P. Quirke

LOCAL RECURRENCE OF RECTAL ADENOCARCINOMA DUE TO INADEQUATE SURGICAL RESECTION: Histopathological Study of Lateral Tumour Spread and Surgical Excision

In 52 patients with rectal adenocarcinoma whole-mount sections of the entire operative specimen were examined by transverse slicing. There was spread to the lateral resection margin in 14 of 52 (27%) patients and 12 of these proceeded to local pelvic recurrence. The specificity, sensitivity, and positive predictive values were 92%, 95%, and 85%, respectively. In a retrospective stage-matched and grade-matched control group there was local recurrence in the same proportion of patients, but in this series no patient had been shown by routine sampling to have lateral spread. In rectal adenocarcinoma, local recurrence is mainly due to lateral spread of the tumour and has previously been underestimated.

Randomized Trial of Laparoscopic-Assisted Resection of Colorectal Carcinoma: 3-Year Results of the UK MRC CLASICC Trial Group

PURPOSE The aim of the current study is to report the long-term outcomes after laparoscopic-assisted surgery compared with conventional open surgery within the context of the UK MRC CLASICC trial. Results from randomized trials have indicated that laparoscopic surgery for colon cancer is as effective as open surgery in the short term. Few data are available on rectal cancer, and long-term data on survival and recurrence are now required. METHODS The United Kingdom Medical Research Council Conventional versus Laparoscopic-Assisted Surgery in Colorectal Cancer (UK MRC CLASICC; clinical trials number ISRCTN 74883561) trial study comparing conventional versus laparoscopic-assisted surgery in patients with cancer of the colon and rectum. The randomization ratio was 2:1 in favor of laparoscopic surgery. Long-term outcomes (3-year overall survival [OS], disease-free survival [DFS], local recurrence, and quality of life [QoL]) have now been determined on an intention-to-treat basis. RESULTS Seven hundred ninety-four patients were recruited (526 laparoscopic and 268 open). Overall, there were no differences in the long-term outcomes. The differences in survival rates were OS of 1.8% (95% CI, -5.2% to 8.8%; P = .55), DFS of -1.4% (95% CI, -9.5% to 6.7%; P = .70), local recurrence of -0.8% (95% CI, -5.7% to 4.2%; P = .76), and QoL (P > .01 for all scales). Higher positivity of the circumferential resection margin was reported after laparoscopic anterior resection (AR), but it did not translate into an increased incidence of local recurrence. CONCLUSION Successful laparoscopic-assisted surgery for colon cancer is as effective as open surgery in terms of oncological outcomes and preservation of QoL. Long-term outcomes for patients with rectal cancer were similar in those undergoing abdominoperineal resection and AR, and support the continued use of laparoscopic surgery in these patients.

Kirsten ras mutations in patients with colorectal cancer: The 'RASCAL II' study

Researchers worldwide with information about the Kirsten ras (Ki-ras) tumour genotype and outcome of patients with colorectal cancer were invited to provide that data in a schematized format for inclusion in a collaborative database called RASCAL (The Kirsten ras in-colorectal-cancer collaborative group). Our results from 2721 such patients have been presented previously and for the first time in any common cancer, showed conclusively that different gene mutations have different impacts on outcome, even when the mutations occur at the same site on the genome. To explore the effect of Ki-ras mutations at different stages of colorectal cancer, more patients were recruited to the database, which was reanalysed when information on 4268 patients from 42 centres in 21 countries had been entered. After predetermined exclusion criteria were applied, data on 3439 patients were entered into a multivariate analysis. This found that of the 12 possible mutations on codons 12 and 13 of Kirsten ras, only one mutation on codon 12, glycine to valine, found in 8.6% of all patients, had a statistically significant impact on failure-free survival (P = 0.004, HR 1.3) and overall survival (P = 0.008, HR 1.29). This mutation appeared to have a greater impact on outcome in Dukes’ C cancers (failure-free survival, P = 0.008, HR 1.5; overall survival P = 0.02, HR 1.45) than in Dukes’ B tumours (failure-free survival, P = 0.46, HR 1.12; overall survival P = 0.36, HR 1.15). Ki-ras mutations may occur early in the development of pre-cancerous adenomas in the colon and rectum. However, this collaborative study suggests that not only is the presence of a codon 12 glycine to valine mutation important for cancer progression but also that it may predispose to more aggressive biological behaviour in patients with advanced colorectal cancer.

