Utility of Glasgow Microenvironment Score as a prognostic tool in colorectal carcinoma

Colorectal carcinoma (CRC) is third most common malignancy in the world. The presence of Lymphocytes particularly at the invasive margin of the tumor have been associated with good immune response indicating better prognosis. The relative tumor stroma is also important in deciding the course of the disease. The Glasgow Microenvironment Score (GMS) comprises of assessment of tumor cell infiltrate using Klintrup-Makinen (KM) grade and tumor stroma percentage.

The aim of the present study is to evaluate the utility of GMS score in relation to parameters of adverse histopathological outcome in carcinoma colon that is grading, staging, LVI, PNI and nodal metastasis.

Colectomy specimens received over 3 year period were subjected to microscopic evaluation for LVI, PNI, grade, stage & lymph node metastasis.

Lymphocytes at the deepest invasive margin of tumor were counted as per KM score in 5 HPF by two independent pathologists . Patients were classified as Low grade (0/1) or high grade (2/3) response. Tumor stroma percentage was calculated as stroma poor (<50%) and stroma rich (>/= 50 %). The GMS was scored by combining the two and scored 0, 1 and 2.

Total 37 patients with no prior therapy were included out of which 23 were males and 14 females. 15 patients (40.54%) had GMS of 0, 6 (16.21%) had GMS 1 and 16 (43.24%) had GMS 2. A high GMS was associated with LVI (P = 0.02), PNI (P = 0.01) lymph node metastasis (P = 0.003). However, no significant association was found between GMS with Grade (P = 0.98) and Stage (P = 0.36).

Low GMS was associated with good outcome and high GMS with poor outcome. This score can be used for risk stratification, can be of clinical utility and may be applied to pathological descriptions of CRC.