Abstract
To determine the prevalence of skip metastases in Oral-squamous-cell-carcinoma (OSCC). This prospective observational study was carried out on 100-cases of biopsy proven OSCC who underwent surgical treatment for the primary tumor along with neck dissection (ND). Data regarding depth of invasion (DOI) by primary tumor, perineural-invasion, lymphovascular-invasion, presence of metastatic-lymph-node (level, size, number and extranodal-extension) were collected from histopathology reports and were analyzed. Out of 100-cases, 73-were-male and 27-were-female. Mean age was 49.5 ± 12.3 years (range 24–4 years). Common subsites of tumor were buccal-mucosa, tongue and lower-alveolus in 40, 37 and 14% respectively. Pathological staging of tumor were stage-I, stage-II, stage-III, stage-IVa and stage-IVb in 22, 14, 25, 22 and 15% cases respectively. Preoperative neck staging was cN0 in 50 necks (47.2%) and cN+ in 56 necks (52.8%). In 100-patients 106-NDs (unilateral-94 and bilateral-6) were performed. Type of NDs were Supraomohyoid, extended-Supraomohyoid and modified radical neck-dissection in 23,07and76 cases respectively. Prevalence of cervical lymph node metastases was 36% (pN + necks). Among 36pN + patients; 25 (69.4%) cases, 20 (55.5%) cases, 9 (25%) cases, 4 (11.1%) cases, 2 (5.5%) cases had metastases to level-I, II, III, IV and V respectively. Skip-metastases was present in four-cases {level-IIb:one-case (2.78%), level-III: two-cases (5.5%) and level-V:one-case (2.78%)}. No-skip-metastasis to level-IV was noticed. All-four-cases of skip-metastases were from advance cases of squamous-cell-carcinoma of tongue with DOI > 5 mm. Skip-metastases to levels IIb, IV and V are uncommon in cases of OSCC. Most of the metastasis in our study was noted to levels I, II and III in a predictable fashion. Thus, extensive ND can be avoided in patients to prevent complications and morbidities associated with the same.
Keywords: Oral-squamous-cell-carcinoma, Neck dissection, Cervical lymph node metastases, Skip metastases, Depth of invasion
Introduction
Oral cavity is considered as one of the common sub-sites for malignancies of the head and neck region over worldwide [1].
In India, cancers of lip and oral cavity account for majority of cancer incidence (16.1%) and mortality (12.3%) in males. Ever growing population, ageing, risk factors like smoking, alcohol, paan chewing and other unhealthy lifestyles along with socio-economic factors have caused oral cavity malignancies to be a major public health problem [2]. Squamous cell carcinoma or one of its variants accounts for more than 90% of all carcinoma of the oral cavity.
Owing to rich lymphatic supply, Oral Squamous Cell Carcinoma (OSCC) is associated with a high risk of cervical nodalmetastasis [3] and this is the most significant prognostic factor, as it is shown to reduce the survival rate by up to 50% [4].
The typical metastatic pattern in oral cavity carcinoma is described as orderly involvement of successive anatomical nodal levels, i.e., “submentalnodes (IA), submandibular nodes(IB), upper jugular nodes (II), middle jugular nodes (III), lower jugular nodes (IV), and posterior cervical nodes (V) [5]. When this is not followed, and if metastases are noted at a higher nodal level without involving “the first echelon node” or any of the intermediary lymph node group, it is termed as “skip metastasis”.
The proper knowledge of skip metastases helps the surgeon to plan an appropriate management strategy with regards to neck dissection (ND) and avoid incomplete clearance of disease [6, 7].
Oral cavity malignancies are managed primarily by a surgical intervention, followed by adjuvant therapy that consists of chemoradiation or radiotherapy alone. The decision-making depends upon postoperative histopathological characteristics such as depth of invasion, nodal involvement, extranodal extension and involvement of margins.
