Clinical study of urine NMP 22 (nuclear matrix protein 22) as a tumor marker in urinary epithelial cancer

Medical follow-up for workers exposed to bladder carcinogens: the French evidence-based and pragmatic statement

BACKGROUND

The aim of this work was to establish recommendations for the medical follow-up of workers currently or previously exposed to carcinogenic substances for the bladder.

METHODS

A critical synthesis of the literature was conducted. Sectors of activity where workers are or were exposed to carcinogenic substances for the bladder were listed and classified according to the level of bladder cancer risk. Performances of techniques available for the targeted screening of bladder cancer were analysed, including a simulation of results among high-risk populations in France.

RESULTS

The risk level for the professional group and the latency period between the start of exposure and the natural history of the disease were selected to define a targeted screening protocol. The NMP22BC test, exclusive haematuria testing, and combinations of urine cytology with, respectively, the NMP22BC test and haematuria test, generated an extremely high proportion of false positive results.

CONCLUSION

Urine cytology is the test that offers the best specificity. Although poor for all bladder cancer stages and grades combined, its sensitivity is better for high grades, which require early diagnosis since late-stage cancers are of very poor prognosis. These results suggest that urine cytology is currently the only technique suitable for proposal within the context of a first line targeted screening strategy for occupational bladder cancer. An algorithm summarising the recommended medical follow-up for workers currently or previously exposed to carcinogenic substances for the bladder is proposed, based on the level of risk of bladder cancer.

Urinary markers in the everyday diagnosis of bladder cancer

Bladder cancer (BC) represents the fourth most common neoplasia in men and the ninth most common cancer in women, with a significant morbidity and mortality. Cystoscopy and voided urine cytology (involving the examination of cells in voided urine to detect the presence of cancerous cells) are currently the routine initial investigations in patients with hematuria or other symptoms suggestive of BC. Around 75-85% of the patients are diagnosed as having non-muscle-invasive bladder cancer (NMIBC). Despite the treatment, these patients have a probability of recurrence at 5 years ranging from 50 to 70% and of progression to muscle invasive disease of 10-15%. Patients with NMIBC must undergo life-long surveillance, consisting of serial cystoscopies, possibly urine cytology and ultrasonography. Cystoscopy is unsuitable for screening because of its invasiveness and costs; serial cystoscopies may cause discomfort and distress to patients. Furthermore, cystoscopy may be inconclusive, falsely positive or negative. Although urine cytology has a reasonable sensitivity for the detection of high-grade BC, it lacks sensitivity to detect low-grade tumors (sensitivity ranging from 4 to 31%). The overall sensitivity and specificity of urine cytology range from 7 to 100 and from 30 to 70%, respectively. There is a need for new urine biomarkers that may help in BC diagnosis and surveillance. A lot of urinary biomarkers with high sensitivity and/or specificity have been investigated. Although none of these markers have proven to be powerful enough to replace standard cystoscopy, some of them may represent accurate predictors of BC. A review of recent studies is presented.