The rationale behind complete mesocolic excision (CME) and a central vascular ligation for colon cancer in open and laparoscopic surgery : proceedings of a consensus conference

BACKGROUND

It has been evident for a while that the result after resection for colon cancer may not have been optimal. Several years ago, this was showed by some leading surgeons in the USA but a concept of improving results was not consistently pursued. Later, surgeons in Europe and Japan have increasingly adopted the more radical principle of complete mesocolic excision (CME) as the optimal approach for colon cancer. The concept of CME is a similar philosophy to that of total mesorectal excision for rectal cancer and precise terminology and optimal surgery are key factors.

METHOD

There are three essential components to CME. The main component involves a dissection between the mesenteric plane and the parietal fascia and removal of the mesentery within a complete envelope of mesenteric fascia and visceral peritoneum that contains all lymph nodes draining the tumour area (Hohenberger et al., Colorectal Disease 11:354-365, 2009; West et al., J Clin Oncol 28:272-278, 2009). The second component is a central vascular tie to completely remove all lymph nodes in the central (vertical) direction. The third component is resection of an adequate length of bowel to remove involved pericolic lymph nodes in the longitudinal direction.

RESULT

The oncological rationale for CME and various technical aspects of the surgical management will be explored.

CONCLUSION

The consensus conference agreed that there are sound oncological hypotheses for a more radical approach than has been common up to now. However, this may not necessarily apply in early stages of the tumour stage. Laparoscopic resection appears to be equally well suited for resection as open surgery.

Evaluation of the seventh edition of the tumour, node, metastasis (TNM) classification for colon cancer in two nationwide registries of the United States and Japan

AIM

The new TNM classification is currently being implemented. We evaluated the TNM-7 staging system based on the two nationwide colon cancer registries in the United States and Japan to clarify whether this system better stratifies patients' prognoses than the TNM-6 did and to determine whether stratification can be effectively simplified.

METHODS

The Surveillance, Epidemiology, and End Results population-based data from 1988 to 2001 for 50139 colon cancer patients and the multi-institutional registry data from the Japanese Society for Cancer of the Colon and Rectum from 1984 to 1994 for 10754 patients were analysed. We devised a modified version of the TNM-7 staging system to allow simpler classification of the TN categories and compared the TNM-6, TNM-7, modified TNM-7, and the Dukes staging system based on survival curves and objective statistical tests such as likelihood ratio χ(2) tests, Akaike's information criterion, and Harrell's c-index.

RESULTS

The TNM-7 was superior to the TNM-6 in all objective statistical tests in the United States (c-index; 0.700 vs 0.696, P<0.001) as well as in the Japan data sets (0.732 vs 0.729, P=0.035). The modified TNM-7 is much simpler, but it nevertheless showed similar values to those of the original TNM-7 (c-index; the United States 0.702, Japan 0.733).

CONCLUSIONS

  The new TNM-7 is complicated but better at stratifying patients than the TNM-6 in the United States and Japan, and could be effectively simplified.

Safety of UFT/LV and S-1 as adjuvant therapy for stage III colon cancer in phase III trial: ACTS-CC trial

BACKGROUND

The Adjuvant Chemotherapy Trial of TS-1 for Colon Cancer (ACTS-CC) is a phase III trial designed to validate the non-inferiority of S-1 to UFT/leucovorin (LV) as postoperative adjuvant chemotherapy for stage III colon cancer. We report the results of a planned safety analysis.

METHODS

Patients aged 20-80 years with curatively resected stage III colon cancer were randomly assigned to receive UFT/LV (UFT, 300 mg m(-2) per day as tegafur; LV, 75 mg per day on days 1-28, every 35 days, 5 courses) or S-1 (80, 100, or 120 mg per day on days 1-28, every 42 days, 4 courses). Treatment status and safety were evaluated.

RESULTS

Of 1535 enrolled patients, a total of 1504 (756 allocated to S-1 and 748 to UFT/LV) were analysed. The completion rate of protocol treatment was 77% in the S-1 group and 73% in the UFT/LV group. The overall incidence of adverse events (AEs) were 80% in S-1 and 74% in UFT/LV. Stomatitis, anorexia, hyperpigmentation, and haematological toxicities were common in S-1, whereas increased alanine aminotransferase and aspartate aminotransferase were common in UFT/LV. The incidences of grade 3 AEs were 16% and 14%, respectively.

