It was a retrospective study done in Cancer Institute, Chennai, a tertiary teaching hospital, in Chennai, Tamil Nadu, India where all clinical early breast cancers treated from January 2011 to October 2014 were analysed, after Institute ethical committee approval and patients consent.

All the patients with invasive breast cancer which were clinical T1 and T2 and either N0 or N1 were reviewed for present study. The demographic features of the patients, clinical history, physical findings and pathological features of the biopsy as well as prognostic markers were looked upon.

All early breast cancers had pathological confirmation either by fine needle aspiration cytology or core biopsy. Patients who had undergone either Modified radical mastectomy or breast conservative surgery with complete axillary dissection, including level 3 lymph nodes were included in analysis. A total of 27 patients who had an excision biopsy for diagnosis were also included. There were a total of 608 patients eligible for study.

Clinical tumours more than five cm (T3), male patients, patients who have undergone excision biopsy elsewhere, who have had incomplete axillary dissection or received neo adjuvant therapy were excluded. A lymph node status was recorded as palpable or non-palpable if it could be felt or not felt respectively by the examiner irrespective of whether, they were identified radiologically.

Pathologic characteristics of the primary tumour considered were size, single or multicentric origin, histological type, nuclear grade, and lymphatic/vascular invasion, ER and PR status and HER-2/neu and Ki-67 were analysed. Number of axillary lymph nodes dissected and number of nodes being positive for metastatic deposits were also noted. Size of the tumours was categorised using the TNM system of the American Joint Committee on Cancer 8^th edition. Invasive carcinomas were classified using the largest dimension of the invasive component to size: T1a-5 mm or less; T1b- 6-10 mm; T1c-11-20 mm; T2- 2-5 cm [9].

The axillary contents and all identified lymph nodes were dissected and sectioned through the hilum and examined histologically. Histological type of the lesion, histological grade of the tumour, and lymphatic and vascular invasion which were evaluated on routine haematoxylin and eosin slides was noted. The ER and PR analyses were based on an IHC assay. IHC analysis was performed on the formalin-fixed, paraffin embedded breast cancer tissue specimens. Any nuclear staining of invasive tumour cells was considered as positive, for ER and PR. HER2 status was also evaluated by IHC. IHC was performed as per the standard methodology using primary antibodies; clone ID5-ER (DAKO, Glostrup, Denmark), clone PgR636-PR (DAKO, Carpinteria-CA), clone HER2/neu (c-erbB2). Ki-67is a proliferative biomarker and is considered to be prognostic factor for breast cancer. Ki-67 expression is measured as the percentage of tumour cells positively stained by the antibody, with nuclear staining being the most common criterion for the positivity. A cut-off point of 14% was considered as distinction between low and high proliferative tumours [10].

The association between the characteristics of the patients and survival was evaluated with a univariate and multivariate analysis. The adjusted OR’s, 95% CI’s and p-values <0.05 were considered to be significant. Statistical analysis was performed using SPSS software (IBM SPSS Statistics Version 17; Chicago IL). Multivariate logistic regression analysis was done to assess the relationship between the nodal status and pathologic variables, adjusting for other factors.

In this study 608 patients of Clinically T1, T2, N0, N1 carcinoma breast that were treated, were analysed. There were 248 patients with pathologically positive nodes [Table/Fig-1].

The minimum age of the patient was 27 years and the maximum age was 80 years with an average of 51 years. Most patients were within the age group of 41 to 50 years comprising of 198 patients, 32.6% of the study group. Next common age group was between 51-60 years. When we combined the age group, 307 (50.5%) were found between 50-75 years of age.

Pathological variables, stratified with axillary nodal status are presented in [Table/Fig-2].

In this study, majority were T2 lesions, which were similar in distribution as that of clinical size. Pathologically, 13 cases were found to be T3 lesions even though clinically T3 lesions were not included. In this study, there was an increasing trend towards the nodal positivity rate as the size of the tumour increases, but was found to be insignificant on multivariate analysis [Table/Fig-3,4].

