Hematopoietic stem cell transplantation for solid tumors in adults

We revised the medical literature regarding autologous and allogeneic hematopoietic stem cell transplantation (HSCT) in the setting of solid tumors. Autologous-HSCT for solid tumors in adult patients show changing patterns in past decades with decreases numbers for many types of solid tumors. Most marked is the previously well-described increase and decrease in autologous HSCT for breast cancer (BC). Autologous-HSCT for BC has been an area of intense controversy. The role of autologous-HSCT for BC at high risk of recurrence (at least four involved axillary lymph nodes) has been assessed by several randomized trials.

Overall, it was shown that high-dose therapy prolonged disease-free survival when used as adjuvant therapy, and showed a benefi t on overall survival in only selected cohorts of patients. In second or further relapsed or primary refractory germ cell tumor, highdose therapy is considered to be a standard therapeutic option, especially when poor prognostic factors are present. In addition, sequential therapy with two to three cycles is felt to be superior to single cycle of HSCT. High-dose therapy can be regarded as a potential clinical option in selected adult patients with Ewing’s sarcoma and medulloblastoma. Currently, in other types of solid tumors the autologousHSCT is generally not recommended or developmental and only used in the context of prospective studies. Numbers of allogeneic HSCT for solid tumors remained stable low number throughout the recent years. Transient increase is observed over the last decade and is primarily due to renal cell carcinoma, BC and colon cancer. Concepts of allogeneic HSCT for solid tumors do not rely on highdose chemotherapy and tumor load reduction but rather on a graft-versus-tumor effect. Attempts to improve the therapeutic effect of allo-HSCT or other cellular therapies in solid tumors by innovative clinical strategies are underway.