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Background: Our aim was to report clinical and biochemical outcomes of transperineal interstitial permanent prostate brachytherapy in the treatment of Japanese patients with clinically organ-confined prostate cancer in Hawaii., Methods: Ninety-five Japanese patients underwent transperineal interstitial permanent prostate brachytherapy using either iodine-125 or palladium-103 for clinical T1c-T2b N0 M0 prostate cancer. These procedures were carried out between December 1998 and December 2002 at The Queen's Medical Center in Honolulu, Hawaii. Prostate-specific antigen measurements were collected from all patients at follow up. Biochemical failure was defined by three consecutive rises in prostate-specific antigen levels, based on the criteria of the American Society for Therapeutic Radiology and Oncology Consensus panel., Results: The median patient age was 71 years (range, 46-87 years). Thirty-six patients were implanted with either iodine-125 or palladium-103 as monotherapy; 59 patients received moderate-dose external beam irradiation first, followed by a prostate brachytherapy boost. The median follow-up length, calculated from the day of implantation, was 801 days (range, 237-1421 days). During this follow-up period, The Kaplan-Meier estimate of freedom from biochemical failure in this series was 94%. No major complications were observed., Conclusions: Clinical and biochemical outcomes in the treatment of Japanese patients in Hawaii suffering from localized prostate cancer, using transperineal interstitial permanent prostate brachytherapy, with or without external beam irradiation, compared favorably to results in similarly treated patients in the general US population.

The genetic variation of sex ratio and sex allocation were examined in a series of half-sib analyses on the sex ratio of braconid parasitoid wasp Heterospilus prosopidis populations collected in Hawaii and Arizona. The mean threshold value and the range of the threshold for change in the sex of offspring in response to resource quality (host size) were determined. Estimates of the narrow-sense heritability (h2) of sex ratio at a specific host size ranged from 0.185 to 0.315, and those of the sex changing point (threshold value) ranged from 0.220 to 0.342. The coefficient of variation (CV(A)) of sex ratio was significantly larger than CV(A) of body weight. We discuss factors that maintained the significant additive genetic variation of sex ratio.

In an attempt to determine the role of environmental factors in the etiology of prostate cancer, we compared the clinical-pathological findings of prostate cancer among Japanese Americans in Hawaii and Japanese living in Japan. Our study showed that prostate cancer in Japanese living in Japan is more advanced than in Japanese Americans. The findings indicate that screening for prostate cancer in Japan is far behind that in the USA. The difference in level of cancer screening also precluded our attempt to analyse environmental factors contributing to prostate cancer progression in the two groups. The variation in method of clinical detection of prostate cancer between the USA and Japan is also likely to contribute to the apparent difference in the incidence of the disease.