Decade of follow up advised after resection of cerebellar astrocytomas
MedWire News: Children who undergo surgical resection of benign cerebellar astrocytomas should have neuroimaging follow up for 8 to 10 years, say researchers who found that almost all cases of progression occurred within this time.
They report that 29 (28.7%) of 101 children (average age 7.3 years at diagnosis) had tumor recurrence. This included 5.9% of 51 patients with total resection and no evidence of residual tumor. Previous researchers have suggested that follow-up imaging is not needed after total resection, but the current findings suggest otherwise, say Tadanori Tomita (Children's Memorial Hospital, Chicago, Illinois, USA) and colleagues.
Recurrence also occurred in 47.8% of 23 patients with total resection but evidence of residual tumor on postoperative imaging, and 55.6% of 27 who underwent subtotal resection because the tumor extended into vital structures such as the brainstem.
Most - 58.6% - patients who had recurrence did so within 2 years after surgery, with four progressing within 6 months. Another 13.8% had recurrence between 2 and 4 years, 10.3% between 4 and 6 years, and 13.8% between 6 and 8 years. One patient, who had residual tumor despite total resection, had recurrence 11 years after surgery.
The average time to recurrence was significantly longer in patients with successful total resection than in those with residual tumor, at 59.7 versus 30.7 months, the team reports in the journal Neurosurgery.
As in previous studies, total resection was strongly protective against tumor progression, reducing the risk by about 90%. Other factors - age, gender, tumor in fourth ventricle, solid tumor, and brainstem extension - did not predict recurrence.
Most patients with tumor recurrence underwent a second operation, with three receiving adjuvant radiotherapy and one adjuvant chemotherapy. Five children were not operated on, but underwent radiotherapy or chemotherapy. At the last follow up, after an average of 18.4 years, all patients were still alive.
Of the 27 patients who had subtotal resections, eight had spontaneous regression of the residual tumor and four had stable residual tumor. Also, eight of 23 patients who had residual tumor after total resection had spontaneous regression of the residual tumor and four had a stable tumor. Seven patients with progressive residual tumor underwent a second subtotal resection, and five had subsequent tumor regression.
"Considering the high probability (48%) of spontaneous regression or arrested growth of residual tumors and the good prognosis for progression by repeated surgery, we believe it is prudent to leave the portions of the tumor invading vital structures (such as brainstem or cerebellar peduncle), rather than to attempt total resection, to avoid neurological deficits," conclude the researchers.
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