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ETIOLOGY PATHOGENESIS CLINICAL FEATURES BY ALBIN JOSE,2002 MBBS ANATOMY OF RECTUM FROM RECTOSIGMOID JUNCTION END AT ANORECTAL JUNCTION 18-20 cm IN LENGTH ANATOMY CONTD. RECTUM HAS THREE LATERAL CURVATURES .UPPER AND LOWER CONVEX TO THE RIGHT .MIDDLE CONVEX TO THE LEFT * ON THE MUCOSAL ASPECT – SEMICIRCULAR FOLDS - HOUSTON'S VALVES ANATOMY CONTD. THE PART BELOW MIDDLE VALVE AMPULLA OF RECTUM ANATOMY CONTD. PERITONEAL RELATIONS UPPER THIRD – IN FRONT AND ON THE LATERAL ASPECTS MIDDLE THIRD – ANTERIOR SURFACE LOWER THIRD – NO PERITONEAL COVERING ANATOMY CONTD. ARTERIAL SUPPLY SUPERIOR RECTAL ARTERY MIDDLE RECTAL ARTERY INFERIOR RECTAL ARTERY ANATOMY CONTD. VENOUS DRAINAGE SUPERIOR HAEMORRHOIDAL VEINS → RECTAL VEINS → SUPERIOR RECTAL VEIN → INFERIOR MESENTERIC VEIN → PORTAL VEIN MIDDLE RECTAL VEIN ANATOMY CONTD. LYMPHATIC DRAINAGE UPPER HALF – PARARECTAL AND SIGMOID NODES → INFERIOR MESENTERIC NODES LOWER HALF – ALONG MIDDLE RECTAL VESSELS TO INTERNAL ILLIAC NODES ANATOMY CONTD. NERVE SUPPLY SYMPATHETIC ( L 1,L 2) VASOCONSTRICTORS INHIBITORY TO MUSCLES MOTOR TO INTERNAL SPHINCTER PAIN SENSATION ANTOMY CONTD. NERVE SUPPLY PARASYMPATHETIC (S2, S3, S4) MOTOR TO MUSCELES INHIBITORY TO INTERNAL SPHINCTER SENSATION OF DISTENTION ANATOMY CONTD. RELATIONS (males) .BLADDER .SEMINALVESICLES .PROSTATE .URETERS .PELVIC MUSCLES .SACRUM COCCYX ANATOMY CONTD. RELATIONS (females) POUCH OF DOUGLAS UTERUS CERVIX POST. VAGINAL WALL SACRUM COCCYX CARCINOMA OF RECTUM CARCINOMA OF RECTUM SECOND COMMENEST VICSERAL TUMOUR OF THE BODY COMMON ABOVE 50 yrs YOUNGER AGE – BAD PROGNOSIS MALE : FEMALE – 1.2 : 1 AETIOLOGY GE0GRAPHIC VARIATION DIETERY FACTORS PRE EXISTING DISEASES ADENOMA – CARCINOMA SEQUENCE HNPCC ALCOHOLISM, CIGARETTE SMOCKING PELVIC RADIOTHERAPY ACROMEGALY GEOGRAPHIC VARIATION DIETERY FACTORS EXCESS CALORIE INTAKE LOW CONTENT OF UNABSORBABLE VEGETABLE FIBRE HIGH CONTENT OF REFINED CARBOHYDRATES INTAKE OF RED MEAT DECREASED INTAKE OF PROTECTIVE MICRONUTRIENTS PREEXCISTING DISEASES INFLAMMATORY BOWELDISEASE ULCERATIVE COLITIS 1% PER YEAR AFTER 10 yrs 10% RISK AFTER 20 yrs CROHNS DISEASE 7% RISK AFTER 20 yrs COLONIC STRICTURESADENO CARCINOMA AT THE SITE OF FIBROTIC NARROWING EXCLUDED SEGMENTS AFTER SEGMENTAL BYPASS PREEXCISTING DISEASES CONTD. DIVERTICULAR DISEASE FOR LONG DURATION HNPCC HEREDITERY NON POLYPOSIS COLON CANCERS 4 – 6 % RECTAL MALIGNANCIES LYNCH SYNDROME 1 .AUTOSOMAL DOMINANT .SITE SPECIFIC WITHIN FAMILY .4% MAY DEVELOP CARCINOMA HNPCC LYNCH SYNDROME 2 AUTOSOMAL DOMINANT DELETION OF MISMATCH REPAIR GENE COLORECTAL,ENDOMETRIAL, GASTRIC AND OTHER TYPES OF CANCERS ADENOMA – CARCINOMA SEQUENCE PROPOSED BY VOGELSTIEN ADENOCARCINOMA DEVELOP FROM