Utilidad del estudio del ganglio centinela en carcinoma ductal in situ diagnosticado mediante biopsia con sistema de corte por vacío

Abstract

IntroductionAbout 24% of patients with ductal carcinoma in situ (DCIS) diagnosed with a core biopsy will also be found to have an invasive component when the lesion is completely excised. This underestimation is reduced when the biopsy is undertaken with a vacuum-assisted device (VAD). We evaluated our experience in the diagnosis of DCIS with a VAD and the final result of the sentinel lymph node biopsy (SLNB) in these patients. MethodsThis study included patients from the CECLINES database in Caracas (Venezuela) from 1998 to 2013. Out of 841 SLNB performed during that period, 64 corresponded to DCIS, diagnosed by a VAD under stereotactic or ultrasound guidance. Patients with microinvasion (pT1mic) or mixed lesions at the time of the pathological evaluation of the biopsy specimen, as well as those diagnosed by a core device, were excluded from this investigation. The methodology for the biopsy consisted of multiple samples from different parts of the lesion. The indications for SLNB in DCIS were: size >30mm (extensive DCIS) or a scheduled mastectomy. ResultsThe detection rate was 95.3% (61/64). Median lesion size was 40mm (SD 19.6). A total of 67.1% (43/64) had a diagnosis of extensive DCIS. In 87.5% (56/64), the mammographic findings were microcalcifications. Most of the lesions (92.1% [59/64]) were non-palpable. A median of 16 (SD 10.4) samples per lesion were obtained. Mastectomy was performed in 82.8% (53/64) of the patients. The distribution of histological grade was: G1 in 15.6% (10/64), G2 in 60.9% (39/64) and G3 in 23.5% (15/64). None of the patients had a positive SLNB. No positive lymph nodes were found in any of the patients who underwent axillary dissection. The underestimation rate for biopsy with a VAD was 6.2% (4/64). ConclusionsThe underestimation rate of DCIS was very low when the biopsy was performed with a VAD and when multiple samples were obtained in non-palpable lesions, regardless of the lesion size or the histological grade. We believe that SLNB can be omitted in selected patients with DCIS.