COLORECTAL CANCER STAGING in 2010 Robert A. Halvorsen, MD, FACR MCV Hospitals / VCU Medical Center Richmond, Virginia I do not have any relevant financial relationships with any commercial interests
COLON RECTUM Colon: local resection possible? Almost always if no metastases Rectum: local resection not possible if fixed Fixed then pre-op Rad Rx
RECTAL CANCER Higher recurrence rate than colon cancer Due to extensive lymphatic drainage of pelvis
SURGERY Only cure for colon cancer Surgery for all: palliation or attempted cure Palliation: colostomy
COLON RECTUM Colon cancer surgery Rectal cancer: surgery or pre op RAD Rx
SURGICAL PRINCIPLES Very low resections possible Anastomosis w/i 1cm dentate Proximal margin 2.5cm OK Limiting factor: Radial margin Males lower survival Prostate limits resection
AP RESECTION Operative mortality: 2-6% Permanent colostomy Complications: 23-75% Urinary retention Impotence Infection
TOTAL MESORECTAL EXCISION Resect rectum, meso-rectal fascia, perirectal fat, vessels & nodes Improves prognosis Replaces AP resections Protects sphincter function
MESORECTAL FASCIA Mesorectal compartment inside fascia contains: Rectum Mesorectal fat Blood vessels Lymphatic vessels and lymph nodes NOT the nerves to the rectal sphincter!
LUNG METS NO LIVER METS Think low rectal cancer Lymphatics follow venous drainage Drainage: internal hemorrhoidal vein to IVC, not portal vein Lung, not liver metastases
LOW RECTAL CANCER Search for metastases: Para-aortic nodes Lung metastases Abdominal/pelvic CT & Chest CT!
RECTUM COLON
STAGING OPTIONS: 2010 CT of abdomen and pelvis CT of chest, abdomen and pelvis PET/CT PET/CT Colonography MR: High-resolution MR with rectal coil 3T MR Trans-rectal ultrasound
STAGING CHOICE CT chest, abdomen and pelvis first Then PET or PET/CT Then? It depends Colon cancer: stop! Rectal cancer: local choice: EUS vs MRI
STAGING COLORECTAL CANCER T: Not important for colon cancer Local invasion is resectable T: Important for rectal cancer Select patients for neo adjuvant Rx Help determine surgical approach Laparotomy, laparoscopy trans-anal excision Veit-Haibach: JAMA 2006
MDCT: COLORECTAL CANCER Accuracy Improved Axial CT Axial & MPR T Staging 73% 83% N Staging 59% 80% (p<0.01) Fillipone: Radiology 2004
MPR: RECTAL CANCER USEFUL Rectal wall invasion Infiltration mesorectum Invasion adjacent vessels, organs
LIMITATIONS Trans-rectal ultrasound: Stenotic cancer: if probe cannot pass then TRUS inadequate Rectal probe: Disposable, expensive, uncomfortable and requires careful positioning
STAGING Colon cancer: CT good for metastases PET/CT good/better for mets Rectal cancer: CT & PET/CT EUS good for local invasion MRI great for meso-rectal invasion
COMPARISON STUDIES PET/CT > CT alone TRUS and MR with or without endorectal coil better than CT or MR for wall penetration or nodes
STAGING COLORECTAL CANCER Prospective trial [n = 47] Compared CT, PET/CT and PET/CT Colonography Veit-Haibach: JAMA 2006
STAGING COLORECTAL CANCER Results: 50 lesions in 47 patients TNM Staging: Better with PET/CT than CT alone Colonography improved T staging
PET: COLORECTAL CANCER LIMITATIONS Mucinous tumors: lower FDG uptake Limited value: T staging N staging reports: Sensitivity: 29-37% Specificity: 83-96%
PET/CT & COLORECTAL CANCER BENEFITS Very successful in detecting distant metastases, altering operative planning
PET/CT & COLORECTAL CANCER BENEFITS Liver mets: PET/CT & CT comparable CT has advantage of multiple phase scanning: hepatic arterial & portal venous phases PET disadvantage: mucinous or small tumors
PET/CT & COLORECTAL Peritoneal mets: CANCER 10-15% of patients at the time of diagnosis! CT sensitivity: 64% PET/CT sensitivity: 89% Selznen: Ann Surg 2004
PET and COLORECTAL CANCER PET promise: more lesions detected than CT alone 11 of 36 patients (31%) Changed Rx: 16% Kantorová: JNM 2003
PET and COLORECTAL CANCER PET problem: Small nodes Sensitivity = 29% Specificity = 88% Kantorová: JNM 2003
COMPARISON STUDIES Nodes are the problem CT, MR, TRUS false positive: 30% MR with endorectal coil false positive: 20%
LOCAL INVASION More dependent upon circumferential tumor spread than longitudinal Local recurrence: 83% of pts with circumferential positive margin developed local recurrence
MESORECTAL FASCIA Surrounds rectum Contains mesorectal fat Defines surgical margin Visible on MR
MR TECHNIQUE No endorectal coil necessary Use phased array surface coil Slices perpendicular to long axis Contrast not proven to be useful
MR RESULTS RECTAL CANCER Penetration through meso-rectal fascia Call positive if tumor within 1mm Accuracy: 95% Bissett: Dis Colon Rectum 2001
CONCLUSION Chest CT for rectal cancer MDCT first, use MPR PET if no mets on CT Predict local invasion for rectal, not colon cancer with TRUS or MRI
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