CONCLUSION

Although AE profiles differed between the groups, feasibility of the protocol treatment was good. Both S-1 and UFT/LV could be safely used as adjuvant chemotherapy.

Transient ligation of umbilical vessels elevates placental tissue oxygen index (TOI) values measured by near-infrared spectroscopy (NIRS) in clawn miniature pig animal model

We recently found a significant elevation in placental tissue oxygen index (TOI) values in cases of fetal growth restriction using near-infrared spectroscopy (NIRS), indicating high oxygenation in the placental tissue. We hypothesized that insufficient fetoumbilical blood flow is causatively associated with high oxygenation levels in placental tissue. We transiently (for 15 sec) ligated the whole umbilicus, umbilical arteries, or veins of pregnant Clawn miniature pigs (102-113 days of gestation) and assessed the changes in TOI values of the placenta and fetus. The ligation significantly increased placental TOI values (p<0.01, respectively), but concomitantly decreased fetal TOI values (p<0.01, respectively), suggesting a decline in oxygen inflow from the maternal to fetal circulation in the placental tissue to be causative of the elevated placental TOI values. These observations suggest the promising clinical use of placental TOI values measured noninvasively by the transabdominal application of NIRS to assess the fetoplacental circulation.

Seismic Velocity Structure of the EDZ Around Drifts at the Kamaishi and Tono Mines in Japan

The excavation disturbed zone (EDZ) is defined as the rock zone where rock properties and conditions have been changed due to the processes induced by excavation, such as excavation damage, stress redistribution and desaturation. In-situ excavation disturbance experiment has been performed to determine the rock properties and width of the EDZ at the Kamaishi and Tono mines in Japan. Rock mass fails when blasting vibration velocity exceeds limit velocity so that we can estimate excavation damaged zone from vibration measurement. The width of the zone where blasting vibration velocity exceeded the limit velocity is roughly consistent with the width of low seismic velocity layer detected from the seismic refraction survey at both mines.

Six months compared with 12 months of capecitabine as adjuvant chemotherapy for stage III (Dukes' C) colon cancer: Rationale for the open-label randomized phase III study, JFMC37-0801

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Background: The standard duration of adjuvant chemotherapy (CT) in patient with stage III colorectal cancer is 6 months. On the other hand, no clinical trial which investigate an optimal duration of oral chemotherapeutic agents has yet been implemented for adjuvant treatments. According to the ACCENT database (Sargent, et al. J Clin Oncol 27: 872- 877, 2009), 83% of recurrences in stage II and III pts have occurred within the first 3 years after surgery and peak was observed around one year after surgery. Also, single-agent FU-based adjuvant CT reduced the hazard rate of OS, DFS, and TTR, although the peak of events around one year was still remained especially for stage III pts. We analyzed the data of recurrent risk of curatively resected colon cancer pts provided by JFMC7-1-7-2-15, X-ACT. Surgery alone group and 6 months CT (5FU/LV or capecitabine [Cape]) showed highest peak between 12 months to 18 months after surgery, but 12 months oral 5-FUs group did not show recurrence peak between 12 months to 18 months after surgery. Therefore, to clarify the benefit of 12 month administration of Cape, we planned a phase III randomized trial for a comparison of 6 months treatment and 12 months treatment.

Methods: JFMC37 is a multicenter, randomized phase III trial. Patients with fully resected stage III colon or recto sigmoid cancer were eligible. Patients were randomized 1:1 to receive Cape of 6 months (arm A) or Cape of 12 months (arm B). Primary endpoint is disease-free survival. The statistical design is based on superiority hypothesis; 5-yrs DFS is 60% in arm A, 67% in arm B; unilateral α=0.05, 1-β=0.8; and planed accrual is 1200 pts.

Results: Between September 2008 to December 2009, 1,304 pts were randomized. Patients characteristics are (armA/armB); number 653/651, gender M352-F301/M343-F308, median age 65 years/65 years, ECOG PS=0-1 620-33/632-19, involvement of lymph nodes=N0-N1-N2 503-130-20/499-128-24. There were no differences in baseline characteristics between arm A and arm B.

Conclusions: This trial is expected to show if 1 year adjutant chemotherapy with capecitabine can reduce the peak of recurrence in 1 year and provide long-term OS benefit.

