April 19th, 2007
Investigators at St. Jude Children’s Research Hospital say they
have found the best way for predicting when patients will need future
surgery to repair hip joints that have deteriorated because of pediatric
leukemia or lymphoma treatment.
The investigators found that if more than 30 percent of the head of
the bone fitting into the hip socket is deteriorated, it is at high
risk of collapsing and requiring reconstructive surgery within two
years.
The study is significant because the intensive use of corticosteroid
drugs that have been implicated in development of osteonecrosis, or
bone deterioration, is a major component of chemotherapy for pediatric
leukemia and lymphoma. The drugs have been key to raising the survival
rates of children with these cancers, and currently there is no adequate
substitute for their use. Therefore, it is important for clinicians
to monitor patients during treatment and identify those at highest
risk for this complication. Eventually, genetic or other tests may
be developed to help predict these patients. This is a subject of ongoing
study.
A report on this work appears in the April 20 issue of Journal
of Clinical Oncology.
Hip collapse occurs following deterioration of the ball-like top part
of the upper leg bone, or femur, which fits into the hip socket. Degeneration
of this area, called osteonecrosis of the capital femoral epiphysis,
is a common problem among children undergoing chemotherapy for leukemia
or lymphoma.
“Being able to predict which children are likely to experience
serious bone deterioration in the future will help investigators identify
and monitor survivors who are at particularly high risk for developing
this problem,” said Sue Kaste, D.O., a member of the Radiological
Sciences department at St. Jude. Kaste is the paper’s senior
author.
Collapse of the femur causes severe pain that might leave the patient
wheelchair bound, according to Evguenia Jane Karimova, M.D., Radiological
Sciences department at St. Jude and the paper’s first author.
To ease the pain, many patients require arthroplasty, or surgery to
rebuild the hip joint.
“Hip collapse and joint replacement carry a worse prognosis
in a young person,” Karimova said. “Young patients tend
to engage in more strenuous activity than older patients with hip replacements,
and that can damage the replacement and further complicate recovery.
Many of these patients are expected to require further surgery in the
future to replace their prostheses, which have a limited life span.”
“Osteonecrosis has become one of the most important side effects
of therapy that affects the quality of life of these long-term survivors,” Kaste
said. “We want the survivors to have the best quality of life
possible. Therefore, we analyzed the extensive amount of data on such
patients accumulated at St. Jude over the years to determine which
factors cause joint collapse and make it likely that the patient will
need arthroplasty.”
The St. Jude team reviewed the medical records and MRI images of 80
patients who developed osteonecrosis of the capital femoral epiphysis
to identify factors that appeared to be linked to the future collapse
of the bone’s surface and the need for arthroplasty. A total
of 23 of the 80 patients, or 29 percent, eventually underwent arthroplasty
for one or both hips at an average of 1.3 years after diagnosis of
osteonecrosis. In cases in which necrosis involved more than 30 percent
of the head of the hip, 80 percent of the hips collapsed within two
years after osteonecrosis was identified, with 50 percent requiring
arthroplasty. The age of the patient at the time of the first arthroplasty
ranged from 15.1 to 35.4 years.
The investigators plan to conduct prospective studies to determine
if it is possible to develop a treatment that prevents this damage
and preserves hip function.
Other authors of this study are Shesh N. Rai, Scott C. Howard, Michael
Neel, Lunetha Britton and Ching-Hon Pui.
This work was supported by the National Institutes of Health, the American
Cancer Society and ALSAC.
Source: St. Jude Children’s Research Hospital |
