Background

At initial diagnosis of mCRC an accurate assessment of patient  prognosis is critical to defining the optimal initial treatment strategy. While performance status and number of metastatic sites are presumed surrogates of TB, to date TB assessment has not been formally examined as a potential prognostic marker in mCRC, despite supportive evidence in other malignancies.

Methods

We developed and refined a CT-based scoring system for TB on 151 consecutive mCRC patients entered onto the TRACC (Treatment of recurrent and advanced Colon Cancer) database. Objective (size and number of metastases) and subjective (clinical judgment) scoring systems were used to separate patients into high, moderate or low TB subsets. Clinicopathologic correlates with TB were then assessed, along with survival outcomes for each subset. 

Results

Of the 151 patients, median age was 68 years and77 (51%) were male . Using the subjective scoring system, 55 (36%), 33 (22%) and 63 (42%) were categorized to high, moderate and low TB subsets.. Increasing TB correlated with a lower ECOG PS and greater number of metastatic sites. For patients with distant metastasis at initial CRC diagnosis, increasing TB was associated with a reduced likelihood of primary CRC resection. Median overall survival was superior in low TB compared to high TB subsets (not reached vs 15.9mths, p < 0.0001). Objective scoring system results will be available at the abstract presentation.   

Conclusions

TB correlates with known prognostic factors for patients with mCRC. Multi-variate analyses will be performed to determine the independent impact of TB and if confirmed, this will be validated using an independent patient cohort. As TB inversely correlated with overall survival and with primary resection for patients with mCRC at presentation, including TB assessment in further analyses of the survival impact of primary CRC resection is one potential application of this measure.