The inadequacies of the currently available soft tissue sarcoma staging systems demonstrated by the clinicopathological assessment of three subtypes of soft tissue sarcoma-myxoid liposarcoma, synovial sarcoma and epithelioid sarcoma

Staging of tumours is important. A widely applied and reliable staging system can give important prognostic information for the patient and treating physicians. This information can be used to determine appropriate treatment, compare outcomes between centres and act as a structure for research into modifications to treatment that aim to improve outcomes. Soft tissue sarcomas are a heterogeneous collection of tumours that are commonly grouped together because of similarities in mesenchymal origin and behaviour but partly because of their individual rarity. Unfortunately the common staging systems for soft tissue sarcoma, although prescribed for application to virtually all STS, have not been validated sufficiently for this application. The staging systems that will be discussed are the American Joint Committee for Cancer (AJCC), Union Internationale Cancer Committee (UICC) and the recently published Royal Marsden Hospital (RMH) Staging Systems. This thesis demonstrates the weaknesses in the current commonly used staging systems for STS by assessing relatively large case series of three subtypes of STS (synovial sarcoma, myxoid liposarcoma and epithelioid sarcoma). Rigorous clinicopathological assessments of each subtype have been done. These data demonstrate the particular characteristics that dominate the clinical behaviour for each subtype. By applying the AJCC / UICC and the RMH staging systems to each subtype I have then demonstrated how the individual characteristics reflect as inadequacies in the prognostic reliability of the staging systems for each of these subtypes. After these individual assessments I present combination data which supports the arguments that the current staging systems for STS represent an averaging of the heterogeneous behaviour of the many subtypes of STS but this \averaging\" is dominated by the more common subtypes. The results indicate that inappropriate information is most probably being given to many individual patients particularly those with the less common and non-extremity lesions. This is because the current staging systems for STS are not taking into account the variability in clinical behaviour seen between the different subtypes of STS or sometimes the influence of the different sites of primary STS. More research needs to be done to develop reliable disease patterns for all the subtypes of STS as well as assessment of specific site differences on possible STS prognostic factors. Most reliably the multi-institution pooling of prospectively collected case series with central review of all pathological material could be used to then develop a staging system (or)individual staging systems / prognostic profiles) that take into account this variability between subtypes of STS. In conclusion the subtype analysis completed in this thesis indicates that in many individual cases the currently published staging systems for STS are not clinically relevant and should only be used as a guideline of essentially academic interest."