Sarcomatoid differentiation levels predict poor RCC survival

By Shreeya Nanda, Senior medwireNews Reporter

Research shows that the degree of sarcomatoid differentiation in patients with grade 4 renal cell carcinoma (RCC) is not only associated with poor survival, but can also serve as an independent prognostic factor in these patients.

The team created a multivariate prognostic model for the prediction of cancer-specific mortality comprising the amount of sarcomatoid differentiation, 2009 primary tumour classifications, regional lymph node involvement and the presence of distant metastases and coagulative tumour necrosis.

The model showed that patients with grade 4 sarcomatoid RCC who were treated with radical or partial nephrectomy between 1970 and 2009 (n=204) had a significant 58% elevated risk of death from RCC compared with those with unilateral, sporadic RCC lacking sarcomatoid features (n=207), irrespective of whether the cancer had metastasised to distant locations and after adjusting for other prognostic factors.

When only patients without distant metastases were considered and other relevant prognostic indicators were adjusted for, the risk of death increased to a statistically significant 82% in those with grade 4 sarcomatoid RCC, report Brian Costello from Mayo Clinic in Rochester, Minnesota, USA, and co-workers.

Moreover, each 10% increase in the level of sarcomatoid differentiation resulted in a significant 6% increase in the risk of cancer-specific death.

Using the median amount of sarcomatoid differentiation (30%) to stratify the study population, the researchers found that participants whose tumours contained 30% or more sarcomatoid differentiation were significantly more likely to die from RCC than those whose tumours were less than 30% differentiated, with a hazard ratio of 1.52.

“This is the first study to show the amount of sarcomatoid differentiation as an independent predictor of survival”, the team remarks.

“We think our prognostic system could be used to risk-stratify patients for future therapeutic trials”, they write in BJU International, adding that, “continued study into the correlation between the amount of sarcomatoid differentiation and response to therapy remains warranted.”

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