Stereotactic biopsy and brachytherapy of brain tumours

This paper discusses 98 patients who had their cerebral lesions stereotactically biopsied. Modified Riechert-Mundinger instrumentation was employed. Of the 98 patients, eight received only biopsy and 90 were then interstitially radiated with iridium-192 (¹⁹²Ir) custom stacked in afterloading catheters. The vast majority of brachytherapeutically treated lesions were anaplastic or malignant astrocytomas. There were some metastatic lesions, and in two instances the tumour occupied the infratentorial compartment. Two-thirds of the patients had received prior teletherapy; in the remainder, stereotaxis provided the initial diagnosis and brachytherapy the principal treatment. The survival data suggest reasons for optimism. Eighty percent of patients with anaplastic astrocytoma were alive 2 yr later, compared with 55% for those harbouring malignant astrocytomas. Since this is the largest database on this topic in the U.S.A., we are in the process of a more critical review. Complication rate is low. Diagnostic tissue was obtained in all instances. Delayed radionecrosis at the site of implant may aggravate neurological deficits when lesions involve functionally sensitive cortex or their pertinent underlying structures. Such reactions may appear 4–18 mnth after brachytherapy and are more likely to occur in patients who were previously radiated.     

A Single-Dose Conformal Delivery of Radiotherapy Following Osteoplasty

Multiple myeloma (MM) is a very radiosensitive tumor. Fractionated external beam radiation, which takes approximately 2 weeks of therapy, is typically used to irradiate myelomatous bone lesions with the goal of palliation. However, traditional radiotherapeutic techniques are not only lengthy but they also involve a considerable amount of healthy bone marrow in the treatment ports, which may undermine the total marrow reserve of a patient. Because of the limited survival time of patients with metastatic cancer, novel treatment concepts shortening the overall treatment time is desirable. We present an innovative approach of delivering targeted intra-operative radiotherapy to a solitary osteolytic metastasis in one application, while sparing healthy bone marrow from radiation toxicity and substantially reducing the overall treatment time. A 78-year-old Caucasian male with MM, previously treated with chemotherapy, who was off chemotherapy for 2 years due to bone marrow suppression, presented with a solitary recurrence at the left anterior superior iliac spine of the left iliac wing as diagnosed by PET-CT scan. This lesion was treated with a minimally invasive osteoplasty and intra-operative brachytherapy with to a dose of 8 Gy delivered to the surgical cavity only, followed by injection of the bone cement into the cavity. Three months after the procedure, the area of treatment demonstrated no uptake on a follow-up PET-CT scan. At 1.5 years after this procedure, 100% local control continues to persist in the treated area, as evidenced on nuclear imaging. To our knowledge, this is the first case of using focal intra-operative brachytherapy confined to the area of the pelvis in a patient treated for a solitary metastasis from MM. The purpose of the article is to present a novel approach as a more convenient and focal treatment of bony lesions of MM.     

Ultrahypofractionated Radiotherapy for Localised Prostate Cancer: How Far Can We Go?

Following adoption of moderately hypofractionated radiotherapy as a standard for localised prostate cancer, ultrahypofractioned radiotherapy delivered in five to seven fractions is rapidly being embraced by clinical practice and international guidelines. However, the question remains: how low can we go? Can radiotherapy for prostate cancer be delivered in fewer than five fractions? The current review summarises the evidence that radiotherapy for localised prostate cancer can be safely and effectively delivered in fewer than five fractions using high dose rate brachytherapy or stereotactic body radiotherapy. We also discuss important lessons learned from the single-fraction high dose rate brachytherapy experience.     

Curiethérapie de débit de dose pulsé dans les cancers du col utérin : pourquoi,comment ?

The end of the production of 192 iridium wires terminates low dose rate brachytherapy and requires to move towards pulsed-dose rate or high-dose rate brachytherapy. In the case of gynecological cancers, technical alternatives exist, and many teams have already taken the step of pulsed-dose rate for scientific reasons. Using a projector source is indeed a prerequisite for 3D brachytherapy, which gradually installs as a standard treatment in the treatment of cervical cancers. For other centers, this change implies beyond investments in equipment and training, organizational consequences to ensure quality.     

