Comparison of coplanar and noncoplanar intensity-modulated radiation therapy and helical tomotherapy for hepatocellular carcinoma

Abstract

BackgroundTo compare the differences in dose-volume data among coplanar intensity modulated radiotherapy (IMRT), noncoplanar IMRT, and helical tomotherapy (HT) among patients with hepatocellular carcinoma (HCC) and portal vein thrombosis (PVT).MethodsNine patients with unresectable HCC and PVT underwent step and shoot coplanar IMRT with intent to deliver 46 - 54 Gy to the tumor and portal vein. The volume of liver received 30Gy was set to keep less than 30% of whole normal liver (V30 < 30%). The mean dose to at least one side of kidney was kept below 23 Gy, and 50 Gy as for stomach. The maximum dose was kept below 47 Gy for spinal cord. Several parameters including mean hepatic dose, percent volume of normal liver with radiation dose at X Gy (Vx), uniformity index, conformal index, and doses to organs at risk were evaluated from the dose-volume histogram.ResultsHT provided better uniformity for the planning-target volume dose coverage than both IMRT techniques. The noncoplanar IMRT technique reduces the V10 to normal liver with a statistically significant level as compared to HT. The constraints for the liver in the V30 for coplanar IMRT vs. noncoplanar IMRT vs. HT could be reconsidered as 21% vs. 17% vs. 17%, respectively. When delivering 50 Gy and 60-66 Gy to the tumor bed, the constraints of mean dose to the normal liver could be less than 20 Gy and 25 Gy, respectively.ConclusionNoncoplanar IMRT and HT are potential techniques of radiation therapy for HCC patients with PVT. Constraints for the liver in IMRT and HT could be stricter than for 3DCRT.

Vascular invasion affects survival in early hepatocellular carcinoma

“…Several modalities, including surgical resection, transcatheter arterial chemoembolization (TACE) and arterial infusion chemotherapy, percutaneous ethanol injection therapy, microwave coagulation therapy, radiotherapy and liver transplantation, have been used in the treatment of HCC (2,3). The optimal choice for patients with early HCC is surgery, as resection may be easily performed, with low mortality rates (4).…”

Noncoplanar verification: a feasibility study using Philips' Pinnacle3 treatment planning system

“…This goal can be achieved by implementing techniques such as 3D‐conformal radiation therapy, intensity‐modulated radiation therapy (IMRT), and intensity‐modulated arc therapy (IMAT). In combination with these techniques, noncoplanar beams play an important role, especially when the organs at risk need to be better spared without sacrificing the dose distribution conformity of the tumor 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . For example, Wang et al (9) showed that in 80% of the cases noncoplanar beam configurations were more effective than the coplanar beams to spare the anatomic structures critical to vision for the treatment of paranasal sinus carcinoma.…”

A dose-volume intercomparison of volumetric-modulated arc therapy, 3D static conformal, and rotational conformal techniques for portal vein tumor thrombus in hepatocellular carcinoma

“…The use of three-dimensional static conformal radiotherapy (3D-CRT) for PVTT was also reported; the local control rate ranged from 37.5–57.9%, and the median survival period ranged from 6.7–10.7 months [14–20]. In addition, intensity-modulated radiotherapy (IMRT), volumetric-modulated arc therapy (VMAT), and tomotherapy were also employed for treating PVTT [21, 22]. However, to the best of our knowledge, dose-escalation studies using VMAT for PVTT have not been reported.…”