Therefore, ND plays a vital role in management of OSCC, both as a part of primary surgery, and determining the need for adjuvant therapy. In addition, determining the level of nodal metastases, and skip metastases in particular, may help curtail the extent of ND and associated morbidity, at the same time, maximize locoregional control and overall survival.
Most of the studies which had been done previously on similar context were retrospective in nature and they had dealt with only a single subsite of oral cavity, commonly the tongue. Thus, this prospective study was conducted to analyze the different patterns and prevalence of cervical lymph node metastases with special attention to skip metastases to levels IIb, IV and V lymph nodes, in 100 consecutive patients with carcinoma of all subsites of the oral cavity. We have also made efforts to identify factors which predict metastases, so that management strategies pertaining to extent of neck dissections can be optimized in the future.
Materials and Methods
This was a prospective observational study which included 100 previously untreated, biopsy proven cases of OSCC, from September 2018 through May 2020 who had undergonesurgical treatment, consisting of excision of primary lesion and ND. The study was undertaken according to the Ethical principles as stated by World Medical Association Declaration of Helsinki (version 2002). The research protocol was approved by the Institutional Ethics Committee. Patients with any previous history of recurrent cancer, loco-regionally advanced, inoperable disease, and those who were previously treated with surgery, radiation therapy or chemotherapy, were excluded from this study.
Patients who fulfilled the inclusion criteria were recruited into this study after getting their written informed consent.
The selected patients were initially subjected to detailed history taking, systemic and local clinical examination. Appropriate investigations, including hematological, biochemical, radiological like ultrasonography, contrast enhanced computerized tomography and magnetic resonance imaging of neck as indicated and histopathological investigations were carried out for definitive diagnosis, assessment of neck node status, metastasis workup and staging of the disease. Clinical TNM staging was done according to the American Joint Committee on Cancer—8th edition classifications and as per staging of the disease, surgical management was planned.
The surgical approach to the primary site of tumour in the oral cavity was based on the size, location, and associated involvement of any adjacent anatomical subsite relative to the tumor’s presentation. Limited (T1) primary lesions were resected trans-orally.
All patients with N0 necks except for carcinoma of tongue were subjected to a selective ND like Supra-Omohyoid neck dissection (levels I–III). Patients with N+ necks and carcinoma of tongue underwent a modified radical neck dissection. Bilateral NDs were performed for patients with bilateral/contra-lateral nodal metastases or when the disease was extensive and reaching up to or crossing the midline.
The excised tumour specimen and dissected out neck nodes (each anatomical level separately), were sent for detailed histopathological examination. The depth of invasion(DOI) by the primary tumour, the status of the resected margin, perineural invasion(PNI), lymphovascular invasion(LVI) and individual level-wise involvement of lymph node (site, size, number and extracapsular spread) were recorded from the histopathology report. After detailed histopathological examination the final report was analyzed and entered in Excel sheet.
The patients were followed up in the outpatient department for the initiation of postoperative chemotherapy or radiotherapy if required.
Statistical Analysis
Statistical analysis was done using IBM-SPSS (International Business Machines corporation- Statistical Package for the Social Sciences) version 20.
The continuous variables were expressed as mean ± standard deviation. Categorical variables were summarized using percentage. Chi-square test was used to compare the baseline characteristics and outcome in the study population. For all statistical tests a p-value of < 0.05 was considered statistically significant.
Results
The study included a total of 100 cases who received primary surgical treatment. The mean age of the study population was 49.5(± 12.3) years, ranging from 24 to 74 years. Out of 100 patients majority (73%) were males. Left sided lesions were found to be more common, and among the subsites, buccal mucosa followed by tongue, were the most frequently involved. The clinicopathological characteristics of patients have been listed in Table 1.
Table 1.
