Colorectal cancer (CRC) is a common disease in the

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1 ORIGINAL CONTRIBUTION Improving the Quality of Colon Cancer Surgery Through a Surgical Education rogram Nicholas. West, M.B.Ch.B. 1 Kate M. Sutton 1 eter Ingeholm, M.D. 2 Rikke H. Hagemann-Madsen, M.D. 3 Werner Hohenberger, h.d. 4 hilip Quirke, h.d. 1 1 athology and Tumour Biology, Leeds Institute of Molecular Medicine, Leeds, United Kingdom 2 Department of athology, Hospital, Copenhagen, Denmark 3 Department of athology, Aarhus University Hospital, Aarhus, Denmark 4 Department of Surgery, University Hospital of Erlangen, Erlangen, Germany UROSE: Recent evidence has demonstrated the importance of dissection in the correct tissue plane for the resection of colon cancer. We have previously shown that meticulous mesocolic plane surgery yields better outcomes and that the addition of central vascular ligation produces an oncologically superior specimen compared with standard techniques. We aimed to assess the effect of surgical education on the oncological quality of the resection specimen produced. METHODS: We received clinicopathological data and specimen photographs from 263 resections for primary colon cancer from 6 in the Capital and Zealand regions of Denmark before a national training program. Ninety-three cases were from Hospital, where surgeons had previously implemented a surgical educational training program in complete mesocolic excision with central vascular ligation and adopted the procedure as standard practice. The specimen Support: Dr West and Dr Quirke are supported by grants from Yorkshire Cancer Research, Harrogate, UK, and Dr Quirke is supported by an infrastructure grant from the Experimental Cancer Medicine Centre initiative, UK. Kate Sutton is a medical student on the Leeds Undergraduate Research Enterprise course financially supported by Sir Jimmy Saville. Financial Disclosure: None reported. resented at the meeting of The American Society of Colon and Rectal Surgeons, Minneapolis, MN, May 15 to 19, Correspondence: Nicholas. West, M.B.Ch.B., athology & Tumour Biology, Leeds Institute of Molecular Medicine, Level 4, Wellcome Trust Brenner Building, St James s University Hospital, Beckett Street, Leeds, LS9 7TF, United Kingdom. n.p.west@leeds.ac.uk Dis Colon Rectum 2010; 53: DOI: /DCR.0b013e3181f433e3 The ASCRS 2010 photographs were assessed for the plane of surgery and tissue morphometry was performed. RESULTS: specimens had a higher rate of mesocolic plane surgery (75% vs 48%;.0001) compared with the other. The surgeons at Hospital also removed a greater length of colon in both fresh (median, 315 vs 247 mm;.0001) and fixed (269 vs 207 mm;.0001) specimens with a greater distance between the tumor and the closest vascular tie in both fresh (105 vs 84 mm;.006) and fixed (82 vs 67 mm;.002) specimens. This resulted in the removal of more mesentery in both fresh (14,466 vs 8706 mm 2 ;.0001) and fixed (9418 vs 6789 mm 2 ;.0001) specimens and a greater median lymph node yield (28 vs 18;.0001). CONCLUSIONS: We have shown that adoption of complete mesocolic excision with central vascular ligation results in a change to the production of an oncologically superior specimen compared with standard techniques. This should improve outcomes toward those reported by centers that have long practiced meticulous colon cancer surgery. KEY WORDS: Colon cancer; Surgical education; athological evaluation; Quality control. Colorectal cancer (CRC) is a common disease in the Western world with approximately 149,000 new cases diagnosed every year in the United States. 1 Although the disease continues to carry high cancer-related mortality, the overall mortality rate has steadily fallen over recent years with the introduction of improved surgical techniques, better imaging, high-quality pathology, and neoadjuvant/adjuvant therapy. Traditionally, patients with rectal cancer had worse outcomes than those with 1594 DISEASES OF THE COLON & RECTUM VOLUME 53: 12 (2010)

