Role of tumor budding and fibrotic cancer stroma in head and neck squamous cell carcinoma.

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is an aggressive cancer with an increased frequency of lymph node metastasis at the time of presentation. Tumour budding, characterised by the presence of a single cell or a small grouping of tumour cells (a cluster containing fewer than five malignant cells) at the invasive front and composition of the fibrotic cancer stroma has been demonstrated to have a growing impact on the behaviour of the solid tumour. However exact role played by them is yet to be defined and a standardized scoring system needs to be incorporated.

MATERIAL AND METHODS

A total of 45 histopathologically confirmed cases of HNSCC were included in the study. Hematoxylin and Eosin staining (H&E staining), and immunohistochemistry for CK and alpha-SMA were applied to study the tumour budding and fibrotic cancer stroma in all HNSCC cases. The tumour budding was graded as, Grade 1: 0-4 tumour buds, Grade 2: 5-9 buds and Grade 3: ≥ 10 buds and the nature of fibrotic cancer stroma was categorized as mature, intermediate or immature.

RESULTS

Among 45 cases analyzed, well differentiated squamous cell carcinoma (WDSCC; Grade 1) accounted for 42.22% (19 cases), whereas moderately differentiated squamous cell carcinoma (MDSCC; Grade 2) and poorly differentiated squamous cell carcinoma (PDSCC; Grade 3) comprised 48.89% (22 cases) and 8.89% (4 cases) respectively. Tumour budding showed instances of 0-4 buds in 33.3% (Grade 1), 5-9 buds in 48.9% (Grade 2), and ≥ 10 buds in 17.8% of cases. Evaluating tumour stroma, Intermediate stroma led at 51.1%, Mature at 37.8%, and 11.1% displayed Immature stroma. Histologically, < 5 buds were seen in 47.4% of Grade 1 cases, while ≥ 10 buds were in 75.0% of Grade 3 cases, proven statistically significant (p = 0.021). However, an association between T&N Stage and tumour budding lacked significance. WDSCC notably had more mature stroma than MDSCC and PDSCC, whereas MDSCC showed higher rates of intermediate and immature stroma (p < 0.001). Comparatively, no significant correlation existed between fibrotic stroma and tumour budding (p = 0.076). Also, fibrotic stroma was compared with tumour budding, however, no significant correlation was found (p = 0.076) CONCLUSION: This study reveals a significant link between tumour budding, cancer stroma, and WHO tumour grade. Thus, evaluating these factors in HNSCC cases can serve as valuable histological prognostic indicators, aiding in treatment planning and prognosis assessment.