Summary of clinicopathological characteristics of study population
| Characteristics | Number of patients (n/%) |
|---|---|
| Age (years) | |
| Mean age (mean ± SD) | 49.5 ± 12.3 |
| Range (years) | 24–74 |
| Gender | |
| Male | 73 (73%) |
| Female | 27 (27%) |
| Chief complaints | |
| Oral ulcer | 100 (100%) |
| Dysphagia | 35(35%) |
| Bleeding | 16 (16%) |
| Trismus | 16 (16%) |
| Weight loss | 2 (2%) |
| Duration of symptoms (months) | |
| Mean duration (mean ± SD) | 7.8 ± 6.7 |
| Range (months) | 1–36 |
| Comorbidities | |
| Healthy | 74 (74%) |
| Diabetes mellitus | 14 (14%) |
| Hypertension | 12 (12%) |
| Chronic obstructive pulmonary disease | 1 (1%) |
| Coronary artery disease | 2 (2%) |
| Hypothyroidism | 3 (3%) |
| Sickle cell disease | 1 (1%) |
| Addictions | |
| No addiction | 17 (17%) |
| Tobacco chewing | 68 (68%) |
| Tobacco smoking | 2 (2%) |
| Both Tobacco chewing and smoking | 12 (12%) |
| Alcohol | 2 (2%) |
| Laterality of the lesion | |
| Left | 63 (63%) |
| Right | 37 (37%) |
| Subsites | |
| Tongue | 37 (37%) |
| Buccal mucosa | 40 (40%) |
| Lip | 4 (4%) |
| Upper alveolus | 3 (3%) |
| Lower alveolus | 14 (14%) |
| Hard palate | 1 (1%) |
| Retromolar trigone | 1 (1%) |
| Clinical TNM staging | |
| I | 13 (13%) |
| II | 21 (21%) |
| III | 23 (23%) |
| IVa | 43 (43%) |
| Neck dissection | |
| Unilateral:94 | |
| Modified radical neck dissection (MRND)—III* | 37 |
| MRND—II** | 31 |
| Supra-omohyoid neck dissection (SOND) | 19 |
| Extended SOND | 7 |
| Bilateral:6 | |
| MRND—III + SOND | 3 |
| MRND—II + SOND | 1 |
| Bilateral MRND—III | 1 |
| MRND—II + MRND—III | 1 |
*Preservation of spinal accessory nerve, internal jugular vein and sternocleidomastoid muscle
**Preservation of spinal accessory nerve and internal jugular vein
There were 57 patients who had required a flap reconstruction during their surgery. Local rotation flaps, pedicled flaps and free flaps had been used as and when indicated. Out of these, the most commonly used flap was observed to be Pectoralis major myocutaneous flap (PMMC), in 21 patients, followed by nasolabial flap in 17 patients.
Postoperative Analysis of Histopathology Reports
Characteristics of Primary Tumour Specimen
The histopathological characteristics of primary tumour specimen are summarised in Table 2.
Table 2.
Histopathological characteristics of primary tumours
| Characteristics | Number of patients (n/%) |
|---|---|
| 1. Degree of differentiation | |
| Well differentiated carcinoma | 75 |
| Moderately differentiated carcinoma | 23 |
| Poorly differentiated carcinoma | 2 |
| 2. Depth of invasion | |
| < 5 mm | 38 |
| 5–10 mm | 26 |
| > 10 mm | 36 |
| 3. Underlying bone involved | 18 |
| 4. Perineural invasion (PNI) | 30 |
| 5. Lymphovascular invasion (LVI) | 14 |
Characteristics of Regional Lymph Nodes
In 100 patients enrolled in our study, 106 neck dissections had been performed, since 6 patients had undergone bilateral neck dissection. In total of 106 operated necks 50 (47.2%) were preoperatively staged N0 and 56 (52.8%) had been staged cN+. Of all the neck node dissection specimens, 36 (33.9%) were seen to be in pN+ group after histopathological evaluation. Of these 36 pN+ necks, 10 had been preoperatively staged as N0. Thus rate of occult metastasis in our study was 10%.
