No increase in cancer incidence detected after cyclophosphamide in a French cohort of patients with progressive multiple sclerosis

BACKGROUND

Cyclophosphamide is still used in progressive forms of multiple sclerosis (MS) in view of its suggested efficacy and safety in the short term. No data exist on its long-term safety in MS, particularly on the risk of malignancy.

OBJECTIVE

The objective of this study was to evaluate cancer incidence in MS after cyclophosphamide treatment.

METHODS

We performed a historical prospective study in a cohort of MS patients treated with cyclophosphamide. We collected demographic data and medical history from medical databases and patient interviews. Reported cancers were histologically confirmed. Cancer incidence was compared with the incidence in the general population by estimating standardized incidence ratios (SIRs).

RESULTS

We included 354 patients, with a median follow-up of 5 years (range 2-15) after cyclophosphamide treatment. Fifteen patients developed a solid cancer, which occurred at a median of 3 years (range 0.5-14) after cyclophosphamide introduction. The cumulative incidence of cancer after cyclophosphamide was 3.1% at 5 years and 5.9% at 8 years. We found no increase in cancer incidence after cyclophosphamide treatment in men (SIR = 0.83, 95% confidence interval [CI] 0.30-1.82), women (SIR = 0.99, 95% CI 0.43-1.95), or men and women combined (SIR = 0.92, 95% CI 0.50-1.54).

CONCLUSION

We found no evidence of an increased risk of cancer associated with cyclophosphamide treatment in MS patients.

First report of molecular characterization of fluoroquinolone-resistant Mycobacterium tuberculosis isolates from a Tunisian hospital

Fluoroquinolones are increasingly used for the treatment of infections caused by multidrug-resistant Mycobacterium tuberculosis. Our study was designed to determine the frequency of the emergence of ciprofloxacin-resistant isolates in a university hospital (Rabta University Hospital Tunis, Tunisia) and to characterize the mutations responsible for the resistance phenotype. A total of 495 clinical M. tuberculosis isolates obtained from January 2005 to July 2008 were investigated for their susceptibility to ciprofloxacin, using the standard proportion method, PCR and DNA sequencing. Four resistant isolates (0.8%) were identified. Among these, only two carried point mutations in gyrA leading to amino acid changes other than the phenotypically silent S95T substitution. No gyrB missense mutations were found in any of the clinical isolates. Although fluoroquinolone resistance is still rare in Tunisia, accurate surveillance is needed in order to control the possible emergence of resistance to fluoroquinolones, which are essential for the successful treatment of multidrug-resistant tuberculosis.