Acute toxicity profile of craniospinal irradiation with intensity-modulated radiation therapy in children with medulloblastoma: A prospective analysis

[Update of guidelines of the AFSOS, SFRO, SFH, SFNCM, SFCE, GFRP for the management of radio-induced nausea and vomiting]

BACKGROUND

Radiation-induced nausea and vomiting have mutiple clinical consequences: delay or refusal of irradiation (decreased antineoplastic efficacy of irradiation), altered quality of life, dehydration, malnutrition, interruption of treatment, decompensation of comorbidities and aspiration. These guidelines aim at defining good clinical practices for management of radiation-induced nausea and vomiting (RINV).

METHODS

AFSOS, SFRO, SFH, SFNEP, SFCE and GFRP applied an expert consensus methodology to propose updated guidelines.

RESULTS

RINV are underdiagnosed and undertreated. Assessment of the emetogenic risk depends on two main factors: 1) the irradiated anatomical localization and 2) the associated concomitant chemotherapy. In case of exclusive radiotherapy, primary antiemetic prophylaxis depends on the emetogenic risk of irradiated anatomical localization. Primary antiemetic prophylaxis is initiated at the onset of irradiation and continues until 24h after the end of the irradiation. In the case of concomitant radiochemotherapy, the emetogenic risk is generally higher for chemotherapy and the primary antiemetic prophylaxis corresponds to that of chemo-induced nausea and vomiting. In the case of persistence of these symptoms, subject to a well-conducted treatment, a rigorous diagnostic procedure must be carried out before being attributed to radiotherapy and precise evaluation of their impact. Remedial treatments are less well codified.

CONCLUSION

It is essential to know and good management practices for radiation-induced nausea and vomiting.

Dynamics and predictors of hematologic toxicity during cranio-spinal irradiation

Background

Craniospinal irradiation (CSI) is a complex radiotherapy (RT) technique required for treating specific brain tumors and some hematologic malignancies. With large volumes of hematogenous bone marrow (BM) being irradiated, CSI could cause acute hematologic toxicity, leading to treatment interruptions or severe complications. We report on the dynamics and dose/volume predictors of hematologic toxicity during CSI.

Materials and methods

Pediatric patients (≤ 18years) undergoing CSI in a tertiary cancer center were included. Medical records were retrospectively reviewed for clinical data and blood parameters were collected at baseline and weekly, until four weeks after the end of RT. The BM substructures were contoured, and dose-volume parameters were extracted. We used Wilcoxon rank-sum test to compare quantitative data, Chi square test for qualitative data and receiver operating characteristics (ROC) curves for dose/volume thresholds.

Results

Fifty-one patients were included. Severe toxicities (grade 3-4) were recorded as follows: 2% anemia, 8% thrombocytopenia, 25% leukopenia, 24% neutropenia. Ninety-eight percent of patients had lymphopenia (grade 1-4) at some point. Twenty-nine percent required granulocyte-colony stimulating factor, 50% had an infection and 8% required a blood transfusion. Dmean > 3.6 Gy and V15 Gy > 10.6% for Pelvic Bones were associated with a higher risk of developing any ≥ G3 toxicities. Dmean > 30-35 Gy to the thoracic and lumbar spine was predictive for G3-4 anemia and thrombocytopenia, and Cervical Spine Dmean > 30 Gy was associated with ≥ G3 neutropenia.

Conclusion

CSI was well tolerated, without life-threatening complications in our cohort, but hematologic toxicity was frequent, with severity increasing with higher mean doses delivered to the hematogenous BM and larger volumes of BM receiving 30-35 Gy.

The Proteasome Inhibitor CEP-18770 Induces Cell Death in Medulloblastoma

Medulloblastomas (MBs) represent the most prevalent malignant solid tumors in kids. The conventional treatment regimen for MBs includes surgical removal of the tumor, followed by radiation and chemotherapy. However, this approach is associated with significant morbidity and detrimental side effects. Consequently, there is a critical demand for more precise and less harmful treatments to enhance the quality of life for survivors. CEP-18770, a novel proteasome inhibitor that targets the 20S subunit, has emerged as a promising candidate, due to its anticancer activity in metastatic solid tumors and multiple myeloma, coupled with an acceptable safety profile. In this study, we aimed to assess the anticancer efficacy of CEP-18770 by employing a variety of MB patient-derived cells and cell lines. Our preclinical investigations revealed that CEP-18770 effectively inhibits proteasome activity and induces apoptosis in MBs cells. Furthermore, we discovered that CEP-18770 and cisplatin, a current component of MB therapy, exhibit a synergistic apoptotic effect. This paper shows that CEP-18770 holds potential as an adjunctive treatment for MB tumors, thereby paving the way for more targeted and less toxic therapeutic strategies.

