Paediatric radiation therapy without anaesthesia - Are the children moving?

PURPOSE

Children who require radiation therapy (RT) should ideally be treated awake, without anaesthesia, if possible. Audiovisual distraction is a known method to facilitate awake treatment, but its effectiveness at keeping children from moving during treatment is not known. The aim of this study was to evaluate intrafraction movement of children receiving RT while awake.

METHODS

In this prospective study, we measured the intrafraction movement of children undergoing treatment with fractionated RT, using pre- and post-RT cone beam CT (CBCT) with image matching on bony anatomy. Study CBCTs were acquired at first fraction, weekly during RT, and at last fraction. The primary endpoint was the magnitude of vector change between the pre- and post-RT scans. Our hypothesis was that 90 % of CBCT acquisitions would have minimal movement, defined as <3 mm for head-and-neck (HN) treatments and <5 mm for non-HN treatments.

RESULTS

A total of 65 children were enrolled and had evaluable data across 302 treatments with CBCT acquisitions. Median age was 11 years (range, 2-18; 1st and 3rd quartiles 7 and 14 years, respectively). Minimal movement was observed in 99.4 % of HN treatments and 97.2 % of non-HN treatments. The study hypothesis of >90 % of evaluations having minimal movement was met. Children who were age >11 years moved less at initial evaluation but tended to move more as a course of radiation progressed, as compared to children who were younger.

CONCLUSION

Children receiving RT with audiovisual distraction while awake had small magnitudes of observed intrafraction movement, with minimal movement in >97 % of observed RT fractions. This study validates methods of anaesthesia avoidance using audiovisual distraction for selected children.

Radiofrequency and microwave ablation for treatment of recurrent gynecologic malignancies

OBJECTIVE

Radiofrequency ablation and microwave ablation are used to vaporize tumors not amenable to surgical resection. We sought to evaluate the safety and efficacy of radiofrequency and microwave ablation for the treatment of isolated lesions in patients with recurrent gynecologic malignancy.

METHODS

Patients with gynecologic malignancies treated with radiofrequency or microwave ablation at a university-affiliated cancer center from April 2007 to January 2020 were evaluated. Clinical records were reviewed for number of prior chemotherapy regimens, response to ablation, time to progression, and location of progression.

RESULTS

Thirty-two patients received ablative therapy for treatment of isolated recurrences. Seventeen (53%) patients had ovarian cancer, seven (22%) had endometrial cancer, and eight (25%) had cervical cancer. Thirteen (41%) patients received radiofrequency ablation and 19 (59%) received microwave ablation. Patients had a median of 2 (range 1-12) prior lines of chemotherapy. Sixteen (50%) patients achieved a partial or complete response with two patients experiencing no progression at time of submission. Six (19%) patients had stable disease and 10 (31%) patients had progression at time of initial follow-up imaging. Median progression-free survival for the cohort was 7.3 months (range 1.4-64.7). No significant improvement in median progression-free survival was seen with the addition of adjuvant systemic therapy to radiofrequency or microwave ablation (6.9 vs 7.7 months; HR 0.7, 95% CI 0.3 to 1.7). Clinical benefit, defined as absence of definitive progression at the site of ablation or new target lesions at 4 months, was seen in 22 (68.8%) patients. No major complications occurred, with two patients reporting pain or weakness at the site of ablation.

CONCLUSION

Radiofrequency and microwave ablation demonstrated that 68.8% (n=22) of patients experienced clinical benefit at 4 months. Ablative therapy may be considered for the treatment of isolated lesions in patients with recurrent gynecologic malignancies.

Outcomes analysis of pre-brachytherapy MRI in patients with locally advanced cervical cancer

INTRODUCTION

Various brachytherapy options are available for treating cervical cancer. This study investigated whether pre-brachytherapy magnetic resonance imaging (MRI) findings could help identify the appropriate brachytherapy technique for cervical cancer.

METHODS

We retrospectively evaluated patients with cervical cancer who underwent pre-brachytherapy MRI within 7 days before their first high-dose rate brachytherapy treatment between December 2009 and September 2015. Patients who could not undergo MRI at pre-treatment and/or pre-brachytherapy and complete radical radiotherapy were excluded. Conventional intracavitary brachytherapy was the preferred treatment for ≤4 cm and symmetrical tumors. Non-conventional intracavitary brachytherapy, including interstitial brachytherapy, was the preferred treatment for bulky tumors, asymmetrical tumors, tumors with severe vaginal invasion, or bulky barrel-shaped tumors. The 3-year rates of overall survival, disease-free survival, and local control were compared using the Kaplan-Meier method and the log-rank test. Overall survival and local control rates were assessed using Cox regression analysis to identify risk factors for poor overall survival and local control outcomes.

RESULTS

A total of 146 patients were included in the study. The median tumor sizes were 52 mm (range 17-85) at the pre-treatment MRI and 30 mm (range 0-78) at the pre-brachytherapy MRI. Six patients had International Federation of Gynecology and Obstetrics (FIGO) stage IB2, 67 patients had stage II, 64 patients had stage III, and nine patients had stage IVA disease. A total of 124 (85%) patients had squamous cell carcinoma and 22 (15%) patients had adenosquamous cell carcinoma or adenocarcinoma. The MRI findings showed severe vaginal invasion (pre-treatment: 19 patients, pre-brachytherapy: 10 patients), asymmetrical bulky tumors (pre-treatment: 28 patients, pre-brachytherapy: 16 patients), and severe corpus invasion (pre-treatment: 39 patients, pre-brachytherapy: 18 patients). Based on the pre-brachytherapy MRI findings, non-conventional intracavitary brachytherapy was administered to 34 (23.3%) patients. Brachytherapy seemed to be appropriate for 133 (91.1%) patients and inappropriate for 13 (8.9%) patients. The 3-year rates were 84.2% for overall survival and 90.1% for local control. Grade 3 late rectal complications occurred in two (1%) patients. Multivariate analysis showed that tumor characteristics (size, shape, and extent of invasion) were not risk factors, although inappropriate brachytherapy was significantly related to poor local control (p<0.001).

CONCLUSION

Pre-brachytherapy MRI may help to select appropriate brachytherapy for cervical cancer and reduce the likelihood of inappropriate brachytherapy leading to poor local control.

Interfractional variation of radiation target and adaptive radiotherapy for totally resected glioblastoma

This study aimed to evaluate the effects of volume adapted re-planning for radiotherapy (RT) after gross total resection (GTR) for glioblastoma. Nineteen patients with glioblastoma who underwent GTR and postoperative RT were analyzed. The volumes of the surgical cavity on computed tomography (CT) obtained one day after GTR (CT0), the first RT simulation CT (sim-CT1), and the second simulation CT for the boost RT plan (sim-CT2) were compared. The boost RT plan was based on the surgical cavity observed on the sim-CT2 (boost RTP2) and was compared with that based on the surgical cavity observed on the sim-CT1 (boost RTP1). The volume reduction ratios were 14.4%-51.3% (median, 29.0%) between CT0 and sim-CT1 and -7.9%-71.9% (median, 34.9%) between sim-CT1 and sim-CT2 (P < 0.001). The normal brain volumes in boost RTP1 were significantly reduced in boost RTP2, especially at high dose levels. Target volume in sim-CT2 which was not covered with the boost RTP1, developed in five cases (26.3%). The surgical cavity volume was reduced following surgery in patients with glioblastoma who underwent GTR. The application of volume-adapted re-planning during RT could decrease the irradiated volume of normal brain and prevent a target miss for boost RT.