In brain tumors, cancer cells are common in the blood

Patients with brain tumors may not donate organs

07/31/2014

Until now, the assumption among doctors was that brain tumors rarely or never metastasize. Therefore, some doctors even spoke out to allow those affected to donate organs. However, German researchers recently showed in their study that in brain tumor patients often circulating cancer cells in the blood are detectable. Accordingly, recipients of organs whose donor was suffering from a brain tumor, could even develop cancer.

Aggressive brain tumors have a poor cure prognosis even without metastases
„Glioblastoma multiforme is the most common and aggressive brain tumor in adults“, write the researchers around Klaus Pantel from the Hamburg University Hospital Eppendorf (UKE) in the journal „Science Translational Medicine”. Gliomas are tumors that occur in the central nervous system. A subgroup form the said glioblastomas, which are considered incurable with very poor prognosis. After being diagnosed, those affected survive on average only for about 12 to 15 months. Every year, around 175,000 people die of the aggressive brain tumor worldwide.

So far, physicians have assumed that such glioblastomas are limited to the brain and do not scatter into other organs. Investigations had shown that only in about 0.5 percent of the affected metastases occur. But this result was most likely due to the short lifetime of those affected. Many glioblastoma patients are therefore often not examined for metastases.

Aggressive brain tumors scatter more often than expected
„The belief that the spread of glioblastoma multiforme is confined to the brain has been challenged by reports of extracranial metastases following organ transplantation from donors with glioblastoma“, The researchers report. They therefore wanted to find out to what extent the aggressive brain tumors do not or only very rarely scatter. Therefore, they examined the blood of 141 glioblastoma patients for circulating cancer cells. In 29 of them (21 percent) they actually discovered malignant cells. About the genetic characteristics, they could find that they come from the brain tumor.

However, as the researchers report, they have not been able to show that tumor surgery, which in some cases is carried out despite a rather poor prognosis, favors the release of the cells. The findings also suggested that the incidence and number of cancer cells in the bloodstream appeared to have no effect on patient survival. In none of the subjects tested did the cancer cells in the blood trigger metastases within the average 17 months.

In brain tumors with circulating cancer cells in the blood should be excluded organ donation
Regarding a possible organ donation of glioblastoma patients, the result of the study has serious consequences. Because the discussion about the approval of those affected to donate organs is not yet completed. So far, the blood of such potential donors has not been screened for circulating cancer cells. However, experts have for some time estimated that in about ten to twenty percent of the recipients of organs of glioblastoma patients, tumors occur in the kidneys, the liver, the pancreas or in the heart. According to the researchers, this percentage is suspiciously close to the proportion of brain tumor patients with blood circulating tumor cells.

„We demonstrated that the hematogenous spread of glioblastoma multiforme is an essential feature of its biology“, They write in the journal. Therefore one should examine organ donors with glioblastoma in the future on the circulating cancer cells. „It may be advisable to exclude these patients as organ donors.”

In an accompanying commentary on the study in the same journal, Lara Perryman and Janine Erler from the University of Copenhagen summarize the results of the study: „The results break with the dogma that glioma cells can only survive in the brain.” This finding suggests the suspicion that some of the cancer cells are lodged in organs where they could not be detected and detected prior to transplantation.

The study comes to another conclusion: advances in the treatment of glioblastomas, which extend the life of those affected, could also lead to more metastases in the lungs or other organs in these patients.