Intraoperative high-dose-rate brachytherapy for the treatment of pediatric tumors: the Ohio State University experience

Intraoperative radiation therapy for pediatric sarcomas and other solid tumors

PURPOSE

To evaluate local failure (LF) and toxicity after intraoperative radiation therapy (IORT) in pediatric solid tumors (ST).

METHODS

A single-institution retrospective study of 96 pediatric patients (108 applications) with ST treated from 1995 to 2022 with IORT. LF was calculated via cumulative incidence function and overall survival (OS) by Kaplan-Meier method, both from the day of surgery.

RESULTS

Median age at time of IORT was 8 years (range: 0.8-20.9 years). Median follow-up for all patients and surviving patients was 16 months and 3 years, respectively. The most common histologies included rhabdomyosarcoma (n = 42), Ewing sarcoma (n = 10), and Wilms tumor (n = 9). Most (95%) received chemotherapy, 37% had prior external beam radiation therapy to the site of IORT, and 46% had a prior surgery for tumor resection. About half (54%) were treated with upfront IORT to the primary tumor due to difficult circumstances such as very young age or challenging anatomy. The median IORT dose was 12 Gy (range: 4-18 Gy), and median area treated was 24 cm2 (range: 2-198 cm2). The cumulative incidence of LF was 17% at 2 years and 23% at 5 years. Toxicity from IORT was reasonable, with postoperative complications likely related to IORT seen in 15 (16%) patients.

CONCLUSION

Our study represents the largest and most recent analysis of efficacy and safety of IORT in pediatric patients with ST. Less than one quarter of all patients failed locally with acceptable toxicities. Overall, IORT is an effective and safe technique to achieve local control in patients with challenging circumstances.

Brachytherapy for Organ and Function Preservation in Soft-Tissue Sarcomas in Adult and Paediatric Patients

Adjuvant radiotherapy is an integral component in the management of soft-tissue sarcomas. Brachytherapy is a very convenient and conformal way of delivering adjuvant radiotherapy in such tumours, which spares the surrounding normal tissue. Randomised studies have established the efficacy of brachytherapy in the adjuvant setting, with a 5-year local control of 80-85%. High dose rate, low dose rate and pulsed dose rate have shown equivalent local control, but high dose rate has gained popularity owing to patient convenience, radiation safety and flexibility in dose optimisation. Freehand insertion perioperative brachytherapy (intraoperative placement and postoperative treatment) is the most commonly used technique in soft-tissue sarcomas, with intraoperative radiotherapy and radioactive seed placement being the less commonly used techniques. Brachytherapy can be used as monotherapy or in combination with external beam radiotherapy, such as in cases of close/positive margins for safe dose escalation. Although the quantum of side-effects with external beam radiotherapy has considerably reduced with the evolution of technology and the introduction of intensity modulation (intensity-modulated radiotherapy), brachytherapy still scores better in terms of dose conformality, especially in recurrent tumours (previously irradiated) and when used to treat paediatric and geriatric patients.

Brachytherapy for Pediatric Patients at Gustave Roussy Cancer Campus: A Model of International Cooperation for Highly Specialized Treatments

PURPOSE

Childhood cancer is rare, and treatment is frequently associated with long-term morbidity. Disparities in survival and long-term side effects encourage the establishment of networks to increase access to complex organ-conservative strategies, such as brachytherapy. We report our experience of an international cooperation model in childhood cancers.

METHODS AND MATERIALS

We examined the outcome of all children referred to our center from national or international networks to be treated according to a multimodal organ-conservative approach, including brachytherapy.

