Colorectal Cancer after Breast Cancer: Magnitude of Risk in Clinical Practice and in the Literature

Abstract

Aims and background

The aim of our study was to estimate the incidence of second primary tumors among breast cancer patients from the Division of Oncology of Andosilla Hospital (Viterbo, Italy). In particular, we studied the relationship between breast and colorectal cancer.

Methods and Study Design

Eligible women were those with primary invasive breast cancer who had been treated and/or followed up at our division. We compared our data with those reported in the literature.

Results

Of 114 women with breast cancer, 21 (18.5%) developed multiple primary cancers, with colorectal cancer accounting for a quarter. We found a higher incidence of colorectal cancer than reported in the literature (5% vs 0.66–1%). At the moment we are not able to explain this difference.

Conclusions

Quite a few studies reported a link between breast and colorectal cancer, but the magnitude of the risk (standardized incidence ratio 1.3–2) does not justify a screening program for colorectal disease in breast cancer patients. However, considering that the risk is small but not negligible – along with the high incidence of colorectal adenomas described in breast cancer patients and the possible existence of common risk factors – we invite clinicians not to neglect the possibility of a colorectal cancer diagnosis in women who have had breast cancer.