Adriana Fonseca - Academia.edu (original) (raw)
Papers by Adriana Fonseca
Frontiers in Oncology, 2020
Primary CNS tumors are the leading cause of cancer-related death in pediatrics. It is essential t... more Primary CNS tumors are the leading cause of cancer-related death in pediatrics. It is essential to understand treatment trends to interpret national survival data. In Canada, children with CNS tumors are treated at one of 16 tertiary care centers. We surveyed pediatric neuro-oncologists to create a national standard of practice to be used in the absence of a clinical trial for seven of the most prevalent brain tumors in children. This allowed description of practice across the country, along with a consensus. This had a multitude of benefits, including understanding practice patterns, allowing for a basis to compare in future research and informing Health Canada of the current management of patients. This also allows all children in Canada to receive equivalent care, regardless of location.
Journal of Neurosurgery, 2021
OBJECTIVE There is no consensus on the optimal clinical management of ventriculomegaly and hydroc... more OBJECTIVE There is no consensus on the optimal clinical management of ventriculomegaly and hydrocephalus in patients with diffuse intrinsic pontine glioma (DIPG). To date, the impact on survival in patients with ventriculomegaly and CSF diversion for hydrocephalus in this population remains to be elucidated. Herein, the authors describe their institutional experience. METHODS Patients diagnosed with DIPG and treated with up-front radiation therapy (RT) at The Hospital for Sick Children between 2000 and 2019 were identified. Images at diagnosis and progression were used to determine the frontal/occipital horn ratio (FOR) as a method to measure ventricular size. Patients with ventriculomegaly (FOR ≥ 0.36) were stratified according to the presence of symptoms and categorized as follows: 1) asymptomatic ventriculomegaly and 2) symptomatic hydrocephalus. For patients with ventriculomegaly who did not require CSF diversion, post-RT imaging was also evaluated to assess changes in the FOR a...
Neuro-Oncology, 2020
INTRODUCTION Primary central nervous system (CNS) sarcomas are rare mesenchymal non-meningothelia... more INTRODUCTION Primary central nervous system (CNS) sarcomas are rare mesenchymal non-meningothelial tumors accounting for less than 0.2% of intracranial lesions. Diagnosis and management are challenging due to the current lack of substantive clinical, histological and molecular data. METHODS We retrospectively identified all patients with diagnosis of primary CNS sarcoma at the Hospital Fundación Pediatrico la Misericordia (HOMI) in Bogota, Colombia. We collected patient demographics, disease characteristics, and outcomes for analysis. RESULTS Between 2008 and 2020, twenty-four consecutive patients were diagnosed at the HOMI representing 6% of all CNS tumors diagnosed over the same time period. The median age at presentation was 9.48 years (range:1.6–13.4). The median time of symptoms prior to diagnosis was 2 weeks (0.1–24). The most common presentation was headache (21/24- 89%) and vomiting (19/24- 79%). The frontal lobe was involved in 63% of patients (15/24) and only one patient p...
Neuro-Oncology, 2020
BACKGROUND The is no consensus in best practices for the management of hydrocephalus in patients ... more BACKGROUND The is no consensus in best practices for the management of hydrocephalus in patients with Diffuse Intrinsic Pontine Glioma (DIPG). To date, the impact on survival of hydrocephalus and Cerebro-Spinal Fluid (CSF) diversion in this population remains to be elucidated. Herein, we describe our institutional experience. METHODS Patients with a clinical and radiological diagnosis of DIPG were identified at the Hospital for Sick Children between 2000–2019. Images at diagnosis and at disease progression were assessed for hydrocephalus using the frontal-occipital ratio (FOR) method. Proportional hazard analyses were used to identify factors correlated with survival. RESULTS Eighty-nine consecutive patients diagnosed with DIPGs were treated at our institution. At diagnosis, 29% (n=26) of patients presented with hydrocephalus, seven patients underwent CSF diversion. Out of the remaining nineteen patients, n=6 had stable or improved hydrocephalus in follow-up scans, n=6 had persisten...
