Achieving a complete resection with clear margins is a logical aimin oncological gastrointestinal surgery. This implies removingthe tumour with sufficiently distant proximal, distal and lateralmargins. The ability to attain this R0 resection (InternationalUnion Against Cancer (UICC) category) has been shown repeat-edly to be a favourable prognostic factor. In the absence of grossresidual tumour the presence of microscopic disease at the surgi-cal resection margins defines a R1 resection. In cancer of thestomach, whether microscopic tumour at the oesophagealmargin affects immediate postoperative outcome, local recur-rence and long-term outcome has not been addressed adequately inthe literature.

In this issue of the Journal a study from Singapore hasfocused on the oesophageal resection margin in patients undergoingeither proximal gastrectomy or total gastrectomy for cancer ofthe stomach.1 It was shown that a microscopically involvedoesophageal margin was not related to anastomotic leakage,postoperative morbidity and mortality. In addition, anastomotic andregional recurrences were not dependent on a positive margin.By multivariate analysis, however, the tumour, nodes and meta-stases (TNM) stage and the status of the oesophageal marginwere independent prognostic factors for survival.

In the immediate postoperative period one may postulate that theonly adverse effect that an involved oesophageal margin per semayhave is anastomotic healing. An increased leakage rate has not beenborne out by this study and is not surprising. Other technicalfactors are much more important in preventing this complica-tion, such as performing a tension-free anastomosis, the use of awell-perfused distal stomach (in proximal gastrectomy) orjejunum (in total gastrectomy), and a carefully constructed anas-tomosis (whether by a hand-sewn or stapling technique). Thechoice of technique is less important than its proper application.Perioperative events such as hypotension and hypoxia are con-tributory and should be avoided. Provided that no gross tumour ispresent at the anastomosis, the influence of microscopic disease atthe resection line is probably of no significance. In studies thatreport a higher leakage rate with a positive margin these patientshad more advanced tumours. A more difficult resection andanastomosis could lead to the higher leakage rate. The periopera-tive periods may also be more complicated in patients withadvanced disease. Attributing a high leakage rate to microscopictumour involvement is not justified.

Although the immediate postoperative outcome is not affected bymicroscopic resection line disease, striving to achieve a negativeoesophageal margin is still an important goal in order to avoid sub-sequent anastomotic recurrence. Long-term prognosis may also beinfluenced. For tumours of the proximal stomach and gastric

cardia that involve the oesophagus, a therapeutic decision at thetime of operation is whether one should increase the proximalmargin attained by adding a thoracotomy for anastomosis. Threeimperative questions arise. First, does a thoracotomy pose sub-stantial risk; and second, is there a reliable method of detectingmargin involvement and subsequent risk of recurrence? Third, isthe resection curative except for the risk of a short and positivemargin?

A thoracotomy is not as morbid a procedure as it used to be.Given modern pain-relief techniques such as epidural analgesia, thedeleterious effects of opening up the chest are much less.2 The sizeof the surgical wound may be a minor component of surgicaltrauma. Minimal-access surgery for oesophageal extirpation, forexample, has not resulted in discernible benefits.3 In patientswith a cancer of the proximal stomach or cardia, extending theproximal margin for a safe anastomosis in the chest requiresonly a low thoracotomy. The extent of mediastinal dissection is alsolimited. At the authors’ institution there is evidence to show that itis the mediastinal dissection above the tracheal bifurcation that isassociated with increased postoperative morbidity, rather thanthe method of surgical access. If surgical dissection is confined tobelow the bifurcation, additional morbidity is minimal (Murthyet al. unpubl. data, 2000). Apart from increasing the proximalmargin, adding a thoracotomy has the advantage of making the con-struction of the anastomosis easier, rather than performing ithigh at the oesophageal hiatus in the abdomen, where surgicalexposure is often suboptimal.

