Intraoperative radiation therapy for high-risk pediatric neuroblastoma

Intraoperative Radiation Therapy for Relapsed or Refractory High-Risk Neuroblastoma: A 27-Year Experience

PURPOSE

To evaluate outcomes after intraoperative radiation therapy (IORT) in high-risk neuroblastoma (NB), including local control, overall survival, and toxicity.

METHODS AND MATERIALS

This was a single institution retrospective study of 92 pediatric patients with NB treated with IORT from 1995 to 2022. Each IORT application was considered a separate event for a total of 110 sites treated. Local failure was calculated using the cumulative incidence function and survival by Kaplan-Meier method from the day of surgery.

RESULTS

All patients had high-risk relapsed or treatment refractory disease. Median age was 6 years (range, 2-34 years). Median follow-up for all patients and surviving patients was 16 months and 4 years, respectively. All patients previously received chemotherapy, 93% had prior external beam radiation therapy to the site of IORT (median dose, 21.6 Gy; range, 10-36 Gy), and 94% had a prior surgery for tumor resection. The median IORT dose was 12 Gy (range, 8-18 Gy) and median area treated was 18 cm2 (range, 2.5-60 cm2). The cumulative incidence of local failure was 23% at 2 years and 29% at 5 years. The overall survival (OS) was 44% at 2 years and 29% at 5 years. Local failure after IORT was associated with worse OS (hazard ratio, 1.74; 95% CI, 1.07-2.84; P = .0267). Toxicity from IORT was rare, with postoperative complications likely related to IORT seen in 7 (8%) patients.

CONCLUSIONS

Our study represents the largest, most recent analysis of the efficacy and safety of IORT in patients with relapsed or refractory NB. Less than one-third of patients failed locally at 5 years, and achieving local control affected overall survival. Minimal toxicities directly related to IORT were observed. Overall, IORT is an effective and safe technique to achieve local control in high-risk relapsed or refractory neuroblastoma.

Impaired Aortic Growth in Neuroblastoma Patients After Intensive Treatment

PURPOSE

This study evaluated the abdominal aortic diameter in high-risk neuroblastoma (NB) patients and the risk of aortic narrowing following intensive treatment.

METHODS

We measured the aortic diameter at four specific levels of the abdominal aorta (diaphragmatic crus, celiac axis, and the root of the superior (SMA) and inferior (IMA) mesenteric arteries) on contrast CT scans. The control group consisted of 56 children with non-oncologic disorders, while the NB group included 35 patients with high-risk abdominal NB. We used regression analysis of age and aortic diameter to determine the regression formula for each level in each group and performed intergroup comparisons using t-test.

RESULTS

We evaluated a total of 160 contrast-enhanced CTs performed in the 35 eligible cases. The aortic diameter of pretreated NB patients was not significantly different from the controls. After receiving any treatment, the aortic diameter was significantly smaller in the NB group (p < 0.01 each). Patients who underwent radical surgery, particularly gross total resection (n = 26), had smaller aortic diameters at all levels compared to controls (p < 0.01 each). Patients treated with radiotherapy (RT) had smaller aortic diameters than controls. External beam radiotherapy (EBRT) patients (n = 24) had smaller aortic diameters at all levels except the celiac axis (crus, SMA, IMA; p < 0.01 each), and intraoperative radiotherapy (IORT) ± EBRT patients (n = 5) had smaller aortic diameters at all levels (p < 0.01 each).

CONCLUSION

Patients with NB may experience impaired development of the abdominal aorta after multimodal therapy, particularly after RT. Close observation and long-term follow-up is essential to monitor for catastrophic vascular complications.

LEVEL OF EVIDENCE

LEVEL III.

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.

Application of high-dose rate (60)Co remote after-loading system for local recurrent neuroblastoma

The local control of neuroblastoma is a very important treatment consideration. We describe a patient who received high-dose rate 60Co remote after loading system treatment for local control of recurrent neuroblastoma and discuss the efficacy of high-dose rate 60Co remote after loading system treatment.

