The relationship between tumour stroma percentage, the tumour microenvironment and survival in patients with primary operable colorectal cancer

The tumour microenvironment, particularly the tumour stroma, has a key role in cancer progression and survival. In the present study, a high tumour stroma percentage (TSP) is identified as a marker of poor prognosis in colorectal cancer, independent of other host and tumour determinants of survival. Furthermore, associations between TSP and clinicopathological characteristics suggest a pertinent role in facilitating tumour growth and invasion.Tumour stroma percentage (TSP) has previously been reported to predict survival in patients with colorectal cancer (CRC); however, whether this is independent of other aspects of the tumour microenvironment is unknown. In the present study, the relationship between TSP, the tumour microenvironment and survival was examined in patients undergoing elective, curative CRC resection. Patients undergoing resection at a single centre (1997-2008) were identified from a prospective database. TSP was measured at the invasive margin and its association with cancer-specific survival (CSS) and clinicopathological characteristics examined. Three hundred and thirty-one patients were included in the analysis. TSP was associated with CSS in patients with stage I-III disease [hazard ratio (HR) 1.84, 95% confidence interval (CI) 1.17-2.92, P = 0.009], independent of age, systemic inflammation, N stage, venous invasion and Klintrup-Makinen score. Furthermore, TSP was associated with reduced CSS in patients with node-negative disease (HR 2.14, 95% CI 1.01-4.54, P = 0.048) and those who received adjuvant chemotherapy (HR 2.83, 95% CI 1.23-6.53, P = 0.015), independent of venous invasion and host inflammatory responses. TSP was associated with several adverse pathological characteristics, including advanced T and N stage. Furthermore, TSP was associated with an infiltrative invasive margin and inversely associated with necrosis. The TSP was a significant predictor of survival in patients undergoing elective, curative CRC resection, independent of adverse pathological characteristics and host inflammatory responses. In addition, TSP was strongly associated with local tumour growth and invasion.