Validation of MSKCC nomogram for prediction of metastasis to nonsentinel lymph nodes in carcinoma breast in Indian patients.

Abstract

e11510 Background: Sentinel node biopsy has emerged as the standard of care in clinically node negative breast cancer (cT1,T2 N0). In cases where sentinel node is negative, ALND can be avoided. In nearly 30-50% cases, the sentinel lymph nodes is the only site of metastases, demonstrated in Indian population too. In ASCOG ZOO11 trial, patients who had metastases in sentinel node did not undergo ALND. Patients in the trial received radiation as part of breast conservation surgery. In Indian patients, this is not applicable as most of the patients undergo mastectomy. It would be highly beneficial to identify the subset of patients, where the sentinel node is the only site of metastasis. Various nomograms have been used to predict the risk of metastasis in non sentinel nodes. MSKCC nomogram has been validated in many studies in the USA and Netherlands. Methods: The records of 240 breast cancer patients between 2007 and 2011 who underwent SLN and / or ALND were selected. Serial hemotoxylin and eosin (HE) analysis and immunohistochemistry were routinely performed on each sentinel node. Various factors like T size, histology and grade, lymphovascular invasion, number of +ve and –ve sentinel nodes, hormonal status, multifocality were recorded. Risk of non sentinel node metastasis were calculated by nomogram. Results: 63 out of 240 patients had sentinel node positivity and underwent ALND 20 out of 63(31%) had metastasis in non sentinel nodes also. Mean predictive risk as per nomogram for SLN was 53% and non SLN mets was 68%. None of our patients had low risk of non sentinel node metastasis as per MSKCC nomogram. Conclusions: MSKCC nomogram is not validated for Indian Breast Cancer patients, in our study population as it could not differentiate between patients having metastasis in sentinel node only from those having non sentinel node metastasis based on risk stratification. Because in India, the mean Tumour (T) size is big and Grade is usually high grade and one of the reason the present MSKCC nomogram is not applicable to Indian Breast cancer patients. In Indian populations, a different nomogram is required to correctly predict the non sentinel node metastasis.