Long-term prognosis of cerebellar astrocytoma ‘good’
MedWire News: The prognosis for children who undergo surgery for cerebellar astrocytomas is good, US researchers believe, after finding that almost half of tumors spontaneously regress or stop growing.
While it is known that the prognosis for completely resected cerebellar astrocytoma is good, the expectation is that residual tumors will progress, despite some remaining tumor arresting growth or regressing over time.
To examine this issue further, Tadanori Tomita and colleagues from the Children's Memorial Hospital, Chicago, Illinois, studied 101 children treated surgically for benign cerebellar astrocytoma between 1983 and 1999. The average length of follow-up was 18.4 years.
Of the tumors, 38.6% were solid type, 35.6% were mural type, 16.8% were cyst-within-tumor type, and 9.0% were mixed. Total resection was achieved in 50.5% of patients, total resection by operative observation with radiological residual tumor in 22.8% of patients, and subtotal resection in 26.7% of patients.
All children were alive at 10 years post-surgery. Tumor recurred in 28.7% of patients, or 5.9% of patients in whom total resection was achieved. Progression of residual tumor occurred in 48.7% of patients with radiologically residual tumor and in 55.6% of patients with subtotal resection. Notably, progression and recurrence rates were higher in patients with solid or mixed-type tumors, at 46.2% and 33.3%, respectively, compared with just 15.1% for all other tumor types combined.
The team also reports in the journal Neurosurgery that spontaneous tumor regression occurred in 29.6% and 34.9% of patients with radiologically residual tumor and subtotal resection, respectively. Spontaneous regression and arrested growth occurred in 32% and 16% of residual tumors, respectively.
On multivariate analysis, none of the factors studied - age, gender, total resection, tumor location, tumor type, and brainstem extension - had an impact on survival, while total resection was significantly associated with tumor recurrence or progression, at a hazard ratio of 0.106.
The team concludes: "The overall prognosis of cerebellar astrocytomas is good."
Noting that nearly all instances of tumor recurrence or progression occurred within 8 years of surgery, they add: "Eight to 10 years is considered to be a reasonable follow-up period by neuroimaging study for benign cerebellar astrocytomas."
By Liam Davenport