Cervical lymph node metastasis in oral cancer: the importance of even microscopic extracapsular spread
Introduction
The presence of cervical lymph node metastasis is universally accepted as the main factor influencing survival in patients with squamous cell carcinoma of the oral and oropharyngeal mucosa (OSCC). In recent years, extranodal extension (extracapsular spread) of the metastatic tumour has been reported as a major prognostic factor by several independent workers [1], [2], [3], [4], [5], [6], [7]. In a previous study [8], we reported a 21% 5-year actuarial survival probability for patients with extracapsular spread (ECS) compared with a 64% survival probability for patients with intranodal metastases. Despite the strong, independent evidence, extranodal spread was only recorded as having controversial significance in a recent Medline review of the reliability and utility of prognostic factors in head and neck cancer [9]. In contrast, the pathological N stage [10], number and anatomical level of positive nodes were all recorded as having proven significance [9]. The significance of the extent of ECS is another contentious issue, particularly when patients receive post-operative radiotherapy [1], [4], [5], [11], [12], [13], [14], [15]. The controversy is compounded by inconsistencies in diagnosing the presence and extent of ECS and the lack of uniform terminology [1], [3], [11], [16]. Since October 1989, all neck dissections from patients treated at the Regional Centre for Maxillofacial Surgery at the University Hospital Aintree, Liverpool, UK, have been reported by a single pathologist (JAW) who follows the proposals of Carter et al. [16] and summarises the descriptive account of the extent of ECS as “macroscopic” or “microscopic”. Macroscopic ECS is evident to the naked eye during the laboratory dissection of the resection specimen and later confirmed by histological assessment. Its extent ranges from involvement of the perinodal fibro-adipose tissue to invasion of surrounding structures [16], [17]. Microscopic ECS is not suspected during the laboratory dissection and is only evident on histologic assessment [16]. It is almost always limited to the immediate perinodal fibro-adipose tissue [17]. The main purpose of the present study is to investigate the prognostic significance of only microscopic ECS. In addition, we will explore the relationship between ECS and the other more traditional histologic measures of the extent of nodal disease (number and size of metastatic nodes) that form the basis of the current UICC staging system [10] as well as clinical and histologic features of the primary tumour, and determine their relative prognostic significance.
Section snippets
Surgical cases
A series of 173 consecutive patients undergoing surgery as the primary treatment for OSCC at the Regional Centre for Maxillofacial Surgery, University Hospital Aintree, Liverpool, UK, between October 1989 and December 1999, and found on histological assessment of the resection specimen to have cervical lymph node metastasis, formed the material for the study. None of the patients had received pre-operative radiotherapy, chemotherapy or previous oro-maxillofacial surgery, other than routine
Histological findings
The pathological T stage [10] was pT1 in 20 cases (12%), pT2 in 50 (29%), pT3 in 17 (10%) and pT4 in the remaining 86 cases (50%). The resection margins were clear in 60 cases (35%), close in 87 (50%) and involved in the remaining 26 cases (15%).
An average of 48 lymph nodes was examined in the radical neck dissections, 40 nodes in the modified level I–V procedures and 25 nodes in selective level I–III/IV procedures. Twenty-eight of the 173 patients (16%) had bilateral positive nodes. Hence, 201
Discussion
The present study provides additional strong evidence of the prognostic significance of ECS in the survival of patients with cervical lymph node metastases from OSCC. Our results clearly show the importance of even microscopic ECS. Although patients with obvious macroscopic ECS die more quickly, the outcome by three years after surgery is exactly the same despite the use of post-operative radiotherapy. The Cox regression shows that ECS is a more important predictor than the nodal features of
References (30)
- et al.
Correlation between prognosis and degree of lymph node involvement in carcinoma of the oral cavity
Am J Surg
(1977) Prognosis in mouth cancertumour factors
Eur J Cancer B Oral Oncol
(1994)- et al.
Survival and patterns of recurrence in 200 oral cancer patients treated by radical surgery and neck dissection
Oral Oncol
(1999) - et al.
Surfing prognostic factors in head and neck cancer at the Millennium
Oral Oncol
(1999) - et al.
Extracapsular spread in the clinically negative neck (N0)implications and outcome
Otolaryngol Head Neck Surg
(1996) - et al.
Recurrence of carcinoma of the oral cavity, oropharynx and maxillary sinus after radical neck dissection
J Maxillofac Surg
(1985) - et al.
Transcapsular spread of metastatic squamous cell carcinoma from cervical lymph nodes
Am J Surg
(1985) Detailed topography of cervical lymph-node metastases from oral squamous cell carcinoma
Int J Oral Maxillofac Surg
(1997)- et al.
Carcinoma of the oral cavity in patients over 75 years of age
Int J Oral Maxillofac Surg
(1993) - et al.
Evolving role of modifications in neck dissection for oral carcinoma
Brit J Oral Maxillofac Surg
(1995)