Experience of Interstitial Permanent I125 Brachytherapy for Extremity Soft Tissue Sarcomas

AimsSoft tissue sarcomas are uncommon, but relatively aggressive tumours. Although surgical resection remains the primary therapeutic modality for all localised tumours, brachytherapy combined with function-preserving excision is a popular treatment for extremity soft tissue sarcomas. The objective of this study was to evaluate the effect of interstitial permanent brachytherapy using I¹²⁵ seeds in patients undergoing the combined modality in the management of soft tissue sarcomas at our institution.Materials and methodsBetween January 2007 and January 2012, 110 adult patients aged 18–86 years (median = 44 years) with extremity soft tissue sarcomas and who underwent interstitial permanent brachytherapy as part of the local treatment were included in this study. Treatment included wide local excision of the tumour and brachytherapy using a permanent I¹²⁵ implantation. Complications were assessed in terms of wound complication and peripheral nerve damage.ResultsAfter a median follow-up of 43.7 months, the local control, disease-free survival and overall survival for the entire cohort studied were 74, 54 and 77%, respectively. The actual rates of wound complications requiring reoperation and nerve damage were 4.5 and 1.8%, respectively.ConclusionsWe conclude that interstitial permanent brachytherapy with I¹²⁵ after function-preserving surgery results in a satisfactory outcome in patients with extremity soft tissue sarcomas and the complication rate is low.     

High dose rate brachytherapy with customized applicators for malignant facial skin lesions

PurposeBrachytherapy is a well-known treatment in the management of skin tumors. For facial or scalp lesions, applicators have been developed to deliver non-invasive treatment. We present cases treated with customized applicators with high dose rate system.Material and methodsPatients with poor performance status treated for malignant skin lesions of the scalp or the facial skin between 2011 and 2014 were studied. Afterloading devices were chosen between Freiburg^® Flap, silicone-mold or wax applicators. The clinical target volume (CTV) was created by adding margins to lesions (10 mm to 20 mm). The dose schedules were 25 Gy in five fractions for postoperative lesions, 30 Gy in six fractions for exclusive treatments and a single session of 8 Gy could be considered for palliative treatments.ResultsIn 30 months, 11 patients received a treatment for a total of 12 lesions. The median age was 80 years. The median follow-up was 17 months and the 2-year local control rate was 91%. The mean CTV surface was 41.1 cm² with a mean thickness of 6.1 mm. We conceived three wax applicators, used our silicone-mold eight times and the Freiburg^® Flap one time. We observed only low-grade radiodermitis (grade I: 50%, grade II: 33%), and no high-grade skin toxicity.ConclusionHigh dose rate brachytherapy with customized applicators for facial skin and scalp lesions is efficient and safe. It is a good modality to treat complex lesions in patients unfit for invasive treatment.     

Quality comparison between three-dimensional T2-weighted SPACE and two-dimensional T2-weighted turbo spin echo magnetic resonance images for the brachytherapy planning evaluation of prostate and periprostatic anatomy

PurposeThe purpose of this study was to compare an isotropic three-dimensional (3D) T2-weighted sequence sampling perfection with application-optimized contrasts by using flip angle evolution (SPACE) with an axial two-dimensional T2-weighted turbo spin echo (TSE) sequence with regard to overall image quality and the delineation of normal prostate and periprostatic anatomy for low-dose-rate prostate cancer brachytherapy planning evaluation.Methods and MaterialsPatients (n = 69) with prostate cancer who had pelvic magnetic resonance imaging (MRI) for low-dose-rate brachytherapy treatment planning were included. Three radiologists independently assessed the visibility of nine anatomic structures on each sequence by using a 5-point scale and overall image quality by using a 4-point scale. The significance of the differences in diagnostic performance was tested with a Wilcoxon signed rank test.ResultsNo significant intersequence differences were found for most (7/9) anatomical structures and overall image quality. The mean scores for visibility of anatomical structures on the 3D SPACE and 2D TSE sequences, respectively, were as follows: the zonal anatomy (3.7; 3.9, p = 0.05), prostate capsule (3.9; 4.0, p = 0.08), neurovascular bundle (2.9; 2.9, p = 0.9), rectoprostatic angle (3.8; 3.8, p = 0.35), rectum (4.2; 4.3, p = 0.26), urethra (3.8; 3.9, p = 0.12), urinary bladder (4.6; 4.6, p = 0.61), and overall image quality (2.9; 2.9, p = 0.33). 3D SPACE was superior for delineation of the genitourinary diaphragm (3.8; 3.6, p = 0.003), whereas 2D TSE was superior for delineation of the seminal vesicles (3.5; 4.0, p < 0.0001).ConclusionsAnatomic delineation of the prostatic and periprostatic anatomy provided by the 3D SPACE sequence is as robust in quality as that provided by a conventional 2D TSE sequence with superior delineation of the genitourinary diaphragm. For MRI-based brachytherapy treatment planning, the 3D SPACE sequence with subcentimeter isotropic resolution can replace the 2D TSE sequence and be incorporated into standard MRI protocols.     