In accessing margin involvement a routine intraoperativefrozen section may be an accurate way of ensuring a clearmargin. A frozen section has high sensitivity and specificity.The problem is that microscopic tumour involvement of theresection margin may not lead to anastomotic recurrence, nordoes a negative margin always preclude its development.4 Theexplanations are that first, those patients with a positive margin mayhave shorter survival, thus they may die of disease elsewherebefore the anastomotic recurrences become evident. Second,when the oesophagus is involved by disease, skip lesions, intra-mural spread, and submucosal embolization of tumours into thesubmucosal lymphatics may be easily missed even by a consci-entious pathologist and thus be mistaken as clear margins in thefirst place. These false negative margins may help explain whysome anastomotic recurrences occur after resection with apparentlyhealthy margins. Third, only symptomatic patients tend to beendoscoped and the actual incidence of recurrence might beunderestimated. Fourth, some anastomotic recurrences mayactually be extrinsic tumour recurrences from regional lymphnodes that had infiltrated back into the anastomosis and were

Aust. N.Z. J. Surg. (2000) 70, 697–698

EDITORIAL

A POSITIVE OESOPHAGEAL MARGIN IN STOMACH CANCER

Editorials in this issue

• A positive oesephageal margin in stomach cancer 697

• Extrafascial excision for rectal cancer 699

not truly originating from the oesophageal wall itself. Distinc-tion of its true tumour origin from the oesophageal margin is notpossible. It has been shown that the incidence of anastomoticrecurrence is dependent on the length of resection marginobtained.4 It seems that even an intraoperative frozen sectionwould not eliminate this problem entirely. Rather than relyingon frozen section, trying to obtain a long resection margin may bea better strategy. The optimal resection margin remains contro-versial, with reports recommending 2–10 cm as optimal. From theauthors’ data in the study of oesophageal cancer an in situmargin of 10 cm (fresh contracted specimen of approximately5 cm) would allow a < 5% chance of anastomotic recurrence. It isconjectural, however, if stomach cancers that involve theoesophagus would behave in the same way. From the aforemen-tioned discussion it does seem that unless a prohibitive risk for athoracotomy exists, performing the anastomosis in the chest is asafer and a better way of avoiding subsequent anastomoticrecurrence.

A positive oesophageal resection margin is shown to be apoor prognostic factor. This may merely reflect the extent ofdisease. In our experience a positive margin is more likely whenresection is carried out with palliative intent. In a study from the Memorial Sloan-Kettering Cancer Centre a positive marginafter gastrectomy was shown to affect survival. In patients whounderwent D2/D3 lymph node dissections, however, onlypatients with five or less lymph nodes involved had their sur-vival worsened by a microscopically involved margin. Thiseffect was not shown for those with more than five positivelymph nodes.5 This finding implies that unless anastomoticrecurrence becomes symptomatic subsequently, achieving anegative margin is of no significance when the overall disease is atan advanced stage. Based on this rationale, when an apparent R0

resection can be carried out all efforts should be made to

achieve a clear margin, because the number of positive lymphnodes can be assessed only after the operation. In the face ofclear palliation only, increasing the risk of a thoracotomy byextending the proximal margin of resection has to be weighedagainst an increased chance of anastomotic recurrence for ashorter proximal margin. There is as yet no adequate data in the literature to define the relationship between the length of proximalresection margin and anastomotic recurrence specifically in the situation where the oesophagus is involved by stomach cancer. A study on this would provide an estimate of this risk and help thesurgeon make this important decision.

REFERENCES1. Chan WH, Wong WK, Khin LW, Chan HS, Soo KC. Significance

of a positive oesophageal margin in stomach cancer. Aust. N.Z. J.Surg.2000;70: 700–3.

2. Tsui SL, Law S, Fok M et al. Postoperative analgesia reduces mor-tality and morbidity after esophagectomy. Am. J. Surg.1997;173: 472–8.

3. Law S, Fok M, Chu KM, Wong J. Thoracoscopic esophagec-tomy for esophageal cancer. Surgery1997; 122: 8–14.

4. Law S, Arcilla C, Chu KM, Wong J. The significance of histo-logically infiltrated resection margin after esophagectomy foresophageal cancer. Am. J. Surg.1998; 176: 286–90.

5. Kim SH, Karpeh MS, Klimstra DS, Leung D, Brennan MF.Effect of microscopic resection line disease on gastric cancersurvival. J. Gastrointest. Surg.1999; 3: 24–33.

Department of Surgery, SIMON LAW AND JOHN WONG

University of Hong Kong Medical Centre, Queen Mary Hospital, Hong Kong

698 LAW AND WONG