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USE OF ‘RAINY DAY’ HAEMATOPOIETIC STEM CELLS OVER 10 YEARS

Aim: High dose therapy and autologous haematopoietic stem cell (AHSC) transplantation is an important treatment for many haematological malignancies. AHSCs can be harvested during remission or consolidation treatment for subsequent transplantation if required (‘rainy day’ collection). Although the practice is widespread, evidence base is minimal. We investigated the eventual transplantation of ‘rainy day’ collections, delay to transplantation and patient outcomes. Methods: This was a retrospective audit of practice between 1/1/2001 and 31/12/2010. ‘Rainy day’ harvest was defined as collection of AHSCs where transplantation was not anticipated in the next 6 months. Results: 532 collections were performed in 474 patients for haematological indications. 342 (71%) patients had rainy day AHSCs collected. Disease indications included non-Hodgkin lymphoma (NHL; n = 205, 60%), multiple myeloma (MM; 45, 13%), Hodgkin lymphoma (HL; 38, 11%), acute myeloid leukaemia (AML; 20, 6%), chronic myelogenous leukaemia (CML; 5, 1%), acute lymphoblastic leukaemia (ALL; 6, 2%), other myeloproliferative neoplasms (21, 6%), chronic lymphocytic leukaemia (CLL; 3, 1%). Overall transplantation rate was 14%. For MM collections 27% were transplanted, compared to 16% for HL and 14% for NHL. Only 5% of collections for AML were transplanted and there were no transplants for CML. The median delay to transplantation was 18 months (range 6.3–112); 81% of patients transplanted engrafted within specified limits. Of the 296 patients who had ‘rainy day’ AHSC collections that have not been transplanted, 255 (85%) are still alive Discussion: ‘Rainy day’ AHSC collection is resource intensive. We found high rates of eventual usage for certain indications (MM, HL) and low rates for others (AML, CML). Findings from this study may help to inform guidelines for ‘rainy day’ AHSC collection.