2 DISEASES OF THE COLON & RECTUM VOLUME 53: 12 (2010) 1595 colon cancer owing to the high rates of local disease recurrence associated with incomplete tumor removal in the rectum. The description of total mesorectal excision (TME), 2 circumferential margins, 3 magnetic resonance imaging, 4 6 preoperative radiotherapy, 7,8 and subsequent dissemination of these techniques helped to address this imbalance. In some countries that undertook national TME educational training programs, better outcomes for rectal cancer compared with colon cancer are now reported. 9,10 The improved outcomes associated with TME surgery center around the principle of removing the tumor and its lymphatic drainage using embryological tissue planes. This reduces the rate of incomplete tumor removal and is associated with lower local disease recurrence and improved survival Whereas this concept is now well accepted for rectal cancer, the evidence for a similar effect in colon cancer is limited. We have previously shown that careful dissection in the mesocolic tissue plane results in significantly better outcomes compared with cases with large intraoperative defects in the mesocolon. 14 groups have shown that standardizing the operative technique by use of sound oncological principles is associated with better outcomes. 15,16 In addition, surgeons performing mesocolic plane surgery with a high vascular tie, known as complete mesocolic excision with central vascular ligation (CME with CVL), report very impressive outcomes. 17 We have demonstrated the oncological superiority of this technique over standard procedures with a higher mesocolic plane resection rate, a greater amount of tissue resected around the tumor, and higher lymph node yields. 18 Outcomes for patients with CRC in Denmark were traditionally less favorable compared with other Western European countries, leading to the introduction of a National Cancer lan in Government-funded schemes to improve outcomes included the establishment of multidisciplinary teams (MDTs) and clinical database monitoring. More recently, CRC MDT workshops have been introduced across the country focusing on TME and surgical optimization of the treatment of low rectal and colon cancer, with the integration of radiologists, oncologists, and pathologists into the teams. To assess the current situation, 6 in the Capital and Zealand regions of Denmark were invited to submit clinicopathological data on a series of resections for primary colon cancer before the regional MDT colon cancer course. However, the surgeons from one of the,, had previously decided to change their methods for colon cancer surgery and attended an educational program in Erlangen focusing on CME with CVL. We aimed to assess the oncological quality of colon cancer resection specimens from the Capital and Zealand regions of Denmark before the regional MDT colon cancer course to set a benchmark against which the influence of the educational program could subsequently be assessed. In addition, we aimed to compare the specimens produced in Hospital, after they decided to change their practice and undergo education in Erlangen, with those produced in the other with use of an assessment of the plane of surgery, tissue morphometry, and lymph node yields. METHODS Cases The 6 participating centers were asked to collect clinicopathological data and specimen photographs from a series of resections for primary colon cancer performed before the regional MDT colon cancer course held on the June 18, The prospective collection of cases started on September 2, Although the collection of cases from Hospital represented a consecutive series, this was not true of the other units where routine photography of specimens was gradually introduced. Surgical Technique Four colorectal surgeons from Hospital attended an educational program in Erlangen, Germany in May 2008 where they observed rofessor Hohenberger perform a series of operations for colon cancer using CME with CVL. Two of these surgeons had previously attended the program in May 2007 and a further 2 surgeons attended in May The precise technique of CME with CVL is described elsewhere, 17 but, in brief, it involves dissection along embryological tissue planes to remove the entire mesocolon within the region of the tumor along with the relevant vascular and lymphatic drainage. The supplying vessels are transected at their origin, eg, division of the ileocolic vessels where they arise from the superior mesenteric artery for right-sided tumors and division of the inferior mesenteric root on the left. For transverse colon and flexure tumors, the middle colic vessels are divided at their origin along with other vessels as appropriate according to the possible patterns of lymphatic spread. 17 From the June 1, 2008, the surgeons at Hospital agreed as a unit to perform CME with CVL surgery in all cases of potentially curative colon cancer, where appropriate. The 2 surgeons who did not attend the program until May 2009 were initially educated in the technique by their colleagues who had previously attended the course. The other surgical units across the region were not known to have standardized their approach for colon cancer to the CME with CVL technique. athological rotocol The specimens were dissected by the local pathologist using standard procedures including 48 hours of formalin fixation and serial cross-sectional slicing through the tumor segment at 3- to 4-mm intervals. 19 The pathologists