RESULTS

We identified 305 patients whose median age at diagnosis was 2.2 years (range, 1.4 months to 17.2 years). Among these patients, 99 (32.4%) were treated between 2015 and 2020; 172 (56.4%) were referred from national centers; and 133 (43.6%) were international patients from 31 countries (mainly Europe). Also, 263 patients were referred for primary treatment and 42 patients were referred for salvage treatment. Genitourinary tumors were the most frequent sites, with 56.4% bladder/prostate rhabdomyosarcoma and 28.5% gynecologic tumors. In addition to brachytherapy, local treatment consisted of partial tumor resection in 207 patients (67.9%), and 39 patients (13%) had additional external radiation therapy. Median follow-up was 58 months (range, 1 month to 48 years), 93 months for national patients, and 37 months for international patients (P < .0001). Five-year local control, disease-free survival, and overall survival rates were 90.8% (95% confidence interval [CI], 87.3%-94.4%), 84.4% (95% CI, 80.1%-89.0%), and 93.3% (95% CI, 90.1%-96.5%), respectively. Patients referred for salvage treatment had poorer disease-free survival (P < .01). Implementation of image guided pulse-dose-rate brachytherapy was associated with better local control among patients with rhabdomyosarcoma referred for primary treatment (hazard ratio, 9.72; 95% CI, 1.24-71.0). At last follow-up, 16.7% patients had long-term severe treatment-related complications, and 2 patients (0.7%) had developed second malignancy.

CONCLUSIONS

This retrospective series shows the feasibility of a multinational referral network for brachytherapy allowing high patient numbers in rare pediatric cancers. High local control probability and acceptable late severe complication probability could be achieved despite very challenging situations. This cooperation model could serve as a basis for generating international reference networks for high-tech radiation such as brachytherapy to increase treatment care opportunities and cure probability.

Intraoperative Radiotherapy in Brain Malignancies: Indications and Outcomes in Primary and Metastatic Brain Tumors

Despite the continued controversy over defining an optimal delivery mechanism, the critical role of adjuvant radiation in the management of surgically resected primary and metastatic brain tumors remains one of the universally accepted standards in neuro-oncology. Local disease control still ranks as a significant predictor of survival in both high-grade glioma and treated intracranial metastases with radiation treatment being essential in maximizing tumor control. As with the emergence and eventual acceptance of cranial stereotactic radiosurgery (SRS) following an era dominated by traditional radiotherapy, evidence to support the use of intraoperative radiotherapy (IORT) in brain tumors requiring surgical intervention continues to accumulate. While the clinical trial strategies in treating glioblastoma with IORT involve delivery of a boost of cavitary radiation prior to the planned standard external beam radiation, the use of IORT in metastatic disease offers the potential for dose escalation to the level needed for definitive adjuvant radiation, eliminating the need for additional episodes of care while providing local control equal or superior to that achieved with SRS in a single fraction. In this review, we explore the contemporary clinical data on IORT in the treatment of brain tumors along with a discussion of the unique dosimetric and radiobiological factors inherent in IORT that could account for favorable outcome data beyond those seen in other techniques.

ACR-ABS-ASTRO practice parameter for the performance of radionuclide-based high-dose-rate brachytherapy

PURPOSE

This practice parameter aims to detail the processes, qualifications of personnel, patient selection, equipment, patient and personnel safety, documentation, and quality control and improvement necessary for an HDR brachytherapy program.

METHODS AND MATERIALS

This practice parameter was revised collaboratively by the American College of Radiology (ACR), the American Brachytherapy Society (ABS), and the American Society for Radiation Oncology (ASTRO).

RESULTS

Brachytherapy is a radiotherapeutic modality in which radionuclide or electronic sources are used to deliver a radiation dose at a distance of up to a few centimeters by surface, intracavitary, intraluminal, or interstitial application. Brachytherapy alone or combined with external beam radiotherapy plays an important role in the management and treatment of patients with cancer. High-dose-rate (HDR) brachytherapy uses radionuclides, such as iridium-192, at dose rates of ≥12 Gy/hr to a designated target point or volume, and it is an important treatment for a variety of malignant and benign conditions. Its use allows for application of high doses of radiation to defined target volumes with relative sparing of adjacent critical structures.

CONCLUSIONS

HDR brachytherapy requires detailed attention to personnel, equipment, patient and personnel safety, and continuing staff education. Coordination between the radiation oncologist and treatment planning staff and effective quality assurance procedures are important components of successful HDR brachytherapy programs.

A Role of brachytherapy in bilateral Wilms tumors: A long-term follow-up of three highly selected cases and literature review

PURPOSE

To describe experience with partial nephrectomy combined with brachytherapy as part of the local management of bilateral Wilms tumor (WT) including a review of the available literature.

