Decreasing Temporal Lobe Dose With Five-Field Intensity-Modulated Radiotherapy for Treatment of Pituitary Macroadenomas

Proton therapy for craniopharyngioma in adults: a protocol for systematic review and meta-analysis

INTRODUCTION

Craniopharyngioma is the most challenging to treat brain tumour with high recurrence rates, which can be effectively reduced by adjuvant radiotherapy. In recent years, proton therapy (PT), with its physical properties of heavy ion beam, that is, Prague peak phenomenon, has been more frequently used in patients with craniopharyngioma. Compared with conventional X-ray beam radiotherapy, PT can reduce the damage to normal tissues and enlarge the damage to tumours. Some studies have shown that PT has advantages in the treatment of craniopharyngioma in adults. However, the optimal management of craniopharyngioma remains controversial. The purpose of this study was to evaluate the efficacy and safety of PT for craniopharyngioma in adults.

METHODS AND ANALYSIS

We will search six databases (MEDLINE, EMBASE, Web of Science, the Cochrane Library, Amed, Scopus), clinical research registration websites and grey literature, aiming to identify randomised controlled trials (RCTs) on PT for craniopharyngioma in adults between 1 January 1954 and 28 September 2021. In the RCTs, PT will be used as the intervention group, and conventional X-ray beam radiotherapy will be used as the comparator group. Tumour recurrence and survival will be the primary outcome, and treatment-related toxicity will be the secondary outcome. The study selection, data extraction, bias risk and quality evaluation will be operated by two to four researchers independently. We will use Review Manager V.5.2 (RevMan V.5.2) for data analysis. If there is significant heterogeneity, we will identify the source of heterogeneity by subgroup analysis.

ETHICS AND DISSEMINATION

Our study is based on existing RCTs and does not require ethical approval. The results of the study will be published in a peer-reviewed journal or at a related conference.

PROSPERO REGISTRATION NUMBER

CRD42020200909.

Radiotherapy of Parasellar Tumours

Parasellar tumours represent a wide group of intracranial lesions, both benign and malignant. They may arise from several structures located within the parasellar area or they may infiltrate or metastasize this region. The treatment of the tumours located in these areas is challenging because of their complex anatomical location and their heterogenous histology. It often requires a multimodal approach, including surgery, radiation therapy (RT), and medical therapy. Due to the proximity of critical structures and the risks of side effects related to the procedure, a successful surgical resection is often not achievable. Thus, RT plays a crucial role in the treatment of several parasellar tumours. Conventional fractionated RT and modern radiation techniques, like stereotactic radiosurgery and proton beam RT, have become a standard management option, in particular for cases with residual or recurrent tumours after surgery and for those cases where surgery is contraindicated. This review examines the role of RT in parasellar tumours analysing several techniques, outcomes and side effects.

Implementation of temporal lobe contouring protocol in head and neck cancer radiotherapy planning: A quality improvement project

Temporal lobe necrosis as result of radiation for nasopharyngeal cancer (NPC) occurs up to 28% of NPC patients. The only effective mitigation is by strict adherence to temporal lobe dose tolerances during radiotherapy planning, which in turn hinges on accurate temporal lobe delineation. We aim to improve the accuracy and to standardize temporal lobe contouring for patients receiving head and neck radiotherapy for NPC in a tertiary teaching hospital in Singapore.The baseline data were obtained from 10 patients in the diagnostic phase and the effect of interventions were measured in 37 patients who underwent head and neck radiotherapy over a 6-month period.We conducted the project based on the Clinical Practice Improvement Program methodology. The baseline pooled mean percentage variation in temporal lobe contouring was 39.9% (0.8%-60.2%). There was a low level of temporal lobe contouring concordance and this provided the impetus for implementation of strategies to improve the accuracy and reproducibility of temporal lobe contouring. The interventions included supervision and training of radiation therapists and residents in temporal lobe contouring, and standardization of temporal lobe contouring with a protocol and contouring atlas.Thirty-seven patients were treated during the study period from June to November 2014. Following implementation of the first set of interventions, the pooled mean percentage variation in temporal lobe contouring decreased but was not sustained. The implementation of the second set of interventions resulted in a decrease from 39.9% (January to September 2014) to 17.3% (October to November 2014) where P = .004 using t test. Weekly variation was seen throughout the study period but the decrease was sustained after standardizing and providing a contouring atlas for temporal lobe contouring.Temporal lobe contouring can be standardized through effective implementation of a temporal lobe contouring protocol and atlas.

