Even though the therapeutic panel for multiple sclerosis (MS) treatment has improved in the last 20 years, safety data especially for the second-line and innovative treatments are lacking. The association between MS and cancer has long been investigated but has led to conflicting results. No studies have reported an increased risk of cancer after long-term exposure to immuno-modulators. The present study will assess whether drugs for the treatment of MS are associated with an increased risk of cancer by analyzing the disproportionality of reports in the World Health Organization (WHO) pharmacovigilance database.

A case non-case study using Vigibase®, the World Health Organization Global Individual Case Safety Reports (ICSRs) database which includesreports forwarded to the WHO Uppsala Monitoring Center by national pharmacovigilance systems from over 130 countries around the world since 1967. Information on the adverse effects reported include patient demographics and medical relevant history, drugs recorded according to the WHO Drug dictionary and adverse drug reactions coded with Medical Dictionary for Regulatory Activities (MedDRA) terms will be perform.

Inclusion Criteria:

• Serious cases reported in the World Health Organization (WHO) database of individual safety case report from 2000 to September 2019
• Cancer overall reported by a term included in the Standardized MedDRA query (SMQ) "Malignant tumours"

Exclusion Criteria:

- Non serious cases

Patients treated with a drug for the treatment of MS