A total of 248 (40.78%) patients were found to have pathological nodes, even-though 528 patients were found to have clinically palpable axillary nodes. The mean number of lymph nodes being evaluated was 16.48 nodes per patient. In this study, 25 patients were found to have pathological N3 disease as shown in [Table/Fig-5].

While clinically, 28 patients had multiple tumours, on final HPE, 49 patients had multiple tumours. Among the multiple tumours patients with positive nodes, 13 patients had multifocal disease and 16 patients had multicentric disease. Grade III lesions were 511 (84%), with 212 (41.48%), having node positive disease. Even though there was increased node positive rate as the grade increased, it was not found to be significant in present study.

Infiltrating Ductal Carcinoma (IDC) was the most common being 95.9%, and Invasive Lobular Carcinoma (ILC) being only 1.7%. IDC had 41.3% Positive nodes; ILC had 50% positive nodes. Mucinous and papillary did not have any positive nodes while medullary tumour had 33.3% positive nodes and histological type of tumour had no significant relation to nodal positivity. 19.9% (121) patients had LVSI and among them 102 (84.29%) patients had positive lymph nodes.

Hormonal receptor status is mentioned in [Table/Fig-6]. Similar to LVSI, ER positive patients had higher nodal positivity rate in 201 patients (44.5%), when compared to ER negative of 47 patients (30.1%), which was highly significant on univariate analysis but not on multivariate analysis. PR positive tumours had higher nodal positivity when compared to PR negative tumours and were statistically significant on univariate analysis but again similar to ER status; on multivariate analysis it was found to be not significant. Among the nodal positive cases 169 were ER and PR positive, while 44 patients were ER and PR negative.

A total of 98 (41.8%) out of 234 HER-2 positive tumours had node positive disease. HER-2 was negative in 151 patients and 51 (33.3%) among them being node positive. On univariate analysis it was found that HER-2 Positive cases had higher rate of nodal positivity compared to HER-2 negative tumours. But it was not statistically significant.

In this study 588 patients had high Ki-67 value, compared to only 20 patients with low value of 0-14. Among them, 241 in the higher group and 7 from the lower group had nodal positive disease.

Axillary dissection remains the gold standard in prognostication, planning further therapy. With mammographic screening becoming prevalent, more tumours are detected at smaller size with lower incidence of axillary nodal metastasis [11]. These patients may not benefit from axillary dissection, and suffer from its complications. This had led to study of factors predicting axillary nodal metastasis in addition to sentinel node biopsies. Factors predicting axillary nodal metastasis, may not predict sentinel node metastasis with similar sensitivity and specificity.

The incidence of breast cancer in Asian women peaks in their forties, whereas among European and American women, it peaks in their sixties [12]. The median age in present study was 51 years with age range between 27-80 years; this was similar to the study by Raina V et al., among Indian patients in whom the median age was 47 years (range 23-82 years) [13]. In study by Tan LGL et al., among Singapore patients, the median age of the subjects was 52 years, with a range from 24 to 87 years [14].

Both in node positive and node negative cases T2 lesion was more common. In the study by Tan LGL et al., among Singapore T2 lesions were 41.1%, whereas in study by Lee JH et al., among Korean population, the T2 lesions comprised of 45.7% [14,15].

The relation of the tumour size and axillary lymph nodal positive rate is evident in multiple other studies also [Table/Fig-7] [14-17]. But this proportional relationship may not be very reliable, as cases with small primary with extensive nodal metastasis have been reported, with an aggressive clinical course [18].

It is well known that a manual clinical examination of the axilla has poor sensitivity and specificity. In present study, although 86.8% had clinically positive node, only 40.78 had pathological nodal positivity. In the study, by Lee JH et al., positive axillary lymph nodes were detected in 104 patients for an overall incidence of 28.8% in early breast cancer, with mean number of lymph nodes of 15.4±5.2 [15]. Of the 380 subjects, studied by Tan LGL et al., 136 (35.8%) were found to be node positive. The median number of nodes examined was 14 (±6.81), with a range of 1-41 [14].

