Analysis and Management of Rectal Gas with Kampo Formulas During Intensity-Modulated Radiotherapy of Prostate Cancer: A Case Series Study.

OBJECTIVES

During intensity-modulated radiation therapy (IMRT) for prostate cancer, the target, bladder, and rectum positions should be kept constant to reduce adverse events, such as radiation proctitis, and to increase local tumor control. For this purpose, decreasing the rectal contents as much as possible is important. Daisaikoto (DST) and bukuryoingohangekobokuto (BIHKT) are traditional Japanese herbal (Kampo) formulas that have been used to treat patients with abdominal bloating or constipation.

MATERIALS AND

METHODS

This study investigated the effect of DST and BIHKT on the rectal gas volume during prostate IMRT according to Kampo diagnosis. Five patients were treated with DST or BIHKT at a dose of 5.0 or 7.5 g/d. The volume of rectal gas in 189 megavoltage computed tomographic images taken before each treatment session and the frequency of rectal gas drainage were evaluated before and after DST or BIHKT administration.

RESULTS

After DST or BIHKT treatment, the mean volume of rectal gas was reduced from 6.4 to 2.1 mL, and the mean frequency of gas drainage decreased from 43% to 9%.

CONCLUSIONS

DST and BIHKT appear to be useful in reducing rectal gas, which would help prevent radiation proctitis and improve the local control of prostate cancer with IMRT.