Detection of micrometastasis in lymph nodes of oral squamous cell carcinoma: A comparative study

Abstract

Background:The annual mortality rate from head and neck squamous cell carcinoma (HNSCC) is over 11,000 worldwide. Squamous cell carcinoma of the head and neck (SCCHN) frequently metastasizes to the regional lymph nodes which are the first site of arrest of tumor cells that have invaded the peritumoral lymphatics, hence the strongest predictor of disease prognosis and outcome.Aim:The present study aims to compare the efficacy of frozen sections (cryosection), step-serial sectioning conventional H and E staining, immunohistochemistry (IHC) and RT-PCR analysis in detection of lymph node micrometastasis.Materials and Methods:A prospective series of 30 patients who were diagnosed with primary squamous cell carcinoma of the oral cavity and underwent surgical treatment including unilateral or bilateral selective neck dissection were considered for the study.Result:Metastatic carcinomatous cells were observed in H and E staining of frozen section in 18 lymph nodes (54%) and in 19 lymph nodes (57%) in step-serial sectioned H and E-stained sections of the 78 lymph nodes from 30 patients. Carcinomatous cells were immunolabeled with pancytokeratin in 18 lymphnodes (54%). CK19 mRNA was detected in 33 lymph nodes of 16 patients. RT-PCR gave positive signals for 24% and 23% of lymph nodes positive by histopathology and immunohistochemistry.Conclusion:Our study demonstrated that RT-PCR is far more sensitive in detection of micrometastasis than any other technique used in routine procedures and immunohistochemistry. Fifty-three percent patients with micrometastasis detected by RT-PCR had large T3/T4 tumors. Prognosis was poor for patients who were positive for micrometastasis detected only by RT-PCR, among which two patients died within a period of 6 months.

Determining the potential of desmoglein 3 as a sensitive and specific immunohistochemical marker for the detection of micrometastasis in patients with primary oral squamous cell carcinoma

“…The five-year survival rate of patients largely depends on the tumour stage at the time of diagnosis, decreasing from 50% in patients without the presence of lymph node metastasis to 90% with nodal metastasis [10–12]. Approximately 30% of patients with OSCC, who present without any clinical or radiographic evidence of regional disease, in fact harbour occult cervical metastasis, which is detected microscopically – divided into three types: macrometastases (> 2–3 mm in the largest dimension), micrometastases (< 2–3 mm in the largest dimension), and isolated tumour cells (individual or small clusters of tumour cells within the lymph node sinuses < 0.2 mm).…”

“…Approximately 30% of patients with OSCC, who present without any clinical or radiographic evidence of regional disease, in fact harbour occult cervical metastasis, which is detected microscopically – divided into three types: macrometastases (> 2–3 mm in the largest dimension), micrometastases (< 2–3 mm in the largest dimension), and isolated tumour cells (individual or small clusters of tumour cells within the lymph node sinuses < 0.2 mm). The size and type of metastasis may influence the prognostic value of nodal metastases [12, 13]. Thus detection of tumour deposits within the lymph nodes is critical for patient care.…”

“…Although cytokeratins have been consistently used as immunohistochemical markers for detection of nodal metastases, they are not very specific. Reticulum cells, ectopic salivary gland inclusions, mesothelial inclusions, and metastatic thyroid follicles can show cytokeratin positivity [12, 14]. Several studies have also found inconsistencies in the precise cytokeratin to be analysed [7].…”

“…Using cytokeratins as markers of micrometastasis detection in HNSCC cases, various authors have shown that the detection rate varies from 1.3% to 68% [4, 12, 18]. Patel et al [7] evaluated formalin-fixed, paraffin-embedded, anonymised tissue sections of non-metastatic (N0) and metastatic (N+) human cervical lymph node biopsies from patients diagnosed with HNSCC for expression of DSG3 and cytokeratin.…”

Feasibility and relevance of level I substation node counts in oropharyngeal carcinoma

“…21 Also, our preliminary data suggest that level I can be involved radiographically but not clinically and can also be occult.…”