ABTA primer excerpt Copyright ABTA
“Diffuse Astrocytoma
also called Astrocytoma, Low Grade or Astrocytoma Grade II
(types: Fibrillary, Gemistocytic, Protoplasmic Astrocytoma)
These low grade astrocytomas tend to be infiltrating tumors, capable of growing into surrounding tissue, but tumors which grow relatively slowly.
These astrocytomas are grouped by the appearance and behavior of the cells for which they are named. For example, the nuclei of Fibrillary astrocytoma cells are cigar-shaped; this type of astrocytoma tends to contain microcysts and mucous-like fluid. Protoplasmic astrocytoma nuclei are round or oval in shape. These tumors also tend to contain microcysts and mucous-like fluid. Gemistocytic astrocytomas are plump, glassy, angular shaped cells. (Until recently there had been some disagreement as to the grade of the gemistocytic astrocytoma. Some pathologists considered this to be a grade III tumor since the gemistocytic astrocytoma, in particular, tends to recur as an anaplastic astrocytoma. The WHO classification system published in 2000 defines these as grade II tumors.)
Regardless of the cellular appearance of these grade II astrocytomas, surgical removal may be suggested for accessible tumors (tumors that may be removed without causing undue neurological damage). If “total” surgical removal can be achieved, periodic follow-up with MRI or CT scans might be the only additional care required. It is important to realize that “total” removal generally means removal of all of the tumor visible to the neurosurgeon’s eye. Microscopic cells, too small to see, can remain behind or may have spread to nearby tissue. Those cells may later begin to re-grow. However, even with incomplete removal these tumors tend to grow very slowly, and it may be several years before symptoms reappear due to tumor regrowth.
In adults and older children, radiation therapy may be suggested in addition to surgery, or radiation may be used to treat a low grade astrocytoma which is unable to be removed. The role of chemotherapy in treating these tumors is under investigation. Further treatment might be recommended only if the tumor recurs. Children younger than three might receive chemotherapy so that radiation can be delayed.
These low grade tumors may recur as a higher grade tumor; thus, periodic follow-up and attention to the return of symptoms is important. Treatment of the recurrent tumor would be based on the tumor’s grade at the time of re-growth.”