PASCA-MM Study. Impact of the PASCA (PArcours de Santé au Cours du CAncer) Program on Complications Associated With Multiple Myeloma and/or Its Treatments in the Context of a First Hematopoietic Stem Cell Autograft, in Adults Aged 18 to 70.

This is a prospective, multicentre, phase III, randomised, controlled intervention study. Two groups of patients with equal numbers will be studied and each patient will be allocated to one of the two groups described below by randomisation (ratio 1:1). Each patient will be allocated to one of the two groups described below by randomisation (ratio 1:1). \- PASCA interventional group For both the 7 complications of interest (primary objective) and the 13 secondary complications (secondary objective), a specific and proactive referral will be made systematically after each screening assessment, depending on the level of risk, estimated according to decision trees (management guide) and through the dedicated PASCA network of healthcare professionals, in order to initiate early treatment and follow-up if necessary. \- Control group For the 7 complications of interest (primary objective) as well as for the 13 complications (secondary objective): all the data from each identification check-up will be sent to the onco-haematological transmitted to the referring onco-haematologists, so that they can initiate their own management. =\> For all patients, regardless of group All patients will receive four screening assessments covering the 7 complications of interest and 13 secondary complications: * Visit No.1 (T1), 1-2 months after the autologous haematopoietic stem cell transplantation (aHSCT), corresponding to the patient's visit to his or her Multiple Myeloma (MM) monitoring consultation and/or the start of his or her consolidation treatment. * Visit No.2 (T2), 4 months after aHSCT, corresponding to a patient's visit for the end of consolidation treatment; * Visit No.3 (T3), 14 months after the last aHSCT, corresponding to a visit by the patient during his or her maintenance treatment; * Visit No.4 (T4), 24 months after the last aHSCT, corresponding to a visit by the patient for a MM monitoring consultation.