RESULTS (METHODS AND CASE DESCRIPTION)

Between 2011 and 2014, three highly selected patients (age nine months, 16 months, and 4 years) with bilateral WT (two synchronous and one metachronous) underwent enucleation and perioperative brachytherapy to the tumor bed. With a minimum follow-up of 5 years, all three patients are in continuous complete remission with preserved kidney function.

CONCLUSIONS

Although nephron sparing surgery aiming at tumor free-margins remains the gold standard for bilateral WT, tumor enucleation followed by brachytherapy may be considered in carefully selected patients at high risk for end-stage kidney failure. Given the rarity and complexity of the procedure, concentration of care of such patients is mandatory.

Pediatric Anesthesia Outside the Operating Room: Case Management

Anesthesiology teams care for children in diverse locations, including diagnostic and interventional radiology, gastroenterology and pulmonary endoscopy suites, radiation oncology units, and cardiac catheterization laboratories. To provide safe, high-quality care, anesthesiologists working in these environments must understand the unique environmental and perioperative considerations and risks involved with each remote location and patient population. Once these variables are addressed, anesthesia and procedural teams can coordinate to ensure that patients and families receive the same high-quality care that they have come to expect in the operating room. This article also describes some of the considerations for anesthetic care in outfield locations.

Interstitial brachytherapy for pediatric soft tissue sarcoma: Evolving practice over three decades and long-term outcomes

PURPOSE

Evaluate long-term clinical outcomes, adverse effects, and evolving practice of interstitial brachytherapy (BT) for pediatric soft tissue sarcomas (STS).

METHODS

From September 1984 to December 2014, 105 children (median age 10 years) were included. There were 60 males and 45 females. The majority (74%) had primary lesions. Synovial sarcoma (22%) was the most frequent histology. Treatment included wide local excision and BT with or without external beam radiotherapy (EBRT). Eighty-five (81%) received BT alone.

RESULTS

After a median follow-up of 65 months, local control (LC), disease-free survival (DFS), and overall survival (OS) at 10 years were 83, 66, and 73%, respectively. On univariate analysis, LC was superior with tumors <5 cm versus >5 cm (93% vs. 75%, P = 0.10), Grade I/II versus Grade III tumors (97% vs. 73%, P = 0.01), nonround cell versus round cell histology (89% vs. 72%, P = 0.03), and trunk/extremity versus head and neck/genitourinary sites (87% vs. 57%, P = 0.0001). On multivariate analysis tumor size (P = 0.03) and location (P = 0.002) retained significance. Children receiving BT alone had comparable LC to those receiving BT and EBRT (84% vs. 80%, P = 0.43). There was no difference in LC between LDR versus HDR BT (86% vs. 83%, P = 0.30). Wound complications were seen in 6%. Subcutaneous fibrosis (25%), limb edema (6%), skeletal abnormalities (3%), and neuropathy (1%) were the late complications. One child (0.9%) developed a second malignancy after 7 years.

CONCLUSION

Interstitial BT with or without EBRT results in excellent outcomes. Radical BT alone, when used judiciously, results in excellent local control and function with minimal treatment-related morbidity.

The American College of Radiology and the American Brachytherapy Society practice parameter for the performance of radionuclide-based high-dose-rate brachytherapy

Brachytherapy is a radiation therapy method in which radionuclide sources are used to deliver a radiation dose at a distance of up to a few centimeters by surface, intracavitary, intraluminal, or interstitial application. This practice parameter refers only to the use of radionuclides for brachytherapy. Brachytherapy alone or combined with external beam therapy plays an important role in the management and treatment of patients with cancer. High-dose-rate (HDR) brachytherapy uses radionuclides such as iridium-192 at dose rates of 20 cGy per minute (12 Gy per hour) or more to a designated target point or volume. High-dose-rate (HDR) brachytherapy is indicated for treating malignant or benign tumors where the treatment volume or targeted points are defined and accessible.

Brachytherapy Combined With Surgery for Conservative Treatment of Children With Bladder Neck and/or Prostate Rhabdomyosarcoma

PURPOSE

To report the results of a conservative strategy based on partial surgery combined with brachytherapy in a prospective cohort of children with bladder-prostate rhabdomyosarcoma (BP RMS).