Among 36 patients who were pN+ in the study, lymph node which was most commonly involved by the tumour was observed to be Level Ib, which was the sole lymph node level involved in 7 cases (19.4%), and along with other lymph node levels in 16 other cases (44.4%). Isolated involvement of level IIb lymph node without any associated metastases was seen only in one case (2.78%) and this was considered for analysis of skip metastases. There were three other cases (8.3%) which had IIb involvement, of which two (5.5%) cases had associated Ib involvement and one case (2.78%) had associated Ib and IIa involvement. Isolated involvement of level III lymph nodes were seen in 2 cases (5.5%). It was seen to be involved along with other lymph node levels in 7 (19.4%) other cases.
There were only four cases (11.1%) with pN (+) in level IV lymph nodes, all of which had associated lymph nodes involvement.
Only two cases (5.5%) among 36 patients had positive nodes at level V. One (2.7%) of them showed isolated skip metastasis to this level without involvement of any other levels. The other case also had positive nodes at level Ib and III lymph node levels (Table 3). Among 36 pN+ cases, 17 cases (42.2%) had extranodal extension.
Table 3.
Levels of pathological lymph node involvement
| Nodes involved | Number of cases (n/%) |
|---|---|
| 1. Single level lymph node involvement | |
| Ia | 1 (2.78%) |
| Ib | 7 (19.44%) |
| IIa | 3 (8.33%) |
| IIb | 1 (2.78%)* |
| III | 2 (5.56%)* |
| IV | 0 (0%) |
| V | 1 (2.78%)* |
| 2. Multiple level lymph node involvement | |
| Ia + Ib | 2 (5.56%) |
| Ia + IIa | 1 (2.78%) |
| Ia + Ib + IIa | 1 (2.78%) |
| Ia + Ib + IIa + III + IV | 1 (2.78%) |
| Ib + IIa | 5 (13.89%) |
| Ib + IV | 1 (2.78%) |
| Ib + IIb | 2 (5.56%) |
| Ib + III | 1 (2.78%) |
| Ib + III + V | 1 (2.78%) |
| Ib + IIa + III | 1 (2.78%) |
| Ib + IIa + IIb | 1 (2.78%) |
| IIa + III | 2 (5.56%) |
| IIa + IV | 1 (2.78%) |
| IIa + III + IV | 1 (2.78%) |
| 3. Extranodal extension | 17(42.2%) |
*Cases with skip metastasis
On analysing the various pathological stage groups based on subsite, we found that the common sites of involvement were buccal mucosa, tongue and lower alveolus in decreasing order of incidence (Table 4).
Table 4.
Pathological stage grouping based on subsites
| Oral cavity subsites | Number of cases (%) | Stage-I (TNM) | Stage-II (TNM) | Stage-III (TNM) | Stage-IVa (TNM) | Stage IVb (TNM) |
|---|---|---|---|---|---|---|
| Buccal Mucosa | 40 (40%) | 10 (25%) | 5 (12.5%) | 10 25%) | 11 (27.5%) | 4 (10%) |
| Tongue | 37 (37%) | 7 (18.9%) | 7 (18.9%) | 12 (32.4%) | 3 (8.1%) | 8 (21.6%) |
| Lower Alveolus | 14 (14%) | 1 (7.1%) | 3 (21.4%) | 1 (7.1%) | 6 (42.8%) | 3 (21.4%) |
| Lower Lip | 4 (4%) | 3 (75%) | 0 | 1 (25%) | 0 | 0 |
| Upper Alveolus | 3 (3%) | 0 | 1 (33.3%) | 1 (33.3%) | 1 (33.3%) | 0 |
| Hard Palate | 1 (1%) | 0 | 0 | 0 | 1 (100%) | 0 |
| Retromolar trigone | 1 (1%) | 1 (100%) | 0 | 0 | 0 | 0 |
| Total | 100 | 22 | 16 | 25 | 22 | 15 |
Skip Metastases
The prevalence of skip metastases was 4% and the primary site was tongue in all the cases. The analysis of cases with skip metastases is depicted in detail in Table 5.
