Clinicopathological Correlation between Depth of Tumor and Neck Node Metastasis in Oral (Tongue and Buccal Mucosa) Carcinoma
Corresponding Author: Anuj H Shah, Department of ENT, Surat Municipal Institute of Medical Education and Research, Surat, Gujarat, India, Phone: +91 8238935656, e-mail: email@example.com
How to cite this article Shah AH, Parikh RP. Clinicopathological Correlation between Depth of Tumor and Neck Node Metastasis in Oral (Tongue and Buccal Mucosa) Carcinoma. Int J Head Neck Surg 2021;12(1):6–10.
Source of support: Department of ENT, Department of Radiology, and Department of Pathology, Surat Municipal Institute of Medical Education and Research, Surat, Gujarat, India
Conflict of interest: None
Aims and objectives: (1) To study the depth of tumor invasion in an oral (tongue and buccal mucosa) carcinoma and its correlation with neck metastasis. (2) To know whether the increase in depth of tumor (depth of invasion) increases the chances of cervical nodal metastasis in the oral tongue and buccal mucosa carcinoma and derive cutoff value of depth of invasion at which the metastasis occurs.
Materials and methods: The study was carried out on 14 tongue and 22 buccal mucosa cases to know the correlation between the depth of tumor and neck node metastasis in the oral (tongue and buccal mucosa) carcinoma.
Results: Among 36 cases, 10 cases were pN+. Out of 10 cases, 7 (70%) were having depth ≥12 mm and 30% cases (pN+) having depth between 8 and %3C;10. We found it statistically significant and so as the depth of tumor increases the chances of nodal metastasis increases. We found the cutoff for a depth of invasion in both tongue and buccal mucosa carcinomas as 8 out of 22 patients had DOI %3E;10 mm and among them 4 were pN+ and among 14 tongue cases, 3 cases had DOI >8 mm and all of them were pN+.
Conclusion: For tongue 8 mm and for buccal mucosa, 10 mm of the depth of tumor invasion was calculated as the cutoff depth, above which the incidence of nodal metastasis increases to 75% and 66.66%, respectively.
Clinical significance: Depth of tumor is an important prognostic indicator in the tongue and buccal mucosa carcinoma to know the cervical nodal metastasis. Hence for an increase in depth of tumor cases, neck must be addressed along with primary tumor excision. Radiological investigations [ultrasonography (USG), magnetic resonance imaging (MRI), computed tomography (CT) scan] play an important role in nodal metastasis detection hence should be considered in carcinoma of the oral tongue and buccal mucosa especially in clinically N0 neck.
Keywords: Buccal mucosa carcinoma, Depth of tumor, Nodal metastasis, Tongue carcinoma..
In Asia, head and neck cancer is considered the most common neoplasm and it is the 5th most common cancer in the world.1 In both developed and developing countries, cancer is a major cause of mortality and morbidity.2 In India, 4 in 10 of all cancers are oral cancers as it is the most common cancer.3 In the developed world, tongue and floor of mouth cancers were common while gingivobuccal cancers were the most common oral cavity cancers in India. However, the incidence of oral tongue cancers has been increasing in India and today it is as common as gingivobuccal cancers in most cancer registries in India.4 In head and neck carcinoma, cervical lymph node metastasis is the most important prognostic factor. As cancer grows, they invade the surrounding tissue and metastasize to cervical lymph nodes due to the rich lymphatic system in the neck.5–8 Currently, tumor thickness is considered as a factor for doing adjuvant neck dissection in oral cavity cancers.9 So many times these tumor thickness and depth of invasion are used synonymously but in reality, both are different and should be clearly differentiated.10–16
“Tumor thickness” is the thickness of the entire tumor mass.
There are so many studies that have found a significant correlation between depth of invasion and cervical nodal metastasis, we also planned to conduct a similar study in our institute to find whether a similar correlation exists or not.
AIMS AND OBJECTIVES
- To study the depth of tumor invasion in an oral tongue and buccal mucosa carcinoma and its correlation with neck metastasis.
- To know whether the increase in depth of tumor increases the chances of cervical nodal metastasis in the oral (tongue and buccal mucosa) carcinoma and derive cutoff value of depth of invasion at which the metastasis occurs.
We conclude our study by saying that in the (tongue and buccal mucosa) carcinoma, depth of tumor (depth of invasion) is an important prognostic indicator.
As the depth of tumor invasion increases chances of cervical lymph node metastasis increases significantly.
For oral tongue 8 mm and for buccal mucosa, 10 mm of the depth of tumor invasion was calculated as the cutoff depth, above which incidence of nodal metastasis increases to 75% and 66.66%, respectively.
Hence, the neck in these patients must be addressed along with primary tumor excision.
Radiological investigations [ultrasonography (USG), magnetic resonance imaging (MRI), computed tomography (CT) scan] play an important role in nodal metastasis detection hence should be considered in carcinoma of the oral (tongue and buccal mucosa) especially in clinically N0 neck.
