How widespread is active surveillance of early‐stage prostate cancer in Japan? Multicenter questionnaire survey on the status of active surveillance of early‐stage prostate cancer in Japan

No nationwide statistics of localized prostate cancer (PCa) treatment in Japan have been reported since 2014.1 In August 2023, we conducted a survey of cancer treatment facilities throughout Japan to assess the status of active surveillance (AS) by emailing to a questionnaire to Japan Clinical Oncology Group (JCOG) or Prostate Cancer Research International Active Surveillance2 (PRIAS)-JAPAN (P-J) facilities. The questionnaire asked respondents to report the percentage of National Comprehensive Cancer Network (NCCN) patients with very low- to favorable intermediate-risk PCa who received AS. In Japan, P-J is conducting a prospective observational study of AS; therefore, P-J providers have a good understanding of patient eligibility for AS and are more committed to AS than other healthcare providers. We therefore decided to compare P-J facilities and non-P-J facilities. Furthermore, we compared the prevalence of AS between urban and rural areas, defined according to the number of patients living close to the facility. The medical area (MA) of each site was estimated using jSTAT MAP (https://jstatmap.e-stat.go.jp/map.html) to estimate the number of residents who could reach the facility within 30 min driving by car at 40 km/h. MAs were classified as small (population <800 000), medium (population 800 000–3 000 000), or large (population >3 000 000). The Mann–Whitney U-test and one-way analysis of variance (ANOVA) with Tukey's post hoc tests were used for two- and three-group comparisons, respectively, using GraphPad Prism 7.00 (GraphPad Software, San Diego, CA, USA). Fifty-one of 60 facilities (85%) responded (Figure 1a), including 15 JCOG-only, 7 P-J-only, and 29 joint JCOG and P-J facilities. Eighteen, 20, and 13 facilities were located in small, medium, and large MAs, respectively. The median AS proportion by facility was 10% (interquartile range [IQR]; 10%–26%) (Figure 1b). The AS proportion did not differ between P-J (12.5%, IQR: 10%–26.5%) and JCOG-only (10%, IQR: 5%–30%) sites (p = 0.8), or between small (15%, IQR: 5%–30%), medium (20%, IQR: 10%–29.3%), and large (10%, IQR: 5%–20%) MAs (p = 0.3), suggesting that participation in P-J and area of residence do not have a major affect AS implementation. In this survey, the proportion of patients with early-stage prostate cancer receiving AS (10%) was similar to that reported in the last national survey in 2010 (12%). In a survey conducted in Europe in 2014,3 the proportion of patients receiving AS was 91%, 74%, and 19% in very low-, low-, and intermediate-risk facilities, respectively.3 In a survey conducted in the United States in 2021,4 approximately 60% of those at low risk received AS. Although AS is cost-effective5 and maintains patients' quality of life,6 the limited use in Japan compared with Western countries indicates overdiagnosis and overtreatment of early-stage PCa in Japan. This study has several limitations. The questionnaire was only sent to P-J and JCOG sites, which are generally university hospitals or large regional cancer centers; therefore, the status of AS implementation in small- and medium-sized hospitals could not be ascertained. Very low- to intermediate-risk categories were grouped to simplify the question about AS implementation. The hospitals included in the survey were high-volume centers that receive referrals of intermediate-risk cases. In Japan, AS of intermediate-risk cases started only recently and has not yet been widely implemented. A national treatment registry is needed to assess AS implementation in small- and medium-sized hospitals and by risk level. Some respondents commented in the free-response section of the questionnaire that patients were referred for curative therapy even if they were eligible for AS. This suggests that small facilities responsible for the initial consultation through to diagnosis may refer patients to larger hospitals for treatment without informing patients about the option of AS. AS monitors patients with localized cancer and requires sufficient time for shared decision-making. In addition, careful follow-up is necessary but is not reflected in the current reimbursement schedule. Reimbursement support such as insurance incentives is needed to promote the use of AS in Japan and enable local clinics and small hospitals to use AS. This study suggests that the implementation of AS in Japan is low, even in facilities that promote AS and specialize in cancer treatment. To promote AS in Japan, both patient education and physician support are required. We thank Akira Yokomizo, Atsunari Kawashima, Atsushi Takahashi, Fumio Ishizaki, Haruyuki Ohsugi, Hiroki Kurata, Hiroshi Fukuhara, Hiroshi Kitamura, Hitoshi Masuda, Isao Hara, Junya Furukawa, Keiichiro Mori, Keisuke Moji, Keita Kobayashi, Kohei Edamura, Kohei Hashimoto, Koichiro Wada, Koji Yoshimura, Kosuke Ueda, Masahiro Nitta, Masashi Nakayama, Mitsugu Kanehira, Naoki Terada, Naoya Kani, Nobumichi Tanaka, Ryoei Minato, Ryuji Matsumoto, Sei Naito, Shinichi Sakamoto, Shinichi Yamashita, Shintaro Narita, Shoichiro Mukai, Shuichi Morizane, Shuichi Tatarano, Takafumi Kawahara, Takahiro Inoue, Takahiro Miura, Takanobu Utsumi, Takayuki Goto, Takeshi Kawahara, Taketo Kawai, Takumi Shiraishi, Tomomi Kamba, Toshihiro Saito, Yasuyuki Sakai, Yoshihito Kusuhara, Yoshitaka Sekine, Yoshiyuki Matsui, Yushi Naito, and Yuto Matsuhita. Finally, we acknowledge Editage (www.editage.com) for the English language editing. Takuma Kato: Conceptualization; data curation; writing – original draft; methodology; formal analysis. Yoichiro Tohi: Conceptualization; data curation; writing – review and editing. Homare Okazoe: Writing – review and editing. Rikiya Taoka: Writing – review and editing. Nobufumi Ueda: Writing – review and editing. Mikio Sugimoto: Conceptualization; writing – review and editing; supervision. Mikio Sugimoto is an Editorial Board member of International Journal of Urology and a co-author of this article. To minimize bias, they were excluded from all editorial decision-making related to the acceptance of this article for publication. The protocol for this research project was approved by the suitably constituted Kagawa University Ethics Committee, Approval No. 2023-100, and it conforms to the provisions of the Declaration of Helsinki. Informed consent was not needed because the survey was an audit that gathered data on facilities, not on individuals. N/A. N/A. No funding was obtained for the present study. The datasets generated and analyzed during the current study are not publicly available owing to our hospital policy but are available from the corresponding author on reasonable request.