Page 44 - ARNM-2-2

Advances in Radiotherapy
& Nuclear Medicine Hypofractionated radiotherapy in craniopharyngioma

RT and was aspirated successfully. This patient was a were alive with stable residue, while the other died with a
4-year-old boy at the time of RT and was treated with CK complete response, at the time of writing this paper.
at 40 Gy in 15 fractions. A pre-operative shunt is rarely Although our HFRT doses were at lower boundary of
needed, but the placement of external ventricular drain at the conventional RT doses, neither tumor progression nor
the beginning of the surgery can provide useful relaxation the measured side effects (visual or neurological) were
in selected patients to prevent hydrocephalus. The same observed in these young patient population. The lower
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patient also had an external ventricular drainage before total dose in the HFRT group may reduce possible risks
RT; after RT and cystic aspiration, he did not manifest any such as secondary cancer, visual or neurological risks in the
related symptoms.
chronic period, especially in young patients. However, due
Merchant et al. conducted a study with 30 patients, to the small number of patients in our study, no evidence
where 15 patients received only surgery as an initial could be presented on this issue.
treatment, and the other 15 patients received limited
surgery and RT. The RT techniques used were EBRT for In a narrative review by Conti et al., the possible
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12 patients, stereotactic radiosurgery (SRS) for one patient, improvement by means of intensity-modulated RT, arc
and 32] P treatment for two patients. The study compared therapy, image guidance, proton radiation, and fractionated
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the patients who underwent surgery only with those who SRS were summarized. They also offer a review on many
received limited surgery and RT in terms of neurologic, published findings regarding outcome and toxicity after
endocrine, and cognitive function, as well as quality of life. RT, including those after application of the relatively
In the study, a full-scale IQ test was administered, revealing outdated RT techniques. Technological developments in
worse outcomes in the operated patients compared to the imaging, radiation planning, and delivery have remedied
combined treatment (STR+RT) group. The outcomes were the distribution of radiation doses to target volumes and
even worse in recurrent patients who had undergone initial reduced the dose to nearby critical normal structures.
surgery. In addition, the group receiving only surgery Unfortunately, in the literature, we could not find
experienced more frequent neurologic, ophthalmic, and a prospective or large retrospective series comparing
endocrine complications. Eventually, 23 out of 30 patients different RT fractions. Therefore, even though we have a
(77%) received RT at some point. Although quality of very limited number of patients, the findings of this study
life or intelligence tests were not performed in our study, utilizing modern techniques with different fractions are
families did not report a decrease in cognitive function or still valuable.
quality of life compared to pre-RT conditions.
Albano et al. reported that up to 60% of patients with
There is limited research on the treatment of parasellar tumors experienced a deterioration of new-onset
craniopharyngioma using SRT and HFRT. In a study by pituitary insufficiency or hypopituitarism 5 to 10 years
Lee et al., all patients with craniopharyngioma were after treatment with fractionated doses of RT ranging from
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treated with CK using 3 – 10 fractions, corresponding to a 50 Gy to 60 Gy. The use of fractionated SRT, as defined in
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mean marginal dose of 21.6 Gy (ranging from 18 –38 Gy) the study, and new irradiation techniques resulted in lower
defined according to a mean 75% isodose line. The dose toxicity rates. Although local control achieved resembles
range was heterogeneous in that study, depending on that with SRT in proton treatment, especially in pediatric
the tumor size and proximity to critical structures. Eight patients, we did not observe long-term side effects such as
patients were treated with five fractions, with a total dose radiation-related tumors and neurocognitive impairment,
ranging from 20 to 27.5 Gy. In our study, we treated three but found that one patient who had already pituitary
patients with SRT using five fractions, corresponding to a insufficiency before RT was in need of a slight increase in
total dose of 20 – 22.5 Gy, through CK without resulting in hormone replacement therapy and that another patient was
significant toxicity or recurrence. The other three patients gaining weight without showing signs of disease progression,
received HFRT with 40 – 42 Gy in 15 fractions, while the as per imaging study. In this review, only one CP trial uses
remaining two patients received a conventional RT scheme HFRT, while other studies use SRT or conventional RT
of 50 – 55 Gy in 25 – 30 fractions. The results showed no dosing regimens. However, the results are similar to our
significant differences in outcomes between the treatment study in terms of survival rates and side effects. The literature
groups. Using α/β values of 10 and 2 for biologically can provide a better interpretation of treatment results by
effective dose calculation, 40 Gy in 15 fractions corresponds including cases of craniopharyngioma treated with HFRT. 28
to 42 and 46.6 Gy as 2 Gy/fraction equivalents, respectively.
These doses fall within the recommended range for the The study has limitations that should be taken into
conventional scheme when α/β is taken as 2. Out of the account when interpreting the results. These limitations
three patients who received 40 – 42 Gy in 15 fractions, two include its retrospective nature, the small number of

Volume 2 Issue 2 (2024) 7 doi: 10.36922/arnm.3041