Sarcoma Patients Experience Clinical Benefit From Molecular Analysis

Molecular analysis can refine sarcoma diagnosis, leading to improved patient care

medwireNews: The French GENSARC study highlights the use of molecular techniques in sarcoma, with testing leading to a change in the initial histological diagnosis of more than 10% of patients, often impacting on prognosis or treatment.

Antoine Italiano, from the Bergonie Cancer Institute in Bordeaux, and team report “diagnosis refinement” in 53 of 384 patients, including nine of 166 patients whose pre-molecular diagnosis was “certain”, 38 of 129 patients who had received a “probable” diagnosis from their pathologist and 69 of 89 patients with a “possible” diagnosis.

Molecular analysis modified the diagnosis in 16% of 50 patients with dermatofibrosarcoma protuberans, 23% of 30 patients with dedifferentiated liposarcoma, 12% of 112 patients with Ewing’s sarcoma, and 16% of 97 patients with synovial sarcoma. In addition, 15% of 46 patients with alveolar rhabdomyosarcoma and 4% of 49 patients with myxoid or round cell liposarcoma were given a different diagnosis.

For example, testing for key gene fusions allowed definitive diagnoses for three patients whose initial morphological and immunohistochemical results for a “certain” histological diagnosis were discordant with molecular testing.

The researchers emphasize in The Lancet Oncology that the effect of molecular analysis on treatment strategy was “very important”.

Two patients were successfully treated with imatinib for relapsed dermatofibrosarcoma protuberans. A further two patients received intensive chemotherapy for alveolar rhabdomyosarcoma that was deemed unnecessary for their original diagnosis of embryonal rhabdomyosarcoma, while one patient whose diagnosis was updated to the embryonal subtype avoided ineffective chemotherapy.

Molecular analysis led to 11 patients being withdrawn from the Euro-EWING 99 trial of an intensive chemotherapy regimen but two additional patients being included in the same study.

And three patients whose diagnosis was changed from a benign to malignant sarcoma type underwent further surgery to achieve a clean tumour margin.

“Based on the present results, the steering committee of the GENSARC study has recommended systematic performance of a molecular test for any suspicion of a mesenchymal tumour type known for harbouring a molecular abnormality”, conclude Antoine Italiano et al.

“The molecular test is recommended even when the diagnosis is claimed as certain by the sarcoma-expert pathologist”, they write, noting that this advice was followed in about 80% of French cases in 2014 using a network of molecular platforms recognised by the French National Cancer Institute.

Reference

Italiano A, Di Mauro I, Rapp J, et al. Clinical effect of molecular methods in sarcoma diagnosis (GENSARC): a prospective, multicentre, observational study. Lancet Oncol 2016; Advance online publication 9 March. DOI: http://dx.doi.org/10.1016/S1470-2045(15)00583-5

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