Embryonal tumours of the central nervous system

MRI Characteristics of Primary Tumors and Metastatic Lesions in Molecular Subgroups of Pediatric Medulloblastoma: A Single-Center Study

BACKGROUND AND PURPOSE

Molecular grouping of medulloblastoma correlates with prognosis and supports the therapeutic strategy. We provide our experience with the imaging features of primary and metastatic disease in relation to the molecular groups.

MATERIALS AND METHODS

One hundred nineteen consecutive patients (mean age, 7.3 ± 3.8 years at diagnosis; male, 79 [66.4%]) with a confirmed diagnosis of medulloblastoma and interpretable pretreatment MRIs were retrieved from our data base from January 2000 to December 2016. Each patient was assigned to wingless, sonic hedgehog, group 3, or group 4 molecular groups. Then, we determined the imaging features of both primary and metastatic/recurrent disease predictive of molecular groups.

RESULTS

In addition to recently reported predictors based on primary tumor, including cerebellar peripheral location for sonic hedgehog (adjusted odds ratio = 9, P < .0001), minimal enhancement of primary group 4 tumor (adjusted odds ratio = 5.2, P < .0001), and cerebellopontine angle location for wingless (adjusted odds ratio = 1.4, P = .03), ependymal metastasis with diffusion restriction and minimal postcontrast enhancement ("mismatching pattern") (adjusted odds ratio = 2.8, P = .001) for group 4 and spinal metastasis for group 3 (adjusted odds ratio = 1.9, P = .01) also emerged as independent predictors of medulloblastoma molecular groups. Specifically, the presence of a metastasis in the third ventricular infundibular recess showing a mismatching pattern was significantly associated with group 4 (P = .02).

CONCLUSIONS

In addition to imaging features of primary tumors, some imaging patterns of metastatic dissemination in medulloblastoma seem characteristic, perhaps even specific to certain groups. This finding could further help in differentiating molecular groups, specifically groups 3 and 4, when the characteristics of the primary tumor overlap.

[Lu]-DOTA-Tyr-octreotate: A Potential Targeted Radiotherapeutic for the Treatment of Medulloblastoma

Medulloblastoma, the most common pediatric brain tumor, is difficult to treat because conventional therapeutic approaches result in significant toxicity to normal central nervous system tissues, compromising quality of life. Given the fact that medulloblastomas express the somatostatin subtype 2 receptor, [(177)Lu-DOTA(0),Tyr(3)]octreotate ([(177)Lu]DOTA-TATE) could be a potentially useful targeted radiotherapeutic for the treatment of this malignancy. The current study was undertaken to evaluate this possibility in preclinical models of D341 MED human medulloblastoma by comparing the properties of [(177)Lu]DOTA-TATE to those of glucose-[(125)I-Tyr(3)]-octreotate ([(125)I]Gluc-TOCA), a radiopeptide previously shown to target this cell line. In vitro assays indicated that both labeled peptides exhibited similar cell-associated and internalized radioactivity after a 30-min incubation at 37°C; however, at the end of the 4 h incubation period, the internalized radioactivity for [(177)Lu]DOTA-TATE (6.22 " 0.75%) was nearly twice that for [(125)I]Gluc-TOCA (3.16 " 0.27%), with similar differences seen in total cell-associated radioactivity levels. Consistent with the results from the internalization assays, results from paired-label tissue distribution studies in athymic mice with subcutaneous D341 MED medulloblastoma xenografts showed a similar degree of tumor accumulation for [(177)Lu]DOTA-TATE and [(125)I]Gluc-TOCA at early time points but by 24 h, a more than 5-fold advantage was observed for the (177)Lu-labeled peptide. Tumor-to-normal tissue ratios generally were more favorable for [(177)Lu]DOTA-TATE at all time points, due in part to its lower accumulation in normal tissues except kidneys. Taken together, these results suggest that [(177)Lu]DOTA-TATE warrants further investigation as a targeted radiotherapeutic for medulloblastoma treatment.

Non-pineal supratentorial primitive neuro-ectodermal tumors (sPNET) in teenagers and young adults: Time to reconsider cisplatin based chemotherapy after cranio-spinal irradiation?

BACKGROUND

Supratentorial PNET (sPNET) are rare CNS tumors of embryonal origin arising in children and adults. The treatment of sPNET for all age groups at our cancer center has been based on the management of medulloblastoma (MB), involving neurosurgical debulking followed by cranio-spinal irradiation (CSI) and systemic chemotherapy.

METHODS

Medical records were reviewed to gather demographic and clinical data about all embryonal CNS tumors in children and adults from 2001 to 2007. Tumor pathology, clinical management and survival data were also assessed, particularly as regards those patients who received the Packer chemotherapy regimen for either sPNET or MB.

RESULTS

Eleven patients (five children and six adults) were identified with non-pineal sPNET, three children with pineal sPNET, and 19 patients (18 children and 1 adult) with MB. There was no difference in overall survival (OS) rates between pediatric and adult sPNET. When all sPNET were compared to all MB, 5-year OS was 14% versus 73%, respectively, but was only 9% for non-pineal sPNET. When only considering those patients treated with the Packer chemotherapy regimen, the 5-year OS was 12% for sPNET versus 79% for MB.

CONCLUSION

This retrospective study demonstrates that non-pineal sPNET are clinically distinct from MB and are resistant to the Packer chemotherapy regimen. We suggest that it is time to reconsider the use of this regimen in teenage and young adult non-pineal sPNET and to investigate the utility of alternative approaches.

