Researchers at the National Cancer Institute (NCI), part of the National Institutes of Health, have determined that children and young adults with a form of cancer called sarcoma are at increased risk of having a thromboembolic event (TE) in their veins.
Thromboembolic events can be a blood clot in a vessel that can interfere with normal blood flow. Clots can sometimes break loose and travel through the blood stream to form new clots at locations in the body that are life-threatening. TEs are almost always treatable if detected early. Investigating the association between sarcoma and TE is important because the majority of children with sarcoma can be cured of their cancer, but the occurrence of TEs could adversely compromise this success.
The study investigators also found that pediatric patients whose cancer had spread beyond the original cancer site were more likely to develop a TE than those with localized cancer. These findings are from a study reported in the April 20, 2007 issue of the Journal of Clinical Oncology*. Researchers reviewed patient records for 122 children and young adults treated for sarcoma in the Pediatric Oncology Branch of the NCI between October 1980 and July 2002.
Cancer creates an environment that is conducive to thrombosis because of the propensity of tumor cells to promote coagulation as well the secretion of cytokines, or signaling compounds, that trigger inflammation. In addition, factors common to cancer patients, such as chemotherapy, surgery, immobilization, having a central venous access device (such as a central line), and having other diseases or conditions, all increase a person's risk for blood clots.
The study results showed that, over the 22-year study period, 16 percent of children and young adults with sarcoma developed a TE. However, the researchers noted that this figure probably underestimates the true frequency of TEs in this pediatric patient population. Since this was a retrospective study of archival patient records, most of the original physicians may not have specifically looked for TEs, so some blood clots would have gone unrecorded. Also, TEs often are asymptomatic and early screening was less accurate. As the study observed, the rate at which TEs were detected in sarcoma patients increased from 7 percent before 1993 to 23 percent since 1993 -- an increase they attributed to improved screening techniques.