Asia-Pacific Journal of Clinical OncologyCochrane Highlights

These highlights are produced with permission from the Cochrane Collaboration. To read the fullfindings and any updates, please visit: http://www.thecochranelibrary.com

Chromoscopy versusconventional endoscopy forthe detection of polyps in thecolon and rectum

Colonoscopy is a diagnostic testthat enables small growths in thebowel (polyps) to be detected.These lesions can develop intocancer in approximately 5% of thecases. Although the test is themost sensitive test that exists forthe detection of these growths,some may be missed. If a simpledye spraying technique(chromoscopy) is used with thecolonoscopic test, the detection ofthese lesions may be enhanced.Several studies have examined theeffect of chromoscopy onenhancing polyp detection but thedata is inconsistent. This reviewinvestigated whether chromoscopycan enhance polyp detectioncompared with conventionalcolonoscopy.

Five randomised trials with a totalof 1059 participants wereincluded. Despite differenceswithin the study designs thereappears to be strong evidence thatchromoscopic colonoscopyenhances the detection of polypsin the colon and rectum.

Brown SR, Baraza W.Chromoscopy versus conventionalendoscopy for the detection of

polyps in the colon and rectum.Cochrane Database of SystematicReviews 2010, Issue 10. Art. No.:CD006439. DOI: 10.1002/14651858.CD006439.pub3

Early enteral nutrition within24h of colorectal surgeryversus later commencementof feeding for postoperativecomplications

There is no obvious advantage inkeeping patients ‘nil by mouth’following gastrointestinal surgery,and this review support the notionon early commencement. Thereview implicated lower incidenceof several post operativecomplications. The immediateadvantage of caloric intake couldbe a faster recovery with fewercomplications. Length of hospitalstay was reduced in nine out offourteen studies. Overall reductioncorresponded to about a day,which is both clinically andeconomically important.Reduction in complication ratesmay explain this observation asmight faster return ofgastrointestinal function uponearly commencement of enteralfeeding.

Andersen HK, Lewis SJ, ThomasS. Early enteral nutrition within24h of colorectal surgery versuslater commencement of feeding for

postoperative complications.Cochrane Database of SystematicReviews 2006, Issue 4. Art. No.:CD004080. DOI: 10.1002/14651858.CD004080.pub2

Energy source instrumentsfor laparoscopic colectomy

Having a laparoscopic (key-hole)approach in surgery to remove asection of a diseased bowel, eithercaused from a benign or cancerouslesion is becoming increasinglycommon. There are three kinds ofsurgical instruments available forthis procedure; these aremonopolar electrocautery scissors(MES), ultrasonic coagulatingshears (UCS) and electrothermalbipolar vessel sealers (EBVS). Thisreview aims to examine theeffectiveness and safety of thesethree instruments. The findingsshowed that UCS results in lessblood loss when compared toMES. Operating time was shorterwhen EBVS was used compared toMES. No marked difference wasobserved between UCS and EBVS.No difference in complicationsbetween all three instruments werereported in the findings. However,it is recognised that more trials areneeded to support the evidenceprovided in this report.

Tou S, Malik AI, Wexner SD,Nelson RL. Energy source

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instruments for laparoscopiccolectomy. Cochrane Database ofSystematic Reviews 2011, Issue 5.Art. No.: CD007886.DOI: 10.1002/14651858.CD007886.pub2

Perioperative bloodtransfusions and recurrenceof colorectal cancer

This review include 36 studies,identified from 278 referencesretrieved until December 2009,and report a moderate associationbetween colorectal cancerrecurrence and perioperativetransfusions, with an OR of 1.42(95% CI, 1.20 to 1.67). Similarestimates are present in severalsubgroup meta-analyses, as well asin meta-analyses stratified forknown risk factors. These findingssupport carefully restrictedindications for perioperative bloodtransfusions in colorectal cancerpatients operated for cure, andcontinue to await the results ofstudies addressing the role ofsurgeon-related risk factors on theneed for transfusion and diseaserecurrence.

Amato A, Pescatori M.Perioperative blood transfusionsand recurrence of colorectalcancer. Cochrane Database ofSystematic Reviews 2006, Issue 1.Art. No.: CD005033.DOI: 10.1002/14651858.CD005033.pub2

Postoperative adjuvantchemotherapy in rectal canceroperated for cure

The use of chemotherapy aftercurative surgery for non metastaticrectal cancer is widely used in theUS, but not in Europe. This

systematic review andmeta-analysis, which is the first inthis field, shows a significantbeneficial effect on both overall(OS) and disease-free survival(DFS) for patients undergoingpostoperative chemotherapy afterremoval of their primary rectaltumour. Further investigation isneeded to define the role ofpostoperative chemotherapy in themultimodal treatment of patientswith rectal carcinoma: forinstance, modern anti-canceragents (including so called “smartdrugs”) and integration withneoadjuvant therapy (such aspreoperative chemoradiation)should be taken into considerationin order to improve theencouraging findings of thismeta-analysis.

Petersen SH, Harling H, KirkebyLT, Wille-Jørgensen P, Mocellin S.Postoperative adjuvantchemotherapy in rectal canceroperated for cure.. CochraneDatabase of Systematic Reviews2012, Issue 3. Art. No.:CD004078. DOI: 10.1002/14651858.CD004078.pub2

Pre-operative chemoradiationfor non-metastatic locallyadvanced rectal cancer

We compared radiotherapy withchemotherapy and radiotherapybefore surgery in rectal cancer. Welooked at people who had rectalcancer that had spread to thelymph glands but not to the liveror other organs.