Octreotide in the therapy of recurrent medulloblastomas

BACKGROUND: Recurrence of medulloblastoma appears after 30% to 40% of the surgeries. Different from primary medulloblastoma, in which five-year survival rate is 50%, the survival time of relapses much shorter and only 20% of the patients manage to survive a year. There is a logical need for additional methods of treatment of recurrent medulloblastomas. The aim of the study is to determine the effects of intracavitary and long-term subcutaneous application of Sandostatin (octreotide) on the recurrent medulloblastomas. METHODS: Fourteen children aged 4 to 9 years, in which, despite of craniospinal irradiation and chemotherapy came to a recurrence of medulloblastoma during the first 6 months after the surgery, were treated subcutaneously with Sandostatin (octreotide) in a longer period of time. Cerebellar medulloblastomas with a diameter bigger than 20 mm and spinal over 10 mm were removed operatively and octreotide with Beriplast was applied intracavitary. RESULTS: Magnetic resonance of cranioaxis shows that the application of octreotide has caused the disappearance of spinal drop metastases in all 7 patients and the cerebellar metastases smaller than 5 mm in all 4 patients. Subcutaneous application of octreotide combined with intracavitary expresses an antitumoral effect in 2/3 of the relapses. The application of octreotide results with a transformation of Chang's stage M0 into M1 in 71.43% of the patients. CONCLUSION: In the case of in loco or metastatic recurrence of medulloblastomas, intracavitarily and subcutaneously applied octreotide results with a regression of the tumor in a 3 year time within 2/3 of the treated patients.

Three-year recurrence-free survival in a patient with recurrent medulloblastoma after resection, high-dose chemotherapy, and intrathecal Yttrium-90-labeled DOTA0-D-Phe1-Tyr3-octreotide radiopeptide brachytherapy

BACKGROUND

Most medulloblastomas express high levels of somatostatin type 2 receptors (sst2). DOTA0-D-Phe1-Tyr3-octreotide (DOTATOC) specifically binds sst2 in the low nanomolar range. The cytotoxic effect is mediated by the chelated, beta-emitting, metallic radionuclide Yttrium 90 (90Y). The authors applied this innovative treatment option in a boy age 8 years who presented with a recurrent medulloblastoma of the cauda equina: a prognostically poor condition. Targeted radiotherapy was administered to treat minimal sst2-expressing tumor remnants, which persisted despite conventional and high-dose chemotherapy and intercurrent resection of the lesion.

METHODS

A medulloblastoma arising from the floor of the fourth ventricle had been removed surgically; then, the patient was treated with standard adjuvant chemotherapy and craniospinal irradiation according to the prospective HIT '91 protocol. Complete remission was achieved for 20 months, when a drop metastasis of the cauda equina manifested with sensorimotor lumbosacral deficits and urinary incontinence. After four cycles of neoadjuvant chemotherapy (which consisted of combined ifosfamide, carboplatinum and etoposide), two cycles of high-dose chemotherapy and autologous stem cell transplantation were performed; in between, the responding residual tumor within the lumbosacral nerve fibers was microscopically removed. Thereafter, an Indium-111-DOTATOC test injection indicated sst2-expressing tumor remnants within the cauda equina. Consequently, 4 cycles of [90Y]-DOTATOC (4x562.5 megabecquerels) were injected directly into the cerebrospinal fluid in monthly intervals.

RESULTS

The consolidating intrathecal brachytherapy using [90Y]-DOTATOC was tolerated well. A complete remission was achieved for a 3-year period. The only remaining deficit was urinary incontinence.

CONCLUSIONS

Intrathecal administration of targeted radiopeptide brachytherapy in combination with conventional and high-dose chemotherapy and surgical removal represents a promising new option to treat recurrent medulloblastoma and should be explored further.

Evaluation of dietetic intervention in children with medulloblastoma or supratentorial primitive neuroectodermal tumors

BACKGROUND

Malnutrition is a common complication of cancer treatment; it can affect energy levels and, as a consequence, quality of life. The goal of the current study was to evaluate the effect of dietetic intervention in a cohort of children treated for medulloblastoma and supratentorial primitive neuroectodermal tumors (PNET) over a 10-year period.

METHODS

A retrospective chart review (1992-2002) of newly diagnosed cases of medulloblastoma/supratentorial PNET was performed. Hospital records were reviewed for data, including demographic characteristics, patient heights and weights, and information on treatment modalities and the use of dietetic intervention. Percent changes in body weight were calculated at time points associated with particular stages of treatment or dietetic intervention.

RESULTS

One hundred three of 112 cases were evaluable. Treatment methods included surgery only (7.8%), surgery + radiotherapy (16.5%), surgery + chemotherapy (14.5%), and surgery + radiotherapy + chemotherapy (61.2%). There was no significant change in patient weight due to surgery (median change in body weight [MCBW], -0.35%) or radiotherapy (MCBW, -0.78%). In contrast, children experienced significant weight loss (MCBW, -4.35%; P < 0.0001) 3 months after starting chemotherapy. A dietician saw 53 of the 103 children in the study cohort. There were 84 dietetic interventions (oral, 36%; parenteral, 27%; enteral, 37%) among these 53 patients. Oral diets did not result in weight gain. Parenteral nutrition was associated with significant weight gain at 1 month (MCBW, +2.7%; P = 0.03), but not at 3 months. The use of enteral feeds resulted in significant weight gain at 1 month (MCBW, +4.8%; P = 0.006) and at 3 months (MCBW, +11.8%; P < 0.0001).

CONCLUSIONS

Current multimodality treatment of intracranial PNET results in significant nutritional morbidity, primarily due to the use of intensive chemotherapy regimens. Dietetic input for pediatric patients with medulloblastoma/PNET is essential, and the implementation of enteral feeding in these children can help to reverse their nutritional morbidity.