Journal of Clinical Oncology, 2020
2503 Background: CNS-NGGCT are rare tumors that have been successfully treated with multimodal th... more 2503 Background: CNS-NGGCT are rare tumors that have been successfully treated with multimodal therapies. With a 5-yr EFS and OS of 72-84% and 82-93% respectively, surveillance and relapse detection is essential. Tumor marker (TM) elevation has proven to be a highly sensitive method of relapse detection in extra-cranial-NGGCT. We aim to determine the role of TM for relapse surveillance in children and adolescents with CNS-NGGCTs. Methods: European and North American data from germ cell tumor trials (SIOP GCT96, SFOP-TGM TC 90/92, COG-ACNS0122 and COG-ACNS1123) were pooled for analysis. Additionally, patients treated in the UK, Germany and France under strict protocol-guidelines were included. Details regarding imaging, pathology and TM elevation at diagnosis and relapse were collected. We report the proportion of relapses detectable by TM elevation. Results: Four-hundred and eighty-four patients enrolled in prospective cooperative group CNS-NGGCT trials from 1989 to 2016 were pooled...
SSRN Electronic Journal, 2019
Over the past decade, wingless-activated (WNT) medulloblastoma has been identified as a candidate... more Over the past decade, wingless-activated (WNT) medulloblastoma has been identified as a candidate for therapy de-escalation based on excellent survival; however, a paucity of relapses has precluded additional analyses of markers of relapse. To address this gap in knowledge, an international cohort of 93 molecularly confirmed WNT MB was assembled, where 5-year progression-free survival is 0.84 (95%, 0.763-0.925) with 15 relapsed individuals identified. Maintenance chemotherapy is identified as a strong predictor of relapse, with individuals receiving high doses of cyclophosphamide or ifosphamide having only one very late molecularly confirmed relapse (p = 0.032). The anatomical location of recurrence is metastatic in 12 of 15 relapses, with 8 of 12 metastatic relapses in the lateral ventricles. Maintenance chemotherapy, specifically cumulative cyclophosphamide doses, is a significant predictor of relapse across WNT MB. Future efforts to de-escalate therapy need to carefully consider not only the radiation dose but also the chemotherapy regimen and the propensity for metastatic relapses.
European Urology Supplements, 2019
Current Oncology Reports, 2018
Purpose of Review Malignant embryonal brain tumors (EBTs) of childhood span a wide clinical spect... more Purpose of Review Malignant embryonal brain tumors (EBTs) of childhood span a wide clinical spectrum but can share remarkably similar morphologic features. This overlap presents significant diagnostic challenges, particularly for tumor entities that are rarely encountered in clinical practice and for which diagnostic criteria were poorly defined. This review will provide an update on the evolving characterization and treatment of rare EBTs. Recent Findings Rapid advances in genomic tools have led to the discovery of robust molecular markers, and identification of novel tumor types and subtypes for almost all major categories of pediatric brain tumors. These developments have had significant impact on improving the diagnostic classification of the rare EBTs, particularly for tumors with newly recognized C19MC alterations, central nervous system primitive neuroectodermal tumors (CNS-PNET), and pineoblastoma (PB). Summary These important developments in the clinical and molecular understanding of rare EBTs are paving the way for novel therapeutic strategies and improved clinical management.
Journal of Clinical Oncology, 2019
10022 Background: Adolescents with extracranial malignant germ cell tumors (GCTs) are often treat... more 10022 Background: Adolescents with extracranial malignant germ cell tumors (GCTs) are often treated on the same regimens developed for children, but more closely resemble the clinical characteristics of young adult patients. We sought to determine whether event-free survival (EFS) for adolescents with GCTs was more like that of children or young adults. Methods: We assembled an individual patient database of ten GCT trials: seven conducted by pediatric cooperative groups and three by an adult group. We selected male patients aged 0-30 years old treated with platinum-based chemotherapy for non-seminomatous malignant GCTs of the testis, retroperitoneum, or mediastinum. We categorized age-group as children (0 to < 11 years), adolescents (11 to < 18 years), or young adults (18 to < 30 years old). We compared EFS among age groups, and adjusted for calculated IGCCCG risk-group using Cox proportional hazards analysis. Results: 593 patients met inclusion criteria, of whom 90 were c...
Journal of Clinical Oncology, 2019
10023 Background: The management of pediatric malignant germ cell tumors (MGCTs) includes inducti... more 10023 Background: The management of pediatric malignant germ cell tumors (MGCTs) includes induction therapy with 3-4 cycles cisplatin, etoposide, bleomycin (PEb). The current practice recommends 2-3 cycles of PEb (total 6 cycles) as consolidation therapy if response is not complete at the end of induction, a significantly different approach than that used in adult patients who receive a standard number of cycles. Furthermore, there is no evidence supporting the addition of a consolidation phase with PEb in pediatric patients with MGCTs. Methods: We retrospectively reviewed all patients enrolled in a phase III, single-arm trial for low-risk and intermediate-risk MGCTs (AGCT0132). All patients received 3 cycles of PEb and underwent response assessment at the end of induction. Complete Response (CR) was defined as negative tumor markers and no viable residual lesion. Patients in CR were not to receive any further chemotherapy. Patients not in CR were prescribed 3 additional cycles of P...
