Autologous Bone Marrow Transplantation - Blog Science Connections

ABMT in Metastatic Neuroblastoma 389
Viral Infections
Thirteen viral infections (four herpes simplex, six herpes zoster, two
varicella, and one CMV) in 8 of 33 patients were observed after the first ABMT.
After the second ABMT, seven viral infections, one herpes simplex, two herpes
zoster, two CMV, one hepatitis B virus, and one human T-cell leukemia virus
(HTLV) infection responsible for an acquired immunodeficiency syndrome
(AIDS), which proved lethal 23 months after the second ABMT were observed in
5 of 18 patients.
Complication-related Deaths
Four complication-related deaths were observed; two occurred after the
first ABMT and were related to a CMV infection in one case and to acute
metabolic disorders in the other. Two occurred after the second ABMT and
were related to diffuse aspergillosis and AIDS.
DISCUSSION
The use of high-dose chemo-radiotherapy as consolidation therapy in
stage IV neuroblastoma is being investigated by several teams. The majority
of the protocols published consist of chemotherapy plus total body irradiation
(TBI) (12,13). The use of TBI appears logical according to the results
published concerning studies both in vivo and in vitro (14,15). However, the
role of radiotherapy in the treatment of stage IV neuroblastoma remains
controversial (16,17). Taking into account these results and the delayed
complications of TBI, especially in children (18), we chose to study a
polychemotherapy regimen. It was based on a possible dose-effect relationship
as already demonstrated in other diseases (10) and especially in a
situation of minimal residual disease (19).
The combination chosen was based on phase II studies previously
performed on neuroblastoma, and especially the wide experience acquired
with high-dose melphalan (2,3). The use of two courses of high-dose
chemotherapy followed by ABMT was based on the same concept of dose
effect on minimal residual disease. Using this approach, encouraging results
have already been published on other malignancies (20).
In the present study, the disease-free survival of the grafted patients
would appear to be significantly higher than that of patients treated with
conventional therapy (1,21). The results are similar to those published
concerning patients in CR or QPR in smaller series (12,13).
Most of the relapses occurred a few months after the first consolidation
course. The bone marrow was the principal site of relapse. In this study, all
patients received bone marrow treated in vitro. It is impossible to know
whether these bone marrow relapses were related to a failure of the
conditioning regimen to eradicate the residual disease or to a failure of the
purging technique to eliminate the residual cells in the graft, or both. The