Does sentinel lymph node biopsy for screening high-grade ductal carcinoma in situ of the breast cause more harm than good?

PURPOSE: Ductal carcinoma in situ (DCIS) of the breast does not metastasize to axillary lymph nodes. Yet high-grade DCIS (HgDCIS) is often subjected to Sentinel Lymph Node Biopsy (SLNB) concomitant with definitive surgery. This is to avoid further axillary surgery in the event of upstaging to invasive carcinoma, which often entails Axillary Lymph Node Dissection (ALND). We wished to examine the validity of this approach. METHODS: This study includes a retrospective analysis of consecutive pre-operatively diagnosed HgDCIS patients from a single screening unit between December/2014 and August/2016. The main outcomes were the overall incidence of upstaging and the independent predictors of upstaging on multivariable analysis. The rates of various complications of SLNB vs ALND in four RCTs were used to calculate the upstaging rate below which SLNB could be safely omitted. RESULTS: There were 224 eligible patients of whom 26 (11.6%) were upstaged. Axillary metastasis (pN1) occurred in two patients (0.9%). On Univariable analysis, upstaged patients were significantly younger (median (IQR) = 56.0 (51.0-63) vs 60.0 (54.0-65.0); p = 0.019). Radiological size, pathological size, type of biopsy, type of operation, and comedo-necrosis were not significant (p > 0.05). On multivariable analysis, age as a continuous variable (OR 0.93; p = 0.031) and core biopsy (OR 2.62; p = 0.036) were the only independent predictors of upstaging. Chi-square test showed that patients < 55 years whose pre-operative diagnosis was made on core biopsy were at significantly higher risk of upstaging than the others (31.8% vs 9.4%; p = 0.002). CONCLUSION: Upstaging of HgDCIS is infrequent. According to the known rates of complications of SLNB relative to ALND, routine SLNB concomitant with surgery seems to be more harmful than its routine omission. A selective approach based on age and type of biopsy could be considered.

The case for the omission of axillary staging in invasive breast carcinoma that exhibits a predominant tubular growth pattern on preoperative biopsy.

True invasive tubular breast carcinoma (TBC) is unlikely to metastasize to axillary nodes, yet it is routinely subjected to sentinel lymph node biopsy (SLNB), even if the diagnosis was suspected preoperatively. The positive predictive value (PPV) of core biopsy for TBC and the incidence and predictors of axillary metastasis in invasive breast carcinomas identified as tubular-rich on core biopsy are unknown. Prospective patient and tumor data regarding postoperatively confirmed TBCs, and tubular-rich carcinoma identified on preoperative core biopsy between January 2005 and May 2016 was analyzed retrospectively. Axillary metastasis occurred in only 4.2% (4/95) of TBCs, all of which measured >15 mm pathologically. In 11.1% (11/99) of TBCs, the initial core biopsy was either indeterminate/suspicious or ductal carcinoma in situ (DCIS); therefore, their true tubular histotype and size were ascertained following operative excision and before SLNB. Nine were ≤15 mm, and all were node-negative. Only 63.9% (46/72) of tubular-rich core biopsies were confirmed as TBCs; the remaining 36.1% (26/72) were well-differentiated invasive nontubular carcinomas. None of the preoperative patient or tumor features were predictive of true TBC on multivariable analysis; 10.1% (7/69) of carcinomas identified as tubular-rich on core biopsy (regardless of their true histotypes) were node-positive; 23.1% (6/26) in nontubular and 2.3% (1/43) in true tubular carcinomas. Preoperative ultrasound size >15 mm was associated with axillary metastasis in 40.0% (4/10) compared to 5.7% (3/53) in those ≤15 mm (OR = 11.11, 95% CI = 1.99-62.04; multivariable P = .010). Axillary metastasis in TBC is dependent on pathological size; therefore, a case is made for omitting SLNB in small true TBCs confirmed following excision. Preoperative tubular-rich core biopsy is not adequately diagnostic of TBC; however, it selects carcinomas that are well-differentiated, small, and unlikely to metastasize to the axilla, thus allowing for the selective omission of SLNB.