Cutaneous dose during preoperative external beam irradiation or perioperative brachytherapy for soft-tissue sarcoma

Radiation dose to the skin is an important factor in wound healing. Lithium fluoride chips used in thermoluminescent dosimetry were placed on the skin over the entire radiation field to measure the cutaneous dose in 41 patients undergoing adjuvant irradiation for soft-tissue sarcoma. Preoperative external beam irradiation (EBI) totaling 5000 cGy given in 25 daily fractions was administered to the tumor compartment plus a 5- to 7-cm margin in 20 patients. Brachytherapy was performed in 21 patients following wide local excision of the sarcoma and interstitial catheter placement, the insertion of iridium-192 radioactive sources was delayed until the fifth postoperative day to allow initial wound healing. The total dose, prescribed 0.5 to 1.0 cm from the plane of the implant, was administered at 5000 cGy during five days to the operative bed. Cutaneous dose (CD) for EBI ranged from 1925 to 4175 cGy as a function of the size of the radiation portal. In the brachytherapy group, CD ranged from 813 to 3096 cGy during the five-day brachytherapy period and was also influenced by the implant size. Wound healing and perioperative complications were equivalent in the two treatment groups. Delayed wound healing occurred in four EBI patients and in four brachytherapy patients. All wounds subsequently healed with conservative management. In conclusion, the dose to the skin surface during adjuvant irradiation with EBI or brachytherapy was comparable. A wide range of CDs was observed with each approach, and the CD was primarily dependent on the treatment volume.