Comparison of passive-scattered and intensity-modulated proton beam therapy of craniospinal irradiation with proton beams for pediatric and young adult patients with brain tumors

PURPOSE

To investigate the dose stability of craniospinal irradiation based on irradiation method of proton beam therapy (PBT).

METHODS AND MATERIALS

Twenty-four pediatric and young adult brain tumor patients (age: 1-24 years) were examined. Treatment method was passive-scattered PBT (PSPT) in 8 patients and intensity-modulated PBT (IMPT) in 16 patients. The whole vertebral body (WVB) technique was used in 13 patients whose ages were younger than 10, and vertebral body sparing (VBS) technique was used for the remaining 11 patients aged 10 and above. Dose stability of planning target volume (PTV) against set-up error was investigated.

RESULTS

The minimum dose (Dmin) of IMPT was higher than that of PSPT (p = 0.01). Inhomogeneity index (INH) of IMPT was lower than that of PSPT (p = 0.004). When the irradiation field of the cervical spinal cord level (C level) was shifted, the maximum dose (Dmax) was lower in IMPT, and mean dose (Dmean) was higher than PSPT as movement became greater to the cranial-caudal direction (p = 0.000-0.043). Dmin was higher and INH was lower in IMPT in all directions (p = 0.000-0.034). When the irradiation field of the lumber spinal cord level (L level) was shifted, Dmax was lower in IMPT as movement became greater to the cranial direction (p = 0.000-0.028). Dmin was higher and INH was lower in IMPT in all directions (p = 0.000-0.022).

CONCLUSIONS

The PTV doses of IMPT and PSPT are robust and stable in both anterior-posterior and lateral directions at both C level and L level, but IMPT is more robust and stable than PSPT for cranial-caudal movements.

TRIAL REGISTRY

Clinical Trial Registration number: No. 04-03.

Novel hybrid treatment planning approach for irradiation a pediatric craniospinal axis

This study presents a new treatment planning approach merging 3D-CRT and VMAT fields into a hybrid treatment plan (HybTP), in order to achieve an optimum dose coverage of the planning target volume (PTV) and protection of OAR. Craniospinal axis irradiation (CSI) treated with 3D conformal radiotherapy (3D-CRT) is associated with high doses to the heart and eye lenses but provides better sparing of lungs and kidneys compared to volumetric modulated arc therapy (VMAT). VMAT treatment spares eye lenses and the heart, but lungs and kidneys are not as effective as 3D-CRT. Thus, a combination of both techniques (HybTP) may be optimal in sparing all these organs at risk (OAR). The results of HybTP are compared with helical tomotherapy (HT), intensity modulated radio therapy (IMRT), VMAT, and 3D-CRT plans. Hybrid, HT, VMAT, IMRT, and 3D-CRT treatment plans for a male child (age 6 years) with medulloblastoma were created and compared. A total dose of 35.2 Gy (PTV) with a dose per fraction of 1.6 Gy was prescribed. The following dose acceptance criteria were defined: The plans were compared regarding dose homogeneity index (HI) and conformity index (CI), PTV coverage, (particularly at cribriform plate) and doses at OARs. Best conformity was achieved with HT (CI = 0.98) followed by VMAT (CI = 0.96), IMRT (CI = 0.91), HybTP (CI = 0.86), and 3D-CRT (CI = 0.83). The homogeneity index varied marginally. For both HT and IMRT the HI was 0.07, and for 3D-CRT, VMAT and HybTP the HI was between 0.13 and 0.15. The cribriform plate was sufficiently covered by HybTP, VMAT, and 3D-CRT. The dose acceptance criteria for OARs were met by HT and HybTP. VMAT did not meet the criteria for lung (Dmean = right 10.4 Gy/left 10.2 Gy), 3D-CRT did not meet the criteria for eye lenses (Dmax = right 32.3 Gy/left 33.1), and heart (V25≈44%) and IMRT did not meet the criteria for lung (Dmean = right 11.1 Gy/left 11.2 Gy) and eye lenses (Dmax = right 12.2 Gy/left 13.1). HybTP meets all defined acceptance criteria and has proved to be a reasonable alternative for CSI. With HybTP that combines VMAT at the brain and heart with 3D-CRT posterior spinal fields (to spare lungs and kidneys), both appropriate coverage of the PTV and sparing of OAR can be achieved.