3 1596 WEST ET AL:IMROVING COLON CANCER SURGERY from across the region attended a course at Hospital to discuss photography and dissection of specimens before the collection of photographs. Histopathological staging was performed using the fifth edition of the International Union Against Cancer TNM system. 20 All specimen photographs were high-resolution digital images and included the whole specimen (either fresh, formalin fixed, or both) along with the cross-sectional slices and a centimeter scale. Assessment of the lane of Surgery The plane of surgery was retrospectively graded from the specimen photographs by one of the authors (N..W.) depending on the presence and extent of any mesocolic disruptions using a previously described method (Fig. 1). 14 In brief, the following categories were used: mesocolic plane (intact mesocolon with no significant defects), intramesocolic plane (significant defects that do not extend down to the muscularis propria), or muscularis propria plane (significant defects that extend down to the muscularis propria). For left-sided resections containing the upper part of the mesorectum, this was assessed in the same way as the integrity of the mesocolon. Tissue Morphometry The photographs included a metric scale for calibration and the site of the tumor and vascular ties were labeled. The distances from the tumor to the closest vascular tie and nearest bowel wall to the vascular tie were accurately measured along with the length of colon and area of mesentery resected (Fig. 2) as previously described, 18 using ImageScope v10 (Aperio Technologies Inc., Vista, CA). FIGURE 2. Method of performing tissue morphometry on the photographs of a fresh sigmoid colectomy specimen. Following calibration against a metric ruler, the area of mesentery is mapped out (yellow) and the length of colon measured (black). The distance between the edge of the bowel wall at the position of the tumor to the closest vascular tie is then measured (blue). If the tumor is not situated in the colon segment closest to the vascular tie, then an additional measurement of the nearest bowel wall to the vascular tie is made. The fresh pictures were analyzed by 2 independent observers (K.M.S., N..W.) to assess for reproducibility. Statistical Analyses Statistical analyses were performed using the Statistical ackage for the Social Sciences (SSS v15.0, Chicago, IL) using the Fisher exact, Mann-Whitney U, and Kruskal- Wallis test as appropriate. Correlation analyses were performed using the Spearman rho. Analyses where the value was less than.05 were considered to represent statistical significance. Ethical Review Individual patient consent was not needed for this study. Ethical approval was granted by the Northern and Yorkshire Research Ethics Committee, Jarrow, UK (unique reference number 07/MRE03/24). RESULTS FIGURE 1. Assessment of the plane of surgery from cross-sectional slices according to the presence and extent of mesocolic disruptions including mesocolic plane with an intact mesocolon (A), intramesocolic plane with significant mesocolic disruptions away from the muscularis (arrow) (B), and muscularis propria plane with significant disruptions extending down to the muscularis (arrow) (C). Cases Clinicopathological data from 277 cases were received initially, although 14 cases were excluded from subsequent analyses: 7 adenomas, 5 rectal cancers (situated 15 cm or less from the anocutaneous junction), and 2 nonepithelial tumors. This left 263 cases of primary colonic adenocarcinoma included in the study. Hospital contributed the largest number of cases (n 93) with the remainder coming from the other 5 (median, 33 cases per ; interquartile range (IQR) 15 54). The

4 DISEASES OF THE COLON & RECTUM VOLUME 53: 12 (2010) 1597 TABLE 1. Clinicopathological data for all cases from and the other atient age (y) Median IQR atient gender Male 56 (60) 75 (44).014 Female 37 (40) 95 (56) Site of tumor Right colon 41 (44) 57 (34).043 Transverse colon and flexures 17 (18) 26 (15) Left colon 35 (38) 86 (51) Unknown 0 1 Values in parentheses represent percentages. IQR interquartile range. operations were performed both open (n 54; 27 rightsided, 17 transverse/flexures, 10 left-sided) and laparoscopically (n 39; 14 right-sided, 25 left-sided). There were a significantly higher proportion of males and right-sided resections in the group compared with the other (Table 1). There was no difference in pathological staging between the 2 groups although pathologists in the other were more likely to report extramural vascular invasion compared with (Table 2). Specimens from contained