METHODS AND MATERIALS

We prospectively documented the outcome of children treated in our department between 1991 and 2015 for BP RMS and undergoing a multimodal approach combining conservative surgery (partial cystectomy and/or partial prostatectomy) and perioperative interstitial low-dose-rate or pulse-dose-rate brachytherapy. Before brachytherapy, children had received chemotherapy with modalities depending on their risk group of treatment.

RESULTS

A total of 100 patients were identified, with a median age of 28 months (range, 5.6 months-14 years). According to the Intergroup Rhabdomyosarcoma Study (IRS) group, 84 were IRS-III, and 12 were IRS-IV tumors. Four patients were treated at relapse. The median number of chemotherapy cycles before local therapy was 6 (range, 4-13). After surgery, 63 patients had a macroscopic tumor residuum. Five patients underwent a brachytherapy boost before pelvic external beam radiation therapy because of nodal involvement, and 95 had exclusive brachytherapy. Median follow-up was 64 months (range, 6 months-24.5 years). Five-year disease-free and overall survival rates were 84% (95% confidence interval 80%-88%) and 91% (95% confidence interval 87%-95%), respectively. At last follow-up most survivors presented with only mild to moderate genitourinary sequelae and a normal diurnal urinary continence. Five patients required a secondary total cystectomy: 3 for a nonfunctional bladder and 2 for relapse.

CONCLUSION

Brachytherapy is effective as part of a conservative strategy for BP RMS, with a relatively low delayed toxicity as compared with previously published studies using external beam radiation therapy. Longer follow-up is required to ensure that the functional results are maintained over time.

High-dose-rate brachytherapy of rhabdomyosarcoma limited to the external auditory canal

PURPOSE

To report on the single-catheter high-dose-rate brachytherapy treatment of a 21-month-old girl child with an embryonal, botryoid-type, rhabdomyosarcoma limited to the external auditory canal (EAC).

METHODS AND MATERIALS

A 2.4-mm diameter catheter was inserted into the right EAC and placed against the tympanic membrane. A computed tomography simulation scan was acquired. A brachytherapy treatment plan, in which 21 Gy in seven fractions was prescribed to a 1-mm depth along the distal 2 cm of the catheter, was generated. Treatments were delivered under anesthesia without complication. A dosimetric comparison between this plan and an intensity-modulated radiation therapy (IMRT) plan was then conducted. A clinical target volume (CTV), which encompassed a 1-mm margin along the distal 2 cm of the catheter, was delineated for both plans. Given positioning uncertainty under image guidance, a planning target volume (PTV = CTV + 3-mm margin) was defined for the IMRT plan. The IMRT plan was optimized for maximal CTV coverage but subsequently normalized to the same CTV volume receiving 100% of the prescription dose (V₁₀₀) of the brachytherapy plan.

RESULTS

The IMRT plan was normalized to the brachytherapy CTV V₁₀₀ of 82.0%. The PTV V₁₀₀ of this plan was 34.1%. The PTV exhibited dosimetric undercoverage within the middle ear and toward the external ear. Mean cochlea doses for the IMRT and brachytherapy plans were 26.7% and 10.5% of prescription, respectively.

CONCLUSIONS

For rhabdomyosarcomas limited to the EAC, a standard brachytherapy catheter can deliver a highly conformal radiation plan that can spare the nearby cochlea from excess radiation.

Intraoperative phosphorus-32 brachytherapy plaque for multiply recurrent high-risk epidural neuroblastoma

Achieving local control is a crucial component in the management of neuroblastoma, but this may be complicated in the setting of prior radiation treatment, especially when the therapeutic target is in proximity to critical structures such as the spinal cord. The authors describe a pediatric patient with multiply recurrent neuroblastoma and prior high-dose radiation therapy to the spine who presented with progressive epidural disease. The patient was managed with resection and intraoperative high-dose-rate brachytherapy using a phosphorus-32 ((32)P) plaque previously developed for the treatment of brain and spine lesions.