Comparison of Craniospinal Irradiation Using Proton Beams According to Irradiation Method and Initial Experience Treating Pediatric Patients

Purpose

This study compared craniospinal irradiation using proton beam therapy (PBT) according to irradiation method and investigated the initial effects.

Methods and Materials

Twenty-four pediatric patients (1-24 years old) who received proton craniospinal irradiation were examined. Passive scattered PBT (PSPT) and intensity modulated PBT (IMPT) were used in 8 and 16 patients, respectively. The whole vertebral body technique was used for 13 patients <10 years old, and the vertebral body sparing (VBS) technique was used for the remaining 11 patients aged ≥10 years. The follow-up period was 17 to 44 (median, 27) months. Organ-at-risk and planning target volume (PTV) doses and other clinical data were examined.

Results

The maximum lens dose using IMPT was lower than that using PSPT (P = .008). The mean thyroid, lung, esophagus, and kidney doses were lower in patients treated using the VBS technique compared with the whole vertebral body technique (all P < .001). The minimum PTV dose of IMPT was higher than that of PSPT (P = .01). The inhomogeneity index of IMPT was lower than that of PSPT (P = .004).

Conclusions

IMPT is better than PSPT at reducing the dose to the lens. The VBS technique can decrease the doses to neck-chest-abdomen organs. The PTV coverage of IMPT is superior to that of PSPT.

Brainstem Toxicity in Pediatric Patients Treated with Protons Using a Single-vault Synchrocyclotron System

Purpose

Cranial radiation therapy remains an integral component of curative treatment for pediatric patients with brain tumors. Proton beam radiation therapy (PBT) can limit collateral radiation dose to surrounding normal tissue, thus reducing off-target exposure while maintaining appropriate tumor coverage. While PBT offers significant advantages over photon therapy for pediatric patients with intracranial malignancies, cases of brainstem necrosis after PBT have raised concerns that PBT may pose an increased risk of necrosis over photon therapy. We investigated the incidence of brainstem necrosis at our institution in children treated with PBT for intracranial malignancies.

Patients and Methods

Patients with pediatric brain tumor treated with passively scattered PBT, using a gantry-mounted, synchrocyclotron single-vault system between 2013 and 2018, were retrospectively reviewed. Inclusion criteria included patients 21 years of age or younger who received a minimum 0.1 cm³ maximum brainstem dose of 50 Gray relative biological effectiveness (GyRBE). Patients were assessed for “central nervous system necrosis” in the brainstem per the Common Terminology Criteria for Adverse Events (CTCAE), version 5.0 (US National Cancer Institute, Bethesda, Maryland) criteria.

Results

Fifty-eight patients were included for analysis. The median age was 10.3 years. Twenty-one (36.2%) patients received craniospinal irradiation. Thirty-four (58.6%) patients received chemotherapy. The median prescription radiation dose was 54 GyRBE. Regarding published dosimetric constraints used at 3 separate proton centers, the goal brainstem D50% <52 GyRBE was exceeded in 23 (40%) patients, but the brainstem Dmax <58 GyRBE was not exceeded in any patients. No patient experienced grade ≥2 brainstem injury. One patient demonstrated radiographic changes consistent with grade 1 toxicity. This patient had myeloablative chemotherapy with tandem stem cell rescue before PBT.

Conclusion

Our data demonstrates a low risk of any brainstem injury in children treated with passively scattered PBT using a single-vault synchrocyclotron.

The comparison of acute toxicities associated with craniospinal irradiation between photon beam therapy and proton beam therapy in children with brain tumors

Introduction

This study aimed to evaluate acute toxicities associated with irradiation between the X‐CSI (photon beam craniospinal irradiation) and P‐CSI (proton beam craniospinal irradiation) groups in children with brain tumors.

