Cancer as a complicATion in reCipients of Autologous Hematopoietic Stem Cell Transplantation for Autoimmune Disease iNdiCation trEated in FRance and Canada?

Autologous Hematopoietic Stem Cell Transplantation (AHSCT) is a treatment option for several types of Autoimmune Disease (AD) in patients who remain active despite disease modifying therapies. In this setting, AHSCT was shown to improve overall survival, event free survival and quality of life, with a grade A level evidence for systemic sclerosis (SSc) and multiple sclerosis (MS) patients and its benefit varies according to the AD type and the patient status for the other indications. The number of AHSCT for AD has increased in the past twenty years at each country level in Europe and also in Canada.

Information about cancer after AHSCT for AD is scant, although the AD patients population per se has an increased rate of cancer. This cancer risk can be explained in part by the long term use of immunosuppressive drugs or by other risk factors related to the AD (as in SSc or Crohn) or to the patient. In addition to pretransplant potential risk factors for cancer in AD patients, the use of conditioning regimen, which may vary from low, medium or high immunosuppressive to myeloablative chemotherapy when irradiation is added to the proecedure, may favor the onset of cancer after AHCST. Updated analysis and review of the literature until march 2023 led us to identify only twenty-two cases of cancer or hematological malignancies reported after AHSCT recipients for an AD.

The incidence of cancer after AHSCT for AD was never considered as a primary endpoint in any previous study.

In this context, the aim of this study is to describe the incidence of cancer after autologous hematopoietic stem cell transplantation (AHSCT) for auto-immune diseases (AD) in the French MATHEC (French scientific network for AD and cellular therapies) and the Ottawa and Calgary patients cohorts from Day 0 until twenty years follow up after AHSCT.