Pattern of Neck Node Metastasis in Laryngeal Carcinoma

Background: Cancer continues to be a major health problem despite advances in medical technology for its diagnosis and treatment. Cancer of the larynx is the eleventh most common cancer in the world. Carcinoma larynx is a multifactorial disease. Smoking, betel-nut, betel-leaf chewing habit and drinking alcohol are the most important factors associated with carcinoma larynx. Objective: To detect the rate and level of cervical lymph node metastasis in laryngeal carcinoma. Methods: Detailed information was obtained in each cases according to protocol. Complete history was taken from accompanying attendants. Thorough clinical examination was done. All the information’s were recorded in the fixed protocol. Patients were randomly assigned to one of three groups by card sampling. Collected data were classified, edited, coded and entered into the computer for statistical analysis by using updated computerized program SPSS-19. Results: Out of 50 cases the mean average age was found 58.5±11.9 years with range from 39 to 78 years. Majority (70.0%) patients presented with supraglottic carcinoma followed by 13(26.0%) glottic carcinoma and 2(4.0%) subglottic carcinoma. More than three fourth (78.0%) patients had difficulty in swallowing followed by 17(34.0%) had hoarseness of voice, 12(24.0%) had discomfort in throat, 10(20.0%) had earache, 6(12.0%) had hemoptysis and 4(8.0%) had cough. Majority (42.0%) patients were found N 0 followed by 15(30.0%) N1, 13(26.0%) N2 and 1(2.0%) N3 of neck node. Majority (42.0%) patients was found in stage T3 followed by 7(14.0%) in stage T1, 18(36.0%) in stage T2 and 4(8.0%) in stage T4. Majority (56.0%) patients was found in level-II of neck nodes followed by 12(24.0%) level III, 4(8.0%) level IV, 3(6.0%) level II+III, 2(4.0%) level III+IV and 1(2.0%) level III+IV+V of neck nodes. Conclusion: Laryngeal carcinoma is a common clinical entity in otolaryngology practice. Male were more predominant and the highest age group was 51-60 years. In our study most common Laryngeal carcinoma was supraglottic in nature. T3 was the commonest stage of involvement. Common clinical presentation was difficulty in swallowing and hoarseness of voice. N 0 and N1 was the most common pattern of neck node metastasis. In our series majority of them were in level II. 1. Classified ENT Specialist & Head-Neck Surgeon,Combined Military Hospital, Jashore Cantonment. 2. Department of Radiology & Imaging, SSMC & Mitford Hospital, Dhaka. 3. Associate Professor, Department of Otolaryngology-Head & Neck Surgery, BSMMU, Dhaka. 4. Associate Professor, Department of Otolaryngology-Head & Neck Surgery, BSMMU, Dhaka. 5. Associate Professor, Department of Otolaryngology-Head & Neck Surgery, BSMMU, Dhaka. 6. Chairman, Department of Otolaryngology-Head & Neck Surgery, BSMMU, Dhaka. Correspondents: Dr. Md. Momin Uddin, Classified ENT Specialist & Head-Neck Surgeon,Combined Military Hospital, Jashore Cantonment


Introduction
Laryngeal carcinoma is the most common head and neck cancer worldwide 1 . It constitutes 0.2% to 1.3% among all malignancies 2 . In UK it has an incidence of 2.9 per 10,0000 people 3 . Laryngeal cancer is more common in male than in women. 3 About 40% of all laryngeal cancer in UK and 30% in north America are supraglottic. Conversely in North America 60% laryngeal carcinoma are glottic and in France it is about 61%. 4 But in our subcontinent supraglottic carcinoma outnumbers glottic carcinoma. In India supraglottic carcinoma is about 57%, glottic carcinoma 39%, subglottic carcinoma is only about 6%. 2 In Bangladeshi study it is found that out of 50 histopathologically proven laryngeal carcinoma 60% laryngeal carcinoma patients presented with regional metastases to the cervical nodes. Highest cases among laryngeal carcinoma were supraglottic carcinoma (72.0%) which also showed the highest rate of lymph node metastases (72.2%). 5 Smoking, alcohol consumption, chewing tobacco, genetic factors, occupational factors, vitamin deficiency is the well known causative factors of laryngeal carcinoma. 6 Male are predominant and common age of presentation over 40 years. 4 Laryngeal carcinoma has high rate of cure in certain sub sites and early stage, may reach over 85% and overall exceeds 50%. Most of the failures in the treatment of laryngeal cancer are due to the delay in diagnosis can contribute to the presentation with later stage diseases and difficulty in eradicating the loco regional disease. 7 A common phenomenon to all malignancy is their ability to metastasize. Patho-physiology of this phenomenon has been the subject of much research & investigation. 2,8 Some tumours have the propensity to extensive local invasion without metastasis, whereas others metastasize early in their development. 3,9 With the exception of distant metastasis, the presence of cervical lymph node metastasis is the single most adverse independent prognostic factor in laryngeal carcinoma. 4,10 The highest incidence of cervical lymph node metastasis is associated with supraglottic carcinoma in comparison to glottic and subglottic carcinoma. Cases with bilateral neck nodes are uncommon. Supraglottic larynx is one of the most common primary site for bilateral neck nodes metastasis. 3,11 A single ipsilateral cervical lymph node metastasis decreases survival by 50% than that of the patients without metastasis. Nodal metastasis are also associated with a high rate of regional recurrence. 12 So, early treatment of the primary tumour as well as lymph nodes is essential for good locoregional control & reduction of distant metastasis & improved survival.
Historically, case can be identified by taking comprehensive history & detail clinical examination. However, further evaluation by fine needle aspiration cytology (FNAC), imaging studies, endoscopy & biopsy is required for confirmative diagnosis and effective management.
This prospective study is designed to find out the pattern of neck node metastasis associated with laryngeal carcinoma and their clinical staging. Laryngeal cancer like all other head and neck cancer are best treated by multidisciplinary approach. Neck node metastasis dictates clinical staging and treatment of the disease. Selective neck dissection is commonly performed for the management of the node negative patients. Positive neck node disease is also treated by comprehensive neck dissection. The major goal of the treatment of cancer of the larynx is to maximize the cure rate while neck dissection ensures survivality and better prognosis of the patients.

