The number of people diagnosed with soft tissue sarcoma (STS) is on the rise with the greatest increase in patients aged over 70, new Australian data reveals.
The study is the first to provide a snapshot of the incidence of the rare group of cancers in an Australian population.
Researchers from South Australia identified a total of 26,970 patients across six Australian states diagnosed with the condition between 1982 and 2009.
STS incidence rates significantly increased from 3.99 to 6.12 per 100,000 people during this period. Incidence rates were stable across all age cohorts, except for people aged over 70 where it increased – a factor researchers put down to increasing awareness and improved diagnostic capabilities for evaluating sarcomas over the length of the study period.
“Our widening therapeutic and diagnostic abilities, as well as changing community expectations have likely led to more thorough investigation of mass lesions in the older population and to the documentation of sarcoma diagnoses, rather than presumptive diagnoses,” they wrote.
The most common STS in Australia was leiomyosarcoma which accounted for 20.43% of all STS, followed by malignant fibrous histiocytoma (MFH), and complex mixed and stromal neoplasms (15.60%).
Speaking to the limbic, study investigator Dr Gillian Caughey from the School of Pharmacy and Medical Sciences at the University of South Australia said that while still relatively uncommon, there had been only modest gains in survival seen in people with STS.
“[This is] the fastest growing segment of Australia’s population and the increasing incidence in this group means that a greater focus of the healthcare needs and potentially awareness of the condition is needed,” she said.
According to Dr Caughey the rarity and heterogeneity of STS had hampered efforts to understand incidence patterns in Australia.
“Given that this is the first Australian population-based study of STS incidence it highlights the challenges associated with assessing the incidence of rare cancers and the importance of determining the magnitude of disease burden at the population level to facilitate care provision and potentially policy and economic directives,” she said
The increase in survival observed (5.80 years in the 1985-89 cohort and 8.18 years in the 2000-04 cohort) was ‘modest’ given improvements in treatment regimens, according to Dr Caughey.
“Treatment regimens have changed … focusing on chemotherapy targeted to the specific sarcoma subtypes. However, despite this, we only observed small increases in survival. We postulate that potentially a lack of clinical trials for people with STS in Australia, together with poor participation in clinical trials especially in the older population, may contribute in part, to the small increases in survival.
The ASCO conference in Chicago in June heard that a fast-tracked treatment, olaratumab, had failed to live up to the promise shown in phase Ib/II trials. Overall survival rates with olaratumab in STS were no better than with doxorubicin, a phase III trial showed. Researchers said doxorubicin remained the standard of care of treatment for STS.
The study is published in Cancer Epidemiology