In the study by Yoshihara E et al., 87.22% of the patients had unifocal tumour and 12.78% had multifocal tumour. In present review 8% patients had multiple tumours on pathological examination. There was two-fold increased chance of multiple tumours being node positive when compared to single tumour with an odds ratio of 2.251 with a 95% CI, and it was found to have statistically significant. But again in multivariate analysis it was not found to be significant [19].

Even though there was increased node positive rate as the grade increased, being 33%, 37% and 41% for Grade I, II, III tumours respectively, it was not found to be significant in present study. Similarly, in the study by Lee JH et al., the nodal positive rate among Grade I, Grade II, Grade III was 4 (3.8%), 28 (26.9%), and 35 (33.7%), respectively and in the study by Tan LGL et al., the nodal positive rate for grade I, II, and III was 21.0%, 34.3% and 50.5% respectively [14,15].

In present study even though ILC had 50% rate of nodal positivity when compared to IDC with a positivity rate of 41.3%, it was not significant, and may be due to the less number of patients. In the study by Lee JH et al.,, IDC was the predominant histological type seen in 315 patients (87%), followed by medullary carcinoma in 20 patients (5%). There was no difference in the distribution of axillary lymph nodal metastasis among the different histological types [15]. In the study by Tan LGL et al., IDC were 84.5% and ILC 3.4% and others being 12.1%. Nodal positive rate was 39.6% for IDC and 30.8% for ILC and 10.9% for others [14]. In the study by Yoshihara E et al., also the Ductal carcinoma constituted 91.39% and Lobular 10.99% [19].

The presence of LVSI is a well-known risk factor for nodal metastasis. Chakraborty A et al., in his review of 426 patients in eastern India had similar results, in patients who had no LVI, 38.97% had axillary node metastases, compared with 76.81% where LVI was present [20]. Tumour with LVI had the highest chance of nodal positivity rate more than 12.5 times the tumour without LVI and it had high statistical significance both in univariate analysis and also on multivariate analysis. Similar results with relation to LVSI and axillary lymph nodes were seen in other studies too. In the study by Tan LGL et al., 75.4% patients were node positive among the patients with LVI [14]. In study by Sandoughdaran S et al., among Iranian population, LVSI emerged as the most powerful independent predictor of axillary nodal metastasis [21].

As in present study, other studies have showed that nodal positivity was more among the patient with ER positivity and or PR positivity [Table/Fig-4]. Recent data have shown incidence of breast cancer increasing in India and Pakistan, particularly ER, PR negative cancers. Only 20-45% of Indian patients were detected to have ER, PR positive tumours. In comparison to western population, Indian patients have been shown to have lower ER positivity. In study by TMH, Mumbai, tumours expressing ER and/or PR comprised 51.2% of which 73.4% expressed both ER and PR [22]. In series by He ZY et al., he noted, that PR concentrations were independently associated with increased risk of axillary nodal metastasis [23].

Ki-67 proliferative index has been shown to have a significant relation to lymph nodal positivity. In the study by Ivkovic-Kapicl T et al., 43% of patients with high Ki-67 had node positivity, in contrast only 14% of low Ki-67 proliferative index were node positive [24]. In present study also tumours with higher Ki-67 had higher chances of nodal positivity but it was not found to be statistically significant.

In patients considered for breast reconstruction, risk of nodal involvement may influence the timing of reconstruction. Patients with low risk of nodal metastasis can be offered primary reconstruction, and in patients with high risk of nodal disease, delayed reconstruction can be considered. Also, patients with high risk of nodal metastasis may still be candidates for sentinel node biopsy, as a subgroup of them, can avoid axillary dissection.

Present main limitation is the retrospective nature of study and being conducted in a single institution.

Our study was aimed at knowing the nodal positivity rate in early breast cancer patients and pathologic predictive factors of nodal positivity in early breast cancer in Indian patients, which may help in predicting the axillary status pre operatively. Although variables such as pT2, multiple tumours, LVSI, ER positive, PR positive and HER2+ was found to have positive predictive value with statistical significance, only LVSI proved to be a highly significant predictor of positive nodes in present study and LVSI emerged as significant independent predictive factors of positive lymph node. These data can be used to tailor treatment protocols for effective diagnosis and treatment, improving the quality of life. Prospective studies are required to further prove the significance of these factors.