Impact of tumor budding on recurrence risk prediction in stage I-III colorectal cancer: a Swedish cohort study.

OBJECTIVES

Tumor budding is an emerging micromorphologic predictor of recurrence in localized colorectal cancer (CRC). Whether its addition to established CRC recurrence risk factors routinely assessed in clinical practice improves prediction accuracy remains unclear.

METHODS

This study included patients with stage I through III CRC. A detailed micromorphologic assessment was performed for each case according to protocol, using hematoxylin-eosin-stained slides. Clinical characteristics, including treatment and follow-up data, were extracted from patient records. Two logistic regression models were devised to assess recurrence risk, both including established recurrence risk factors chosen a priori. One model also included tumor budding as a dichotomous variable. Receiver operating characteristic curves were used to evaluate and compare the prognostic performance of each model.

RESULTS

Of the 1083 cases of CRC included in the study, 441 (41%) displayed tumor budding. Tumor budding was more common in right-sided colon cancer, following a right-to-left gradient in the bowel. It occurred more frequently in patients with adverse prognostic factors and in patients presenting with surgical emergencies necessitating emergency resection. Median follow-up time was 4.3 years. Tumor budding was strongly associated with disease recurrence in univariate analysis, but the association was not maintained in multivariate analysis. There was no statistically significant difference between the areas under the curve of the 2 models.

CONCLUSIONS

Tumor budding did not substantially contribute to recurrence risk prediction in this study. Further research exploring the association between tumor budding, established recurrence risk factors, and CRC prognosis is warranted.