SIU 2018: Prostate Cancer Screening: Japanese Perspective
The diagnosis and treatment of prostate cancer in Asian countries may be suboptimal according to Dr. Egawa. The 5-year cancer specific survival of prostate cancer in Korean patients has risen significantly in the last 20-25 years, from 55.9% in 1993-1995 to 82.4% in 2003-2007.1 This could be due to improved screening. The annual mortality/incidence ratio of prostate cancer varies significantly among Asian countries, with a high ratio in Vietnam, China. Malaysia, and the Philippines (0.42-0.63) and a low ratio in Singapore, Korea, and Japan (0.18-0.22). However, generally, this ratio is higher in Asian countries than in the US, and this could be as a result of higher access to screening and availability of appropriate management in the US. In general, 70-80% of US patients are exposed to the option of screening and the proportion of metastasis is 5%. In contrast, in Japan only 10% of patients are exposed to screening, and 20-30% of patients are metastatic.
A study assessing the prevalence of prostate cancer and its precursor lesions in Russian Caucasian, and Japanese men in autopsy specimens was published in 2013.2 It involved 320 autopsies during 2008-2011. The results demonstrated that 35% of Asian men and 37.3% of Caucasian men had prostate cancer. However, the percentage of Gleason 7-10 disease was significantly higher in Japanese men compared to US men (51.4% vs. 23.2%).
The Japanese clinical guidelines attempted to answer if screening ca reduce the prevalence and mortality of metastatic prostate cancer, give recommended PSA threshold and intervals for screening, provide recommended age-range screening, describe the merits and demerits of screening, and see if screening is cost-effective. According to these guidelines, a PSA cut-off of 4 ng/ml is recommended for all ages, and an age-specific cut-offs are also given with 0-3 ng/ml for ages 50-64, 0-3.5 ng/ml for ages 64-69, and 0-4 ng/ml for men aged over 70. The Japanese guidelines also support a grade B recommendation that PSA should be tested before the age of 60, because of its significance to the outcomes later on in life, and to get a baseline value early on.
Dr. Egawa concluded by showing the results of a large Japanese survey of over 450,000 patients who were screened. These results of this survey demonstrated that PSA >4 ng/ml was prevalent in 7.3% of patients. A total of 8% of the patients participating in the survey were recommended a biopsy by their physicians, but only a third of them had actually undergone a biopsy with a prostate cancer detection rate of 1.11% (40% of biopsied men). Out of the patients who had a positive biopsy, localized disease was found in 42% of them, locally advanced disease was found in 36% of cases, and metastatic disease was found in 22%. Screening is still underutilized in Asian countries, and Dr. Egawa believes this must change in order to improve the outcomes of prostate cancer patients in the future.
References:
1. Ito K. Urology 2014
2. Zlotta A et al. NCI 2013
Presented by: Shin Egawa, MD
Written By: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre Twitter: @GoldbergHanan at the 38th Congress of the Society of International Urology - October 4- 7, 2018 - Seoul, South Korea
Read More:
Prostate Cancer Screening: European Perspective
Prostate Cancer Screening: American Perspective
Prostate Cancer Screening: Latin American Perspective