Abstract

Squamous cell carcinoma is the commonest cancer in the head neck. Surgical excision is the treatment of choice and this is in form of a wide excision of primary and a neck dissection followed by an appropriate adjuvant therapy as indicated. The prime goal for any surgical resection is achieving optimum surgical margins. The reason margin is of such importance is because it is the only prognostic factor which is under direct control of the operating surgeon. Resection margin is the cuff of normal tissue around the tumor. Margins are not just limited to circumferential margins but also refer to the deep margin in a three-dimensional tumor. The tumor with its free margins measures the completeness of the surgical resection. Having said that, the distance and histopathological and molecular properties of this normal cuff of tissue is a matter of interest for researchers.

The importance of margin on local recurrence and survival had been analyzed by Loree and strong in their seminal paper. The overall survival being 52% in positive margins as compared to 60% in free margins [1]. The margin cut off was considered as >5 mm to be free. The two important landmark randomized trials by EORTC 22931 and RTOG 9501 found positive margins as one of the most important factors warranting adjuvant chemoradiation. Both the trials defined positive margin differently EORTC as <5 mm and RTOG group as tumor at the cut margin [2,3]. A meta-analysis on the subject by Anderson et al showed a reduction in local recurrence by 21%, when margins were 5 mm or more [4]. Now, this leaves us with, several pertinent questions on margins, that remain unanswered. i) What is the distance of adequate margin? ii) How does worst pattern of invasion or microscopic spread of disease beyond tumor be addressed? iii) Does more margin proportionately translates into better survival? Many of these important issues have been dealt in the retrospective analysis by Mishra, et al. [5].

The study had shown that with increasing margin the Local Recurrence Free Survival (LRFS) improves. There is an incremental benefit on LRFS as the margin increases by each milli meter. However, this improvement is seen till 7 mm pathological margins and then the impact plateaus. Beyond this, taking an additional margin was not associated with any significant improvement in LRFS. Another aspect of the margin that is addressed in the study is the worst pattern of invasion or the microscopic spread of disease beyond gross tumor, which may alter the final margin status. The incidence of microscopic spread is shown in around 8.7% of patients and this does alter the final margin status.