SIU 2018: Prostate Cancer Screening: Japanese Perspective

Seoul, South-Korea (UroToday): Dr. Egawa began his presentation by demonstrating some global data on prostate cancer. In 2008 the global prevalence of prostate cancer was ~899000 cases with 258,000 new cases per year, which are predicted to increase to 1.7 million by 2030. When assessing global data on prostate cancer, several factors must be considered, These include genetic variation, lifestyle differences, screening rates and accessibility to globally acceptable cancer registries.

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


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