Update on the Surgical Management of Craniopharyngiomas
of radiotherapy for craniopharyngioma is the radio-sensitivity of the adjacent visual pathways, which are generally restricted to a dose of
Despite these limitations, GKS can play an important role in reducing recurrence rates when GTR is not feasible.
Although the optimal dose has been reported to range from 9 to 12Gy, and thus exceeds the dose limit of the optic pathways, therapeutic effect has been reported with a lower marginal dose of 6Gy.30,32–34
Stereotactic treatment carries advantages over conventional fractionated radiation therapy by allowing for greater precision and thereby reducing the volume of irradiated brain tissue.35
In addition,
this modality allows delivery of higher radiation doses with less damage to adjacent neurological structures; for example, the tolerance of the optic chiasm to fractionated stereotactic radiotherapy is reported to be 54Gy/30 fractions compared with a reported 8–9Gy tolerance when delivered as a single fraction.36 Minniti et al.37
themselves often dictate the indicated treatment, thus the variable efficacies demonstrated in each study may be a function of differences in tumour characteristics rather than solely differences in treatment. This is an important consideration when reviewing treatment outcomes.
Literature values for overall survival range from 80 to 91% at five- year follow-up regardless of treatment modality.43,44
The best
predictor of survival has been shown to be an absence of recurrence. When recurrences do occur, they do so at mean or median intervals ranging from one to 4.3 years. Treatment of recurrences is difficult, and peri-operative mortality is significantly increased compared with treatment of primary tumour. Scarring from the primary surgery or from radiotherapy decreases the rate of total removal and increases the peri-operative mortality.8,14
reported a five-year progression-free survival rate of 92% for fractionated stereotactic radiosurgery compared with 80–90% for complete excision and 50–60% for partial resection. However, despite these encouraging survival rates, vasculitis, neuropsychological changes, increased visual deficits and secondary tumours can complicate the use of fractionated stereotactic radiotherapy.38
Instillation of intracavitary radiation such as yttrium-90 or phosphorus-32 beta-emitting isotopes has been shown to be an effective primary treatment for cystic craniopharyngiomas.38,39 Studies have shown that this therapeutic modality can result in control rates of 96% for cystic tumours and 88% for all partially cystic tumours.31
Although intracavitary
radiation is effective for cystic tumours, it is not effective for solid tumours40
of the tumour.
Some authors have advocated the combination of GKS and intracavitary irradiation with yttrium-90 or phosphorus-32 isotopes as primary therapy for mixed cystic–solid tumours.38–40
This
recommendation is based on the observation that solid portions of mixed tumours are more responsive than cystic portions to GKS and that solid tumours and the solid portions of mixed tumours are less responsive than cystic tumours to intracavitary radiation.
Outcomes Tumour Recurrence and Survival
Case series have reported 10-year recurrence-free survival rates for GTR of 74–81%,15,30,41
for partial removal of 41–42%30,42,43 combination of surgery and radiotherapy of 83–90%.30,42,43
and for a Ten-
year recurrence-free survival rates for GTR, STR and STR with radiotherapy have been reported by Karavitaki et al. to be 100, 38 and 77%, respectively.11
Only 18% of patients in the afore-
mentioned study underwent GTR, in contrast to higher rates of GTR (49–84%) in other studies. These authors explained their results by stating that the favourable prognosis associated with GTR may have been due to selection bias: the most aggressively growing tumours were only partially removed and subsequently given radiotherapy. Their rationale highlights the limitation faced by studies assessing the efficacy of each treatment modality for craniopharyngiomas (e.g. GTR, STR, STR and adjuvant radiotherapy). The tumours
EUROPEAN NEUROLOGICAL REVIEW
One of the most common presenting symptoms in patients with craniopharyngioma are visual field defects. Visual fields/visual acuity reportedly improved or stabilised in 74% of patients.45 However, despite this, the incidence of long-term major visual field defects has been reported to be 48% at 10-year follow-up.11 Furthermore, patients can experience a variety of neurological and psychiatric manifestations secondary to their tumour and its treatment. Pereira et al. report the prevalence of short-term memory loss, personality changes, cranial nerve deficits, epilepsy, anosmia and position-dependent vertigo as 40, 31, 26, 17, 16 and 12%, respectively.45
Despite a progressive reduction in the intraoperative trauma to the hypothalamus due to advances in microsurgical technique, tumours of the sellar region can still result in hypothalamic dysfunction, which can manifest as appetite changes, apathy, sleep disorders and memory deficits.14 26–52% of post-operative patients.1
Hyperphagia and obesity occurs in The sequelae of obesity in
craniopharyngioma patients are similar to those seen in the general population; one study recently reported that long-term mortality rates in adult patients with craniopharyngioma are five-fold higher
111
Radiotherapy with or without surgery is an effective treatment modality for recurrent tumour and significantly prevents further tumour progression. Hakuba et al.26
free survival of 72% after radiotherapy, while Stripp et al.8 10-year local control rate of 83% after radiotherapy.
report a 15-year progression- report a
Complications of intracavitary radiation include panhypopituitarism, diabetes insipidus and CNS and visual dysfunction, including blindness.31,39,40
and carries the possibility of progression of solid portions
Morbidity and Management of Complications Patients with craniopharyngioma often suffer from endocrine dysfunction and surgical intervention does not seem to reverse existing pre-operative pituitary hormone deficits. The probabilities of GH, follicle-stimulating luteinising hormone (FSH/LH), adrenocorticotropic hormone (ACTH), and TSH deficiencies and diabetes insipidus as 88, 90, 86, 80, and 65, respectively, were reported by Karavitaki et al.11
Conditions that
should be addressed during the pre-operative evaluation include diabetes insipidus, hypoadrenalism, and hypothyroidism, which have all been shown to increase intra- and post-operative morbidity rates.32
Treatment of long-term hormone deficits
varies based on the type of deficiency and is best addressed by an endocrinologist. Despite advances in microsurgical technique, hypopituitarism is extremely common and often requires lifelong treatment.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116