Table 5.
Analysis of cases with skip metastases
| Total number of skip metastasis | 4 | |
|---|---|---|
| Level of Skip metas*tasis | IIb | 1 (25%) |
| III | 2 (50%) | |
| IV | 0 | |
| V | 1 (25%) | |
| Age | Mean (years) | 43.5 |
| Standard deviation | 13.7 | |
| Range (years) | 30–62 | |
| Gender | Male | 3 (75%) |
| Female | 1 (25%) | |
| Site of lesion | Tongue | 4 (100%) |
| BM | 0 | |
| LIP | 0 | |
| Upper alveolus | 0 | |
| Lower alveolus | 0 | |
| Hard Palate | 0 | |
| RMT | 0 | |
| Grade of tumour | Well differentiated | 3 (75%) |
| Moderately differentiated | 1 (25%) | |
| Poorly differentiated | 0 | |
| Depth of invasion | < 5 mm | 0 |
| 5–10 mm | 2 (50%) | |
| > 10 mm | 2 (50%) | |
| PNI | Present | 2 (50%) |
| Absent | 2 (50%) | |
| LVI | Present | 0 |
| Absent | 4 (100%) | |
| ENE | Present | 2 (50%) |
| Absent | 2 (50%) | |
| Pathological staging | I | 0 |
| II | 0 | |
| III | 2 (50%) | |
| IVa | 1 (25%) | |
| IVb | 1 (25%) | |
Discussion
In OSCC, neck metastasis is considered as the prime determinant of prognosisand also plays a major role in decision making for adjuvant therapy. The cervical nodal metastases usually follow a predictable pattern to neck nodal levels I to V. In some cases, there occur normal anatomic lymphatic channels which may bypass this orderly pattern of cervical nodal spread, wherein the lower nodal stations may be involved without involving the preceding nodal levels. This is termed as skip metastases.
Knowledge regarding pattern of lymphatics spread allows for modifications of neck dissection, wherein there is lesser postoperative morbidity while preserving the oncological outcomes.
In this study, we have attempted to demonstrate the patterns and prevalence of cervical lymph node metastases in OSCC with special reference to skip metastases to levels IIb, IV and V lymph nodes, which were usually not addressed in selective neck dissection.
A total of 100 patients had been included in the study and each one had undergone a neck dissection along with excision of primary with or without reconstruction.
Nineteen out of 100 patients (19%) underwent SOND (Levels Ia, Ib, IIa, IIb, III). Seven patients underwent extended SOND (7%). Sixty eight (68%) patients had undergone MRND. 6 (6%) patients had undergone bilateral neck dissection. The bilateral neck was addressed in cases where the lesion was extending upto or beyond midline as in carcinoma tongue, or when a clinically palpable node was found over the opposite side.
Thus in 100 patients 106 neck dissection had been performed. In total 50 necks (47.2%) of 106 dissections performed had been preoperatively categorised as N0. Fifty six (52.8%) were staged cN+. Of all the neck dissection specimens, 36 (33.9%) cases were noticed to be pN+ on histopathological evaluation in post-op period. Of the 36 pN+ necks, 10 cases had been N0 preoperatively, and this accounts for the occult metastases rate.
Among 36 patients who had positive neck nodes, 25 (69.4%) cases had metastases to level I lymph nodes. 20 (55.5%) cases had metastasised to Level II lymph nodes, 9 25%) cases to level III, 4 (11.1%) cases to level IV and 2 (5.5%) cases to level V lymph nodes and these are comparable to observations made in previous studies [8–10].
Considering individual lymph nodes into account in our study, the most commonly involved by the tumour was observed to be Level Ib, which was involved in 23 cases (63.8%)), followed by level IIa which showed positive nodes in a total of 17 cases (42%).
In the present study, the overall rate of neck metastases was 36%. This was also consistent with the older studies [9, 11–13].
