Second malignant neoplasms among survivors of pediatric Hodgkin disease treated with low-dose radiation (15-25.5 Gy) and chemotherapy
Title: Second malignant neoplasms among survivors of pediatric Hodgkin disease treated with low-dose radiation (15-25.5 Gy) and chemotherapy
Reviewer: Arpi Thukral, MD
Presenter: M. M. O'Brien
Affiliation: Stanford University
There has been a steady improvementin the survival rates ofpediatric patients with Hodgkin's diseaseas more effective treatment and more accurate staging techniqueshave become available in the last few decades. As the number ofHodgkin's disease (HD) survivors increases, we are seeing an increasing number of late-term toxicities, including second malignant neoplasms (SMN), which are the most common cause of death in these patients. It is well-known that the occurrence of second malignant neoplasms in these patients is associated with both chemotherapy and radiation. Currently published studies that have reported rates of second malignancies in pediatric patients with HD are all looking at treatments given 20-30 years ago, with larger fields and higher radiation doses (often exceeding 40 Gy) than are typically given today. Modern protocols use much lower doses of radiation in children with HD, however these studies have been limited by short follow up (median f/up is approximately 10 years). While it is theorized that lower radiation doses may be associated with lower SMN risk, long-term follow-up of children treated with low-dose radiation is lacking. Therefore, we do not have adequate data on second malignancy risk in these patients.
This study analyzed pediatric Hodgkin's survivors at Stanford University, who were treated between 1970 and 1990 with low dose radiation. 110 of 112 patients achieved remissions and had a median follow up of 20.6 years. In this group, 4 patients developed secondary leukemias and 15 patients developed 17 solid tumors (thyroid, breast, sarcoma, bladder, melanoma and 2 others). All but the melanoma occurred in the field of radiation. The rates of SMNs were actually similar to those seen in pediatric patients who had received high dose radiation therapy.
We must be cautious when trying to reduce radiation treatment doses for pediatric patients with HD because this may come atthe expense ofa higher relapse rate, which has been seen when chemotherapy is used alone. Our foremost goal is improvingthe Hodgkin's disease cure rate, and therefore we must balance the need to reduce late toxicities, such as SMNs, with the need to continue delivering appropriate therapy for the patients' initial HD.
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