380 likes | 810 Views
Sarcomas. Perspectives and Background. Sarcomas: Themes. Sarcomas are a heterogeneous collection of diseases and families of diseases Individual diseases/families may be defined molecularly and a molecular derangement characterizes each tumor type (usually)
E N D
Sarcomas Perspectives and Background
Sarcomas:Themes • Sarcomas are a heterogeneous collection of diseases and families of diseases • Individual diseases/families may be defined molecularly and a molecular derangement characterizes each tumor type (usually) • Molecular derangement supersedes histomorphology in defining disease • Unlikely that characteristic molecular derangement is the entire story • Prototypic diseases which span the child/young adult age range
The Sarcomas • Osteosarcoma • Ewing family of tumors • Ewing sarcoma of bone and soft tissue • Peripheral Primitive neuroectodermal tumor • Soft tissue sarcomas • Non-rhabdomyosarcoma STS • Rhabdomyosarcoma • Embryonal rhabdomyosarcoma • Alveolar rhabdomyosarcoma • Other variants
Five Year Survival Rates Among Children with Sarcomas: Improvement Over Time From: Arndt C and Crist W. N Engl J Med 341:342-352, 1999
Osteosarcoma: Distribution by Site, Age, and Sex From: Dahlin DC, Unni KK. Bone Tumors: General Aspects and Data on 8542 Cases (ed 4). Springfield, IL: Charles C Thomas; 1986
Molecular Derangements in Osteosarcoma • Mutations in RB gene (inactivation) • Mutations in p53 (inactivation) • MDM2 amplification (and thus inactivation of p53) • Over-expression of HER2/erbB-2 No single molecular derangement defines osteosarcoma
Multi-Institutional Osteosarcoma Study (1981-1986): Outcome of All Patients Treated with Chemotherapy
Intergroup Osteosarcoma Study (1993-1997):Event-Free Survival for all Patients
Metastatic Osteosarcoma: Outcome 100 80 60 Probability (%) 40 Survival 20 Event-free survival 0 0 4 7 6 1 3 2 5 Years followed
Ewing Sarcoma: Distribution by Site, Age and Sex From: Dahlin DC, Unni KK. Bone Tumors: General Aspects and Data on 8542 Cases (ed 4). Springfield, IL: Charles C Thomas; 1986
Molecular Pathogenetic Mechanisms in Rhabdomyosarcoma and Ewing’s Sarcoma From: Arndt C and Crist W. N Engl J Med 341:342-352, 1999
The 11;22 Translocation And The Family of Ewing’s Sarcomas • Reciprocal translocation t(11;22)(q24;q12) • Found consistently in bone and soft tissue Ewings, PNET, Askin tumors • Unifying diagnostic criterion for Ewing’s family of tumors • EWS (RNA binding protein) fused to FLI-1 or ERG (transcription factors of the ETS family) • Translocation results in a tumor-associated fusion gene • Fusion transcript present in > 95% of tumors of Ewings family
Gene Fusions with Novel Chimeric Protein Products Activation of aberrant gene program t(2;13)(q35;q14) PAX3 FKHR Malignant transformation Chromosome 2 Chromosome 13
Genetic Features of Rhabdomyosarcoma • Embryonal rhabdomyosarcoma • Associated with inactivation of tumor suppressor gene located at 11p15.5 • Cases with hyperdiploid DNA content associated with better outcome • Alveolar rhabdomyosarcoma • Cases with tetraploid DNA content fare poorly • Characteristic reciprocal translocation t(2;13)(q35;q14) • Results in fusion of PAX3 (transcriptional regulatory protein expressed during embryogenesis) to FKHR (member of the forkhead family of transcription factors) • Infrequently, t(1;13)(p36;q14) involving PAX7 and FKHR
Overall Survival: Metastatic Patients Only 1.0 0.9 0.8 PAX7 0.7 0.6 0.5 Global : p = 0.0026 PAX3 vs PAX7: p = 0.0015 Proportion Negative 0.4 PAX3 0.3 0.2 0.1 0.0 0 1 2 3 4 5 6 7 8 9 10 Overall survival (years)
Failure-free Survival of Patients with Local/Regional Rhabdomyosarcoma on IRS-IV by Chemotherapy Regimen 1.0 0.9 0.8 VIE 0.7 VAC VAI 0.6 Failure-free Survival 0.5 0.4 0.3 0.2 0.1 Log Rank Test: p=0.52 0.0 0 1 2 3 4 5 6 Years
Sites 7% Orbit 28% Head & Neck 11% Trunk 2% Intrathoracic 2% GI-Hepatic 6% Retroperitoneum 18% GU 2% Perineum-Anus 24% Extremities
Failure-free Survival, IRS-IV for Patients with Local/Regional Tumors by Primary Site 1.0 0.9 Orbit GU non-B/P 0.8 H & N GU B/P 0.7 Extremity PM 0.6 Other Failure-free Survival 0.5 0.4 0.3 0.2 0.1 Log Rank Test: p<0.001 0.0 0 1 2 3 4 5 6 Years
Results of Univariate Analysis • Adolescents (>10 years) more often have*: • alveolar tumors (p<0.001) • tumors arising in extremity or paratestis sites (p=0.001) • large tumors (>5 cm, p<0.001) • invasive tumors (i.e. T2, p=0.007) • + regional nodes (i.e. N1, p<0.001) • metastatic disease (p<0.001) • unfavorable tumor stage (p<0.001) *compared to children (1 to 9 yrs of age)
Estimated Relative Risk of Failure by Age Group(Cox Proportional Hazards Model)
The Common Soft Tissue Sarcomas in Children • Rhabdomyosarcoma • Soft tissue Ewing/PNET • Synovial Sarcoma • Malignant Peripheral Nerve Sheath Tumor • Malignant Fibrous Histiocytoma • Sarcoma NOS • Leiomyosarcoma • Fibrosarcoma • Clear cell sarcoma • Epithelioid sarcoma • Liposarcoma
Outcome of Children with Localized Non-Rhabdomyosarcoma Soft Tissue Sarcomas From Pratt C et al J Clin Oncol 17:1219, 1999
Considerations of Linking Studies of Sarcomas • Diseases occur in children, adolescents and young adults (excluding non-rhabdo STS) • Diseases in adults and children may be similar on a molecular level • But, heterogeneity even within major subclasses of sarcomas • Histopathological • Biological • Other significant molecular derangements and differences in gene expression likely • Limited numbers of patients • Relatively high cure rate with current therapy limits subjects available for experimental therapies Therefore: Combine efforts among adult and pediatric patients where the disease appears to be a continuum encompassing pediatric and young adults
Challenges in Linking Studies in Children and Adults • Older patients fare less well in all varieties of sarcoma • ?True age-related biological differences • Older age associated with higher risk features and more advanced disease • Age remains independently prognostic • ?Differences in host tolerance for therapy • ?Difference in compliance with intensive therapies • ?Differences in physician compliance with intensive therapies • Mindset of medical v. pediatric oncologists
Novel Targets for Biological Agents in Sarcomas • Osteosarcoma • Her2 via herceptin • PDGF signal transduction pathway blockade via STI-571 • Agents which target p53 and Rb • Rhabdomyosarcoma • PAX/FKHR fusion gene products • Ewing family • EWS/FLI1 and EWS/ERG fusion gene products • Stem cell factor/c-kit signal transduction pathwayblockade via STI-571 • Desmoplastic Small Round Cell tumor • PDGF signal transduction pathway blockade via STI-571 • Other Soft Tissue Sarcomas • Products of associated fusion genes