Excellent local control and survival after intraoperative and external beam radiotherapy for pediatric solid tumors: long-term follow-up of the Mayo Clinic experience

Use of external beam radiotherapy (EBRT) for pediatric solid malignancies is generally limited by the tolerance of normal tissue in developing organs. Intraoperative electron radiotherapy (IOERT) allows a more focal delivery of radiation dose because vital organs can be displaced and avoided during treatment. From February 1983 to July 2003, 20 children underwent IOERT for treatment of locally advanced or recurrent malignancies of the extremity or abdominopelvic area. All patients underwent EBRT and received IOERT doses of 7.5 to 25 Gy with 6-MeV to 15-MeV electrons. At a median follow-up of 11.6 years (range, 2.1 to 25.5 y), 13 patients (65%) were alive and without evidence of disease. Patients who underwent gross total resection had better local control (88% vs. 67%) and survival (71% vs. 33%) than patients for whom the resection was not achieved. Among 7 patients, 11 grade 3 toxicity events were reported. No grade >3 toxicities or second malignancies were observed during follow-up. Use of IOERT in combination with surgery and EBRT in management of pediatric solid malignancies provides excellent local control with reasonable toxicity. IOERT should be considered as an integral part of a multimodality regimen for pediatric solid malignancies, especially for patients with abdominopelvic malignancies.

Local control, survival, and operative morbidity and mortality after re-resection, and intraoperative radiation therapy for recurrent or persistent primary high-risk neuroblastoma

BACKGROUND/PURPOSE

Patients with locally recurrent or persistent high-risk neuroblastoma are difficult to treat. We describe our experience using intraoperative radiation therapy (IORT) after re-resection in this high-risk population.

METHODS

We retrospectively reviewed 44 consecutive patients who received IORT at our institution between April 2000 and September 2009 after gross total resection of recurrent/persistent tumor. Specifically, we evaluated local recurrence rates, complications, and overall survival.

RESULTS

The median age at diagnosis was 41.5 months. Median follow-up after IORT was 10.5 months. Each patient received prior chemotherapy and surgery, while 94.5% had previous external beam radiation therapy. MYCN was amplified in 34% of patients. There were no operative or postoperative deaths, and 18 patients (40.9%) had postoperative complications. There was a 50.4% probability of local control. MYCN amplification did not affect local control (local recurrence rate of 53.9% vs 52.4%, P = .89). Median overall survival was 18.7 months (95% confidence interval, 11.7-25.6 months). Mean survival for MYCN-amplified patients was 13.0 vs 39.2 months for those without MYCN amplification (P = .035).

CONCLUSIONS

Intraoperative radiation therapy after re-resection of locally recurrent/persistent neuroblastoma results in a reasonable rate of local control with acceptable morbidity and survival. This approach should be considered in this high-risk population.

Spinal deformity after intra-operative radiotherapy for paediatric patients

The purpose of this study was to clarify the incidence and characteristics of late-onset complications of the spine in children who underwent intra-operative radiation therapy (IORT) for common paediatric malignant tumours. 12 children with more than 4 years of follow-up after IORT were included and, in 11 of these, thoracic and/or lumbar spines were irradiated. To compare doses of irradiation to the spine with the resulting deformities, dose simulations of IORT were carried out on two selected cases using a radiation treatment planning system with a pencil-beam algorithm. The mean follow-up period was 135 months (range, 53-234 months). Radiographic reviews found spinal deformity in six patients. Only one patient was symptomatic and the spinal deformity was severe (Grade 3), whereas spinal deformity was mild in the remaining five patients without clinical symptoms (Grade 1). In all of the six patients, anterior wedge-shaped deformity was dominant, and scoliosis was found in only two patients. In one particular case with nephrectomy, irradiation had penetrated much deeper than usual at the site of nephrectomy, and dose distribution was asymmetric, causing clinically significant spinal deformity with scoliosis. In conclusion, specific deformities of the spine observed after IORT can be explained on the basis of dose distribution of the electron beam to the spine.

Extra-anatomic bypass for recurrent abdominal aortic and renal in-stent stenoses following radiotherapy for neuroblastoma

We describe the case of an 11-year-old girl with an abdominal neuroblastoma which was operated and intraoperatively irradiated nine years ago. After six years, she developed stenoses of the infrarenal abdominal aorta and both renal arteries. Initial treatment of the stenosed vessels comprised endovascular balloon dilatations and repeated stent-graft implantations, including drug eluting stents. However, severe in-stent stenoses occurred during follow-up and the girl developed acute renal failure. Open surgery was performed with two extra-anatomic bypasses, a thoracic-to-abdominal aortic bypass and a left iliac-to-renal bypass, on an urgent basis. The postoperative course was uneventful and the patient was discharged home two weeks after the operation with full recovery of renal function. We conclude that endovascular stent-graft placement in children can only be a palliative treatment due to outgrowing of the stent-graft and the potential risk of re-stenosis, especially after a history of irradiation. Vascular surgery with placement of extra-anatomic bypasses will provide a definite treatment.

