Mycosis fungoides: electron beam therapy in England

Since 1962, total-skin electron-beam therapy has been available in London, England, for the treatment of patients with mycosis fungoides and skin lymphomas. The 6-mev linear accelerator produces a pencil beam of electrons at 7 mev, which are scattered through a brass scatterer and decelerated by either of two carbon decelerators or a copper decelerator to produce a beam of effective energy of 2.5, 3, or 3.5 mev; these beams have an 80% isodose distribution at 5.5, 8, and 11.5 mm, respectively. The patient receives 200 rads to the anterior, posterior, and right and left lateral fields, for a total dose of between 1600 and 2600 ras in ten treatments over 5--7 weeks. Complete clearing of the disease can be predicted in all patients except those with the most advanced tumors. However, the duration of remission after electron-beam therapy is approximately 18 months and we are presently investigating the combination of psoralens and ultraviolet light therapy as maintenance treatment following lower-dose electron-beam therapy.