We found that both groups hadthe same number of people aliveafter 5 years. In other words;neither treatment was better atmaking people live longer thanthe other. People who had

chemotherapy and radiotherapyhad more short term problems(such as diarrhoea) than peoplewho just had radiotherapy.However, we found that peoplewho had both treatments had lesscancer return at the site of theoriginal tumour after 5 years. Thisis an important finding andsuggests that this treatment is maybe more beneficial.

McCarthy K, Pearson K, Fulton R,Hewitt J. Pre-operativechemoradiation for non-metastaticlocally advanced rectal cancer.Cochrane Database of SystematicReviews 2012, Issue 12. Art. No.:CD008368. DOI: 10.1002/14651858.CD008368.pub2

Preoperative chemoradiationversus radiation alone forstage II and III resectablerectal cancer

Patients with cancer of the rectum,the end part of the large bowelimmediately above the anus, aretreated with surgery. When thetumour is deemed to present ahigh risk of recurrence aftersurgery, a course of radiotherapy(RT) is administered before theoperation. It has been proven inclinical studies that this‘preoperative’ radiotherapyimproves the outcome in rectalcancer patients. Recently, severalstudies have investigated thecombination of radiotherapy withchemotherapy (CRT) beforesurgery. In theory, addingchemotherapy enhances theantitumour activity ofradiotherapy. This meta-analysishas summarized the results of fivestudies that compared preoperativeRT alone with preoperative CRTin rectal cancer patients. All ofthese studies were randomized,

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which means that the decision toadminister either RT or CRT wasdetermined by chance (ballotdraw). The results of themeta-analysis may be summarizedas follows. Compared to RTalone, preoperative CRT leads toincreased side effects duringtreatment. Also, postoperativecomplications are somewhatincreased, although the risk ofdying from postoperativecomplications is similar.Preoperative CRT is more effectivein causing tumour shrinkage(downstaging), and in preventinglocal recurrence of the disease.However, addition ofchemotherapy did not result inmore sphincter preservingsurgeries, and did not affect theoverall survival in rectal cancerpatients.

De Caluwé L, Van NieuwenhoveY, Ceelen WP. Preoperativechemoradiation versus radiationalone for stage II and IIIresectable rectal cancer. CochraneDatabase of Systematic Reviews2013, Issue 2. Art. No.:CD006041. DOI: 10.1002/14651858.CD006041.pub3

Propofol for sedation duringcolonoscopy

Irrespective of the initial screeningtest, colonoscopy is the final stepin colorectal cancer screening.With the advent of the colorectalcancer screening programs inmany countries, an increasingnumber of colonoscopies are beingperformed each year. Sedation forcolonoscopy can improve patients’tolerance of the procedure andenhance colonoscopy completionrates. There is no consensus on thepreferred drugs for sedationduring colonoscopy. This review

found that use of propofol forsedation during colonoscopy canlead to faster recovery after theprocedure and higher patientsatisfaction, without any increasein side-effects as compared to theuse of drugs traditionally used(narcotics and/or benzodiazepines)for sedation during colonoscopy.

Singh H, Poluha W, Cheang M,Choptain N, Inegbu E, Baron K,Taback SP. Propofol for sedationduring colonoscopy. CochraneDatabase of Systematic Reviews2008, Issue 4. Art. No.:CD006268. DOI: 10.1002/14651858.CD006268.pub2

Resection versus nointervention or other surgicalinterventions for colorectalcancer liver metastases

Almost half of patients withcolorectal cancer developmetastases many of which arelocated in the liver, and a quarterof which may be amendable tosurgery. If all disease is removedthese patients have a 30% to 50%chance of survival at five years.Treatment options include surgicalremoval of the diseased section ofthe liver as well as othermodalities such as cryosurgery andradiofrequency thermal ablation.Although new treatments allowsafe destruction of livermetastases, often without the needfor major surgery, there are still noclear guidelines on the appropriatemanagement of patients withcolorectal cancer liver metastases.Only one low quality study whichreported improved disease-freesurvival in patients whounderwent cryosurgery comparedwith conventional techniques, wasincluded in this review.

There is very limited evidence tosupport the effectiveness orotherwise of a single approach,either surgical resection or othersurgical procedure for themanagement of colorectal livermetastases. Further research isrequired to evaluate the effects ofthese treatment options and theirrole in increasing disease-freesurvival and in decreasingrecurrence. Treatment decisionsshould continue to be based onindividual circumstances andclinician’s experience.

Fedorowicz Z, Lodge M, Al-asfoorA, Carter B. Resection versus nointervention or other surgicalinterventions for colorectal cancerliver metastases. CochraneDatabase of Systematic Reviews2008, Issue 2. Art. No.:CD006039. DOI: 10.1002/14651858.CD006039.pub4

Screening for colorectalcancer using the faecal occultblood test, Hemoccult

Regular screening of faeces forblood can detect colorectal cancerearlier and hence may reducemortality in populations at risk,such as older patients. Thescreening test used in these trialsto detect colorectal (bowel)cancer was the faecal occultblood test (FOBT). If the FOBTis positive, the bowels areexamined closely with furtherdiagnostic test (coloscopy, flexiblesigmoidoscopy, double-contrastbarium enema), but these testsoften cause discomfort and cancause serious adverseconsequences. As blood identifiedin faeces may be due to severalreason (unrelated to cancer), itmay cause people unnecessarystress and expose them to

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possible harm. This review foundthat FOBT screening is likely toavoid approximately 1 in 6colorectal cancer deaths.

Hewitson P, Glasziou PP, Irwig L,Towler B, Watson E. Screening forcolorectal cancer using the faecaloccult blood test, Hemoccult.

Cochrane Database of SystematicReviews 2007, Issue 1. Art. No.:CD001216. DOI: 10.1002/14651858.CD001216.pub2

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