One of the most prevalent cancers in the world, especially in poor nations, is oral squamous cell carcinoma (OSCC), which makes up 90–95% of all oral cancers [1]. Due to widespread use of tobacco, both smoked and smokeless, chewing betel quid, alcohol consumption, poor oral hygiene, malnutrition, and delayed presentation to medical facilities, India has a disproportionately high incidence of oral cancer. Despite advancements in surgical methods and adjuvant therapy, OSCC's tendency for local invasion, regional lymph node metastases, and recurrence remains a major therapeutic issue [2].

OSCC exhibits a variety of biological behaviors. The need for trustworthy histopathological prognostic indications beyond traditional TNM staging is highlighted by the fact that patients with malignancies of identical clinical stage frequently have noticeably divergent outcomes. Prognosis has historically been predicted using histopathological grading based on the level of cellular differentiation. However, a number of studies have shown that lymph node metastasis and overall survival cannot be effectively predicted by tumor grade alone [3].

Recent research has shown that tumor budding is a significant physical indicator of the epithelial-mesenchymal transition (EMT), a biological process that promotes tumor invasion and metastasis. At the invasive front of the carcinoma, isolated single tumor cells or clusters of less than five tumor cells are referred to as tumor buds. These separated cells are thought to be the first stage of metastatic spread because of their enhanced ability to migrate [4-5]. In a number of cancers, including colorectal, esophageal, and oral squamous cell carcinomas, high tumor budding has been linked to poor differentiation, lymphovascular invasion, perineural invasion, cervical lymph node metastasis, local recurrence, and a lower overall survival rate.

The worst pattern of invasion (WPOI), which was initially proposed by Brandwein-Gensler and associates, is another interesting histopathological metric. Instead of focusing on the predominant tumor morphology, WPOI assesses the architectural pattern of tumor invasion at the advancing front. From broad pushing borders (Pattern I) to dispersed satellite tumor islands situated more than 1 mm from the primary tumor, five invasion patterns have been identified [6].

Tumor invasiveness may be better understood when tumor budding and WPOI are evaluated together than when they are evaluated separately. Both may supplement traditional histopathological grading in predicting metastatic potential and reflect distinct facets of tumor-host interaction at the invasive front [7].

Several studies conducted internationally have demonstrated the prognostic significance of tumor budding and WPOI. However, relatively limited data are available from the Indian population where OSCC exhibits distinct epidemiological characteristics related to tobacco and areca nut exposure. Establishing the relationship between these histopathological parameters and lymph node metastasis in Indian patients may improve risk stratification and optimize therapeutic planning[8].

Aim: To evaluate the correlation of tumor budding and worst pattern of invasion with histopathological grade and lymph node metastasis in oral squamous cell carcinoma.

Objectives

1. To assess tumor budding in histopathologically confirmed cases of oral squamous cell carcinoma.
2. To evaluate the worst pattern of invasion (WPOI) at the invasive front of oral squamous cell carcinoma.
3. To determine the association between tumor budding and histopathological grade.
4. To determine the association between WPOI and histopathological grade.
5. To evaluate the relationship of tumor budding and WPOI with cervical lymph node metastasis.
6. To identify whether combined assessment of tumor budding and WPOI can serve as useful prognostic indicators in oral squamous cell carcinoma.

Hospital-based cross-sectional observational study, Department of Pathology at a tertiary care teaching hospital for 18 months. 100 histopathologically confirmed cases of oral squamous cell carcinoma.

Inclusion Criteria

1. Patients aged 18 years and above.
2. Histopathologically confirmed primary oral squamous cell carcinoma.
3. Patients undergoing surgical resection with adequate biopsy specimens.
4. Availability of complete histopathological and lymph node evaluation.

Exclusion Criteria

1. Patients receiving neoadjuvant chemotherapy or radiotherapy.
2. Recurrent oral squamous cell carcinoma.
3. Inadequate tissue specimens.
4. Histologically diagnosed non-squamous malignancies.
5. Cases with incomplete clinicopathological records.

Data Collection

Clinical information including age, gender, site of lesion, tobacco habits, tumor size, and lymph node status was obtained from hospital records. Formalin-fixed paraffin-embedded tissue blocks were retrieved, and hematoxylin and eosin-stained sections were reviewed independently by two experienced pathologists blinded to clinical outcomes.

Lymph Node Assessment

Regional cervical lymph nodes obtained during neck dissection were examined histopathologically and categorized as:

Positive metastasis

Negative metastasis

Statistical Analysis

Data were entered into Microsoft Excel and analyzed using SPSS version 26.0. Continuous variables were expressed as mean ± standard deviation, while categorical variables were presented as frequency and percentage. Associations between tumor budding, WPOI, histopathological grade, and lymph node metastasis were analyzed using the Chi-square test or Fisher's exact test wherever appropriate. A p-value <0.05 was considered statistically significant, and p<0.001 was considered highly significant.

A total of 100 histopathologically confirmed cases of oral squamous cell carcinoma (OSCC) were included in the study. The mean age of the study population was 54.8 ± 11.6 years (range: 31–78 years). Male patients constituted 68% of the study population, while females accounted for 32%, yielding a male-to-female ratio of approximately 2.1:1.

Histopathological examination revealed that 46 patients (46%) exhibited high tumor budding, whereas 54 patients (54%) demonstrated low tumor budding. Based on the worst pattern of invasion (WPOI), 48 patients (48%) had aggressive invasion patterns (Patterns IV and V), while 52 patients (52%) exhibited non-aggressive patterns (Patterns I–III).

Table 1. Distribution of Histopathological Grade According to Tumor Budding (n = 100)

High tumor budding was significantly more common among moderately and poorly differentiated tumors, whereas low tumor budding predominated in well-differentiated lesions. The association between tumor budding and histopathological grade was highly statistically significant (p < 0.001), indicating that increasing tumor budding is associated with poorer tumor differentiation.