Decreased aortic growth and middle aortic syndrome in patients with neuroblastoma after radiation therapy

BACKGROUND

Long-term CT follow-up studies are required in pediatric patients who have received intraoperative radiation therapy (IORT) and external beam radiation therapy (EBRT) to assess vascular toxicities and to determine the exact complication rate.

OBJECTIVE

To analyze with CT the effects of radiation therapy (RT) on the growth of the aorta in neuroblastoma patients.

MATERIALS AND METHODS

Abdominal CT scans of 31 patients with intraabdominal neuroblastoma (stage II-IV), treated with RT (20 IORT+/-EBRT, 11 EBRT alone), were analyzed retrospectively. The diameter of the abdominal aorta was measured before and after RT. These data were compared to normal and predicted normal aortic diameters of children, according to the model of Fitzgerald, Donaldson and Poznanski (aortic diameter in centimeters = 0.844 + 0.0599 x age in years), and to the diameters of a control group of children who had not undergone RT. Statistical analyses for the primary aims were performed using the chi-squared test, t-test, Mann-Whitney test, nonparametric Wilcoxon matched-pairs test and analysis of variance for repeated measures. Clinical files and imaging studies were evaluated for signs of late vascular complications of neuroblastoma patients who had received RT.

RESULTS

The mean diameter before and after RT and the growth of the aorta were significantly lower than expected in patients with neuroblastoma (P<0.05 for each) and when compared to the growth in a control group with normal and nonirradiated aortas. Among the patients who had received RT, there was no difference due to the type of RT. Seven patients from the IORT+/-EBRT group developed vascular complications, which included hypertension (five), middle aortic syndrome (two), death due to mesenteric ischemia (one) and critical aortic stenosis, which required aortic bypass surgery (two).

CONCLUSION

Patients with neuroblastoma who had received RT showed impaired growth of the abdominal aorta. Significant long-term vascular complications occurred in seven patients who received IORT+/-EBRT. Thus, CT evaluation of patients with neuroblastoma who receive RT should include not only reports of changes in tumor extension, but also documentation of perfusion, and the size and growth of the aorta and its branches over time.

Long-Term Outcome and Toxicities of Intraoperative Radiotherapy for High-Risk Neuroblastoma

PURPOSE

To review a historical cohort of consecutively accrued patients with high-risk neuroblastoma treated with intraoperative radiotherapy (IORT) to determine the therapeutic effect and late complications of this treatment.

METHODS AND MATERIALS

Between 1986 and 2002, 31 patients with newly diagnosed high-risk neuroblastoma were treated with IORT as part of multimodality therapy. Their medical records were reviewed to determine the outcome and complications. Kaplan-Meier probability estimates of local control, progression-free survival, and overall survival at 36 months after diagnosis were recorded.

RESULTS

Intraoperative radiotherapy to the primary site and associated lymph nodes achieved excellent local control at a median follow-up of 44 months. The 3-year estimate of the local recurrence rate was 15%, less than that of most previously published series. Only 1 of 22 patients who had undergone gross total resection developed recurrence at the primary tumor site. The 3-year estimate of local control, progression-free survival, and overall survival was 85%, 47%, and 60%, respectively. Side effects attributable to either the disease process or multimodality treatment were observed in 7 patients who developed either hypertension or vascular stenosis. These late complications resulted in the death of 2 patients.

CONCLUSIONS

Intraoperative radiotherapy at the time of primary resection offers effective local control in patients with high-risk neuroblastoma. Compared with historical controls, IORT achieved comparable control and survival rates while avoiding many side effects associated with external beam radiotherapy in young children. Although complications were observed, additional analysis is needed to determine the relative contributions of the disease process and specific components of the multimodality treatment to these adverse events.

Late complications after surgery in patients with neuroblastoma

PURPOSE

The purpose of this study was 2-fold: to study the complications of neuroblastoma treatment and to establish surgical guidelines.

MATERIALS AND METHODS

The medical records of 92 patients with neuroblastoma (stage 1 or 2, n = 33; stage 3, n = 21; stage 4, n = 31; stage 4S, n = 7) who had undergone surgery in our department between 1985 and 2001 were reviewed, with an emphasis on treatments and late complications.