Evaluation of depressive mood and cognitive functions in patients with acromegaly under somatostatin analogue therapy

AIMS

Acromegaly is caused by a pituitary adenoma that releases excess growth hormone (GH) and a concomitant increase in insulin-like growth factor 1 (IGF-1). Acromegaly results not only in phenotypic changes, but also in neurologic complications as peripheral neuropathy and cognitive dysfunction. This study aimed to compare depressive mood and cognitive function in patients with acromegaly and in healthy controls as well as to determine the factors underlying cognitive dysfunction in the acromegalic patients.

MATERIALS AND METHODS

This study included 42 patients with acromegaly that were receiving somatostatin analogue therapy and 44 healthy controls. Memory, attention, visuospatial function, inhibitory function, abstract thinking, verbal fluency, and depressive mood were measured in the patients and controls.

RESULTS

Patients with acromegaly had lower learning (p = 0.01), planning (p = 0.03), complex attention and inhibitory function (p = 0.04) scores than the controls. There was no significant difference in depressive mood between the patients and controls (p > 0.05). Gamma knife radiosurgery did not negatively affect cognitive function (p > 0.05).

CONCLUSION

The present findings show that acromegaly negatively affects learning, attention, and planning.

Updates in outcomes of stereotactic radiation therapy in acromegaly

Purpose Treatment of acromegaly has undergone important progress in the last 20 years mainly due to the development of new medical options and advances in surgical techniques. Pituitary surgery is usually first-line therapy, and medical treatment is indicated for persistent disease, while radiation (RT) is often used as third-line therapy. The benefits of RT (tumor volume control and decreased hormonal secretion) are hampered by the long latency of the effect and the high risk of adverse effects. Stereotactic RT methods have been developed with the aim to provide more precise targeting of the tumor with better control of the radiation dose received by the adjacent brain structures. The purpose of this review is to present the updates in the efficacy and safety of pituitary RT in acromegalic patients, with an emphasis on the new stereotactic radiation techniques. Methods A systematic review was performed using PubMed and articles/abstracts and reviews detailing RT in acromegaly from 2000 to 2016 were included. Results Stereotactic radiosurgery and fractionated stereotactic RT (FSRT) for patients with persistent active acromegaly after surgery and/or during medical therapy provide comparable high rates of tumor control, i.e. stable or decrease in size of the tumor in 93-100% of patients at 5-10 years and endocrinological remission in 40-60% of patients at 5 years. Hypofractionated RT is an optimal option for tumors located near the optic structures, due to its lower toxicity for the optic nerves compared to single-dose radiosurgery. The rate of new hypopituitarism varies from 10 to 50% at 5 years and increases with the duration of follow-up. The risk for other radiation-induced complications is usually low (0-5% for new visual deficits, cranial nerves damage or brain radionecrosis and 0-1% for secondary brain tumors) and risk of stroke may be higher in FSRT. Conclusion Although the use of radiotherapy in patients with acromegaly has decreased with advances in medical treatments, it remains an effective treatment option after unsuccessful surgery and/or resistance or unavailability of medical therapy. Long-term studies evaluating secondary morbidity and mortality rate after the new stereotactic techniques are needed, in order to evaluate their potential brain-sparing effect.

A comparison of the doses received by normal cranial tissues during different simple model conventional radiotherapeutic approaches to pituitary tumours

This aim of this study was to compare the doses received by critical cranial organs when three different radiation techniques were used to treat pituitary tumours. Cranial computed tomography scans of a RANDO phantom and 30 patients were used for pituitary macroadenoma radiotherapy treatment planning. For each slice, target volumes and other critical organs were contoured and three techniques were applied: (A) two parallel-opposed lateral fields, (B) two oblique fields (45°) in coronal plane and (C) two parallel-opposed lateral and anterior fields while the head was tilted 45° in the sagittal plane. The doses received by the target volume and the critical organs for each technique were calculated for all patients. Irradiation was repeated three times for each technique. Finally, the doses that reached the organs of interest resulting from these techniques were compared. The dose delivered to the temporal lobes was 105, 9 and 72 % of the prescribed dose using techniques A, B and C, respectively. The dose received by the cochlea was the lowest in technique C (27 % of prescribed dose) compared with techniques A (79 %) and B (48 %). All techniques delivered 100 % of the prescribed dose to the chiasma. Technique A increased the dose to temporal lobes and the cochlea to such an extent that they exceeded the tolerance dose. Technique B spared the temporal lobes better than technique C; however, technique C was preferred since the dose received by the cochlea in this case was the lowest of all techniques. None of the techniques spared the chiasma.