Preoperatively diagnosed ductal carcinoma in situ: risk prediction of invasion and effects on axillary management.

BACKGROUND: Preoperatively diagnosed ductal carcinoma in situ (DCIS) has the potential to have occult invasion. The predictors of invasive carcinoma underestimation in patients with DCIS diagnosed by preoperative percutaneous biopsy were identified and the effects of underestimation on axillary management were evaluated.

METHODS: Medical records of 280 patients preoperatively diagnosed as DCIS who underwent surgery were retrospectively analyzed. The patients were divided into non-invasive and invasive carcinoma groups according to the final pathological diagnosis. Risk predictors of invasive carcinoma underestimation and axillary lymph node (ALN) metastasis were analyzed. The axillary status estimated by pathological diagnosis and one-step nucleic acid amplification (OSNA) assay was evaluated.

RESULTS: The presence of an invasive carcinoma was overlooked in 104 (37.1 %) patients. A clinically palpable mass was an independent risk predictor of invasive carcinoma underestimation by multivariate analysis. There was no risk predictor of ALN metastasis. No ALN metastasis was seen in non-invasive carcinoma group. Six (6.2 %) patients in invasive carcinoma group had macro- or micrometastasis in sentinel lymph nodes (SLNs). Non-SLN metastasis was observed in 3 patients of them. Fourteen patients with only isolated tumor cells (ITCs) or only OSNA-positive SLNs had no metastasis in non-SLNs.

CONCLUSIONS: SLN biopsy and, if necessary, subsequent ALN dissection (ALND) should be performed in patients with DCIS who have a risk predictor of underestimation. ALND can be avoided in patients who have histologically negative or ITC-positive SLNs, regardless of the presence of invasion on final pathological diagnosis.