The primary subsites from which nodal metastases had been observed in our study were tongue in 16 cases, buccal mucosa in 13 cases and lower alveolus in 7 cases. A similar study by DeSilva et al. [14] also showed that a significantly higher proportion of nodal metastasis was observed in tongue cancers than in buccal mucosa cancers. Anatomically, the tongue is situated over the floor of the oral cavity and this area is characterized by rich lymphovascular supply in comparison to buccal mucosa, or any other subsites in the oral cavity. Moreover, due to its high vascular nature, mobility, and free communication with the lymphatics on the contralateral side, SCC of tongue is prone to metastasize early.
Skip Metastasis to Level IIb
Among 36 cases of pathologically positive nodal metastases, four were cases of skip metastases. Skip metastasis to Level IIb was seen only in one case (2.78%). According to previous studies [8, 15–18] isolated metastasis to level IIb had been rare and mostly associated with involvement of adjacent nodes.
Skip Metastasis to Level III
Skip metastasis to level III lymph nodes were seen in 2 cases (5.5%). The reported incidence of skip metastasis to Level III varies from 3.3 to 3.8% and they were mostly reported in cases of tongue carcinoma [9, 12, 15, 17, 19].
Skip Metastasis to Level IV
Considering Level IV lymph nodes in our series, there were only four cases (11.1%) with nodal metastases. No isolated skip metastasis to this level was noted. This observation is consistent with most of the studies which had been done to assess metastasis especially at level IV. As reported by Iqbal et al. [20] a total of 14 (7.6%) patients had metastases in level IV but no isolated involvement was seen. Other studies also failed to report any isolated skip metastasis to Level IV [8, 9, 17]. Though we were unable to find any skip metastases to level IV, many authors have reported very high rate of skip metastases to level IV ranging from 0.9% to 15.8% [7, 12, 19, 21, 22]. Most of these studies had observed tongue to be the primary site of tumour.
In Byers et al. [7] retrospective study 15.8% had either level IV metastasis as the only manifestation of disease in the neck or the level III node was the only node present without disease in level I–II.
Skip Metastasis to Level V
In our study, only two cases among 36 patients (5.5%) had positive nodes at level V. One (2.7%) of them showed isolated skip metastasis to this level without involvement of any other levels. The other case also had positive nodes at level Ib and III lymph node levels. Haranadh et al. [8] had reported one case of skip metastasis to level V, from a buccal mucosa lesion. Lim et al. [16] and Pantvaidya et al. [17] had showed incidence of nodal metastases to Level V in their studies (5 and 3.3% respectively) but there were no reported cases of isolated skip metastasis to this nodal level in their series. But Dias et al. [7] in their retrospective study found that 2% of their patients had skip metastasis to level V.
Haranadh et al. [8] reported that there was no statistically significant association between the nodal positivity in any level and any of the factors such as depth of invasion, grade of the tumour and presence of perineural invasion and our study is in accordance with this observation. The level IIB involvement in their study was significantly associated with the presence of lymphovascular space invasion at the primary site and a significant correlation was seen between level V involvement and clinical T staging.
Assessment of depth of invasion in our cases showed that 50% cases with skip metastasis had a value which lied between 5 and 10 mm and in the rest (50%) DOI was more than 10 mm. Studies on DOI and tumour thickness as independent predictive factors for skip metastases had been performed by Byers et al. [7] and Rastogi et al. [19] and they had found that strong association exists between tumor sizes, tumor thickness, and skip metastasis with the help of logistic regression models for multivariate analysis.
From this study, we were thus able to observe that lymph node metastases from OSCC usually follows a predictable pattern of spread with involvement of Levels I, II, III in most cases. Overall incidence of skip metastasis was 4% in 100 cases. This is in accordance with findings made by previous studies.
