A TECHNIC FOR LARGE-DOSE IRRADIATION OF CONNECTIVE-TISSUE SARCOMA OF AN EXTREMITY.

Abstract

When radiation is administered to a connective-tissue sarcoma of an extremity with curative intent, large tumor doses ranging from 6,500 to 9,000 rads may be necessary. Doses of this magnitude, delivered through two to four cross-firing portals, commonly produce constricting fibrosis with blockage of blood and lymph flow. When the entire cross section of an extremity has been so treated, the resultant ederna distal to the constriction becomes very severe and may even necessitate amputation. To avoid this complication, one portion of an extremity should be spared when feasible. The author describes a technic designed for this purpose. Case Report T. A., a 57-year-old white woman, had a low grade myxosarcoma arising from the fascia of the biceps muscle of the right arm. On April 19, 1961, a group of three coalesced encapsulated tumors were excised, the largest one measuring 3 × 2 × 1 cm. One year later, a superficial recurrence in the form of two adjacent nodules was excised on May 3, 1962. Radiation therapy was started June 14, 1962. A sheet of Lucite was bent to form a hemicylinder and snugly applied to the lateral (remote) aspect of the arm (Fig. 1). During each x-ray treatment force was applied to the lateral aspect of the prosthesis to compress the underlying tissues. At the same time, this force displaced the tumor-containing tissues of the medial half of the arm away from the bone. Supervoltage (2 Mv) x radiation was directed at the medial half of the arm through two cross-firing portals, each measuring 8 × 20 cm. The total tissue dose throughout the tumor ranged from 8,600 rads (maximum) to 7,800 rads (minimum) in forty-three days. This produced a mild second-degree epidermitis which healed eight days after the last treatment. Two months after irradiation, dense fibrosis appeared in the biceps and brachialis muscles. The resultant contracture grew progressively worse. One year after treatment extension of the elbow joint lacked 40 degrees. This improved to 20 degrees after physical therapy. To date there have been no interference with circulation and no edema in the distal forearm and hand because of the integrity of all the soft tissues in the posterior half of the arm at the level of irradiation (Fig. 2). Conclusion When massive doses of radiation are given an extremity, a portion of its cross section should be protected against postradiation constriction fibrosis, thereby avoiding crippling edema or possible amputation. A technic for this purpose has been described.