Table 2. Association of Worst Pattern of Invasion (WPOI) with Histopathological Grade

Aggressive WPOI (Patterns IV and V) was predominantly observed in moderately and poorly differentiated OSCC, while non-aggressive WPOI (Patterns I–III) was more frequent in well-differentiated tumors. This association was statistically significant (p = 0.002).

Table 3. Association between Tumor Budding and Cervical Lymph Node Metastasis

Patients with high tumor budding demonstrated a markedly higher incidence of cervical lymph node metastasis (65.2%) compared with patients exhibiting low tumor budding (22.2%). This association was highly statistically significant (p < 0.001), suggesting that tumor budding is a strong predictor of nodal metastasis.

Table 4. Association of Worst Pattern of Invasion with Cervical Lymph Node Metastasis

Patients with aggressive invasion patterns (WPOI IV and V) had a significantly higher frequency of cervical lymph node metastasis compared with those having WPOI I–III. The association was highly significant (p < 0.001), indicating that WPOI is an important histopathological predictor of metastatic spread.

Despite improvements in diagnosis and therapy, oral squamous cell carcinoma (OSCC), one of the most common head and neck cancers, is still linked to significant morbidity and mortality. The presence of cervical lymph node metastases, which dramatically lowers survival and raises the chance of recurrence, is the primary predictor of prognosis in OSCC [9]. Finding trustworthy histopathological indicators that can forecast aggressive tumor behavior is therefore crucial from a therapeutic standpoint. In this investigation, 100 patients with OSCC had their tumor budding (TB) and worst pattern of invasion (WPOI) correlated with lymph node metastases and histological grade [10].

The mean age of the 100 histopathologically confirmed OSCC cases in this investigation was 54.8 ± 11.6 years, and 68% of the patients were male. This demographic distribution is similar to earlier research that found a male predominance as a result of increased exposure to alcohol, tobacco, betel nut chewing, and smoking. Males continue to make up the bulk of affected individuals in the majority of Indian research, despite an increase in the prevalence of OSCC among women in recent years.

As a sign of the epithelial-mesenchymal transition (EMT), tumor budding has recently drawn a lot of attention [11]. Epithelial tumor cells undergo EMT, which results in the loss of cell-to-cell adhesion, the acquisition of mesenchymal traits, and the ability to invade nearby tissues and spread to distant locations. This biological phenomenon is microscopically represented by tumor buds, which are isolated single cells or tiny clusters of fewer than five cells.

One of the study's most important clinical results is the connection between cervical lymph node metastases and tumor budding. Cervical lymph node metastases occurred in 65.2% of patients with high tumor budding and only 22.2% of patients with low tumor budding. This correlation was substantial (p < 0.001). These findings suggest that tumor budding may be an early sign of concealed nodal illness and is closely linked to metastatic dissemination [12].

In this investigation, aggressive WPOI (Patterns IV and V) was present in 48% of tumors. Poor histological differentiation was significantly correlated with advanced invasion patterns (p = 0.002). When compared to well-differentiated lesions, poorly differentiated tumors showed a significantly higher percentage of WPOI IV and V [13]. This result suggests that when tumor differentiation declines, infiltrative growth patterns become more noticeable.

WPOI was first suggested by Brandwein-Gensler et al. as a significant prognostic indicator for malignancies of the oral cavity. Their research showed that diffuse infiltrative invasion and satellite tumor islands are linked to poor survival and a higher risk of local recurrence. The prognostic usefulness of WPOI in predicting disease development has been repeatedly validated by subsequent studies [14]. Similar results have been shown in a number of published investigations. According to Li et al., WPOI IV and V considerably lower disease-free survival and raise the risk of cervical lymph node metastases. Infiltrative invasion patterns are also independent indicators of poor clinical outcome, according to Kane and colleagues.

The current study has a number of advantages. Initially, every case was verified histopathologically and assessed using uniform standards. Second, the evaluation of WPOI and tumor budding made it possible to compare two new prognostic indicators at the same time. Third, the 100-patient sample size offered enough statistical power to identify relationships that were clinically significant [15].

Overall, the current study's findings provide compelling evidence that both tumor budding and the worst invasion pattern are trustworthy markers of aggressive biological behavior in oral squamous cell carcinoma [16]. These criteria should be included in standard pathological reporting because of their strong correlation with cervical lymph node metastases and histopathological grade. These low-cost histopathological markers have the potential to improve treatment planning, enable individualized patient care, and eventually improve survival rates by identifying high-risk cancers early.

The present study demonstrated that tumor budding (TB) and worst pattern of invasion (WPOI) are significant histopathological indicators of tumor aggressiveness in oral squamous cell carcinoma (OSCC). High tumor budding showed a strong association with poor histopathological differentiation and cervical lymph node metastasis. Similarly, aggressive invasion patterns (WPOI IV and V) were significantly correlated with higher tumor grade and increased incidence of regional lymph node metastasis.

These findings suggest that both TB and WPOI provide prognostic information beyond conventional histopathological grading and TNM staging. Since both parameters can be evaluated on routine hematoxylin and eosin-stained sections without additional cost or specialized investigations, they are practical and reproducible tools for routine pathological assessment. The combined evaluation of tumor budding and WPOI may help identify patients at high risk for occult nodal metastasis and poor clinical outcomes, thereby assisting clinicians in selecting appropriate treatment strategies such as elective neck dissection, adjuvant therapy, and intensive postoperative surveillance. Incorporation of these parameters into routine histopathology reporting may contribute to improved risk stratification and personalized management of patients with oral squamous cell carcinoma.

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