significantly more lymph nodes overall compared with specimens from the other, although this did not result in a greater number of involved nodes or upstaging of the disease (Table 2). When broken down according to the site of the tumor, specimens contained significantly more lymph nodes in right-sided tumors (median, 29 (IQR 26 38) vs 19 (16 25);.0001), transverse and flexure tumors (median, 32 (IQR 25 45) vs 21 (16 25);.002) and also left sided tumors (median, 26 (IQR 14 35) vs 16 (13 22);.0001) compared with the other. lane of Surgery An assessment of the plane of surgery could be performed on 92 (99%) of the resections and 166 (98%) of the others. surgeons were significantly more likely to operate in the mesocolic tissue plane compared with surgeons from the other and this was independent of the site of the tumor (Fig. 3). In the cases there was no significant difference in the mesocolic plane rate between open (70%) and laparoscopic surgery (82%;.183). Tissue Morphometry In total, 123 fresh- and 145 fixed-specimen photographs were suitable for morphometric analysis. Overall, resections from contained a greater length of colon in both the fresh (Table 3) and fixed (Table 4) specimens. TABLE 2. Histopathological staging data for all cases from and the other pt stage T1 9 (10) 4 (2).285 T2 7 (8) 17 (10) T3 57 (61) 106 (63) T4 20 (22) 41 (24) Unknown 0 2 pn stage N0 57 (61) 85 (51).134 N1 18 (19) 44 (26) N2 18 (19) 39 (23) Unknown 0 2 Distant metastases present Yes 5 (5) 8 (5).553 No 88 (95) 162 (95) Extramural vascular invasion Yes 21 (23) 66 (39).006 No 72 (77) 102 (61) Unknown 0 2 Complete resection (R0) Yes 83 (91) 163 (97).069 No 8 (9) 5 (3) Unknown 2 2 Synchronous cancer Yes 4 (4) 2 (1).189 No 89 (96) 168 (99) Number of nodes retrieved Median IQR 24 to to 23 Number of positive nodes Median IQR 0to2 0to3 Values in parentheses represent percentages. IQR interquartile range. There was no difference in the amount of small bowel resected, where present. A greater amount of central mesocolon was removed by surgeons between the closest vascular tie and the tumor/nearest bowel wall with the result that a greater amount of mesentery was resected (Tables 3 and 4). These trends were replicated when broken down according to the site of the tumor in both fresh (Table 5) and fixed (Table 6) specimens. In the cases, there was no significant difference in tissue morphometry measurements between open and laparoscopic surgery in right-sided tumors. However, in resections for left-sided tumors, the specimens contained a greater length of colon when performed open but a smaller distance between the tumor and the vascular tie compared with the laparoscopic specimens (Table 7). In the fresh specimens, there was good correlation between the 2 observers for the length of colon removed (R 0.945,.0001), distance from the nearest bowel wall to the vascular tie (R 0.738,.0001), distance from the tumor to the vascular tie (R 0.508,.008), and area of mesentery resected (R 0.910,.0001).

5 1598 WEST ET AL:IMROVING COLON CANCER SURGERY A ercentage of cases 100 HillerØd B ercentage of cases <.0001 = Mesocolic plane C ercentage of cases 100 Intramesocolic Muscularis plane propria plane Mesocolic plane D ercentage of cases 100 Intramesocolic Muscularis plane propria plane = = Mesocolic plane Intramesocolic Muscularis plane propria plane Mesocolic plane Intramesocolic Muscularis plane propria plane FIGURE 3. Comparison of the plane of surgery in all assessable resections between the 2 groups for all cases (A), right-sided tumors (B), transverse and flexure tumors (C), and left-sided tumors (D). Seventy-nine specimens had both fresh and fixed photographs suitable for tissue morphometry (Fig. 4). There was significant shrinkage following formalin fixation (Table 8) in terms of the length of colon removed (median change, 20%; IQR 8% 31%), distance between the tumor and the vascular tie (median change, 21%; IQR 6% 32%), distance between the nearest bowel wall and the vascular TABLE 3. Tissue morphometry data for the fresh resection specimens for all cases from and the other Median (mm) IQR 259 to to 283 Length of SB resected Median (mm) IQR 60 to to 85 Median (mm) IQR 64 to to 86 Distance from tumor to HT Median (mm) IQR 84 to to 101 Area of mesentery resected Median (mm 2 ) IQR 9833 to to IQR interquartile range; LB large bowel; SB small bowel; NBW nearest bowel wall; HT high tie. TABLE 4. Tissue morphometry data for the fixed resection specimens for all cases from and the other Median (mm) IQR Length of SB resected Median (mm) IQR Median (mm) IQR Median (mm) IQR Median (mm 2 ) IQR IQR interquartile range; LB large bowel; SB small bowel; NBW nearest bowel wall; HT high tie.