Comparison between preoperative and real-time intraoperative planning ¹²⁵I permanent prostate brachytherapy: long-term clinical biochemical outcome

Background

The purpose of the study is to evaluate the long-term clinical outcome through biochemical no evidence of disease (bNED) rates among men with low to intermediate risk prostate cancer treated with two different brachytherapy implant techniques: preoperative planning (PP) and real-time planning (IoP).

Methods

From June 1998 to July 2011, 1176 men with median age of 67 years and median follow-up of 47 months underwent transperineal ultrasound-guided prostate ¹²⁵I-brachytherapy using either PP (132) or IoP (1044) for clinical T1c-T2b prostate adenocarcinoma Gleason <8 and prostate-specific antigen (PSA) <20 ng/ml. Men with Gleason 7 received combination of brachytherapy, external beam radiation and 6-month androgen deprivation therapy (ADT). Biological effective dose (BED) was calculated using computerized tomography (CT)-based dosimetry 1-month postimplant. Failure was determined according to the Phoenix definition.

Results

The 5- and 7-year actuarial bNED rate was 95% and 90% respectively. The 7-year actuarial bNED was 67% for the PP group and 95% for the IoP group (P < 0.001). Multivariate Cox regression analyses identified implant technique or BED, ADT and PSA as independent prognostic factors for biochemical failure.

Conclusions

Following our previous published results addressing the limited and disappointing outcomes of PP method when compared to IoP based on CT dosimetry and PSA kinetics, we now confirm the long-term clinical, bNED rates clear cut superiority of IoP implant methodology.

American Brachytherapy Society (ABS) consensus statement for sarcoma brachytherapy

PURPOSE

To present recommendations for the use of brachytherapy (BT) in patients with soft tissue sarcoma (STS).

METHODS

A group of practitioners with expertise and experience in sarcoma BT formulated recommendations for BT in STS based on clinical experience and literature review.

RESULTS

The indications for adjuvant BT are discussed. There is no consensus on the use of BT alone or in combination with external beam radiation therapy (EBRT), but factors that influence the selection of this modality include tumor grade and size, prior surgeries, and tumor recurrence. Low-dose-rate, high-dose-rate, and pulsed-dose-rate radiation are all acceptable BT modalities to use for STS. Recommendations are made for patient selection, techniques, dose rates, and dosages. Outcome data and toxicity data are reviewed.

CONCLUSIONS

BT is a useful component of the treatment of STS. The advantages of BT are the targeted dose distribution, low integral dose, and short treatment times. Ultimately the clinician should select the modality or combination of modalities that are most familiar to the treatment team and suitable to the patient.

Brachytherapy in paediatric malignancies - review of indications

Paediatric malignancies are relatively rare, with an annual frequency of 13-14 in 100 000 children up to 15 years, and account for less than 1% of all cancer in developed countries. Paediatric tumours are generally managed with a multi-modality treatment programme that includes surgery, chemotherapy, and external beam radiation therapy (EBRT). Treatment strategies directed towards the reduction of late side effects have significantly increased interest in brachytherapy, in particular of soft tissue sarcoma and clear cell adenocarcinoma, as in these malignancies often only a limited target volume needs to be treated by a significant radiation dose. Current indications for brachytherapy in paediatric malignancies are presented briefly in this study.

Successful treatment of high risk and recurrent pediatric desmoids using radiation as a component of multimodality therapy

PURPOSE

To evaluate the role of radiation therapy (RT) as a component of multimodality therapy for pediatric desmoids.

METHODS AND MATERIALS

Twenty-one children diagnosed between 1987 and 2005 were identified. Median age at start of treatment was 13 years (range, 2-21). Primary therapy consisted of resection alone (10), resection + external beam radiation therapy (EBRT) (5), resection + chemotherapy (CT; 3), EBRT alone (1), and CT alone (2).

RESULTS

The median follow-up from start of treatment is 75.7 months (range, 16-162). Examining patients with gross total resections (GTRs) (-) margins and those who had GTRs (+) margins followed by EBRT, only 2 of 7 failed primary treatment. Conversely, 13 of 14 patients with other primary treatments failed locally. Of the 15 patients who recurred, only 1 patient had a GTR (-) margins. Seven of these patients had salvage therapy that did not include RT, and of these only 2 have no evidence of disease (NED) at last follow-up. In contrast, the remaining 8 patients received RT as a component of their final salvage therapy and 7 of these are NED at last follow-up. At last follow-up, no patient has died, although toxicities of therapy have occurred.

