Recent Clinical Experience with the Grid in the X-Ray Treatment of Advanced Cancer

When all sites and types of cancer are included, the cure rate from currently accepted methods of treatment does not exceed 25 per cent. This means that about 75 per cent of all cancer victims must be considered incurable and can be treated only palliatively for prolongation of useful life or relief of symptoms, or both. The value of radiotherapy as a palliative agent is not universally appreciated. There is often a lack of interest in the hopeless or incurable patient and either no active treatment is given or only meaningless token therapy. Recently, renewed interest has been displayed in the use of grids for roentgen therapy of advanced cancers. Grids have been used in roentgen therapy since 1909, when Alban Köhler (1) made his first report. Later, in 1933, Liberson (2) suggested the use of a metallic lead grid and worked out the biological and physical aspects which are, for the most part, valid to this day. Others, including Haring (3), Grynkraut (4), and Jolles (5) have also suggested the use of grids, all to the same end, to improve the dose to the tumor without compromising normal tissues. Biophysicists have repeatedly indicated a greater normal tissue tolerance to ionizing radiation through small portals in experimental animals (6), and in the recent work with grids it has been shown that this increased tolerance may be obtained through the use of large aggregates of small portals separated by relatively opaque areas. The most recent clinical report on this subject in this country was made in June 1949, by Dr. Hirsch Marks, who read a paper on the use of a grid with roentgen therapy before the Radiological Section of the American Medical Association in Atlantic City. In February 1950, Marks presented some of his treated patients at the Mount Sinai Hospital, New York. Two features which impressed us at this time were the degree of palliation obtained and the tolerance of normal tissue for doses of x-ray in excess of any hitherto employed on human material. Marks substituted a lead-rubber grid for Liberson's metallic one and employed the same grid openings throughout the treatment. Furthermore, he increased the total dose far beyond that suggested by Liberson. Marks' (7) suggested dose in February 1950 was 24,000 r in air, in daily fractions, in a over-all period of twenty-eight days, through a grid in which the proportion of closed to open spaces was 40 to 60 per cent. More recently he has recommended a total dose of 10,000 r in air with a 20 × 20-cm. grid and 12,000 r in air with a 10 × 15-cm. grid. Loevinger (8), of our physics department, made measurements with the grid which have guided us in our use of this method up to the present. From February 1950 until Sept. 1, 1951, 149 patients with cancer proved by biopsy, and established as hopeless from the point of view of surgery or conventional radiotherapy, were treated by this method.