FYI - The studies on rodents and cancer were done on Flagyl (same class), not Tinidazole. I haven't seen anything on Tinidazole increasing cancer risk.
I also found this:
." Matthew Falagas, of New England Medicine Center and Tufts University School of Medicine, reported data on patients who received the drug as outpatients between 1975 and 1983. The 30,000 users included 21,000 females and 9,000 males (usually, the sexual partners of women treated for vaginal infections). Patients were compared with matched controls (nonusers).
The all-site incidence of cancer after the first 7 years of follow-up was 652 per 100,000 person-years for metronidazole users, compared with 662 for nonusers. No site was associated with an increased risk for cancer, and in the first 7 years after use, nonusers actually had a higher cancer rate, Dr. Falagas reported."
www.cancernetwork.com/articles/short-term-metronidazole-not-linked-cancer