The study was carried out on 14 tongue and 22 buccal mucosa cases coming to the ENT department of the tertiary care center and who underwent surgery to know the correlation between the depth of the invasion and neck node metastasis in the oral (tongue and buccal mucosa) carcinoma. The lymph nodes were considered metastatic or positive histologically only.
All the patients presenting with ulcer or growth on the tongue and buccal mucosa were examined in ENT OPD.
From September 2015 to November 2016.
The sample size was calculated using openepi version 2.
- P = prevalence = 9.9% = 0.099
- q = (1 − p) = 0.901
- l = 10% = 0.1
(*National Cancer Registry Programme, ICMR: 3-year report of PBCRs 2006–2008.)
Sample size of 34 is calculated using openepi version 2.
Descriptive analysis and Chi-square test.
- All patients with biopsy-proven oral (tongue and buccal mucosa squamous cell) carcinoma operated in the ENT department of our institute.
- Patient with an ulcer over the tongue and buccal mucosa but biopsy negative.
- Patients with non-squamous cell carcinoma of tongue and buccal mucosa.
- Patients with a traumatic ulcer over the tongue.
- Patient with advanced stage making it inoperable.
- Patients with biopsy-proven oral cavity carcinoma except for tongue and buccal mucosa.
- Patients with tongue and buccal mucosa carcinoma previously treated with chemotherapy or radiotherapy.
- Patients with residual or recurrent lesions of squamous cell carcinoma of the oral tongue and buccal mucosa.
Depth of tumor invasion (DOI) is a strong predictor for cervical lymph node involvement in squamous cell carcinoma of the oral cavity but the precise cutoff point is still variable. Two of the most important variable for neck metastasis are depth of invasion histologically and tumor thickness. Thickness measurement: Moore et al.17 explained the difference between the depth of invasion and tumor thickness (Figs 5 to 8).
Depth of Invasion18
Depth of invasion is the extent of cancer growth into the tissue beneath an epithelial surface. In cases, if epithelium is destroyed, some investigators reconstruct a surface line and measure it from this line.
Tumor thickness means entire tumor mass and it is measured by using an ocular micrometer.18 Tumor thickness is used for the measurement of a tumor’s vertical bulk and it includes both the exophytic and endophytic portions of the tumor.19
There is a big difference in the concept of tumor thickness, e.g., by Giacomarra et al.,20 who says that “tumor thickness is commonly used as a synonym of depth of invasion and it shows the part of the tumor which is under the line of the basal membrane” compared with authors who adopted the technique proposed by Breslow,21 which measures tumor thickness from either the tumor surface or from the base of the ulcer. Moore et al. reported about the reconstruction of a “normal mucosal line” as the basement membrane line in case of both exophytic and/or verrucous tumors. Ambrosch et al. and Woolgar et al.22 both used techniques based on the “normal mucosal line”. Ambrosch et al. interpreted it as the basement membrane line, whereas Woolgar et al. used the surface line of the surrounding healthy mucosa.18
Hoçal et al. reported that patients having a tumor depth of %3C;9 mm showed significantly better outcome than those whose depth was %3E;9 mm (p < 0.05) and so tumor depth should always be taken into consideration while deciding on neck management.23
Ambrosch et al. reported that tumor depth has a strong correlation with node metastasis. Their study showed that 2 mm depth was a valuable threshold for determining the risk of nodal metastasis.24 Shah et al. reported that there is a 50% rate of node metastasis when tumor depth is between 2 mm and 9 mm.25
Fukano et al. did a study on 34 cases with a cutoff value of DOI as 5 mm. The nodal metastatic rate was 64.7% with DOI >5 mm as compared to 5.9% for DOI <5 mm. Hence, elective neck dissection is strongly indicated for DOI >5 mm.12
Yuen et al. also suggested tumor thickness was the only significant factor for the prediction of local recurrence, nodal metastasis, and survival and proved the cutoff value for DOI as 3 mm.26
For DOI >8 mm in carcinoma oral tongue cases, the cervical nodal metastasis rate (pN+) was found to be 75% while for DOI >10 mm in carcinoma buccal mucosa, cervical nodal metastasis rate (pN+) was 66.66%.
A similar study was published by Samanta, Surendra Nath Senapati, and Ashish Upadhyaya in the Journal of Clinical Oncology at ASCO annual meeting in 2016. In this study for DOI >6 mm in carcinoma tongue cases, cervical nodal metastasis rate (pN+) was 73.68% while for DOI >8 mm in carcinoma buccal mucosa cases, cervical nodal metastasis rate (pN+) was 62.79%.27 This is comparable to our study.
Although we faced the problem of small sample size, our study also found a significant cutoff for tongue and buccal mucosa carcinoma and so we suggest END at depth 8 and 10 mm for tongue and buccal mucosa carcinoma, respectively.
Depth of tumor invasion is a more important parameter than tumor thickness per se, as in exophytic growth the tumor spreads in the available space which does not affect the normal anatomy much, whereas in endophytic growth the tumor cells replace the normal cells or displace them to make space for rapidly progressing mitosis of tumor cells. Therefore, we must measure the depth of tumor invasion rather than tumor thickness before deciding for performing elective neck dissection.
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