CONCLUSIONS

Local control is difficult to achieve in pediatric patients with desmoids. In the setting in which negative surgical margins cannot be achieved, RT plays a key role in achieving NED status. Even after multiple recurrences, successful salvage is achievable, particularly when high-dose focal therapy is incorporated.

[Brachytherapy in combination with function-preserving surgery. An interdisciplinary challenge]

A multimodal, interdisciplinary approach known as intensity-modified brachytherapy is a promising alternative for patients with advanced head and neck cancer infiltrating the orbita and skull base. An 87-year-old man presented with a recurrence of squamous cell carcinoma of the medial corner of the left eye that had been locally resected and irradiated by external beam radiotherapy multiple times. The cancer was resected with preservation of the eye with close margins, implantation of afterloading catheters, and reconstruction of the defect with a median forehead flap. The patient was irradiated with a total radiation dose of 30 Gy IMBT. After 1 year, there was no evidence of locoregional recurrence. The background of this therapeutic process and analysis of the current literature regarding this interdisciplinary treatment of head and neck cancer infiltrating the orbita and skull base are discussed based on this case report.

High-dose-rate brachytherapy for soft tissue sarcoma in children: a single institution experience

Purpose

To report our experience treating soft tissue sarcoma (STS) with high dose rate brachytherapy alone (HBRT) or in combination with external beam radiotherapy (EBRT) in pediatric patients.

Methods and materials

Eighteen patients, median age 11 years (range 2 – 16 years) with grade 2–3 STS were treated with HBRT using Ir-192 in a interstitial (n = 14) or intracavitary implant (n = 4). Eight patients were treated with HBRT alone; the remaining 10 were treated with a combination of HBRT and EBRT.

Results

After a median follow-up of 79.5 months (range 12 – 159), 14 patients were alive and without evidence of disease (5-year overall survival rate 84.5%). There were no local or regional failures in the group treated with HBRT alone. One patient developed distant metastases at 14 months and expired after 17 months. In the combined HBRT and EBRT group, there was 1 local failure (22 months), and 3 patients developed pulmonary metastatic disease 18, 38 and 48 months after diagnosis and no these patients were alive at the time of this report. The overall local control to HBRT alone and HBRT plus EBRT were 100 and 90%, respectively. The acute affects most common were local erythema and wound dehiscence in 6 (33%) and 4 (22%) patients.

Late effects were observed in 3 patients (16.5%).

Conclusion

Excellent local control with tolerable side effects have been observed in a small group of paediatric patients with STS treated by HBRT alone or in combination with EBRT.

Use of brachytherapy in children with cancer: the search for an uncomplicated cure

Brachytherapy is a sophisticated radiation method in which radioisotopes are placed inside or at a short distance from the tumour. The volume of tissue that receives the prescribed dose of radiotherapy is therefore fairly small compared with that used in standard radiotherapy techniques. In paediatric oncology, this method of radiation delivery can have a favourable effect on several undesirable long-term side-effects that sometimes develop in children who receive radiotherapy, such as growth retardation and development of second primary tumours. Here, we describe the rationale for use of brachytherapy in children with cancer, the methods of the different brachytherapy techniques available, and the results obtained with several brachytherapy regimens in expert institutions throughout the world.

Combination of external-beam radiotherapy with intraoperative electron-beam therapy is effective in incompletely resected pediatric malignancies

PURPOSE

Intraoperative electron-beam radiotherapy (IOERT) has been applied for local dose escalation in over 1,400 patients in Heidelberg since 1991. Among these were 30 children, in 18 of whom IOERT was employed in radiation treatment with external-beam radiotherapy (EBRT) on account of incomplete resection. We address the question whether IOERT is able to compensate for microscopic or macroscopic tumor residue if employed in the overall radiation regimen.

METHODS AND MATERIALS

The data of the aforementioned 18 children were analyzed with regard to local recurrence, overall survival, and complication rates. All children suffered from either sarcomas or neuroblastomas. In all children, IOERT was employed for local dose escalation after or before EBRT.