RESULTS

The disease-free survival rate was 98.3% (58/59) in infantile patients, whereas it was 36.4% (12/33) in advanced patients older than 1 year. The rate was improved up to greater than 50% after the introduction of intensive local therapy with intraoperative radiation (IOR). The treatment-associated morbidity rate was 15.0% in nonadvanced infantile patients, was 42.1% in advanced infantile patients, and was 33.3% in advanced older patients. In the advanced cases, renovascular problems were most frequently seen especially after IOR. Furthermore, pulmonary problems, cardiac problems, and second cancer were highlighted as fatal problems; thyroid dysfunction, vertebral deformity, and growth retardation were also noted.

CONCLUSIONS

Higher incidences of late morbidity and treatment-associated mortality appeared to be more strongly related to disease stage rather than to patient age. Appropriate surgery and IOR with lower doses should be recommended as a surgical strategy for high-risk patients.

Phase I study of intraoperative radiotherapy with photon radiosurgery system in children with recurrent brain tumors: preliminary report of first dose level (10 Gy)

PURPOSE

To describe the preliminary results after intraoperative radiotherapy (IORT) with the photon radiosurgery system in children with recurrent brain tumors treated at the first dose level (10 Gy) of a Phase I protocol.

METHODS AND MATERIALS

A Phase I IORT dose escalation protocol was initiated at Children's Memorial Hospital to determine the maximal tolerated IORT dose in children with recurrent brain tumors.

RESULTS

Fourteen children have received IORT thus far. Eight had been previously irradiated. Thirteen children had ependymoma. The median follow-up was 16 months. Three patients (21%) developed radiation necrosis on follow-up MRI scans 6 to 12 months after IORT. They had not been previously irradiated and had received 10 Gy to a depth of 5 mm. One required surgery and the other two had resolution of their lesions without treatment. All 3 patients were asymptomatic at the last follow-up. No other late toxicity was observed at the last follow-up visit. Eight patients (57%) had tumor control within the surgical bed after IORT.

CONCLUSION

Our findings have demonstrated the safety and feasibility of IORT to a dose of 10 Gy to 2 mm in children with previously irradiated brain tumors. IORT to a dose of 10 Gy at 5 mm was associated with a greater complication rate.

Aggressive surgical therapy and radiotherapy for patients with high-risk neuroblastoma treated with rapid sequence tandem transplant

BACKGROUND/PURPOSE

The treatment approach for patients with high-risk neuroblastoma has been one of dose intensification chemotherapy and aggressive treatment of the primary tumor. Local tumor control is examined in high-risk patients treated with tandem stem cell transplant, aggressive surgery, and selected radiation therapy (XRT).

METHODS

Seventy-six patients with high-risk stage III/IV neuroblastoma were treated on a standard protocol incorporating aggressive surgical resection with or without local XRT followed by tandem high-dose chemotherapy and stem cell rescue. Patients were evaluated for degree of surgical resection, site of progression, and outcome.

RESULTS

Overall event-free survival for the series is 56%. Forty-eight had gross total resection, 12 had greater than 90% resection, 10 had 50% to 90% resection, and 6 had biopsy only or no surgery. Surgical complications occurred in 29% with no deaths. There were no isolated local failures. Two patients had local recurrence after gross total resection. Surgeon assessment of completeness of resection agreed with postoperative radiological findings 66% of the time.

CONCLUSION

Aggressive surgical treatment with local XRT and myeloablative chemotherapy with stem cell rescue provides excellent local control in high-risk neuroblastoma, although distant failures, particularly osseous, remain a problem. Poor correlation exists between the surgeon's perception of completeness of resection and findings on postoperative imaging studies.

Differences in pediatric oncologists' estimates of curability and treatment recommendations for patients with advanced cancer

BACKGROUND

When goals of therapy for children with advanced cancer are called into question, physician recommendations regarding treatment goals have been shown to be important for families. However, there has been no demonstration of the degree of variation between pediatric oncologists' recommendations in such situations.

PROCEDURE

We provided 48 pediatric oncologists with two identical case histories and identical prognostic data from the literature. Individual interviews were then performed to assess variation in (1) recommended treatment goal, (2) perceived chances for cure, and (3) degree to which further curative intervention would be considered desirable for each patient.

