Prognostic Significance of Worst Pattern of Invasion in oral cavity Squamous Cell Carcinoma in relation to lymph node metastasis —A Retrospective Study from tertiary care centre

Introduction: Squamous cell carcinoma is the most common head and neck carcinoma, comprising 90% of cancers of the head and neck region1.Globally, oral cancer ranks sixth among all types of cancer. India has the largest number of oral cancer cases and one-third of the total burden of oral cancer globally. It is an important cause of morbidity and mortality worldwide. Oral cavity Squamous Cell Carcinoma(OSCC) commonly results from potentially malignant lesions or normal epithelium linings. Oral SCC spread typically occurs via lymphatic system. Conventional OSCC is aggressive, with a propensity for local invasion & early lymph node metastasis. Lymph node involvement is important prognostic factor in OSCC. So it’s important to access most influencing histological parameter in association with lymph node metastasis. This study was conducted to evaluate the role of histological parameters including Worst pattern of invasion (WPOI) and Depth of invasion (DOI) to determine the risk of LN metastasis in cases of OSCC. Objective: To evaluate the role of worst pattern of invasion to determine risk of lymph node metastasis in oral squamous cell carcinomas. Methodology: After receiving an approval of institutional ethical committee the study was conducted in histopathology section of pathology department. This was a retrospective study. All the cases of buccalmucosa and tongue SCC who underwent resection with cervical lymph node dissection in our institute from October 2021 to January 2023 were included. Cases where patient received preoperative radiotherapy or chemotherapy or where LN dissection was not performed or where slides were not available for review were excluded. Total 108 cases were evaluated and slides were stained by H & E and examined microscopically. Collected data is entered in Microsoft excel. Observation And Results: A total of 108 cases were studied, which included 94 males and 14 females (M:F = 6.7:1). 76 (70.37%) cases were of above 50 years of age and 32 (29.6%) cases were of below 50 years of age (average: 47.2 years). The most common site in our study was buccal mucosa (42 cases i.e. 38.8%). P value is 0.00(at 5% level of significance), so there is strong association between DOI of tumor with WPOI. p value is 0.0092(at 10% level of significance ), so there is strong association between lymph node metastasis and WPOI. In this study number of cases of moderately and poorly differentiated tumors is 48 out of which 24 (50%) cases were positive for LN metastasis and out of 60 well differentiated tumors 12 (20%) were positive for Lymph node metastasis with p value 0.02 at 5% level of significance. Other parameters such as tumor grade, tumor stage, lymphovascular emboli(LVE), perneural infiltration(PNI), Tumor thickness do not show any significant association with WPOI. Conclusion: The present study concluded that aggressive POI are significantly associated with number of lymph nodes metastasis and Depth of invasion and hence can be an independent histopathologic prognostic parameter in OSC