Journal of clinical oncology : official journal of the American Society of Clinical Oncology, Jan 21, 2018
To investigate relapse detection methods among children and adolescents with nongerminomatous mal... more To investigate relapse detection methods among children and adolescents with nongerminomatous malignant germ cell tumors (MGCTs) and to determine whether tumor markers alone might be sufficient for surveillance. We retrospectively reviewed all patients enrolled in a phase III, single-arm trial for low-risk and intermediate-risk MGCTs. The method used to detect relapse was assessed based on case report forms, tumor markers, imaging, and pathology reports. Relapses were classified into one of two categories on the basis of whether they were (1) detectable by tumor marker elevation or (2) not detectable by tumor markers. A total of 302 patients were enrolled, and 284 patients had complete data for review. Seven patients had normal tumor markers at initial diagnosis, and none experienced a relapse. At a median follow-up of 5.3 years, 48 patients (16.9%) had experienced a relapse. After central review, 47 of 48 relapses (98%) were detected by tumor marker elevation. Of the 47 patients, 1...
Pediatric Blood & Cancer, 2017
Background: Orthotopic liver transplantation (OLT) is considered the standard for children with h... more Background: Orthotopic liver transplantation (OLT) is considered the standard for children with hepatoblastoma (HB) in whom complete surgical resection is not possible. However, OLT is not always available or feasible. Objective: To describe the outcome of children with HB who were initially deemed unresectable and underwent complex hepatectomy with planned close margins, and ultimately avoided OLT. Methods: Demographic data, surgical and pathologic details, and survival information were collected from children treated for HB between January 2010 to December 2015. Results: Among six children (median age 12 months (3-41 months)), PRETEXT classification was III (n = 2), III/IV (n = 1), and IV (n = 3). Patients received a median of six cycles (range 4-7) of platinum-based induction chemotherapy; five received doxorubicin. Experienced pediatric surgeons performed extended right and left hepatectomy in five and one patients, respectively, with assistance of an experienced liver transplant surgeon (n = 4). Microscopic margins were positive (n = 2) and negative but close (n = 4; 2-5 mm). Two patients required vascular reconstruction of the vena cava. At median follow-up of 3.3 years (1.7-4.6 years), there was no evidence of local recurrence. One patient had recurrence of pulmonary disease 3 months after surgery. Conclusions: Patients with advanced HB treated with complex surgical resections with positive or close negative margins had good outcomes without OLT. We suggest that planned positive or close microscopic margins in highly selected HB patients may spare the morbidity of OLT and offer an alternative for those ineligible for OLT. Our experience illustrates the importance of a multidisciplinary team specialized in the management of liver tumors.
Progress in Tumor Research, 2016
Germ cell tumors (GCTs) represent a group of biologically complex malignancies that affect patien... more Germ cell tumors (GCTs) represent a group of biologically complex malignancies that affect patients at different sites within the body and at different ages. The varying nature of these tumors reflects their cell of origin which is the primordial germ cell, which normally gives rise to ovarian and testicular egg and sperm producing cells. These cells retain an ability to give rise to all types of human tissues, and this is illustrated by the different kinds of GCTs that occur. In adolescent and young adult (AYA) patients, GCTs predominantly present as testicular, ovarian or mediastinal primary GCTs, and represent some of the most complex therapeutic challenges within any AYA practice. The varying types of GCTs, defined by primary site and/or age at presentation, can look very similar microscopically. However, there is growing evidence that they may have different molecular characteristics, different biology and different requirements for curative treatments. Whilst in adult testicular GCTs there is evidence for an environmental cause during fetal development and a genetic component, these causative factors are much less well understood in other GCTs. GCTs are some of the most curable cancers in adults, but some patients exhibit resistance to standard treatments. Because of this, today's clinical research is directed at understanding how to best utilize toxic therapies and promote healthy survivorship. This chapter explores the biology, behavior and treatment of GCTs and discusses how the AYA group of GCTs may hold some of the keys to understanding fundamental unanswered questions of biological variance and curability in GCTs.