PREEXCISTING ADENOMA ADENOMA – CARCINOMA SEQUENCE CONTD. HIGH PREVELENCE ADENOMA HAS HIGH PREVELENCE OF CARCINOMA DISTRIBUTI0N OF ADENOMA WITHIN THE RECTUM IS COMPARABLE TO THAT OF CARCINOMA IN CASE OF EARLY INVASIVE Ca , SORROUNDING TISSUE SHOWS PRECEDING CHANGES OF EVOLUTION ADENOMA –CARCINOMA SEQUENCE CONTD. PEAK INCIDENCE OF ADENOMA ANTEDATES BY SOME YEARS THE PEAK OF Ca RECTUM RISK OF Ca DECLINES WITH REMOVAL OF ALL IDENTIFIED ADENOMAS ADENOMA –CARCINOMA SEQUENCE CONTD. RISK OF DELOPING CARCIN0OMA NUMBER SIZE – LARGE TYPE – VILLOUS COMPONENT AETIOLOGY CONTD. ALCOHOLISM CIGARETTE SMOCKING MOLECULAR CARCINOGENESIS APC/β-CATENIN PATHWAY MICROSATELLITE INSTABILITY MECHANISM APC/β-CATENIN PATHWAY LOSS OF APC TUMOUR SUPPRESSOR GENE LONG ARM OF CHROMOSOME 5 80% OF SPORADIC CASES ACCUMULATED β-CATENIN TRANSLOCATES TO THE NUCLEUS TRANSCRIPTION OF MYC & CYCLIN D PROMOTE CELLULAR PROLIFERATIONADENOMAS DEVELOP APC/β-CATENIN PATHWAY CONTD. POINT MUTATION IN K-RAS GENE EXCESSIVE ACTIVATION OF THIS GENE PROMOTES MITOSIS AND PREVENTS APOPTOSIS 50 % OF ALL RECTAL CARCINOMAS APC/β-CATENIN PATHWAY CONTD. 18 q21 DELETION CANCER SUPPRESSOR GENE LOST IN 6070 % OF CANCERS DCC GENE DPC 4 , SMAD 4 SMD 2 ENCODE FOR TGF-β REGULATOR OF CELL CYCLE APC/β-CATENIN PATHWAY CONTD. LOSS OF TP 53 GENE IN 70-80% OF CANCERS APC/β-CATENIN PATHWAY CONTD. MICROSATELLITE INSTABILITY 10-15% OF RECTAL CANCERS NO MORPHOLOGICALLY IDENTIFIABLE CHANGES LOSS OF DNA REPAIR GENES REPETITIVE DNA SEQUENCES BECOME UNSTABLE DURING REPLICATION TGF-β GENE BAX GENE LOSS OF MLH 1GENE LOSS OF THESE RESULTS IN LOSS OF APOPTOSIS AND A DYSREGULATED GROWTH MICROSATELLITE INSTABILITY PATHOLOGY MACROSCOPICAL ANNULAR ENCIRCLING LESIONS NAPKIN RING CONSTRICTIONS CENTRAL ULCERATIONS WITH ELEVATED MARGINS PAPILLEFEROUS INFILTRATING TYPE EARLY LESIONS ARE SMALL BUTTON LIKE AREAS OF ELEVATION MICROSCOPICAL 95% ARE ADENOCARCINOMAS MICROSCOPICAL 10% OF THESE ARE COLLOID CARCINOMAS MICROSCOPICAL 5 % ARE UNDIFFERENTIATED CARCINOMA SIGNET CELL CARCINOMA ADENO-SQUAMOS HISTOLOGICAL WELLDIFFERENTIATED MODERATELY DIFFERENTIATED POORLY DIFFERENTIATEDANAPLASTIC SPREAD OF THE CARCINOMA LOCAL SPREAD LYMPHATIC HAEMATOGENOUS SPREAD PERITONEAL DISSEMINATION LOCAL SPREAD CIRCUMFERENTIAL SORROUNDING MESORECTUM LOCAL SPREAD ANTERIOR IN MALES PROSTATE,BLADDER& SEMINAL VESICLES. IN FEMALES UTERUS ,CERVIX, POSTERIOR WALL OF VAGINA, POUCH OF DOUGLAS LOCAL SPREAD POSTERIOR SACRUM&SACRAL PLEXUS LATERAL- URETER DOWNWARD- ANAPLASTIC CARCINOMA LYMPHATIC ABOVE THE PERITONEAL REFLECTION- TO THE INFERIOR MESENTERIC NODES BELOW THIS LEVEL TO ABOUT 1-2cm OF THE ANAL ORIFICE IS ALSO TO THE INFERIOR MESENTERIC NODES IN THE FIELD OF MIDDLE RECTAL ARTERIES SPREAD ALONG THESE VESSELS PRE