Level II LNs are located in and around the upper third of the internal jugular vein and share a close relationship with the spinal accessory nerve as it crosses this lymph node level obliquely, dividing it into anteroinferior and posterosuperolateral parts, the latter of which has been termed as sublevel IIB. Dissection over this surgical area is likely to cause injury to the nerve resulting in “shoulder syndrome”. The dissection of the stage IV node station or the lower jugular group is in the lower neck, and it is associated with damage to the lymphatic channels, which may lead to chyle leak in the postoperative period in some patients. “Postoperative shoulder dysfunction” is also observed with dissection of level V occurring secondary to traction or with ischemic injury to the spinal accessory nerve.
The observations made by our study will have a definite bearing on the managing cases of OSCC. As we see it in most of the buccal mucosa carcinoma cases, which form the major chunk of our study group, we can safely perform neck dissection without addressing level II B and level V nodes, particularly in early T1-T2 lesions which would clearly help in bringing down the potential threat to the integrity and functionality of spinal accessory nerve. We need to address these levels if there is an evident metastasis to adjacent nodal groups like IIa and III. We also advocate that dissection of the Level IV lymph nodes need to be done if there arises a suspicion intraoperatively regarding involvement of level II and III lymph node groups.
Most of the previous studies had included only clinicoradiologically node negative necks in their study groups [23–25]. Many had studied on heterogeneous sites (oral cavity, oropharynx, larynx etc.) and some of them had included only one subsite in their study (tongue, floor of mouth, buccal mucosa) [24, 26–28]. Main strengths of our study are that this was a prospective one, including consecutive patients of OSCC, irrespective of their clinical nodal status, thus reducing the biases associated with a retrospective study pattern. In this study we had patients with homogeneous site (only oral cavity), and we have taken all the subsites of oral cavity into account. We also have a decently large sample size of 100 patients.
Limitations and Recommendations
Although the total number of patients enrolled in this prospective study had been 100, when it came to analysis of individual subsite of the oral cavity like lip, hard palate and retromolar trigone, it was found that only very few patients had been categorised under them. Thus any observation which has been put forth by the study pertaining to these subsites will not be statistically significant and thus, it cannot by extrapolated to the general population. Also, postoperative complications like shoulder dysfunction and chyle leak, eventually leading to flap failure and wound infection, had not been assessed and analysed in the study. Though patient had been followed up for adjuvant therapy, cervical nodal recurrences, if any, had not been assessed by this study. Thus, we recommend that a larger study, over a longer period of time, with more number of patients in individual subsite groups, covering all the above mentioned limitations encountered, may be conducted to have a better understanding on skip metastases and clinical implication.
Conclusions
The incidence of pathologically positive cervical metastases was 36%. Most common lymph node groups involved by tumour in our cases were levels Ib and IIa. There were only four (4%) cases of skip metastasis observed, and these were to levels IIb in one case, Level III in 2 cases and Level V in one case. No skip metastasis was seen to level IV in any case and these findings were in concordance with previous studies. All the cases of skip metastasis were from primary subsite in tongue. There were a total of 37 cases of tongue carcinoma among 100 patients and thus 4 (10.8%) among them had skip metastasis. Since most of the metastasis from oral cavity carcinoma in our study was noted to levels I, II and III in a predictable fashion as earlier observed, we suggest that one can avoid dissection of level IIB, IV and V to prevent associated complications and morbidity to the patient. These levels should be addressed if suspicious nodes are found in adjacent levels of lymph node.
Author’s Contributions
Anupama Giresh-Data collection and analysis, writing the manuscript and approving the final draft of manuscript. Pradipta Kumar Parida: Study design, Data collection and analysis, writing the manuscript and approving the final draft of manuscript. Chapity Preetam: Study design,Data collection and analysis, writing the manuscript and approving the final draft of manuscript. Amit Kumar Adhya: Study design,Data collection and analysis, writing the manuscript and approving the final draft of manuscript. Pradeep Pradhan: Study design, Data collection and analysis, writing the manuscript and approving the final draft of manuscript.
Funding
Nil.
Declarations
Conflict of interest
The authors declare that they have no conflict of interest.
Footnotes
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