Five‐year follow‐up of the Medical Research Council CLASICC trial of laparoscopically assisted versus open surgery for colorectal cancer

The UK Medical Research Council CLASICC trial assessed the safety and efficacy of laparoscopically assisted surgery in comparison with open surgery for colorectal cancer. The results of the 5‐year follow‐up analysis are presented.

Rates of Circumferential Resection Margin Involvement Vary Between Surgeons and Predict Outcomes in Rectal Cancer Surgery

ObjectiveTo analyze the potential variability in rates of circumferential resection margin (CRM) involvement between different surgeons and time periods and to determine the suitability of using CRM status as an immediate predictor of outcome after rectal cancer surgery. Summary Background DataAfter disease stage has been taken into account, survival in rectal cancer has been shown to be very variable between surgeons and institutions. One of the major factors influencing survival is local recurrence, and this in turn is strongly related to inadequate tumor excision, particularly at the CRM. MethodsIn a study involving 608 patients who underwent surgery for rectal cancer in Leeds during the 12-year period 1986 to 1997, the authors examined the role of CRM status as an immediate predictor of likely outcome, paying particular attention to its relationships with different surgeons and time periods. ResultsOf 586 patients on whom full clinical follow-up was obtained, 165 (28.2%) had CRM involvement by carcinoma on pathologic examination. Up to the end of 1998, 105 (17.9%) patients had developed local recurrence. A significantly higher proportion (38.2%) of CRM-positive patients developed local recurrence than CRM-negative ones (10.0%). Kaplan-Meier survival analysis showed significant improvements in survival for CRM-negative patients over CRM-positive patients. Survival analysis in relation to two gastrointestinal surgeons and a group of other surgeons showed survival improvements that paralleled a reduction in the rates of CRM involvement for the two gastrointestinal surgeons during the period of the study. No improvement in survival or reduction in rates of CRM involvement was seen in the group of other surgeons. ConclusionsThese results show that CRM status may be used as an immediate predictor of survival after rectal cancer surgery and serves as a useful indicator of the quality of surgery. The frequency of CRM involvement can be used both for overall surgical audit and for monitoring the value of training programs in improving rectal surgery by individual surgeons. Its use in the current MRC CR07 study is valid and the best indicator of a requirement for further local therapy.

Low Rectal Cancer: A Call for a Change of Approach in Abdominoperineal Resection

PURPOSE Despite the major improvements that have been made due to total mesorectal excision (TME), low rectal cancer still remains a challenge. METHODS By investigating a prospective randomized rectal cancer trial in which surgeons had undergone training in TME the factors responsible for the poor outcome were determined and a new method for assessing the quality of surgery was tested. RESULTS Survival differed greatly between abdominoperineal resection (APR) and anterior resection (AR; 38.5% v 57.6%, P = .008). Low rectal carcinomas have a higher frequency of circumferential margin involvement (26.5% v 12.6%, P < .001). More positive margins were present in the patients operated with APR (30.4%) compared to AR (10.7%, P = .002). Furthermore, more perforations were present in these specimens (13.7% v 2.5%, P < .001). The plane of resection lies within the sphincteric muscle, the submucosa or lumen in more than 1/3 of the APR cases, and in the remainder lay on the sphincteric muscles. CONCLUSION We systematically described and investigated the pathologic properties of low rectal cancer in general, and APR in particular, in a prospective randomized trial including surgeons who had been trained in TME. The poor prognosis of the patients with an APR is ascribed to the resection plane of the operation leading to a high frequency of margin involvement by tumor and perforation with this current surgical technique. The clinical results of this operation could be greatly improved by adopting different surgical techniques and possibly greater use of radiochemotherapy.