Methods

Sixty‐two consecutive patients who received initial craniospinal irradiation (CSI) for brain tumors in our center between January 1, 2011 and May 31, 2021, were included in the study. Acute toxicities were retrospectively evaluated during CSI using Common Terminology Criteria for Adverse Events version 5.0. Maximum grades of fatigue, headache, insomnia, nausea, vomiting, dermatitis, constipation, abdominal pain, oropharyngeal mucositis, and hematological toxicities were evaluated.

Results

Thirty‐six patients received X‐CSI, and 26 patients received P‐CSI. The median dose of CSI was 18.0 Gy in the X‐CSI group and 23.4 Gy (relative biological effectiveness) in the P‐CSI group (p < 0.001). The P‐CSI group had a lower incidence of more than grade 2 nausea (11.5% vs. 69.4%, p = 0.008) and vomiting (7.7% vs. 38.8%, p < 0.001), compared with the X‐CSI group. Multivariate logistic regression analysis with adjustments for potential confounding factors of doses of CSI showed that proton radiation therapy was associated with a marked reduced risk of more than grade 2 nausea and vomiting during CSI (adjusted odds ratio, 0.050; 95% confidential interval, 0.011–0.24; p < 0.001).

Conclusion

The present study suggests that P‐CSI reduces the acute gastrointestinal toxicities associated with irradiation.

Out-of-field doses in pediatric craniospinal irradiations with 3D-CRT, VMAT and scanning proton radiotherapy - a phantom study

PURPOSE

Craniospinal irradiation (CSI) has greatly increased survival rates for patients with a diagnosis of medulloblastoma and other primitive neuroectodermal tumors. However, as it includes exposure of a large volume of healthy tissue to unwanted doses, there is a strong concern about the complications of the treatment, especially for the children. To estimate the risk of second cancers and other unwanted effects, out-of-field dose assessment is necessary. The purpose of this study is to evaluate and compare out-of-field doses in pediatric CSI treatment using conventional and advanced photon radiotherapy (RT) and advanced proton therapy. To our knowledge, it is the first such comparison based on in-phantom measurements. Additionally, for out-of-field doses during photon RT in this and other studies, comparisons were made using analytical modeling.

METHODS

In order to describe the out-of-field doses absorbed in a pediatric patient during actual clinical treatment, an anthropomorphic phantom which mimics the 10-year-old child was used. Photon 3D-conformal radiotherapy (3D-CRT) and two advanced, highly conformal techniques: photon volumetric modulated arc therapy (VMAT) and active pencil beam scanning (PBS) proton radiotherapy were used for CSI treatment. Radiophotoluminescent (RPL) and poly-allyl-diglycol-carbonate (PADC) nuclear track detectors were used for photon and neutron dosimetry in the phantom, respectively. Out-of-field doses from neutrons were expressed in terms of dose equivalent. A two-Gaussian model was implemented for out-of-field doses during photon RT.

RESULTS

The mean VMAT photon doses per target dose to all organs in this study were under 50% of the target dose (i.e., <500 mGy/Gy), while the mean 3D-CRT photon dose to oesophagus, gall bladder and thyroid, exceeded that value. However, for 3D-CRT, better sparing was achieved for eyes and lungs. The mean PBS photon doses for all organs were up to 3 orders of magnitude lower compared to VMAT and 3D-CRT and exceeded 10 mGy/Gy only for the oesophagus, intestine and lungs. The mean neutron dose equivalent during PBS for 8 organs of interest (thyroid, breasts, lungs, liver, stomach, gall bladder, bladder, prostate) ranged from 1.2 mSv/Gy for bladder to 23.1 mSv/Gy for breasts. Comparison of out-of-field doses in this and other phantom studies found in the literature showed that a simple and fast two-Gaussian model for out-of-field doses as a function of distance from the field edge can be applied in a CSI using photon RT techniques.

CONCLUSIONS

PBS is the most promising technique for out-of-field dose reduction in comparison to photon techniques. Among photon techniques, VMAT is a preferred choice for most of out-of-field organs and especially for the thyroid, while doses for eyes, breasts and lungs, are lower for 3D-CRT. For organs outside the field edge, a simple analytical model can be helpful for clinicians involved in treatment planning using photon RT but also for retrospective data analysis for cancer risk estimates and epidemiology in general. This article is protected by copyright. All rights reserved.

