Wound repair after fractionated external beam radiation therapy and concomitant hyperthermia in an experimental rat model.

BACKGROUND: Fractionated radiation therapy (RT) with adjuvant hyperthermia (HT) is being used in the treatment of cancer with noted clinical success. However, little information regarding wound repair in tissues receiving this combination therapy is available for comparison of surgical risk. Consequently, this study was undertaken to assess the effects of this combined therapy on wound healing by quantitatively evaluating wound repair using tensile strength measurements. METHODS: Four treatment cohorts were designated: sham control, RT alone (600 cGy/d for 4 days), HT alone (water bath at 41.8 degrees C, subcutaneous temperature of 41.0 +/- 0.5 degrees C for 60 minutes on days 1 and 4), and combined RT and HT. At 1 week after treatment, surgical incisions of the dorsal flank were made. Tensile strength measurements of wounds were obtained at 14 and 21 days after incision. RESULTS: No significant differences were observed in the combined treatment arm (RT and HT) compared with the reduced wound breaking strength of RT alone. Statistically significant differences in tensile strength were seen when the control group or HT alone was compared with RT and HT or RT alone. CONCLUSIONS: Concomitant exposure to fractionated RT and specific HT conditions demonstrated no disproportionate alteration in wound tensile strength compared with radiation exposure alone in this animal model.

Permanent interstitial implantation using palladium-103: the New York Medical College preliminary experience.

Palladium-103 is a low energy photon emitter available for permanent interstitial implantation. Pd-103 has energy and safety characteristics similar to Iodine-125, but its initial peripheral dose rate is approximately three times greater. This may provide improved control of rapidly proliferating tumors. At the Westchester Campus of New York Medical College, 15 patients with residual or recurrent unresectable lesions were implanted with Pd-103. There were five males and 10 females with an age range of 41 to 93 years (median 58). Implanted sites included the chest wall, nasopharynx, vagina, and zygomatic region. Peripheral doses ranged from 55 to 203 Gy (median 107 Gy). A complete response was achieved in eight patients and a partial response in seven patients, for an overall response rate of 100%. We noted improved control with smaller volumes and peripheral doses at or above 115 Gy. No unusual skin or mucosal reactions were recorded. Possible advantages of Pd-103 as a substitute for I-125 include improved control of rapidly proliferating tumors and a more rapid clinical response of lesions. Disadvantages include current higher cost and an impracticality in maintaining a running inventory because of the short half-life of the isotope. Our experience suggests that Pd-103 is an attractive alternative to I-125.