[Table: see text]

The final report of post-marketing surveillance for cetuximab in colorectal cancer in Japan

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Background: Cetuximab (ERBITUX) was approved in Jul 2008 in Japan with indication for EGFR-positive and unresectable metastatic or refractory colorectal cancer. Post-marketing surveillance is required by Japanese Health Authority to collect, obtain, verify or validate information on the safety, efficacy and quality of medicines. We conducted this surveillance in all patients treated with cetuximab to access in practical use since clinical data on Japanese patients are limited.

Methods: The target number of patients was 1,800. Following adverse drug reactions were investigated: infusion reaction, skin disorders, interstitial lung diseases, electrolyte abnormalities (including hypomagnesemia), heart toxicities, gastrointestinal disorders, thrombosis/embolism, delayed wound healing, and eye disorders.

Results: Between Sep 2008 until Jan 2010, 2,126 pts registered, 2,006 pts were evaluable for safety (safety population), 1,687 pts for efficacy (efficacy population). Of the 2,006 pts, 1,975 pts (98.5%) were EGFR-positive. Patients characteristics: male/female; 1,234/772 (61.5%/38.5%), median age; 64 (range 18-87), site of primary tumor; colon/rectal/others (multiple selection); 1,235/775/3 (61.6%/38.6%/0.2%), PS0/PS1; 1,370/630 (68.3%/31.4%), combination chemotherapy; cetuximab monotherapy/CPT-11/FOLFIRI: 460/1,255/256 (22.9%/62.56%/12.8%). Of the 2,006 pts, 133 pts (6.6%) and 1,869 pts (93.2%) were treated in second-line and in third-line or later treatment, respectively. The adverse drug reactions incidence was 89.9%. Incidence of skin disorders, gastrointestinal disorders, electrolyte abnormality including hypomagnesaemia, and infusion reaction were 83.7%, 23.1%, 11.5%, and 5.7%, respectively. Efficacy result: Of the 1,687 pts, 658 pts (39.0%) were evaluated to be effective. Of the 658 pts, 614 pts (93.3%) experienced skin adverse reactions.

Conclusions: This post-marketing surveillance confirms the safety and efficacy of cetuximab in the Japanese population treated in clinical practice. The outcome of this surveillance with Japanese 2,006 pts would be useful for clinical use of cetuximab.

[Table: see text]

Clinicopathological features in metastatic colorectal cancer patients with KRAS wild type compared with codon 12 and codon 13 mutant: Results from a multicenter, cross-sectional study by the Japan study group of KRAS mutation in colorectal cancer

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Background: The KRAS mutation mainly located in the codon 12 and 13 indicates unresponsiveness of patients with metastatic colorectal cancer (CRC) to anti-epidermal growth factor receptor (EGFR) antibodies. Many studies have reported that approximately 30%-40% of CRC patients have KRAS mutations. However, the clinicopathological features of KRAS mutant CRC have not been fully clarified, especially in Asian populations. This study aimed to clarify the clinicopathological features of KRAS mutant CRC in comparison with KRAS wild type in large-scale Japanese population.

Methods: The key eligibility criteria included histologically confirmed colorectal adenocarcinoma with adequate tumor samples. Formalin-fixed paraffin-embedded tumor blocks or thinly sliced tumor sections from 389 centers were sent to commercial laboratories. Almost all KRAS point mutations in the codon 12 and 13 were investigated by direct sequencing (96%). The logistic regression analysis was used to estimate the odds ratios (ORs) and compute 95% confidential intervals (CIs).

Results: Of 5,887 registered tumor samples between Oct. 2009 and Mar. 2010, the KRAS testing were performed for 5,790 samples. As of the cut-off date, Sep. 2010, we have successfully determined the KRAS mutational status of 5,732 samples (99%).The median age was 65 years old, and 61% were male. The primary tumor site was right colon, left colon, and rectum in 30, 38, and 32% patients, respectively. The frequency of KRAS mutation was 37.6% (2,155/5,732), of which the 80% (1,714/2,155) mutations were located in codon 12. On logistic regression analysis, female gender (OR=1.212, 95% CI=1.083-1.356), older age > 50 years (OR=1.312, CI=1.056-1.628) and right colon (versus left: OR=2.177, CI=1.905- 2.489; versus rectum: OR=1.500, CI=1.308-1.720) were independent risk factors of KRAS mutant CRC. Clinicopathological features were similar between codon 12 and 13 mutant CRC.

Conclusions: This study disclosed that KRAS mutant CRC was different from KRAS wild type CRC in terms of clinicopathological features.

No significant financial relationships to disclose.