Chronological Analysis of Acute Hematological Outcomes after Proton and Photon Beam Craniospinal Irradiation in Pediatric Brain Tumors

Purpose

This study aimed to compare the early hematological dynamics and acute toxicities between proton beam craniospinal irradiation (PrCSI) and photon beam craniospinal irradiation (PhCSI) for pediatric brain tumors.

Materials and Methods

We retrospectively reviewed patients with pediatric brain tumors who received craniospinal irradiation (CSI). The average change in hemoglobin levels (ΔHb_avg), absolute lymphocyte counts (ΔALC_avg), and platelet counts (ΔPLT_avg) from baseline values was evaluated and compared between the PrCSI and PhCSI groups at 1 and 2 weeks after the initiation of CSI, 1 week before and at the end of radiotherapy, and 3–4 weeks after the completion of radiotherapy using t-test and mixed-model analysis.

Results

The PrCSI and PhCSI groups consisted of 36 and 30 patients, respectively. There were no significant differences in ΔHb_avg between the two groups at any timepoint. However, ΔALC_avg and ΔPLT_avg were significantly lower in the PhCSI group than in PrCSI group at every timepoint, demonstrating that PrCSI resulted in a significantly lower rate of decline and better recovery of absolute lymphocyte and platelet counts. The rate of grade 3 acute anemia was significantly lower in the PrCSI group than in in the PhCSI group.

Conclusion

PrCSI showed a lower rate of decline and better recovery of absolute lymphocyte and platelet counts than PhCSI in the CSI for pediatric brain tumors. Grade 3 acute anemia was significantly less frequent in the PrCSI group than in the PhCSI group. Further large-scale studies are warranted to confirm these results.

Assessment of the results and hematological side effects of 3D conformal and IMRT/ARC therapies delivered during craniospinal irradiation of childhood tumors with a follow-up period of five years

Background

Craniospinal irradiation (CSI) of childhood tumors with the RapidArc technique is a new method of treatment. Our objective was to compare the acute hematological toxicity pattern during 3D conformal radiotherapy with the application of the novel technique.

Methods

Data from patients treated between 2007 and 2014 were collected, and seven patients were identified in both treatment groups. After establishing a general linear model, acute blood toxicity results were obtained using SPSS software. Furthermore, the exposure dose of the organs at risk was compared. Patients were followed for a minimum of 5 years, and progression-free survival and overall survival data were assessed.

Results

After assessment of the laboratory parameters in the two groups, it may be concluded that no significant differences were detected in terms of the mean dose exposures of the normal tissues or the acute hematological side effects during the IMRT/ARC and 3D conformal treatments. Laboratory parameters decreased significantly compared to the baseline values during the treatment weeks. Nevertheless, no significant differences were detected between the two groups. No remarkable differences were confirmed between the two groups regarding the five-year progression-free survival or overall survival, and no signs of serious organ toxicity due to irradiation were observed during the follow-up period in either of the groups.

Conclusion

The RapidArc technique can be used safely even in the treatment of childhood tumors, as the extent of the exposure dose in normal tissues and the amount of acute hematological side effects are not higher with this technique.

NPI-0052 and γ-radiation induce a synergistic apoptotic effect in medulloblastoma

Medulloblastoma (MB) is the most common malignant solid paediatric brain tumour. The standard treatment for MB is surgical resection of the tumour, radiation and chemotherapy. This therapy is associated with high morbidity and adverse side effects. Hence, more targeted and less toxic therapies are vitally needed to improve the quality of life of survivors. NPI-0052 is a novel proteasome inhibitor that irreversibly binds the 20S proteasome subunit. This compound has anti-tumour activity in metastatic solid tumours, glioblastoma and multiple myeloma with a good safety profile. Importantly, NPI-0052 has a lipophilic structure and can penetrate the blood–brain barrier, making it a suitable treatment for brain tumours. In the present study, we performed an in silico gene expression analysis to evaluate the proteasome subunit expression in MB. To evaluate the anticancer activity of NPI-0052, we used a range of MB patient-derived MB cells and cell lines. The synergistic cell death of NPI-0052 with γ-radiation was evaluated in tumour organoids derived from patient-derived MB cells. We show that high expression of proteasome subunits is a poor prognostic factor for MB patients. Also, our preclinical work demonstrated that NPI-0052 can inhibit proteasome activity and activate apoptosis in MB cells. Moreover, we observe that NPI-0052 has a synergistic apoptotic effect with γ-radiation, a component of the current MB therapy. Here, we present compelling preclinical evidence that NPI-0052 can be used as an adjuvant treatment for p53-family-expressing MB tumours.

