From the Guidelines
No, Schistosoma japonicum infection is not associated with an increased risk of bladder cancer. Unlike Schistosoma haematobium, which is strongly linked to bladder cancer, S. japonicum primarily affects the intestines and liver rather than the urinary tract. S. japonicum eggs typically lodge in the intestinal wall and liver, causing intestinal disease, hepatomegaly, and potential liver fibrosis or cirrhosis. The carcinogenic relationship exists with S. haematobium because its eggs specifically target the bladder wall, causing chronic inflammation and tissue damage that can lead to squamous cell carcinoma of the bladder over time 1.
Key Points to Consider
- The primary sites of infection for S. japonicum are the intestines and liver, not the urinary tract, which reduces the risk of bladder cancer associated with this parasite 1.
- Schistosoma haematobium is the species most commonly linked to bladder cancer due to its preference for lodging in the bladder wall, leading to chronic inflammation and potential carcinogenesis 1.
- If concerned about schistosomiasis, the standard treatment is praziquantel, with a recommended dose of 60 mg/kg in two divided doses for S. japonicum infections, effectively eliminating the adult worms 1.
- Prevention involves avoiding contact with freshwater in endemic areas, as infection occurs when larval forms penetrate the skin during water contact.
Clinical Implications
- When diagnosing and managing patients with suspected schistosomiasis, it's crucial to identify the specific species involved, as this impacts the risk assessment for bladder cancer and guides treatment decisions.
- For S. japonicum infections, the focus should be on managing intestinal and liver complications, rather than bladder cancer screening, unless other risk factors are present.
- Regular follow-up and monitoring for signs of intestinal or liver disease are essential for patients treated for S. japonicum infection, given the potential for long-term complications 1.
From the Research
Schistosoma Japonicum and Bladder Cancer
- Schistosoma japonicum infection is associated with an increased risk of bladder cancer, as stated in a study published in the European journal of microbiology & immunology 2.
- The study mentions that urogenital symptoms of schistosomiasis include haematuria, bladder fibrosis, kidney damage, and an increased risk of bladder cancer.
- Another study published in Nature reviews. Disease primers also mentions that eggs trapped in the surrounding tissues and organs, such as the liver and bladder, cause inflammatory immune responses that result in intestinal, hepato-splenic or urogenital disease, including bladder cancer 3.
Association with Bladder Cancer
- The exact mechanism of how Schistosoma japonicum infection increases the risk of bladder cancer is not fully understood, but it is thought to be related to the chronic inflammation and tissue damage caused by the parasite.
- A study published in the European journal of microbiology & immunology mentions that schistosomiasis affects more than 250 million people and causes approximately 70 million Disability-Adjusted Life Years (DALYs), mainly in Africa, South America, and Asia, highlighting the significant burden of the disease 2.
- Other studies focus on the treatment and control of Schistosoma japonicum infection, but do not provide direct evidence on the association with bladder cancer 4, 5, 6.