6 DISEASES OF THE COLON & RECTUM VOLUME 53: 12 (2010) 1599 TABLE 5. Tissue morphometry data for the fresh resection specimens according to the site of the tumor (right, transverse, or left) from and the other tie (median change, 24%; IQR 4% 41%), and area of mesentery resected (median change, 33%; IQR 15% 55%). DISCUSSION Right-sided tumors Median (mm) IQR Length of SB resected Median (mm) IQR Median (mm) IQR Median (mm) IQR Median (mm 2 ) 15, IQR 11,887 20, ,672 Transverse/flexure tumors Median (mm) IQR Median (mm) IQR Median (mm) IQR Median (mm 2 ) 21,728 10, IQR 13,163 24, Left-sided tumors Median (mm) IQR Median (mm) IQR Median (mm) IQR Median (mm 2 ) 12, IQR ,321 IQR interquartile range; LB large bowel; SB small bowel; NBW nearest bowel wall; HT high tie. The introduction of TME for rectal cancer through surgical education programs has led to significant improvements in outcome for a number of countries around the world TME surgery involves careful dissection in the mesorectal tissue plane immediately outside the layer of mesorectal fascia that surrounds the infraperitoneal mesorectum. This ensures that the tumor is removed in an intact fascial-lined package that includes the potential routes of metastatic tumor spread. 2 This reduces the rate of incomplete tumor removal at the circumferential resection margin, which has been previously linked to local disease recurrence within the pelvis. 3 It has been suggested that CME with CVL surgery for colon cancer is analogous to TME in the rectum because the same sound oncological principles apply, namely the removal of the tumor with its vascular and lymphatic drainage in an intact package. We sought to investigate what effect the adoption of CME with CVL had TABLE 6. Tissue morphometry data for the fixed resection specimens according to the site of the tumor (right, transverse, or left) from and the other Right-sided tumors Median (mm) IQR Length of SB resected Median (mm) IQR Median (mm) IQR Median (mm) IQR Median (mm 2 ) IQR , ,676 Transverse/flexure tumors Median (mm) IQR Median (mm) IQR Median (mm) IQR Median (mm 2 ) 16,070 10, IQR , ,968 Left-sided tumors Median (mm) IQR Median (mm) IQR Median (mm) IQR Median (mm 2 ) IQR , IQR interquartile range; LB large bowel; SB small bowel; NBW nearest bowel wall; HT high tie.

