Reduction of Respiratory Liver Tumor Motion by Abdominal Compression in Stereotactic Body Frame, Analyzed by Tracking Fiducial Markers Implanted in Liver

Self Cite

Metastases LiverStereotactic body radiation therapy a b s t r a c t Aim: To investigate whether the impact of dose escalation in our patient population represented an improvement in local control without increasing treatment related toxicity. Materials and methods:A cohort of consecutive patients with colorectal liver metastases treated with stereotactic body radiation therapy (SBRT) between December 2002 and December 2013 were eligible for this study. Inclusion criteria were a Karnofsky performance status ≥80% and, according to the multidisciplinary tumor board, ineligibility for surgery or radiofrequency ablation. Exclusion criteria were a lesion size >6 cm, more than 3 metastases, and treatment delivered with other fractionation scheme than 3 times 12.5 Gy or 16.75 Gy prescribed at the 65-67% isodose. To analyze local control, CT or MRI scans were acquired during follow-up. Toxicity was scored using the Common Toxicity Criteria Adverse Events v4.0.Results: A total of 40 patients with 55 colorectal liver metastases were included in this study.We delivered 37.5 Gy to 32 lesions, and 50.25 Gy to 23 lesions. Median follow-up was 26 and 25 months for these two groups. Local control at 2 and 3 years was 74 and 66% in the low dose group while 90 and 81% was reached in the high dose group. No significant difference in local control between the two dose fractionation schemes could be found. Grade 3 toxicity was limited and was not increased in the high dose group.Conclusions: SBRT for colorectal liver metastases offers a high chance of local control at long term. High irradiation doses may contribute to enhance this effect without increasing toxicity.

Section: Treatment Preparation and Deliverymentioning

confidence: 99%

Institutional experience in the treatment of colorectal liver metastases with stereotactic body radiation therapy

Romero

Keskin-Cambay

et al. 2017

Self Cite

“…2,3 Several techniques can be used to manage tumor motion, such as active breath control, abdominal compression, respiratory gating and real-time tumor tracking. [4][5][6][7][8][9] In this study, we used the respiratory gating technique with an external surrogate placed on the patient's abdominal wall associated with implanted fiducial markers to manage liver motion. 5,10 The aim of this technique is to limit the radiation exposure during specific phases of the breathing cycle and to create a correlation model between the internal target motion and the external surrogate (skin surface), and finally to control the radiation beam delivery thanks to the external surrogate signal.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of reproducibility of tumor repositioning during multiple breathing cycles for liver stereotactic body radiotherapy treatment

Bedos

Riou

Aillères

et al. 2017

a b s t r a c tAim: To evaluate the tumor repositioning during gated volumetric modulated arc therapy (VMAT) for liver stereotactic body radiotherapy(SBRT) treatment using implanted fiducial markers and intrafraction kilovoltage (kV) images acquired during dose delivery. Materials and methods:Since 2012, 47 liver cancer patients with implanted fiducial markers were treated using the gated VMAT technique with a Varian Truebeam STx linear accelerator.The fiducial markers were implanted inside or close to the tumor target before treatment simulation. They were defined at the maximum inhalation and exhalation phases on a 4-dimensionnal computed tomography (4DCT) acquisition. During the treatment, kV images were acquired just before the beam-on at each breathing cycle at maximum exhalation and inhalation phases to verify the fiducial markers positions. For the five first fractions of treatment in the first ten consecutive patients, a total of 2705 intrafraction kV images were retrospectively analyzed to assess the differences between expected and actual positions of the fiducial markers along the cranio-caudal (CC) direction during the exhalation phase. Results:The mean absolute intrafractional fiducial marker deviation along the CC direction was 1.0 mm at the maximum exhalation phase. In 99%, 95% and 90% cases, the fiducial marker deviations were ≤4.5 mm, 2.8 mm and 2.2 mm, respectively. Conclusion:Intrafraction kV images allowed us to ensure the consistency of tumor repositioning during treatment. In 99% cases, the fiducial marker deviations were ≤4.5 mm corresponding to our 5 mm treatment margin. This margin seems to be well-adapted to the gated VMAT SBRT treatment in liver disease.

“…26,27 Although several techniques, like the use of active breath control devices (allowing a gated beam delivery) and Stereotactic body frame (with or without an abdominal compression plate), have attempted to negate liver motion or to reduce it. [28][29][30] The management of intrafraction variability in liver position remains aleatory.…”

Section: Discussionmentioning

confidence: 99%

Imaged-guided liver stereotactic body radiotherapy using VMAT and real-time adaptive tumor gating. Concerns about technique and preliminary clinical results

Llacer-Moscardo

Riou

Azria

et al. 2017