Acute cystitis signaled the presence of urogenital cancers in middle-aged men and women, according to the results of a Swedish cohort study published in BMJ Public Health. Based on these findings, the researchers suggested that acute cystitis could be used as a clinical marker for urogenital cancers.
“The present study adds to the accumulating evidence of infections as markers of increased cancer risk. For clinicians, the findings indicate that acute cystitis could be a clinical marker for urogenital cancer (at least when no other cause is obvious), and particularly for occult urogenital cancer, as the risks for cancers were highest within 3 months of cystitis diagnosis,” the study authors said. “It is plausible that urogenital cancer, and perhaps even pre-cancerous changes in the urogenital organs, might increase the risk of cystitis because of compromised urinary tract and host defense.”
Rationale and Study Methods
Previous research has suggested that acute cystitis could be linked to an increased risk for urogenital cancers. The researchers aimed to further examine this association.
They conducted a Swedish nationwide cohort study, looking at several national population and health registers and primary health-care data sources for a total of 1,668,371 eligible men and 1,889,211 eligible women between the years of 1997 and 2018, focusing on primary care facility data. Of these individuals, 177,736 men and 427,821 women were diagnosed with acute cystitis (17%).
Key Study Findings
Within the study population, 199,144 men and 57,882 women aged 50 or older were diagnosed with a urogenital cancer, including 24,137 individuals (9.5%) diagnosed after a bout of cystitis. The most common cancers were prostate cancer (62%) followed by bladder cancer (16.5%) and endometrial cancer (10%).
The risk for urogenital cancers was highest within 3 months of the acute cystitis bout, but the risk for most cancers persisted for several years. The standardized incidence ratio for bladder cancer within 3 months of acute cystitis was 33.69 (95% confidence interval [CI] = 32.02‒35.43) for men and 30.00 (95% CI = 28.02‒32.09) for women. The excess cancer rates per 10,000 person-years was 483.72 for men and 96.00 for women.
For prostate cancer, the standardized incidence ratio within 3 months of acute cystitis was 7.05 (95% CI = 6.74‒7.37) and the excess cancer rate was 550.88 per 10,000 person-years, but the excess rate was 104.89 per 10,000 person-years between 3 and 12 months of follow-up for acute cystitis.
For kidney cancer, the standardized incidence ratio within 3 months of acute cystitis was 11.28 for men and 7.72 for women.
Urogenital cancer risk persisted throughout the follow-up period for both sexes, but excess cancer rates dropped throughout the period, with rates of 9 for men and 2.5 for women after 5 years. The risk of urogenital cancer in men who had cystitis was greater than the risk for women, amounting to about a two-times higher risk for men in their 50s, 57% higher for men in their 60s, and 23% higher for men in their 70s.
The study did not, however, explore other potentially influential factors, including smoking, obesity, and diabetes.
Disclosure: For full disclosures of the study authors, visit bmjpublichealth.bmj.com.