Twenty years experience in treating childhood medulloblastoma: Between the past and the present

PURPOSE

Medulloblastoma is the most common primary malignant central nervous system tumour in children. These last decades, treatment modalities have largely evolved resulting in better survival rates. Nevertheless, long-term toxicity is a major concern in this setting. The purpose of this study was to analyse the clinical results and medical outcomes of a cohort of paediatric patients treated for medulloblastoma in Xhinhua Hospital in Shanghai. These results are compared with those from other centres reported in literature.

PATIENTS AND METHODS

This was a retrospective study conducted at Xhinhua Hospital in Shanghai, China. It included 121 patients treated for medulloblastoma from 1993 to December 2013.

RESULTS

Mean age at diagnosis was 6.7 years (range: 1-14.3 years). Total surgical resection was achieved in 60% of the cases. Classic medulloblastoma was found in 59% of the cases. Adjuvant radiotherapy was delivered in all cases and chemotherapy concerned 70.2% of the studied cohort. The median follow-up time of the study was 84 months (range: 24-120 months). Five- and 10 years progression-free survival rates were 83.2%, and 69.5% and 5 years and 10 years. Overall survival rates were 82.5%, and 72.5%. Patient's age significantly influenced survival: patients under 3 years old had the worse outcomes (P=0.01). T and M stages also significantly impacted survival rates: advanced stages were associated with lower rates (P=0.08 and 0.05 respectively). Finally, patients receiving temezolomide had bad outcomes when compared to the new standard protocol used in the department (P=0.03). The most commonly reported late toxicity was growth suppression in 35 patients (52.2%). Hypothyroidism requiring hormone replacement was recorded in 29% of the cases. Hearing loss, and problems including poor concentration, poor memory and learning difficulties were reported in 19% and 25% of the cases respectively. Second cancers were noted in three cases.

CONCLUSION

Overall, our results are comparable to those reported in literature. Nevertheless, efforts should be made to ensure longer follow-ups and correctly assess treatment-related toxicity.

Polyamine Metabolism as a Therapeutic Target inHedgehog-Driven Basal Cell Carcinomaand Medulloblastoma

Hedgehog (Hh) signaling is a critical developmental regulator and its aberrant activation,due to somatic or germline mutations of genes encoding pathway components, causes Basal CellCarcinoma (BCC) and medulloblastoma (MB). A growing effort has been devoted at theidentification of druggable vulnerabilities of the Hedgehog signaling, leading to the identificationof various compounds with variable efficacy and/or safety. Emerging evidence shows that anaberrant polyamine metabolism is a hallmark of Hh-dependent tumors and that itspharmacological inhibition elicits relevant therapeutic effects in clinical or preclinical models ofBCC and MB. We discuss here the current knowledge of polyamine metabolism, its role in cancerand the available targeting strategies. We review the literature about the connection betweenpolyamines and the Hedgehog signaling, and the potential therapeutic benefit of targetingpolyamine metabolism in two malignancies where Hh pathways play a well-established role: BCCand MB.

Hair disorders in patients with cancer

Cytotoxic chemotherapies, molecularly targeted therapies, immunotherapies, radiotherapy, stem cell transplants, and endocrine therapies may lead to hair disorders, including alopecia, hirsutism, hypertrichosis, and pigmentary and textural hair changes. The mechanisms underlying these changes are varied and remain incompletely understood, hampering the development of preventive or therapeutic guidelines. The psychosocial impact of chemotherapy-induced alopecia has been well documented primarily in the oncology literature; however, the effect of other alterations, such as radiation-induced alopecia, hirsutism, and changes in hair color or texture on quality of life have not been described. This article reviews clinically significant therapy-related hair disorders in oncology patients, including the underlying pathophysiological mechanisms, severity grading scales, patient-reported quality of life questionnaires, management strategies, and future translational research opportunities.

Hair disorders in cancer survivors

With increasing survival rates across all cancers, survivors represent a growing population that is frequently affected by persistent or permanent hair growth disorders as a result of systemic therapies, radiotherapy, surgical procedures, and therapeutic transplants. These hair disorders include persistent chemotherapy-induced alopecia, persistent radiotherapy-induced alopecia, endocrine therapy-induced alopecia and hirsutism, postsurgery alopecia and localized hypertrichosis, and persistent stem cell transplantation and targeted therapy-induced alopecia. The information contained in this continuing medical education series should facilitate a better understanding on hair disorders in cancer survivors so that adequate support and therapies may be provided.

