Is complete axillary lymph node dissection neccessary in T1 stage invasive pure tubular carcinomas of the breast?

Omission of Surgical Axillary Lymph Node Staging in Patients with Tubular Breast Cancer

BACKGROUND

With more effective screening and treatment strategies, there is debate over whether surgical axillary staging should be deescalated for patients with small favorable breast cancers, such as tubular carcinoma (TC).

PATIENTS AND METHODS

We identified patients with TC [defined as > 90% tubular tubules (angulated, not multilayered)] and known surgical axillary staging from our institutional database (2000-2018). Using the National Cancer Database (NCDB) (2004-2015), we identified patients with TC, ductal carcinoma in situ (DCIS), and pT1 estrogen receptor (ER)-positive invasive ductal carcinoma (IDC). We determined the rates of lymph node (LN) metastases, and the 5- and 10-year overall survival (OS) for patients with LN-negative versus LN-positive disease using the Kaplan-Meier method and propensity match analysis.

RESULTS

In our institutional cohort, we identified 112 patients with T1 TC; only one (0.9%) patient had nodal involvement. In the NCDB cohort, we identified 6938 patients with T1 TC; 323 (4.7%) patients had axillary LN disease. The rate of axillary LN involvement for TC was comparable to that identified for patients with DCIS (4.2%), and much lower than that found for patients with grade I-III, T1, ER-positive IDC (20.5%), and patients with grade I, T1, ER-positive IDC (14.4%). There was no difference in 5-year (94.6% versus 95.4%, p = 0.67) and 10-year (83.9% versus 85.2%, p = 0.98) OS between TC patients with or without LN involvement. Kaplan-Meier survival curves even after propensity score matching suggest that tubular histology is independently associated with improved survival.

CONCLUSIONS

T1 TC is an excellent starting point for deescalation of surgical axillary staging.

Expression of cathepsin D and galectin 3 in tubular carcinomas of the breast

Tubular carcinoma (TC) is a distinctive type of grade I (G1) ductal carcinoma with particularly favourable outcome and low rate of axillary metastases. To the best of our knowledge, few data are available in the literature concerning the expression of molecules mediating intercellular and cell-matrix interactions in TC. We examined with immunohistochemical methods the expression of galectin 3 and cathepsin D in 17 TC and in 33, 31 and 28 ductal carcinomas of G1, grade II (G2) and grade III (G3), respectively. Results were compared using Chi-square test. Galectin 3 expression was higher in TC than in G1 carcinomas (p<0.05). The pattern of immunostaining was also different with a focal cytoplasmic apical reinforcement in TC. However, cathepsin D stromal and epithelial expression was similar in TC and G1 cases (p>0.05), and lower than in G2 and G3 patients at a stromal level. The higher expression of galectin 3 in TC and its focal staining (apical) pattern suggests that within the group of G1 carcinomas, galectin 3 expression varies according to histological type, and may correlate with prognosis and metastatic potential. We also suggest that cathepsin D could not be involved in neoplastic progression and metastasis in low-grade (G1) ductal breast carcinomas.

Microvessel and lymphatic density in tubular carcinoma of the breast: Comparative study with invasive low-grade ductal carcinoma

Tubular carcinoma (TC) of the breast is an uncommon variant of ductal carcinoma, which has an extremely low metastatic potential and an excellent prognosis. Studies concerning the vascular and lymph vessel status in TC are not numerous and hampered by a lack of specific markers. We immunohistochemically analysed the expression of CD31 and D2-40 antibodies in 15 TC measuring less than 2cm in diameter. We compared the results with those observed in 30 low-grade ductal breast carcinomas (LGDC) of no specific type with similar dimensions. Neither microvascular density (MVD) nor lymphatic vessel density (LVD) was statistically different in the groups: MVD was 26.5+/-28.2 and 32.1+/-17.9 vessels/mm(2) in TC and LGDC, respectively (P=0.08). LVD, low in both tumour types, was 0.5+/-0.3 and 0.6+/-0.4 vessels/mm(2), respectively (P>0.1). These data suggest that the favourable prognosis and the low rate of lymph node metastases in TC are not explained by lymphangiogenetic and angiogenetic potential and are supported by recent analyses in the literature.