7 1600 WEST ET AL:IMROVING COLON CANCER SURGERY TABLE 7. Tissue morphometry data for the open and laparoscopic resection specimens from Fresh/fixed (open) (laparoscopic) Right-sided tumors Fresh Median (mm) IQR Fixed Length of SB resected Fresh Median (mm) IQR Fixed Fresh Median (mm) IQR Fixed Fresh Median (mm) IQR Fixed Fresh 15,567 14, Median (mm 2 ) 12,909 20, ,696 IQR Fixed 10, , ,859 Left-sided tumors Fresh Median (mm) IQR Fixed Fresh Median (mm) IQR Fixed Fresh Median (mm) IQR Fixed Fresh 13,548 12, Median (mm 2 ) 10,476 28, ,939 IQR Fixed 10, , IQR interquartile range; LB large bowel; SB small bowel; NBW nearest bowel wall; HT high tie. on the oncological quality of the resection specimen in Hospital compared with the other in the Capital and Zealand regions of Denmark before a regional training program. We have shown that surgeons from Hospital, who chose to undergo an educational program in CME with CVL surgery and subsequently standardized their approach as a unit before the study, were more likely to operate in the mesocolic tissue plane, remove more tissue around the tumor both centrally and longitudinally, and achieve a greater lymph node yield compared with surgeons who had not implemented such techniques. We have previously shown that careful resection of colon cancer with no significant mesocolic defects is associated with significantly better overall survival at 5 years compared with specimens with extensive defects that extend down to the muscularis propria. 14 Mesocolic plane resections had a 15% greater survival compared with those in the muscularis propria plane with the difference rising to 27% in stage III disease. The mesocolic plane approach adheres to the principles of surgical oncology because the tumor is removed in an intact package enclosed by peritoneum and fascia where present. By contrast, disruption of either the mesocolon, the peritoneal surface, or fascial resection margin in patients with advanced tumors which have spread into the mesocolon could potentially result in tumor spillage into the peritoneal cavity and the operative bed leading to disease recurrence. Colonic tumors have long been recognized to spread centrally toward the midline lymph nodes situated at the origin of the supplying arteries. The concept of mesocolic plane dissection with high vascular ligation as a means of adequately clearing colonic tumors is not new, having first being described in Leeds in Modern implementation of high vascular ligation has been associated with variable outcomes, with some studies failing to show a benefit

8 DISEASES OF THE COLON & RECTUM VOLUME 53: 12 (2010) 1601 FIGURE 4. A right hemicolectomy specimen photographed both fresh and after 48 hours of formalin fixation. There is obvious shrinkage of the length of colon and size of the mesentery in this specimen following fixation. compared with standard techniques However, as far as we are aware, there was no effort to standardize the plane of mesocolic dissection in these studies with the potential benefit of removing the central nodes possibly being lost by mesocolic disruptions. studies certainly have shown a clear benefit to high ligation, including in centers that use careful mesocolic dissection The outcomes reported by the group in Erlangen are particularly impressive with up to 89% cancer-related survival at 5 years in a consecutive series of potentially curative resections treated by CME with CVL. Japanese surgeons routinely perform CME with CVL in stage III disease and also report excellent survival rates similar to the Erlangen group. 29 We have previously demonstrated that CME with CVL results in a TABLE 8. Tissue morphometry data for the fresh and fixed resection specimens for all cases that had both fresh and fixed photographs Fresh specimens Fixed specimens Reduction, % Median (mm) IQR Distance from NBW to HT Median (mm) IQR Distance from tumor to HT Median (mm) IQR Area of mesentery resected Median (mm 2 ) 14, IQR , ,409 IQR interquartile range; LB large bowel; NBW nearest bowel wall; HT high tie. mesocolic plane resection rate of 92% compared with only 40% with standard techniques. 18 In addition, this technique removed significantly more tissue around the tumor both longitudinally, in terms of the length of colon resected, and centrally, measured by the distance between the tumor/nearest bowel wall to the closest vascular tie. It is apparent that the resection specimens produced by the other in the Capital and Zealand region of Denmark are very similar to those produced by surgeons in Leeds, who have also not switched to the CME with CVL technique. The plane of surgery profile in Denmark is virtually identical to that reported in Leeds (mesocolic, 48% vs 40%; intramesocolic, 46% vs 48%; muscularis propria, 6% vs 12%), and the median length of colon resected (247 mm vs 206 mm) and distance between the tumor and the vascular tie (84 mm vs 90 mm) measured on the fresh specimen are very similar. 18 However, surgeons at Hospital produce a significantly different specimen. The plane of surgery approaches the quality reported in Erlangen (mesocolic, 75% vs 92%; intramesocolic, 25% vs 8%; muscularis propria, 0% vs 0%), and the median length of colon resected (315 mm vs 314 mm) and distance between the tumor and the vascular tie (105 mm vs 131 mm) measured on the fresh specimen are again similar. 