Medulloblastoma: From Molecular Subgroups to Molecular Targeted Therapies

Brain tumors are the leading cause of cancer-related death in children, and medulloblastoma (MB) is the most common malignant pediatric brain tumor. Advances in surgery, radiation, and chemotherapy have improved the survival of MB patients. But despite these advances, 25-30% of patients still die from the disease, and survivors suffer severe long-term side effects from the aggressive therapies they receive. Although MB is often considered a single disease, molecular profiling has revealed a significant degree of heterogeneity, and there is a growing consensus that MB consists of multiple subgroups with distinct driver mutations, cells of origin, and prognosis. Here, we review recent progress in MB research, with a focus on the genes and pathways that drive tumorigenesis, the animal models that have been developed to study tumor biology, and the advances in conventional and targeted therapy.

IDO1 involvement in mTOR pathway: a molecular mechanism of resistance to mTOR targeting in medulloblastoma

Medulloblastoma (MB) is the most common malignant brain tumor in children. Despite therapeutic advancements, high-risk groups still present significant mortality. A deeper knowledge of the signaling pathways contributing to MB formation and aggressiveness would help develop new successful therapies. The target of rapamycin, mTOR signaling, is known to be involved in MB and is already targetable in the clinical setting. Furthermore, mTOR is a master metabolic regulator able to control cell growth versus autophagy decisions in conditions of amino-acid deprivation that can be due to IDO1 enzymatic activity. IDO1 has been also implicated in the regulation of inflammation, as well as of T cell-mediated immune responses, in a variety of pathological conditions, including brain tumors. In particular, IDO1 induces expansion of regulatory T-cells (Treg), preventing immune response against tumor cells. Analysis of 27 MB tissue specimens for the expression of both mTOR and IDO1 showed their widespread expression in all samples. Testing their cooperation in vitro, a significant involvement of IDO1 in mTOR immunogenic pathway was found, able to counteract the aim of rapamycin treatment. In MB cell lines, inhibition of mTOR strongly induced IDO1 expression and activity, corroborating its ability to recruit Treg cells in the tumor microenvironment. The mTOR/IDO1 cross talk was found to be strictly specific of MB cells. We demonstrated that mTOR pathway cross talks with IDO1 pathway to promote MB immune escape, possibly contributing to failure of mTOR- targeted therapy.

Impact of acute hematological toxicity on treatment interruptions during cranio-spinal irradiation in medulloblastoma: a tertiary care institute experience

To analyze treatment interruptions due to acute hematological toxicity in patients of medulloblastoma receiving cranio-spinal irradiation (CSI). Prospectively collected data from case records of 52 patients of medulloblastoma treated between 2011 and 2014 was evaluated. Blood counts were monitored twice a week during CSI. Spinal irradiation was interrupted for patients with ≥grade 2 hematological toxicity and resumed after recovery to grade 1 level (TLC >3000; platelet count >75,000). Treatment interruptions and hematological toxicity were analyzed. Median age was 11 years. All patients received adjuvant CSI of 36 Gy, followed by boost of 18 Gy to posterior fossa, at 1.8 Gy per fraction. Concurrent chemotherapy was not given. Adjuvant chemotherapy was given after CSI for high risk patients. Spinal fields were interrupted in 73.1% of patients. Cause of first interruption was leucopenia in 92.1%, thrombocytopenia in 2.6%, and both in 5.3%. Median number of fractions at first interruption was 8, with 25% of interruptions in first week. Median duration for hematological recovery after nadir was 5 days for leucopenia and 3 days for thrombocytopenia. Half of the patients had at least 2 interruptions, and 19% subsequently developed grade 3 toxicity. On multivariate analysis, significant correlation with duration of delay was observed for pre-treatment haemoglobin, number of fractions at first interruption, grade and duration of recovery of leucopenia. Acute hematological toxicity with CSI is frequently under-reported. Patients with low pre-treatment hemoglobin, early onset leucopenia, profound leucopenia and prolonged recovery times are at a higher risk of having protracted courses of irradiation. Frequent monitoring of blood counts and timely interruption of spinal fields of irradiation at grade 2 level of hematological toxicity minimizes the risk of grade 3 and grade 4 toxicity, while reducing the interruptions in irradiation of the gross tumour bed.