RESULTS

After a median follow-up of 60.5 months, 15 of the treated children are alive. One local failure has been observed. Six children show clinically significant late morbidity, including the loss of a treated limb (Radiation Therapy Oncology Group Grade 4 [RTOG 4]), a severe nerve lesion (RTOG 3), an orthopedic complication (RTOG 2), a ureteral stenosis (not clinically significant), and a kidney hypotrophy (not clinically significant). In 1 child a fracture due to radionecrosis (RTOG 4) was diagnosed; however, in the follow-up, local tumor relapse was diagnosed as another possible reason for the fracture.

CONCLUSIONS

Regarding the low incidence of local failure, IOERT seems to be able to compensate incomplete tumor resection in childhood sarcoma and neuroblastoma patients. The incidence of late morbidity is low enough to justify the employment of IOERT as part of the radiation treatment regimen for pediatric patients.

High dose rate brachytherapy: its clinical applications and treatment guidelines

Brachytherapy has the advantage of delivering a high dose to the tumor while sparing the surrounding normal tissues. With proper case selection and delivery technique, high-dose-rate (HDR) brachytherapy has great promise, because it eliminates radiation exposure, allows short treatment times, and can be performed on an outpatient basis. Additionally, use of a single-stepping source, allows optimization of dose distribution by varying the dwell time at each dwell position. However, when HDR brachytherapy is used, the treatments must be executed carefully, because the short treatment times do not allow any time for correction of errors, and mistakes can result in harm to patients. Hence, it is very important that all personnel involved in HDR brachytherapy be well trained and be constantly alert. It is expected that the use of HDR brachytherapy will greatly expand over the next decade and that refinements will occur primarily in the integration of imaging (computed tomography, magnetic resonance imaging, intraoperative ultrasonography) and optimization of dose distribution. It is anticipated that better tumor localization and normal tissue definition will help to optimize dose distribution to the tumor and reduce normal tissue exposure. The development of well-controlled randomized trials addressing issues of efficacy, toxicity, quality of life, and costs-versus-benefits will ultimately define the role of HDR brachytherapy in the therapeutic armamentarium.

Intraoperative high-dose-rate brachytherapy

Although several modalities have been discussed, a comprehensive intraoperative program should have IOERT, IOHDR, and perioperative brachytherapy facilities available to treat all sites. Interstitial brachytherapy is preferable for the treatment of gross residual tumor; IORT (IOERT for accessible sites and IOHDR for poorly accessible sites) is added to irradiate intraoperatively the surrounding margins after gross resection; and fractionated EBRT could be used in moderate doses post-operatively to irradiate the entire area of potential microscopic disease. Depending on the volume and location of the tumor, and the available expertise and equipment, IOERT, IOHDR, or perioperative brachytherapy could be used along with EBRT and surgery for the optimal management of malignancies. Finally, the best results of IOHDR are obtained when used as a conformal boost to the tumor bed after resection in conjunction with supplementary EBRT.

Long-term morbidity in children treated with fractionated high-dose-rate brachytherapy for soft tissue sarcomas

BACKGROUND

The purpose of this study was to determine the long-term local control, disease-free survival, and morbidity of fractionated high-dose-rate brachytherapy (F-HDR) in infants and children with soft tissue sarcomas.

PATIENTS AND METHODS

Fifteen children (13 girls and 2 boys, ages 5-101 months) with soft tissue sarcomas were treated with chemotherapy, organ-preserving surgery, and F-HDR (36 Gy in 12 fractions) to post-chemotherapy volumes. External beam radiotherapy was not part of the primary treatment, although four patients (27%) subsequently received salvage external beam radiotherapy after treatment failure. Chemotherapy was administered to all patients based on their tumor histology and stage.

RESULTS

After a median follow-up of 10 years (range 32-154 months), 12 patients (80%) were alive without evidence of disease. Ten-year overall survival and local control rates were both 80% (12/15 children). The overall survival was better (91%) for children with microscopic residual versus gross residual disease (75%). With longer follow-up, grade 3 to 4 brachytherapy-related late morbidities increased from 8% (1/12) to 20% (3/15) and included trismus/osteonecrosis, vaginal stenosis, and periurethral fibrosis. There were two late complications associated with puberty that occurred 8 to 10 years after the initial treatments. Acute toxicity occurred in five patients (38%) and consisted primarily of grade 1 to 3 skin and mucosal reactions.

