Significant antitumor effect of intratumoral ethanol injection on renal cell carcinoma

The effects of intratumoral ethanol injection on renal cell carcinoma (RCC) heterotransplanted in nude rats were evaluated.

The OUR95AF human RCC cell line was inoculated subcutaneously into the backs of nude rats. Four weeks after transplantation, the size of tumors became 1.5-2.0 cm in maximal length, and 95% ethanol was injected intratumorally once a week for five weeks. The effectiveness of this treatment was evaluated by measurement of tumor volume, magnetic resonance (MR) imaging using Gadopentetate-diethylenetriaminepentaacetic acid (Gd-DTPA) and histological examinations.

In the ethanol injected group, no increase in tumor volume was recognized. The growth of the tumors was significantly suppressed after the third injection. Non-enhanced parts in MR imaging were observed in the central region of the tumors at the second injection, and increased at the third injection. After the fifth injection, only small parts of non-enhanced regions remained. Degenerative necrosis was histologically found in the non-enhanced parts of the MR image. The signal to noise ratio (SNR) and the contrast to noise ratio (CNR) calculated from T1 weighted imaging using Gd-DTPA, and relative enhancement (RE) were thought to be good parameters for evaluating the effect of ethanol injections.

Intratumoral ethanol injection was very effective against RCC. Five weekly injections of ethanol induced necrosis of the tumor. MR imaging using Gd-DTPA may be a useful method for evaluating the effect of ethanol injection.