Date Published: June 29, 2017
Publisher: Public Library of Science
Author(s): Jia-Cheng Lee, Keh-Shih Chuang, Yi-Wei Chen, Fang-Yuh Hsu, Fong-In Chou, Sang-Hue Yen, Yuan-Hung Wu, Deric M. Park.
Diffuse intrinsic pontine glioma is a very frustrating disease. Since the tumor infiltrates the brain stem, surgical removal is often impossible. For conventional radiotherapy, the dose constraint of the brain stem impedes attempts at further dose escalation. Boron neutron capture therapy (BNCT), a targeted radiotherapy, carries the potential to selectively irradiate tumors with an adequate dose while sparing adjacent normal tissue. In this study, 12 consecutive patients treated with conventional radiotherapy in our institute were reviewed to evaluate the feasibility of BNCT. NCTPlan Ver. 1.1.44 was used for dose calculations. Compared with two and three fields, the average maximal dose to the normal brain may be lowered to 7.35 ± 0.72 Gy-Eq by four-field irradiation. The mean ratio of minimal dose to clinical target volume and maximal dose to normal tissue was 2.41 ± 0.26 by four-field irradiation. A therapeutic benefit may be expected with multi-field boron neutron capture therapy to treat diffuse intrinsic pontine glioma without craniotomy, while the maximal dose to the normal brain would be minimized by using the four-field setting.
Diffuse intrinsic pontine glioma (DIPG) is a very frustrating disease for patients, families, and doctors. Because of the tumor’s location in the brain stem, surgical removal is often impossible. For radiotherapy, the dose constraint of the brain stem impedes dose escalation. Almost all patients expire within 1 year of diagnosis despite radical treatment. Boron neutron capture therapy (BNCT), a targeted radiotherapy, may have the potential to deliver an adequate radiation dose to the tumor cells while sparing the normal brain stem.
In this study, we reviewed the simulation CT scans of 12 consecutive patients treated by conventional radiotherapy in our institution. We found that, without craniotomy, the prescribed therapeutic dose to the CTV may be fulfilled while complying with the dose constraints to the NB, ON, and CW. Specifically, a therapeutic benefit may be achieved by applying multi-field BNCT to treat DIPG without craniotomy, while the therapeutic gain, defined by CTVmin/NTmax, was greatest in 3F and 4F plans. To the best of our knowledge, the current study is the first to show that, dosimetrically, treatment of DIPG by BNCT without craniotomy may be feasible.
Therapeutic benefits may be achieved using multi-field BNCT in patients with DIPG. The maximal dose to normal brain would be minimal and the prescription dose to tumor would be higher by four fields. To initiate a clinical trial on this devastating disease might be worthwhile.