Frontiers in Oncology, 2020
Primary CNS tumors are the leading cause of cancer-related death in pediatrics. It is essential t... more Primary CNS tumors are the leading cause of cancer-related death in pediatrics. It is essential to understand treatment trends to interpret national survival data. In Canada, children with CNS tumors are treated at one of 16 tertiary care centers. We surveyed pediatric neuro-oncologists to create a national standard of practice to be used in the absence of a clinical trial for seven of the most prevalent brain tumors in children. This allowed description of practice across the country, along with a consensus. This had a multitude of benefits, including understanding practice patterns, allowing for a basis to compare in future research and informing Health Canada of the current management of patients. This also allows all children in Canada to receive equivalent care, regardless of location.
Journal of Neurosurgery, 2021
OBJECTIVE There is no consensus on the optimal clinical management of ventriculomegaly and hydroc... more OBJECTIVE There is no consensus on the optimal clinical management of ventriculomegaly and hydrocephalus in patients with diffuse intrinsic pontine glioma (DIPG). To date, the impact on survival in patients with ventriculomegaly and CSF diversion for hydrocephalus in this population remains to be elucidated. Herein, the authors describe their institutional experience. METHODS Patients diagnosed with DIPG and treated with up-front radiation therapy (RT) at The Hospital for Sick Children between 2000 and 2019 were identified. Images at diagnosis and progression were used to determine the frontal/occipital horn ratio (FOR) as a method to measure ventricular size. Patients with ventriculomegaly (FOR ≥ 0.36) were stratified according to the presence of symptoms and categorized as follows: 1) asymptomatic ventriculomegaly and 2) symptomatic hydrocephalus. For patients with ventriculomegaly who did not require CSF diversion, post-RT imaging was also evaluated to assess changes in the FOR a...
Neuro-Oncology, 2020
INTRODUCTION Primary central nervous system (CNS) sarcomas are rare mesenchymal non-meningothelia... more INTRODUCTION Primary central nervous system (CNS) sarcomas are rare mesenchymal non-meningothelial tumors accounting for less than 0.2% of intracranial lesions. Diagnosis and management are challenging due to the current lack of substantive clinical, histological and molecular data. METHODS We retrospectively identified all patients with diagnosis of primary CNS sarcoma at the Hospital Fundación Pediatrico la Misericordia (HOMI) in Bogota, Colombia. We collected patient demographics, disease characteristics, and outcomes for analysis. RESULTS Between 2008 and 2020, twenty-four consecutive patients were diagnosed at the HOMI representing 6% of all CNS tumors diagnosed over the same time period. The median age at presentation was 9.48 years (range:1.6–13.4). The median time of symptoms prior to diagnosis was 2 weeks (0.1–24). The most common presentation was headache (21/24- 89%) and vomiting (19/24- 79%). The frontal lobe was involved in 63% of patients (15/24) and only one patient p...
Neuro-Oncology, 2020
BACKGROUND The is no consensus in best practices for the management of hydrocephalus in patients ... more BACKGROUND The is no consensus in best practices for the management of hydrocephalus in patients with Diffuse Intrinsic Pontine Glioma (DIPG). To date, the impact on survival of hydrocephalus and Cerebro-Spinal Fluid (CSF) diversion in this population remains to be elucidated. Herein, we describe our institutional experience. METHODS Patients with a clinical and radiological diagnosis of DIPG were identified at the Hospital for Sick Children between 2000–2019. Images at diagnosis and at disease progression were assessed for hydrocephalus using the frontal-occipital ratio (FOR) method. Proportional hazard analyses were used to identify factors correlated with survival. RESULTS Eighty-nine consecutive patients diagnosed with DIPGs were treated at our institution. At diagnosis, 29% (n=26) of patients presented with hydrocephalus, seven patients underwent CSF diversion. Out of the remaining nineteen patients, n=6 had stable or improved hydrocephalus in follow-up scans, n=6 had persisten...