AORTIC,INTERNAL ILLIAC AND SACRAL LYMPH NODES HAEMATOGENOUS SPREAD VIA THE VENOUS SYSTEM ANAPLASTIC AND RAPIDLY GROWING TUMOURS SITES .LIVER- 34% .LUNGS- 22% .ADRENALS- 11% .BRAIN,BONE,OVARY33% PERITONEAL DISSEMINATION FOLLOW PENETRATION OF PERITONEAL CAVITY BY A HIGH LYING RECTAL CARCINOMA CLINICAL FEATURES BLEEDING EARLIEST, COMMON SYMPTOM FRESH BLEEDING BLOOD STAINING STOOLS BLOOD STAINING THE UNDER CLOTHINGS CLINICALFEATURES CONTD. SENSE OF INCOMPLETE DEFECATION TENESMUS - CANCERS OF LOWER RECTUM SPURIOUS DIARRHOEA BLOODY SLIME CLINICAL FEATURES CONTD. ALTERATION IN BOWEL HABIT EARLY MORNING BLOODY DIARRHOEA ANNULAR CARCINOMA- INCREASING CONSTIPATIION GROWTH AT AMPULLA OF RECTUMEARLY MORNING DIARRHOEA CLINICAL FEATURES CONTD. PAIN COLICKY TYPE- ADVANCED GROWTH AT RECTOSIGMOID JUNCTION SEVERE – DEEP CARCINOMATOUS ULCER ERODES THE PROSTATE OR BLADDER PAIN IN BACK OR SCIATICA – SACRAL PLEXUS CLINICAL FEATURES CONTD. WEIGHT LOSS ANAEMIA EXAMINATION ABDOMINAL EXAMINATION NORMAL IN EARLY LESIONS ADVANCED GROWTHSSIGNS OF LARGE INTESTINAL OBSTRUCTION, COLON LOADED WITH FAECES MAY BE FELT LIVER PALPATED FOR METASTASIS ASCITES EXAMINATION CONTD. PER RECTAL EXAMINATION EARLY CASES – PLATEAU OR A NODULE WITH AN INDURATED BASE CENTRE ULCERATION – SHALLOW DEPRESSION WITH EVERTED RAISED EDGES FINGER SMEARED WITH BLOOD OR MUCOPURELENT MATERIAL TINGED WITH BLOOD PER RECTAL EXAMINATION CARCINOMA OF LOWER PART AFFECTED LYMPH NODES MAY BE FELT EXAMINATION CONTD. IN FEMALES VAGINAL EXAMINATION SHOULD BE DONE SUMMARY STAGING OF CANCER DUKES STAGING A- GROWTH LIMITED TO THE RECTAL WALL STAGING B- THE GROWTH EXTENDED TO THE EXTRA RECTAL TISSUE BUT NO METASTASIS TO REGIONAL LYMPH NODES STAGING C- THERE ARE SECONDARY DEPOSITS IN THE REGIONAL LYMPHNODES .C 1- LOCAL PARARECTAL LYMPHNODES ALONE .C 2- NODES ACCOMPANYING THE SUPPLYING VESSELS STAGING D- PRESENCE OF WIDE SPREAD METASTASIS STAGING ASTER COLLER STAGING A- MUCOSA ONLY ASTER-COLLER STAGING B1- SUBMUCOSA INVOLVED ASTER-COLLER STAGING B2- MUSCULARIS INVOLVED ASTER-COLLER STAGING C1- INVOLVEMENT OF MUSCULARIS AND NODES ASTER-COLLER STAGING C2- INVOLVEMENT OF SEROSA AND NODES ASTER-COLLER STAGING D- DISTANT METASTASIS TNM STAGING Tx – PRIMARY TUMOUR CANNOT BE ASSESSED Tis – CONFINED TO THE MUCOSA T 1 - EXTEND UPTO SUBMUCOSA T 2 – EXTENDS INTO THE MUSCULARIS PROPRIA T 3 – EXTENDS IN TO THE SUB SEROSA BUT NOT TO ADJACENT STRUCTURES T 4 – INVOLVES ADJACENT STRUCTURES TNM STAGING Nx – CANNOT BE ASSESSED N O – NO LYMPH NODE METS. N 1 – CANCER CELLS FOUND IN 1 TO 3 NEARBY NODES N 2 – CANCER CELLS IN 4 OR MORE NODES N 3 – CANCER CELLS IN NODES ALONG NAMED VESSELS TNM STAGING Mx – DISTANT METS. CANNOT BE ASSESSED M 0 – NO DISTANT METS. M 1 – DISTANT METS. PRESENT