18 It is clear that whereas the surgeons have modified their operative technique, they do not have such a high mesocolic plane rate and are not removing quite as much tissue centrally as the group in Erlangen. This may reflect differential patient anatomy between the series, although we believe it more likely demonstrates that, although a switch in technique produces an instant change, it takes time, practice, and audit to gain the full benefit. High lymph node yields are known to depend on both the surgeon and the pathologist 30 and are associated with better outcomes in both lymph node-negative 31,32 and lymph node-positive disease. 33 We have previously shown that CME with CVL results in a significantly higher yield compared with standard surgery, even within a center employing specialized gastrointestinal pathologists who perform a meticulous dissection. 18 In the current study, we have shown that specimens contain a greater number of lymph nodes compared with the other in the region. Again, similar comparisons can be made between and Erlangen (median yield, 28 vs 30) and the other and Leeds (median yield, 18 vs 18), validating the increased nodal yield associated with the resection of a greater amount of mesentery in CME with CVL surgery. 18 We believe that the quality of pathology is unlikely to have significantly contributed to the lower yields reported in the other, because the nodal yields and reporting of extramural vascular invasion in all centers after undergoing identical pathological training comfortably exceed historical data and the minimum targets of the United Kingdom Royal College of athologists. 34 Although stage migration can be expected following CME

9 1602 WEST ET AL:IMROVING COLON CANCER SURGERY with CVL, there was no specific evidence of upstaging in this study, so no additional patients would be likely to receive chemotherapy. However, we believe that the higher rate of mesocolic plane resections will have a significant influence on patient survival by preventing tumor dissemination, as suggested by the Leeds study. 14 Although local recurrence is not perceived to be a common problem in colon cancer compared with rectal cancer, it has been shown to occur in up to 22% of muscularis propria plane resections. 35 The high vascular ligation may be of additional benefit to cases with involved central lymph nodes and removal of extra colon length may benefit cases with longitudinal lymphatic spread, which does occasionally occur. It is not known what effect, if any, CME with CVL will have on the distant metastasis of tumor cells. This present study is weakened by the lack of clinicopathological data and specimen photographs from before the implementation of CME with CVL. Despite this limitation, the study has provided a useful insight as to what changes might be seen in the other after the regional educational program that took place in June The collection of these data and subsequent audit is currently being undertaken and will be reported in due course. Although improvement in the oncological quality of the specimen is evident, we do not yet have any data on the morbidity and mortality associated with a switch to CME with CVL, and a positive effect on long-term patient outcome remains to be confirmed. However, CME with CVL surgery in the Erlangen study was associated with very acceptable postoperative complication and mortality rates of 19.7% and 3.1%, respectively. 17 In this study, we have provided further evidence that the pathological evaluation of colon cancer specimens across a series of cases by assessing the plane of surgery, performing tissue morphometry, and auditing lymph node yields can be used to assess oncological quality in appropriately selected patients undergoing curative surgery. We have demonstrated the oncological superiority of CME with CVL for colon cancer and provide further justification for large-scale surgical education and audit programs that can be expected to directly influence the quality of the specimen produced and should improve outcomes for this commonly fatal disease. Such programs have previously been demonstrated to improve survival in rectal cancer and are very cost effective compared with the increasing costs of new palliative chemotherapeutic treatments. ACKNOWLEDGMENTS The authors thank the following lead pathologists who contributed their photographs and data: Dr. eter Engel (Department of athology, Roskilde Hospital, Region Zealand, Denmark), Dr. Ulla Engel (Department of athology, Hvidovre Hospital, Capital Region, Denmark), Dr. Anders Glenthøj (Department of athology, Bispebjerg Hospital, Capital Region, Denmark), Dr. Marianne Bøgevang Jensen (Department of athology, Slagelse Hospital, Region Zealand, Denmark), and Dr. Dorte Linnemann (Department of athology, Herlev Hospital, Capital Region, Denmark). In addition, we thank all the colorectal surgeons in the Capital and Zealand regions of Denmark who have generously allowed us to collect and audit their data. REFERENCES 1. American Cancer Society. 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