Treatment of female urethral carcinoma in medically inoperable patients using external beam irradiation and high dose rate intracavitary brachytherapy.

PURPOSE: We developed and present our experience with high dose rate brachytherapy for treatment of carcinoma of the urethra in medically inoperable women. MATERIALS AND METHODS: Since 1991, 4 women with localized urethral cancer, medically unable to undergo resection or interstitial implantation, were treated with external beam and high dose rate intracavitary implantation rather than external beam irradiation alone. The fractionated implants were delivered with a high dose rate remote afterloader using a shielded vaginal applicator and modified urethral catheter. The urethral catheter was inserted through the lumen of a 20F Foley tube to improve depth dose. Homogeneous dose distribution was achieved and customized to the individual patient. RESULTS: All high dose rate brachytherapy treatments were given at the clinic without use of sedation or anesthesia. Treatment was well tolerated, and all patients maintained voluntary urinary function and local control at 12 to 55 months after therapy. Chronic morbidity due to urethral, bladder, vaginal or rectal injury, including urethral stenosis, necrosis or fistula, was not noted. Isodose distributions were compared among this technique, interstitial implantation and external beam radiotherapy alone. CONCLUSIONS: Although we prefer interstitial implantation as the boost technique for women with urethral cancer, high dose rate brachytherapy is a reasonable option for medically inoperable patients. This outpatient treatment is well tolerated, preserves voluntary urinary function and enhances quality of life.

Neoplastic transformation of a human prostate epithelial cell line by the v-Ki-ras oncogene.

Investigations of mechanisms of human prostate carcinogenesis are limited by the unavailability of a suitable in vitro model system. We have demonstrated that an immortal, but nontumorigenic, human epithelial cell line (267B1) established from fetal prostate tissue can be malignantly transformed by a biological carcinogen, and can serve as a useful model for investigations of the progression steps of carcinogenesis. Activated Ki-ras was introduced into 267B1 cells by infection with the Kirsten murine sarcoma virus. Morphological alterations and anchorage-independent growth were observed; when cells were injected into nude mice, poorly differentiated adenocarcinomas developed. These findings represent the first evidence of malignant transformation of human prostate epithelial cells in culture, and support a role for Ki-ras activation in a multistep process for prostate neoplastic transformation.