Validation study on the 2 mm diameter cutoff in lymph node-positive cases following radical prostatectomy in accordance with the AJCC/UICC TNM 8th edition: Real-world data analysis from a Japanese cohort.

The American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) 8th edition has proposed micrometastasis as a lymph node metastasis (LN+) of diameter ≤2 mm in prostate cancer. However, supporting evidence has not described. We evaluated LN+ patients' survival after radical prostatectomy (RP) based on the LN maximum tumor diameter (MTD).

Data from 561 LN+ patients after RP and pelvic LN dissection (PLND) treated between 2006 and 2019 at 33 institutions were retrospectively investigated. Patients were stratified by a LN+ MTD cutoff of 2 mm. Outcomes included castration resistance-free survival (CRFS), metastasis-free survival (MFS), cancer-specific survival (CSS), and overall survival (OS).

In total, 282 patients were divided into two groups (LN+ MTD >2 mm [n = 206] and ≤2 mm [n = 76]). Patients of LN+ status >2 mm exhibited significantly decreased CRFS and MFS, and poorer CSS and OS. No patients developed CRPC in the LN+ status ≤2 mm group when the PLND number was ≥14. Multivariate analysis showed the number of LN removed, RP Gleason pattern 5, and MTD in LN+ significantly predicted CRFS.

Patients of LN+ status ≤2 mm showed better prognoses after RP. In all the patients in the ≤2-mm group, the progression to CRPC could be prevented with appropriate interventions, particularly when PLND is performed accurately. Our findings support the utility of the pN substaging proposed by the AJCC/UICC 8th edition; this will facilitate precision medicine for patients with advanced prostate cancer.

International journal of urology : official journal of the Japanese Urological Association. 2024 Feb 29 [Epub ahead of print]

Masashi Kato, Masaki Shiota, Takahiro Kimura, Ryoichi Hanazawa, Akihiro Hirakawa, Dai Takamatsu, Kojiro Tashiro, Yoshiyuki Matsui, Katsuyoshi Hashine, Ryoichi Saito, Akira Yokomizo, Yoshiyuki Yamamoto, Shintaro Narita, Kohei Hashimoto, Hiroaki Matsumoto, Shusuke Akamatsu, Naotaka Nishiyama, Masatoshi Eto, Hiroshi Kitamura, Toyonori Tsuzuki, Japanese Urological Oncology Group

Department of Urology, Nagoya University, Nagoya, Japan., Department of Urology, Kyushu University, Fukuoka, Japan., Department of Urology, The Jikei University School of Medicine, Tokyo, Japan., Department of Clinical Biostatistics, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University, Tokyo, Japan., Department of Urology, National Cancer Center Hospital, Tokyo, Japan., Department of Urology, National Hospital Organization Shikoku Cancer Center, Matsuyama, Japan., Department of Urology and Andrology, Kansai Medical University, Osaka, Japan., Department of Urology, Harasanshin Hospital, Fukuoka, Japan., Department of Urology, Osaka International Cancer Institute, Osaka, Japan., Department of Urology, Akita University, Akita, Japan., Department of Urology, Sapporo Medical University, Sapporo, Japan., Department of Urology, Yamaguchi University, Ube, Japan., Department of Urology, Kyoto University, Kyoto, Japan., Department of Urology, University of Toyama, Toyama, Japan., Department of Surgical Pathology, Aichi Medical University, Nagakute, Japan.