Journal of Clinical Oncology, 2020
2503 Background: CNS-NGGCT are rare tumors that have been successfully treated with multimodal th... more 2503 Background: CNS-NGGCT are rare tumors that have been successfully treated with multimodal therapies. With a 5-yr EFS and OS of 72-84% and 82-93% respectively, surveillance and relapse detection is essential. Tumor marker (TM) elevation has proven to be a highly sensitive method of relapse detection in extra-cranial-NGGCT. We aim to determine the role of TM for relapse surveillance in children and adolescents with CNS-NGGCTs. Methods: European and North American data from germ cell tumor trials (SIOP GCT96, SFOP-TGM TC 90/92, COG-ACNS0122 and COG-ACNS1123) were pooled for analysis. Additionally, patients treated in the UK, Germany and France under strict protocol-guidelines were included. Details regarding imaging, pathology and TM elevation at diagnosis and relapse were collected. We report the proportion of relapses detectable by TM elevation. Results: Four-hundred and eighty-four patients enrolled in prospective cooperative group CNS-NGGCT trials from 1989 to 2016 were pooled...
SSRN Electronic Journal, 2019
Over the past decade, wingless-activated (WNT) medulloblastoma has been identified as a candidate... more Over the past decade, wingless-activated (WNT) medulloblastoma has been identified as a candidate for therapy de-escalation based on excellent survival; however, a paucity of relapses has precluded additional analyses of markers of relapse. To address this gap in knowledge, an international cohort of 93 molecularly confirmed WNT MB was assembled, where 5-year progression-free survival is 0.84 (95%, 0.763-0.925) with 15 relapsed individuals identified. Maintenance chemotherapy is identified as a strong predictor of relapse, with individuals receiving high doses of cyclophosphamide or ifosphamide having only one very late molecularly confirmed relapse (p = 0.032). The anatomical location of recurrence is metastatic in 12 of 15 relapses, with 8 of 12 metastatic relapses in the lateral ventricles. Maintenance chemotherapy, specifically cumulative cyclophosphamide doses, is a significant predictor of relapse across WNT MB. Future efforts to de-escalate therapy need to carefully consider not only the radiation dose but also the chemotherapy regimen and the propensity for metastatic relapses.
European Urology Supplements, 2019
Current Oncology Reports, 2018
Purpose of Review Malignant embryonal brain tumors (EBTs) of childhood span a wide clinical spect... more Purpose of Review Malignant embryonal brain tumors (EBTs) of childhood span a wide clinical spectrum but can share remarkably similar morphologic features. This overlap presents significant diagnostic challenges, particularly for tumor entities that are rarely encountered in clinical practice and for which diagnostic criteria were poorly defined. This review will provide an update on the evolving characterization and treatment of rare EBTs. Recent Findings Rapid advances in genomic tools have led to the discovery of robust molecular markers, and identification of novel tumor types and subtypes for almost all major categories of pediatric brain tumors. These developments have had significant impact on improving the diagnostic classification of the rare EBTs, particularly for tumors with newly recognized C19MC alterations, central nervous system primitive neuroectodermal tumors (CNS-PNET), and pineoblastoma (PB). Summary These important developments in the clinical and molecular understanding of rare EBTs are paving the way for novel therapeutic strategies and improved clinical management.
Journal of Clinical Oncology, 2019
10022 Background: Adolescents with extracranial malignant germ cell tumors (GCTs) are often treat... more 10022 Background: Adolescents with extracranial malignant germ cell tumors (GCTs) are often treated on the same regimens developed for children, but more closely resemble the clinical characteristics of young adult patients. We sought to determine whether event-free survival (EFS) for adolescents with GCTs was more like that of children or young adults. Methods: We assembled an individual patient database of ten GCT trials: seven conducted by pediatric cooperative groups and three by an adult group. We selected male patients aged 0-30 years old treated with platinum-based chemotherapy for non-seminomatous malignant GCTs of the testis, retroperitoneum, or mediastinum. We categorized age-group as children (0 to < 11 years), adolescents (11 to < 18 years), or young adults (18 to < 30 years old). We compared EFS among age groups, and adjusted for calculated IGCCCG risk-group using Cox proportional hazards analysis. Results: 593 patients met inclusion criteria, of whom 90 were c...
Journal of Clinical Oncology, 2019
10023 Background: The management of pediatric malignant germ cell tumors (MGCTs) includes inducti... more 10023 Background: The management of pediatric malignant germ cell tumors (MGCTs) includes induction therapy with 3-4 cycles cisplatin, etoposide, bleomycin (PEb). The current practice recommends 2-3 cycles of PEb (total 6 cycles) as consolidation therapy if response is not complete at the end of induction, a significantly different approach than that used in adult patients who receive a standard number of cycles. Furthermore, there is no evidence supporting the addition of a consolidation phase with PEb in pediatric patients with MGCTs. Methods: We retrospectively reviewed all patients enrolled in a phase III, single-arm trial for low-risk and intermediate-risk MGCTs (AGCT0132). All patients received 3 cycles of PEb and underwent response assessment at the end of induction. Complete Response (CR) was defined as negative tumor markers and no viable residual lesion. Patients in CR were not to receive any further chemotherapy. Patients not in CR were prescribed 3 additional cycles of P...
