Introduction: Sentinel lymph node biopsy (SLNB) in ductal carcinoma in situ (DCIS) is not indicated. However, in certain cases (size >3 cm, high grade, mass effect on mammography, or palpable mass), it may be possible to find incidental invasive carcinoma (IC) that requires an SLNB. We studied the correlation of the aforesaid factors with the probability of finding IC in the surgical specimen.
Methods: Data was collected from 3 different institutions between 2010 and 2016, recording characteristics such as, but not limited to: high grade, size >3 cm, mass effect on mammography, and palpable mass.
Results: On the whole, 468 "high-risk" DCIS cases were identified, 139 (29%) of which had IC. When the DCIS was high grade or the size was >3 cm, there was no significant difference in the probability of finding IC in the surgical specimen (OR = 1.13; 95% CI 0.84-1.51; OR = 1.2; 95% CI 0.85-1.40). Nevertheless, when a high grade and size (>3 cm) were combined, IC was more likely to exist (72.7 vs. 27.3%; p = 0.001). In addition, mass effect and palpation were independently associated with a significantly greater degree of IC (OR = 12.76; 95% CI 6.93-23.52).
Conclusions: The results suggest that high-grade DCIS or DCIS with a size >3 cm, independently, does not require SLNB. Nonetheless, in the event that both factors are found in the same case, SLNB may be indicated. Additionally, SLNB is advisable for DCIS cases that are palpable or show a mass effect on mammography.
Keywords: Ductal carcinoma in situ; Sentinel node; Type of surgery in situ.
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