KRAS and BRAF Mutations in Advanced Colorectal Cancer Are Associated With Poor Prognosis but Do Not Preclude Benefit From Oxaliplatin or Irinotecan: Results From the MRC FOCUS Trial

PURPOSE Activating mutation of the KRAS oncogene is an established predictive biomarker for resistance to anti-epidermal growth factor receptor (anti-EGFR) therapies in advanced colorectal cancer (aCRC). We wanted to determine whether KRAS and/or BRAF mutation is also a predictive biomarker for other aCRC therapies. PATIENTS AND METHODS The Medical Research Council Fluorouracil, Oxaliplatin and Irinotecan: Use and Sequencing (MRC FOCUS) trial compared treatment sequences including first-line fluorouracil (FU), FU/irinotecan or FU/oxaliplatin in aCRC. Tumor blocks were obtained from 711 consenting patients. DNA was extracted and KRAS codons 12, 13, and 61 and BRAF codon 600 were assessed by pyrosequencing. Mutation (mut) status was assessed first as a prognostic factor and then as a predictive biomarker for the benefit of adding irinotecan or oxaliplatin to FU. The association of BRAF-mut with loss of MLH1 was assessed by immunohistochemistry. RESULTS Three hundred eight (43.3%) of 711 patients had KRAS-mut and 56 (7.9%) of 711 had BRAF-mut. Mutation of KRAS, BRAF, or both was present in 360 (50.6%) of 711 patients. Mutation in either KRAS or BRAF was a poor prognostic factor for overall survival (OS; hazard ratio [HR], 1.40; 95% CI, 1.20 to 1.65; P < .0001) but had minimal impact on progression-free survival (PFS; HR, 1.16; 95% CI, 1.00 to 1.36; P = .05). Mutation status did not affect the impact of irinotecan or oxaliplatin on PFS or OS. BRAF-mut was weakly associated with loss of MLH1 staining (P = .012). CONCLUSION KRAS/BRAF mutation is associated with poor prognosis but is not a predictive biomarker for irinotecan or oxaliplatin. There is no evidence that patients with KRAS/BRAF mutated tumors are less likely to benefit from these standard chemotherapy agents.

Value of Mismatch Repair, KRAS, and BRAF Mutations in Predicting Recurrence and Benefits From Chemotherapy in Colorectal Cancer

PURPOSE It is uncertain whether modest benefits from adjuvant chemotherapy in stage II colorectal cancer justify the toxicity, cost, and inconvenience. We investigated the usefulness of defective mismatch repair (dMMR), BRAF, and KRAS mutations in predicting tumor recurrence and sensitivity to chemotherapy. PATIENTS AND METHODS Immunohistochemistry for dMMR and pyrosequencing for KRAS/BRAF were performed for 1,913 patients randomly assigned between fluorouracil and folinic acid chemotherapy and no chemotherapy in the Quick and Simple and Reliable (QUASAR) trial. RESULTS Twenty-six percent of 695 right-sided colon, 3% of 685 left-sided colon, and 1% of 407 rectal tumors were dMMR. Similarly, 17% of right colon, 2% of left colon, and 2% of rectal tumors were BRAF mutant. KRAS mutant tumors were more evenly distributed: 40% right colon, 28% left colon, and 36% rectal tumors. Recurrence rate for dMMR tumors was half that for MMR-proficient tumors (11% [25 of 218] v 26% [438 of 1,695] recurred; risk ratio [RR], 0.53; 95% CI, 0.40 to 0.70; P < .001). Risk of recurrence was also significantly higher for KRAS mutant than KRAS wild-type tumors (28% [150 of 542] v 21% [219 of 1,041]; RR, 1.40; 95% CI, 1.12 to 1.74; P = .002) but did not differ significantly between BRAF mutant and wild-type tumors (P = .36). No marker predicted benefit from chemotherapy with efficacy not differing significantly by MMR, KRAS, or BRAF status. The prognostic value of MMR and KRAS was similar in the presence and absence of chemotherapy. CONCLUSION MMR assays identify patients with a low risk of recurrence. KRAS mutational analysis provides useful additional risk stratification to guide use of chemotherapy.