Out-of-field doses from pediatric craniospinal irradiations using 3D-CRT, IMRT, helical tomotherapy and electron-based therapy

Medulloblastoma treatment involves irradiation of the entire central nervous system, i.e. craniospinal irradiation (CSI). This is associated with the significant exposure of large volumes of healthy tissue and there is growing concern regarding treatment-associated side effects. The current study compares out-of-field organ doses in children receiving CSI through 3D-conformal radiotherapy (3D-CRT), intensity modulated radiotherapy (IMRT), helical tomotherapy (HT) and an electron-based technique, and includes radiation doses resulting from imaging performed during treatment. An extensive phantom study is performed, using an anthropomorphic phantom corresponding to a five year old child, in which organ absorbed doses are measured using thermoluminescent detectors. Additionally, the study evaluates and explores tools for calculating out-of-field patient doses using the treatment planning system (TPS) and analytical models. In our study, 3D-CRT resulted in very high doses to a limited number of organs, while it was able to spare organs such as the lungs and breast when compared to IMRT and HT. Both IMRT and HT spread the dose over more organs and were able to spare the heart, thyroid, bladder, uterus and testes when compared to 3D-CRT. The electron-based technique considerably decreased the out-of-field doses in deep-seated organs but could not avoid nearby out-of-field organs such as the lungs, ribs, adrenals, kidneys and uterus. The daily imaging dose is small compared to the treatment dose burden. The TPS error for out-of-field doses was most pronounced for organs further away from the target; nevertheless, no systematic underestimation was observed for any of the studied TPS systems. Finally, analytical modeling was most optimal for 3D-CRT although the number of organs that could be modeled was limited. To conclude, none of the techniques studied was capable of sparing all organs from out-of-field doses. Nevertheless, the electron-based technique showed the most promise for out-of-field organ dose reduction during CSI when compared to photon techniques.

SHP2, SOCS3 and PIAS3 Expression Patterns in Medulloblastomas: Relevance to STAT3 Activation and Resveratrol-Suppressed STAT3 Signaling

BACKGROUND

Activated STAT3 signaling is critical for human medulloblastoma cells. SHP2, SOCS3 and PIAS3 are known as the negative regulators of STAT3 signaling, while their relevance to frequent STAT3 activation in medulloblastomas remains unknown.

METHODS

Tissue microarrays were constructed with 17 tumor-surrounding noncancerous brain tissues and 61 cases of the classic medulloblastomas, 44 the large-cell medulloblastomas, and 15 nodular medulloblastomas, which were used for immunohistochemical profiling of STAT3, SHP2, SOCS3 and PIAS3 expression patterns and the frequencies of STAT3 nuclear translocation. Three human medulloblastoma cell lines (Daoy, UW228-2 and UW228-3) were cultured with and without 100 μM resveratrol supplementation. The influences of resveratrol in SHP2, SOCS3 and PIAS3 expression and SOCS3 knockdown in STAT3 activation were analyzed using multiple experimental approaches.

RESULTS

SHP2, SOCS3 and PIAS3 levels are reduced in medulloblastomas in vivo and in vitro, of which PIAS3 downregulation is more reversely correlated with STAT3 activation. In resveratrol-suppressed medulloblastoma cells with STAT3 downregulation and decreased incidence of STAT3 nuclear translocation, PIAS3 is upregulated, the SHP2 level remains unchanged and SOCS3 is downregulated. SOCS3 proteins are accumulated in the distal ends of axon-like processes of resveratrol-differentiated medulloblastoma cells. Knockdown of SOCS3 expression by siRNA neither influences cell proliferation nor STAT3 activation or resveratrol sensitivity but inhibits resveratrol-induced axon-like process formation.

CONCLUSION

Our results suggest that (1) the overall reduction of SHP2, SOCS3 and PIAS3 in medulloblastoma tissues and cell lines; (2) the more inverse relevance of PIAS3 expression with STAT3 activation; (3) the favorable prognostic values of PIAS3 for medulloblastomas and (4) the involvement of SOCS3 in resveratrol-promoted axon regeneration of medulloblastoma cells.