Journal of clinical oncology : official journal of the American Society of Clinical Oncology, Jan 21, 2018
To investigate relapse detection methods among children and adolescents with nongerminomatous mal... more To investigate relapse detection methods among children and adolescents with nongerminomatous malignant germ cell tumors (MGCTs) and to determine whether tumor markers alone might be sufficient for surveillance. We retrospectively reviewed all patients enrolled in a phase III, single-arm trial for low-risk and intermediate-risk MGCTs. The method used to detect relapse was assessed based on case report forms, tumor markers, imaging, and pathology reports. Relapses were classified into one of two categories on the basis of whether they were (1) detectable by tumor marker elevation or (2) not detectable by tumor markers. A total of 302 patients were enrolled, and 284 patients had complete data for review. Seven patients had normal tumor markers at initial diagnosis, and none experienced a relapse. At a median follow-up of 5.3 years, 48 patients (16.9%) had experienced a relapse. After central review, 47 of 48 relapses (98%) were detected by tumor marker elevation. Of the 47 patients, 1...
Pediatric Blood & Cancer, 2017
Background: Orthotopic liver transplantation (OLT) is considered the standard for children with h... more Background: Orthotopic liver transplantation (OLT) is considered the standard for children with hepatoblastoma (HB) in whom complete surgical resection is not possible. However, OLT is not always available or feasible. Objective: To describe the outcome of children with HB who were initially deemed unresectable and underwent complex hepatectomy with planned close margins, and ultimately avoided OLT. Methods: Demographic data, surgical and pathologic details, and survival information were collected from children treated for HB between January 2010 to December 2015. Results: Among six children (median age 12 months (3-41 months)), PRETEXT classification was III (n = 2), III/IV (n = 1), and IV (n = 3). Patients received a median of six cycles (range 4-7) of platinum-based induction chemotherapy; five received doxorubicin. Experienced pediatric surgeons performed extended right and left hepatectomy in five and one patients, respectively, with assistance of an experienced liver transplant surgeon (n = 4). Microscopic margins were positive (n = 2) and negative but close (n = 4; 2-5 mm). Two patients required vascular reconstruction of the vena cava. At median follow-up of 3.3 years (1.7-4.6 years), there was no evidence of local recurrence. One patient had recurrence of pulmonary disease 3 months after surgery. Conclusions: Patients with advanced HB treated with complex surgical resections with positive or close negative margins had good outcomes without OLT. We suggest that planned positive or close microscopic margins in highly selected HB patients may spare the morbidity of OLT and offer an alternative for those ineligible for OLT. Our experience illustrates the importance of a multidisciplinary team specialized in the management of liver tumors.
Progress in Tumor Research, 2016
Germ cell tumors (GCTs) represent a group of biologically complex malignancies that affect patien... more Germ cell tumors (GCTs) represent a group of biologically complex malignancies that affect patients at different sites within the body and at different ages. The varying nature of these tumors reflects their cell of origin which is the primordial germ cell, which normally gives rise to ovarian and testicular egg and sperm producing cells. These cells retain an ability to give rise to all types of human tissues, and this is illustrated by the different kinds of GCTs that occur. In adolescent and young adult (AYA) patients, GCTs predominantly present as testicular, ovarian or mediastinal primary GCTs, and represent some of the most complex therapeutic challenges within any AYA practice. The varying types of GCTs, defined by primary site and/or age at presentation, can look very similar microscopically. However, there is growing evidence that they may have different molecular characteristics, different biology and different requirements for curative treatments. Whilst in adult testicular GCTs there is evidence for an environmental cause during fetal development and a genetic component, these causative factors are much less well understood in other GCTs. GCTs are some of the most curable cancers in adults, but some patients exhibit resistance to standard treatments. Because of this, today's clinical research is directed at understanding how to best utilize toxic therapies and promote healthy survivorship. This chapter explores the biology, behavior and treatment of GCTs and discusses how the AYA group of GCTs may hold some of the keys to understanding fundamental unanswered questions of biological variance and curability in GCTs.