Risk of invasion and axillary lymph node metastasis in ductal carcinoma in situ diagnosed by core-needle biopsy.

BACKGROUND

The aim of the study was to assess the risk of invasion and axillary lymph node metastasis in patients with ductal carcinoma in situ (DCIS) diagnosed by preoperative core-needle biopsy. The data were used to select criteria for patients in whom sentinel node (SN) biopsy might be indicated.

METHODS

One hundred and seventy-one women with 172 DCIS lesions diagnosed by core-needle biopsy were analysed. Axillary staging was performed by SN biopsy, axillary node sampling, or level 1-2 axillary lymph node dissection.

RESULTS

Invasive breast cancer was found in the surgical specimens from 45 tumours (26.2 per cent). Risk factors for invasion were a palpable lesion (odds ratio (OR) 2.95 (95 per cent confidence interval 1.20 to 7.26); P = 0.019), presence of a mass on mammography (OR 3.06 (1.43 to 6.56); P = 0.004), and intermediate (OR 5.81 (1.18 to 28.57); P = 0.030) or poorly differentiated (OR 5.46 (1.17 to 25.64); P = 0.031) tumour grade. Lymph node metastases were found in ten women with DCIS and invasion on final pathology. Factors associated with metastases were age 55 years or less (P = 0.030), invasion of 1.0 cm or more (P < 0.001) and the presence of vascular invasion (P = 0.001).

CONCLUSION

SN biopsy should be considered in women with an initial diagnosis of DCIS on core-needle biopsy who are at risk for invasion; this includes women with a palpable lump, a mass on mammography, and intermediate or poor tumour grade.