Reirradiation for locally recurrent lung cancer in the chest wall with boron neutron capture therapy (BNCT)

Reirradiation is rarely applied to locally recurrent tumor in the previously irradiated region due to the expectation of severe side effects. Boron neutron capture therapy (BNCT) can deposit a large dose with a steep gradient between the tumor and surrounding normal tissues. We treated a patient with recurrent lung cancer in the previously irradiated chest wall with two-fractionated BNCT. In this case, most of the tumor regressed at seven months after the BNCT. No acute or late adverse events were observed. Locally re-recurrent tumor was found at the margin of the radiation field due to the inhomogeneous distribution of the neutron beam in the beam field. Although two-fractionated BNCT may be feasible for the treatment of locally recurrent shallow-seated tumors, especially from the view of palliation, attempts to improve the dose distribution should be considered.