Methodology
The prospective cross-sectional clinical study was carried out in the Department of ENT and Head Neck Surgery, Combined Military Hospital, Dhaka from March 2016 to September 2016. All patients of diagnosed as laryngeal carcinoma with neck metastasis were taken as sampling population. Patients/ attendance was briefed about the study and consent was taken. Brief history was taken included with symptoms and risk factors. Relevant physical examination, 12 lead ECG was done on admission and routinely thereafter. Blood glucose level e"11.0 mmol/ l or 198 mg/dl was considered as admission hyperglycemia. Baseline investigations including-cardiac biomarkers, serum creatinine, lipid profile and echocardiography were done for each patient. Collected data were classified, edited, coded and entered into the computer for statistical analysis by using updated computerized program SPSS-19.
It is well known that supraglottis is the commonest site of laryngeal carcinoma in subcontinent. 6 The result of this study also coincides with this fact. Here 72% patients presented with supraglottic carcinoma, 26% with glottic and 2% with subglottic carcinoma. Supraglottic carcinoma is characterized by higher prevalence of regional metastases compared with carcinoma of other laryngeal sites. 18,19 In Ahsan et al. 5  In present study showed that out of 35 supraglotic common primary tumor was T3 14(40%), T2 was 13(37.14%), T1 was 05(14.29%). Out of 13 Glottic, among them majority was found T3 which was 05(38.46%), T2 was found 04(30.77%), T1 was 03(23.08%) and T4 was 1(7.69%). Two patients was found subglottic, among 01(50%) was T2 and 01(50%) was T3. Koirala and Sharma 13 found their study out of total 31 patients of T3 stage, 28 had supraglottic malignancy. Albeit, neck node metastasis is mainly a 'supraglottic issue'. In fact, because of the profuse lymphatic network of the supraglottic larynx, carcinomas of this area metastasize frequently to the cervical lymph nodes, and failure of treatment is usually a result of metastasis rather than local disease. 21,22 The incidence of patients with clinically positive lymph nodes at the time of diagnosis is 23-50% for all supraglottic sites and stages combined. 23,24 A substantial number of those patients with clinically negative necks are found to have histologic disease, as demonstrated when neck dissection is performed, or, if left untreated, they convert to clinically positive necks. 25 In supra-glottic cancers, the probability of cervical metastasis and the probability of delayed contralateral metastasis increase in direct proportion to the size of the primary lesion (i.e., the T stage). 15 16 study 58% (29 cases) were found to be N 0 stageconstituted by 58.3% of the supraglottic lesions, 100% of the glottis lesions and 51.5% of the transglottic lesions. On the other hand, 42% (21 cases) were found to have a clinically positive neck at the time of presentation -47.6% being in N 2 stage, 38.1% in N~ stage and only 14.3% being in N 3 stage. Anicin and Zargi 17 study the regional in-field recurrence rate after selective neck dissections in postoperatively irradiated N2b and N1 cases was 12.5% and 8.3%, respectively.
The highest incidence of malignant cervical lymph node is associated with supraglottic tumour compared to glottic and subglottic carcinoma of larynx. 3 The frequency distribution of supraglottic and glottic carcinoma has got wide geographical variation. 27 In Indian 28 subcontinent, supraglottic area is the commonest site of origin which is about 57% and in UK 27 it is about 40%. On the other hand Glottis is the commnest site in North America (60%) and France (61%). 4 Subglottic carcinoma is rare and least frequent type all over the world with a 5% or less in different series. 4 Like Indian subcontinent, supraglottic carcinoma is the top among the laryngeal carcinomas in Bangladesh. 6 In two different previous studies in Bangladesh, supraglottic cancer was found in 67% 6 , and 70% cases. Since the chance of regional metasteses is more in supraglottic carcinoma and it is the commonest among the laryngeal carcinomas in Bangladesh, metastatic lymph nodes in laryngeal carcinoma is also common in Bangladesh.  (7), T1 (6) and T4 (2) respectively. Pinilla et al. 29 carried out a retrospective study on 430 patients of carcinoma larynx from 1983 to 1993 in Spain.
In their study, 58% of patients were of glottic origin while 42% were of supraglottic origin. T3 stage was the most common category (36%) followed by T4 (35%), T2 (23%) and T1 (6%). There was a direct correlation of tumor size with presence of histological neck node involvement. However Akmansu et al. 14 and Suo et al. 30 reported no significant correlation to exist between T and N stages in laryngeal cancers. Ahsan et al. 5

Conclusion
Laryngeal carcinoma is a common clinical entity in otolaryngology practice. Male were more predominant and the highest age group was 51-60 years. In our study most common Laryngeal carcinoma was supraglottic in nature. T3 was the commonest stage of involvement. Common clinical presentation was difficulty in swallowing and hoarseness of voice. N 0 and N1 was the most common pattern of neck node metastasis. In our series majority of them were in level II.
Early detection and management yield better prognosis. Special emphasis on neck node metastasis in carcinoma larynx is an important determinating factor in treatment modality as well as meaningful outcomes after definitive treatment.