RESULTS

There was a large variability in each of the areas examined. For both patients, there was wide divergence (2:1 and 2:3) in whether to recommend cure as the goal of treatment. There were also differences in physician estimates for likelihood of cure for each patient. Finally, even among those with identical estimates for likelihood of cure, there were differences in the treatment goals physicians would recommend and how strongly they would counsel for them.

CONCLUSIONS

This study demonstrates that even with identical clinical data and prognostic evidence from the literature, pediatric oncologists vary widely in their recommendations regarding goals of treatment for children with advanced cancer.

Radiotherapeutical innovations in pediatric solid tumors

There have been considerable technical improvements in radiation therapy for the past two decades. In children affected with cancer, these have been likely overshadowed by concommittant major chemotherapy-based advances, and at least in part ignored and misused. This article outlines principles, technological requirements, and clinical applications of innovations that aim at improving ballistical selectivity (such as conformal, intensity modulation, stereotactic photons, charged particles, and intraoperative therapies), as well as at influencing tumors and normal tissues sensitivity to radiations (such as high LET particles, and altered fractionations).

Clinical significance of intensive surgery with intraoperative radiation for advanced neuroblastoma: does it really make sense?

PURPOSE

The aim of this study was to evaluate the significance of intensive surgery combined with intraoperative radiation therapy (IORT) in advanced neuroblastoma.

METHODS

Clinical features and outcome were reviewed in 33 advanced neuroblastoma patients (24 with INSS stage 4, 9 with stage 3), who had surgery (total excision 29, subtotal excision 4) with IORT (10 to 15 Gy) against the primary tumor site.

RESULTS

Three patients (8.8%) had relapse at the primary site, all of which arose from the unirradiated area after stem cell transplantation. Among 29 patients with total excision, disease-free survival was obtained in 15 (51.7%) for an average of 6.9 years, which included 5 survivors of 9 patients (55.9%) with amplified N-myc. In contrast, none of 4 patients with macroscopic residual survived. The Kaplan-Meier analysis showed significantly longer survival rates in the patients with total resection compared with those with macroscopic remnants.

CONCLUSIONS

The intensive surgery with IORT dramatically increased the local eradication and improved the outcome even in advanced neuroblastoma with N-myc amplification. However, long-term survival was not obtained in patients with unresectable residual disease. These results may indicate the key role of surgical eradication in advanced neuroblastoma.

Neuroblastoma: Management, recurrence, and follow-up

The clinical use of N-myc amplification in neuroblastoma management has served as a paradigm for "bench to bedside" medicine. It is hoped that the quest for molecular markers such as neurotrophin, TrkA, and TrkB will continue to advance the understanding of neuroblastoma. In addition, animal models of neuroblastoma (N-myc transgenic mice, and neuroblastoma xenografts) have been established to assess the efficacy of novel treatments. These advances are likely to improve clinical practice in the future.

Potential of mobile intraoperative radiotherapy technology

Mobile IORT units have the potential to change the way patients who have cancer are treated. The integration of IORT into cancer treatment programs, made possible by the new technologies of mobile linear accelerators that can be used in unshielded operating rooms, makes IORT significantly less time-consuming, less costly, and less risky to administer. It is now practical for IORT to be used in early-stage disease, in addition to advanced disease, and in sites for which patient transportation in the middle of surgery is considered too risky. Preliminary results of trials for early-stage breast and rectal cancer indicate benefits of IORT. Pediatric patients and patients who have lung cancer, previously underserved by IORT therapies, can be offered potential gains when patient transport issues do not limit IORT. Furthermore, because many of these mobile systems require no shielding, it is now practical for mobile units to be shared between hospitals, making this new mobile technology much more widely available.

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.

Novel techniques in the delivery of radiation in pediatric oncology

The field of radiation oncology continues to develop at a rapid pace, due to concurrent progress in high speed computing, improved sensitivity in diagnostic imaging (both anatomic and physiologic), and the introduction of rational new therapeutics built on solid radiobiologic principles. These innovations will become critically important in the field of pediatric oncology, as they will allow for an increased therapeutic ratio in the developing child. Maximizing the benefit of lower dose radiation through the use of radiation modifiers (hypoxic cell sensitizers, signal transduction pathway inhibitors, concurrent chemotherapy), increasing the tolerance of normal tissues (radioprotectors) and tailoring the target area more closely to the desired critical tissues (IMRT, functional simulation with PET and MRS, radiolabeled monoclonal antibodies) will lessen the short and long term toxicity of radiation and increase its effectiveness.