台灣與美國男性原發性尿道癌之演變：砷暴露減少的潛在影響

陳偉安¹、蔡育賢²

¹國立成功大學附設醫院 教學中心;²泌尿部

Temporal trends of Male Primary Urethral Carcinoma: Potential Impact of Reduced Arsenic Exposure in Taiwan versus the USA

Wei-An Chen¹, Yuh-Shyan Tsai²

Education Center¹, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Urology², College of Medicine, National Cheng Kung University, Tainan, Taiwan

Purpose: Primary urethral cancer (PUC) is a rare urological malignancy. Prior research linked a higher prevalence of bulbomembranous adenocarcinoma in Taiwan to historical chronic arsenic exposure in drinking water. However, recent decades have seen successful public health measures to reduce this exposure. This study aimed to investigate the changing trends of male PUC in Taiwan compared to the United States of America (USA).

Materials and Methods: We conducted a retrospective analysis of data on male PUC patients at National Cheng Kung University Hospital (NCKUH), the only medical center near the black foot disease endemic area between 1975 to 2020. We also identified male PUC patients within Surveillance, Epidemiology and End Results (SEER) database to evaluate trends of PUC in USA. To investigate potential trends over time, we categorized male PUC patients into two groups based on their diagnosis year. The year 2003 served as the dividing point.

Results: From 1975 to 2020, 24 and 1291 male PUC patients were diagnosed in NCKUH and in SEER database respectively. Within NCKUH, a marked decrease in the prevalence of adenocarcinoma (43% to 0%) and a corresponding increase in transitional cell carcinoma (TCC, 21% to 90%) were observed. The predominant site of male PUC shifted from the bulbomembranous urethra (50%) to the penile urethra (50%). The SEER data, on the other hand, showed TCC remaining the most prevalent histological type (72% to 68%). However, a trend towards more advanced stages (29% to 38%, p < 0.001) and increase of chemotherapy (13% to 29%, p < 0.001) was seen. Additionally, the SEER database exhibited a significant decrease in the incidence rate of male PUC cases (5.4 to 3.7 per 1,000,000, p < 0.001), particularly for TCC (3.9 to 2.6 per 1,000,000, p < 0.001), with an annual percentage change of -1.9 per 1,000,000.

Conclusions: Our analysis revealed a significant decline in the prevalence of bulbomembranous adenocarcinoma among male PUC patients at NCKUH, potentially reflecting the success of public health measures in reducing arsenic exposure in Taiwan. On the other hand, the SEER database from the USA showed a lower overall incidence of male PUC but a concerning trend towards more advanced stages at diagnosis. This intriguing observation warrants further investigation into potential risk factors and disease progression patterns in the USA.