Complete Mesocolic Excision With Central Vascular Ligation Produces an Oncologically Superior Specimen Compared With Standard Surgery for Carcinoma of the Colon

PURPOSE The plane of surgery in colonic cancer has been linked to patient outcome although the optimal extent of mesenteric resection is still unclear. Surgeons in Erlangen, Germany, routinely perform complete mesocolic excision (CME) with central vascular ligation (CVL) and report 5-year survivals of higher than 89%. We aimed to further investigate the importance of CME and CVL surgery for colonic cancer by comparison with a series of standard specimens. METHODS The fresh photographs of 49 CME and CVL specimens from Erlangen and 40 standard specimens from Leeds, United Kingdom, for primary colonic adenocarcinoma were collected. Precise tissue morphometry and grading of the plane of surgery were performed before comparison to histopathologic variables. RESULTS CME and CVL surgery removed more tissue compared with standard surgery in terms of the distance between the tumor and the high vascular tie (median, 131 v 90 mm; P < .0001), the length of large bowel (median, 314 v 206 mm; P < .0001), and ileum removed (median, 83 v 63 mm; P = .003), and the area of mesentery (19,657 v 11,829 mm(2); P < .0001). In addition, CME and CVL surgery was associated with more mesocolic plane resections (92% v 40%; P < .0001) and a greater lymph node yield (median, 30 v 18; P < .0001). CONCLUSION Surgeons in Erlangen routinely practicing CME and CVL surgery remove more mesocolon and are more likely to resect in the mesocolic plane when compared with standard excisions. This, along with the associated greater lymph node yield, may partially explain the high 5-year survival rates reported in Erlangen.

The Modern Abdominoperineal Excision: The Next Challenge After Total Mesorectal Excision

Objectives:Examine the cause of local recurrence (LR) and patient survival (S) following abdominoperineal resection (APR) and anterior resection (AR) for rectal carcinoma and the effect of introduction of total mesorectal excision (TME) on APR. Methods:A total of 608 patients underwent surgery for rectal cancer in Leeds from 1986 to 1997. CRM status and follow-up data of local recurrence and patient survival were available for 561 patients, of whom 190 underwent APR (32.4%) and 371 AR (63.3%). Also, a retrospective study of pathologic images of 93 specimens of rectal carcinoma. Results:Patients undergoing APR had a higher LR and lower survival (LR, 22.3% versus 13.5%, P = 0.002; S, 52.3% versus 65.8%, P = 0.003) than AR. LR free rates were lower in the APR group and cancer specific survival was lowered (LR, 66% versus 77%, log rank P = 0.03; S, 48% versus 59%, log rank P = 0.02). Morphometry: total area of surgically removed tissue outside the muscularis propria was smaller in APR specimens (n = 27) than AR specimens (n = 66) (P < 0.0001). Linear dimensions of transverse slices of tissue containing tumor, median posterior, and lateral measurements were smaller (P < 0.05) in the APR than the AR group. APR specimens with histologically positive CRM (n = 11) had a smaller area of tissue outside the muscularis propria (P = 0.04) compared with the CRM-negative APR specimens (n = 16). Incidence of CRM involvement in the APR group (41%) was higher than in the AR group (12%) (P = 0.006) in the 1997 to 2000 cohort. Similar results (36% and 22%) were found in the 1986 to 1997 cohort (P = 0.002). Conclusions:Patients treated by APR have a higher rate of CRM involvement, a higher LR, and poorer prognosis than AR. The frequency of CRM involvement for APR has not diminished with TME. CRM involvement in the APR specimens is related to the removal of less tissue at the level of the tumor in an APR. Where possible, a more radical operation should be considered for all low rectal cancer tumors.