Crniopharyngiomas

Diagnosis Pathology Surgical Treatment Radiation Shunting Results

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It was long doubtful whether radiation therapy could destroy craniopharyngioma epithelium and whether it had a role in treatment of these tumors. In 1961, Kramer and his colleagues reported a group of six children and four adults who had been treated with radiation therapy prior to 1954. All six of the children survived after follow-up periods approaching 20 years. Results in adults were much poorer. Since this initial report, many have indicated that radiation therapy both increases survival and prolongs the interval before tumor recurrence. The survival rates for patients treated with surgery and radiotherapy are better than for those treated with surgery alone; the recurrence-free survival rates are improved to an even greater extent.

The effectiveness of radiotherapy has led some groups to advocate a conservative operative approach for craniopharyngioma. However, Shapiro and coworkers have described better recurrence-free rates for patients undergoing "radical subtotal removal" before radiotherapy than for those with biopsy and cyst drainage prior to irradiation.

Radiotherapy is not without hazard. Radiation necrosis, endocrine deficiency, optic neuritis, and dementia have all been reported as complications. Many neurosurgeons have expressed concern over intellectual performance after irradiation in children. Significant vasculopthy may follow irradiation in children. A conservative operation followed by radiation therapy probably sacrifices the chance of a cure. An attempt at radical surgical resection may result in greater damage to the hypothalamus and neuroendocrine axis, and several reviews have stressed that the success of radical removal of these tumors depends strongly on the experience of the surgeon. Final agreement on the optimum initial therapy for craniopharyngioma certainly has not been reached.

There has not been any greater unanimity of opinion for radio­therapy in the treatment of recurrent tumors than for radiotherapy as the initial treatment. Some surgeons who advocate radical tumor resection at initial operation advise against reoperation for recurrence as being unduly hazardous, and radiation therapy following CT evidence of recurrence has been recommended. In recent years there has been an increasing tendency to reoperate on children with recurrence successfully, either electively or in the presence of renewed tumor symptoms, with only slightly higher risk than for the primary operation. This treatment protocol must be regarded as experimental until greater numbers of patients have been treated in this fashion.

Cystic tumors may be treated by the introduction of radioisotopes into the cavity. This technique was pioneered by Leksell more than 60 years ago and was coupled with stereotactic placement in the treatment of a wide variety of tumor types. The initial agent used was phosphorus (32P), and dosage was determined by an ingenious volume-dilution method. 32P is a beta-emitting isotope and was aspirated with cyst fluid. 32P was later replaced with 90Y, which has somewhat greater tissue penetration. 198 Au was also used in earlier therapy, but because of its emission of gamma as well as beta rays, radiation occasionally penetrated beyond the tumor capsule. More recent advances in dosimetry and administration have refocused attention on this isotope. Intracystic isotope treatment is limited to craniopharyngiomas that have a large volume cystic component; it is not applicable to solid tumors or to tumors with very thick or calcified walls. Reports on this therapy indicate that it has the advantages over external radiation therapy of little operative trauma and less long-term endocrine and intellectual deficit. However, this method does not seem to be risk­free. Further experience with greater numbers of patients at many centers will be required to compare it with other forms of therapy
 


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