From the clinical standpoint identification of histological
From the clinical standpoint, identification of histological subtype is essential for surgical planning, and this is the first thing an expert centre or a network of reference centres treating STS ensure. In France, for example, patients with retroperitoneal STS managed outside the Clinical Reference Network for Sarcomas-GIST-Desmoids (NetSarc) were five times less likely to have a histological diagnosis before definitive surgery, three times less likely to have a case discussion by a multidisciplinary team, and four times less likely to have relevant preoperative imaging . This preparation is important because, with appropriate adherence to diagnostic and therapeutic guidelines and with better initial identification of histological subtype, patients with retroperitoneal STS in France in 2014 were reported to have median overall survival of 96 months and a 5-year overall survival rate of 66%, which appeared to be an improvement on the 5-year overall survival rate of ≈50% generally reported for retroperitoneal STS .
Survival data by anatomical site Overall, the 5-year survival for STS can vary widely depending on disease stage  and the complex interplay between anatomical site and histology for different STS subtypes . For example, the prognosis and therapeutic implications are very different for a well-differentiated liposarcoma of a limb compared with a well-differentiated liposarcoma arising from the retroperitoneum, where surgery is more difficult . Five-year relative survival for STS in Italy (AIRTUM data) was generally similar to that in Europe (Table 3) [1,17]. No survival data were available in Italy regarding BAY-598 and paraorbital sites because of the limited number of cases observed, and a survival difference of >5% was noted in Italy versus Europe for STS arising at the following anatomical sites: genitourinary tract (56.1 vs 50.4%), viscera (49.6 vs 42.1%), and pelvis (55.3 vs 47.4%) [1,17]. The significantly smaller sample size of the AIRTUM compared with the RARECAREnet database cannot solely explain such divergent survival [1,17]. However, these are descriptive statistics that are not age standardised or corrected for factors that could affect survival, such as different case and stage mix; thus, these results should be interpreted with caution. STS prognosis is also affected by adherence to clinical practice guidelines and by the expertise of the treating centre. Indeed, a side study of the CONTICANET project, which included 151 patients with sarcoma who were prospectively enrolled in the Veneto region of Italy, revealed that patients not treated according to clinical practice guidelines had a significant, 5-fold increase in the risk of local relapse (p < 0.001) and a significant, 4-fold reduction in sarcoma-specific survival (p < 0.001), irrespective of tumour stage . Several other studies also support the benefits of adherence to clinical guidelines in STS, including a prospective population-based cohort study conducted in the Rhone-Alpes region of France .
The emerging importance of Italian and European reference centres and networks One of the major benefits of cancer registries is the creation of large databases for data analyses, with important implications for clinical research into rare tumours. Indeed, registries provide significant sources of information for researchers and clinicians and, in some cases, facilitate the creation of control groups for clinical trials. Expertise of the treating centre is one of the most significant factors affecting survival in STS: treatment within specialised multidisciplinary teams is crucial, since expertise in all areas of diagnosis and treatment (dedicated radiologist, pathologist, surgeon/s, radiotherapist, and medical oncologist) is required to manage STS appropriately. Moreover, conformity to approved treatment guidelines is clearly improved when patients are treated by a multidisciplinary team in a reference centre . Results of the previously mentioned prospective population-based cohort study conducted in the Rhone-Alpes region between 2005 and 2007 demonstrated a beneficial impact of treatment in regional expert centres, not only on adherence to clinical practice guidelines but also on survival of patients with STS . The study authors noted that a possible reason for the improved adherence to clinical practice guidelines may be related to a consistent use of multidisciplinary assessments and treatment planning in expert centres compared with other institutions . Interestingly, data from 1431 adults with STS revealed that almost half of all patient treatment programmes deviated from clinical practice guideline recommendations. This underscores the importance of promoting increased adherence to relevant guidelines, with the attendant likelihood of reduced treatment costs and improved sarcoma care .