CONCLUSIONS

As the sole radiation modality, F-HDR achieved excellent local control and disease-free survival in properly selected children with soft tissue sarcomas while preserving normal bone and organ development. A significant percentage of patients experience adverse late sequelae as a result of this treatment.

Pediatric soft tissue sarcomas

Many of the soft tissue sarcomas that occur in children are of the same histology as those in adults; however, the relative prevalence of these sarcomas is different between children and adults. In some cases, the biologic behavior of pediatric sarcomas is more benign than that in adults. Treatment for sarcomas in children is also different. Pediatric sarcomas are more commonly responsive to chemotherapy. Furthermore, in children who are still growing, surgery and radiation are associated with higher morbidity than in adults. This article discusses the diagnosis and treatment of rhabdomyosarcoma and undifferentiated sarcomas, with an emphasis on surgical considerations, and the diagnosis and treatment of nonrhabdomyosarcomatous soft tissue sarcomas in children.

Brachytherapy for pediatric tumors

PURPOSE

Pediatric tumors are generally managed with a multi-modality treatment program that includes surgery, chemotherapy, and teletherapy. The use of teletherapy in young children can result in significant long-term toxicity (especially retardation of growth of bones and organs). The use of brachytherapy is an attractive alternative because brachytherapy irradiates small volumes and can thus potentially minimize complications.

METHODS AND MATERIALS

The brachytherapy techniques used are similar to those used in adults. Low-dose-rate brachytherapy with manually-afterloaded removable 192Ir is commonly used though it is associated with some radiation exposure hazards. Low energy radionuclides and remote afterloading technology have been used to reduce the radiation exposure hazards. Teletherapy is often added in the treatment of more extensive tumors, especially in older children.

RESULTS

Brachytherapy (as the sole radiation modality) to small volumes in conjunction with chemotherapy and surgery has produced good local control with growth preservation and acceptable late complications in selected patients with localized tumors.

CONCLUSION

Brachytherapy increases local control with a decrease in the probability of late complications (especially altered bone and organ growth) in comparison to EBRT. Low energy radionuclides and remote afterloading technology (HDR, IOHDR, and PDR) have been used to extend treatment to infants and younger children while reducing the radiation exposure to patients, family, and medical personnel.

Intraoperative high-dose-rate brachytherapy for pediatric solid tumors: a 10-year experience

PURPOSE

To evaluate the efficacy and toxicity of intraoperative high-dose-rate brachytherapy (IOHDR) in the management of pediatric solid tumors.

METHODS AND MATERIALS

The records of 66 pediatric patients who underwent IOHDR for a solid tumor from February 1993 through December 2002 were retrospectively reviewed. The median age was 7 years (range 9 months to 24 years). Thirty-five patients (53%) were treated for recurrent disease and 24 (36%) had documented metastatic disease. Twenty-nine patients (44%) received both EBRT and IOHDR. The IOHDR dose was prescribed to a depth of 0.5 cm from the surface of a multichannel tissue-equivalent applicator. The median prescription dose was 12 Gy (range, 4-15 Gy).

RESULTS

After a median follow-up of 12 months, the 2-year actuarial rates of local control and overall survival were 56% and 54%, respectively, with a median survival of 29 months. Post-operative EBRT significantly improved (p=0.002) 2-year local control (83% v. 29%). Perioperative complications occurred in 8 of 66 patients while late complications occurred in only 3. The actuarial 2-year late complication rate was 12%. Late events that occurred in or near the IOHDR treatment site included small bowel obstruction, broncho-esophageal fistula, and bone growth retardation.

CONCLUSIONS

IOHDR is emerging as an integral part of multimodality therapy for pediatric solid tumors as an adjunct to EBRT for local control. IOHDR alone may not be appropriate in the majority of patients. Subacute toxicities occurred rarely and may be related to the combination of extensive surgery, EBRT, and multi-agent chemotherapy in this population.