Evaluating reimbursement of skin radiation therapy: Technique and fractionation

PurposeMultiple skin radiation therapy techniques exist including electron beam therapy, high-dose-rate (HDR) brachytherapy, superficial/orthovoltage, and electronic brachytherapy (EB). The purpose of this analysis was to compare reimbursement between these modalities by fractionation regimen.Methods and MaterialsReimbursement was derived from the 2020 Medicare Physician Fee Schedule by fractionation schedule or from the 2020 Hospital Outpatient Prospective Payment national benchmarks. A secondary analysis evaluating incorporation of daily simulation codes was also performed to factor in coding heterogeneity.ResultsSuperficial/orthovoltage was the least costly and EB the next least costly technique regardless of fractionation. When incorporating variations in coding of simulations, reimbursement with superficial/orthovoltage was still least costly, with a reduction in cost of $1,755, $2,715, $5,076, and $7,436 compared with HDR brachytherapy for 6, 10, 20, and 30 fractions, respectively, and a reduction in cost of $1,325, $2,170, $4,281, and $6,392 compared with EB. HDR brachytherapy and EB costs can increase by 63–110% based on nonrecommended variation in daily simulation billing, with superficial/orthovoltage experiencing the highest relative increase. Reimbursement per course can vary by a factor of 4.5–9.3x depending on the modality and fractionation scheme utilized.ConclusionsSuperficial/orthovoltage followed by EB were the least costly modalities with regard to reimbursement; however, costs can vary with frequency of simulation code billing. Consistency and standardization in skin radiation therapy reimbursement is needed, and case rates within a radiation oncology alternative payment model may help to minimize reimbursement heterogeneity among treatment options.     

The impact of rectal/bladder filling and applicator positioning on in vivo rectal dosimetry in vaginal cuff brachytherapy using an enhanced therapy setting

PurposeThe impact of rectal filling and bladder volume on in vivo rectal dosimetry (IVD) in vaginal cuff brachytherapy (VCBT) is unknown. The purpose of this study was to compare rectal doses from IVD with those calculated from treatment planning and to identify influencing factors.Materials and MethodsWe collected data of 80 VCBT sessions, four for each of 20 patients. Each was retrospectively compared with doses determined by the treatment planning system. Factors potentially predicting the IVD rectum dose were analyzed.ResultsFor a series of 80 brachytherapy applications, the calculated mean dose to the rectum was 2.52 Gy. The mean difference between all calculated and measured doses for the 80 applications with five probe positions each was 0.09 Gy (p = 0.952) proving high overall accordance between IVD and calculated doses at the rectum. The mean volume of the rectum was 119 ± 57 cm³. The rectal volume was not statistically significantly associated with the IVD or the calculated rectum doses. At the third and fourth rectal probe position in craniocaudal ordering, increased filling of the urinary bladder resulted in decreased measured and calculated doses (p < 0.05 for both). A rectum pointing position of the applicator significantly increased the maximum rectum dose compared with a bladder-oriented position (p < 0.05).ConclusionsIVD provided valuable data for rectal exposure in VCBT. Increased bladder filling and vaginal applicator positioning off the rectum elicited related with less rectal radiation exposure, whereas rectal filling did not. Further confirmation including assessment of IVD in bladder is pending to define optimal dosimetric conditions in VCBT.     

FMEA-guided transition from microSelectron to Flexitron for HDR brachytherapy

PurposeTo utilize failure mode and effects analysis (FMEA) to effectively direct the transition from the Elekta microSelectron to the Flexitron high dose-rate afterloader system.Materials and MethodsOur FMEA was performed in two stages. In the first stage, the lead brachytherapy physicists used FMEA to guide the brainstorming sessions and to identify vulnerabilities during this transition. The second stage of FMEA was carried out 2 months after the clinical release of the Flexitron system. The process map was examined again to further refine and improve the entire process.ResultsIn the first-stage FMEA, 81 process steps were identified. Moreover, 80 failure modes and their categorized causes were recognized. Checklists and data books containing the corresponding applicator information were verified and updated. Next, based on outcomes of our first-stage FMEA, we chose to implement the commissioning process in two phases. The second stage of FMEA identified error-prone steps in our newly updated processes. This second stage of analysis resulted in the development of new tools and checklist items.ConclusionsThe two-stage FMEA approach successfully directed the transition to the Flexitron system by identifying the necessary changes in the checklists and workflows for all applicators utilized in our clinic. It also led to the decision to use a two-phase commissioning approach. This allowed for minimization clinical downtime, avoidance of an extra source change, and facilitation of efficient staff training. Additionally, multiple project-level failures were discovered. Our experience and outcomes from this FMEA-guided transition should provide valuable information to the brachytherapy community.