larger planning target volume (PTV), is associated with increased target control without undue normal tissue injury. 7,8 Further reduction in the probability of geographic miss may be achieved by incorporation of 2- …”

“…[1][2][3] Intrafraction motion of cancer targets due to breathing now can be reduced by patient-responsive breath hold techniques, 4 patient mouthpiece active breathing coordination, 5 respiration-correlated computed tomography, 6 or image-guided tracking of fiducials implanted within and around a moving tumor. [7][8][9] The Cyberknife system (Accuray [Sunnyvale, CA]) utilizes a radiation linear accelerator mounted on a industrial robotic arm that accurately follows patient respiratory motion by a camera-tracked set of light-emitting diodes (LED) impregnated on a vest fitted to a patient. 10 Substantial reductions in radiation therapy margins can be achieved by motion tracking, ultimately rendering a smaller planning target volumes that are irradiated with submillimeter accuracy.…”

Stereotactic body radiation therapy in head and neck, gynecologic, and pediatric malignancies

“…Innovative technology effectively pairing clinical radiation accelerators to helical scanners (Tomotherapy [25,26]) or to robotic arm mounts (Cyberknife®, [27][28][29][30]) with respiratory gating [31,32] has been a market force for recently-realized radiotherapeutic gains in gynecologic radiation oncology [33]. For purposes of discussion here, the subclass of stereotactic radiosurgery dealing with robotics [Cyberknife®, Accuray (Sunnyvale, CA, USA)] will be the focus given the preponderance of clinical data accumulated worldwide [27][28][29][30]. Robotic cyberknife stereotactic body radiosurgery for gynecologic cancers most commonly involves ablative dose (>8 Gy) delivery [34,35], over a 30-60-min irradiation time span, with sub-millimeter precision [36,37] and with motion tracking [38] all in an effort to avoid injury to normal abdominopelvic tissues.…”

“…For purposes of discussion here, the subclass of stereotactic radiosurgery dealing with robotics [Cyberknife®, Accuray (Sunnyvale, CA, USA)] will be the focus given the preponderance of clinical data accumulated worldwide [27][28][29][30]. Robotic cyberknife stereotactic body radiosurgery for gynecologic cancers most commonly involves ablative dose (>8 Gy) delivery [34,35], over a 30-60-min irradiation time span, with sub-millimeter precision [36,37] and with motion tracking [38] all in an effort to avoid injury to normal abdominopelvic tissues. Paramount to the integration of robotic stereotactic body radiosurgery in clinical radiation oncology practice is better understanding of natural systems of DNA damage repair.…”