Colon Cancer with Conor Delaney
With Dr. Conor Delaney · hosted by Dr. Jeffrey Ponsky · StayCurrentMD
Cued at 6:13 · stops at 6:58 · press play
Educational content from recorded physician discussions — not medical advice. Talk to your (or your child's) care team about your situation.
Only a few other public items share this expert — go deeper there →
Video
Pediatric Surgical Oncology Research Collaborative (PSORC): Studying Rare Pediatric Tumors
56 s · Published May 2026
Video
Update Course Rewind 2025: Hirschsprung + ARM: Rare but Real
1 min · Published May 2026
Video
Update Course Rewind 2025: Hirschsprung + ARM: Rare but Real
1 min · Published May 2026
Video
Pooling Patients to Study Rare Pediatric Tumors: An Introduction to PSORC
56 s · Published May 2026
Video
The fetal frontier: A review of current and emerging fetal therapies for genetic diseases
44 s · Published May 2026
Video
Indocyanine green assists with sentinel lymph node mapping in pediatric and adolescent patients
1 min · Published May 2026
What the experts said
Colonoscopy is still the best test for colon cancer detection, finding the vast majority of cancers and polyps, though not perfect.
Serrated adenomas (previously misclassified as hyperplastic polyps, particularly large ones in the right colon) have genetic predisposition, tie into family cancer syndromes, and carry very high cancer risk.
Finding serrated adenomas requires family assessment for hereditary cancer syndromes and may necessitate changes in colonoscopy frequency and family member screening.
Serrated polyps can be flat and difficult to visualize; retroflexion in the cecum is increasingly used because they are often on the inferior or superior side of folds.
For rectal cancer, distal margin requirements are 5 cm if achievable, 2 cm if necessary, and 1 cm for very low tumors as long as they are not poorly differentiated.
The measurement '6 centimeters from the anal verge' varies significantly by patient body habitus and can represent different anatomical locations (anorectal ring vs. near dentate line).
Distant staging for rectal cancer is best performed with CT abdomen (for liver metastases) and CT chest (replacing chest X-ray per current guidelines).
MRI has become the standard for local staging of rectal cancer, with high-resolution, high-Tesla magnets using standardized protocols developed by Bill Heald and Gina Brown at the Royal Marsden.
MRI is particularly good at distinguishing T3 and T4 tumors and assessing circumferential resection margins, though less accurate at distinguishing T1 from T2.
Circumferential resection margin is the most important margin (or many think more important than distal margin) for preventing local recurrence in rectal cancer.
Historical local recurrence rates for rectal cancer from good institutions were 20–38%, with some series up to 50%.
With optimized surgery and imaging, local recurrence rates for rectal cancer should now be under 10%; Cleveland Clinic's rate over the last 10 years was about 3%.
Total mesorectal excision (TME) can be performed with about 5 mL of blood loss because it follows a bloodless embryological plane; bleeding indicates wrong plane unless deliberately outside TME plane.
Neoadjuvant therapy for rectal cancer is indicated for T3 tumors (outside the rectal wall) or node-positive disease.
Stage 1 rectal cancer (node-negative, T1 or T2), particularly in the upper third of the rectum, does not require neoadjuvant therapy.
MRI is 90 to mid-90s percent accurate for T-staging and high 80s to 90% accurate for nodal staging of rectal cancer.
Endoscopic ultrasound is only about 70% accurate for predicting nodal involvement in rectal cancer and is much more operator-dependent than MRI.
Transanal resection for rectal cancer is generally limited to T1 tumors less than one-third circumference and ideally less than 2 cm.
Historical local recurrence rates for transanally excised rectal cancers were about 18%, remarkably consistent across multiple centers.
Transanal endoscopic microsurgery (TEM) may produce better outcomes than traditional transanal excision, though it is unclear whether this is due to technology or improved surgical understanding.
For young, curable patients, radical resection is generally favored over transanal resection; transanal resection is typically reserved for patients unfit for radical surgery or those who would require permanent stoma.
For rectal cancer, full-thickness excision is required; ESD or EMR is never appropriate for proven cancer, only for benign polyps.
Short-course radiation (5×5 Gy over 5 days, surgery 1–2 weeks later) is commonly used in Europe; long-course chemoradiation (40–45 Gy over 6 weeks with 6–8 week wait) is standard in the US.
25 Gy over a short period is radiotherapeutically equivalent to 40–45 Gy over a longer period, but long-course therapy may produce better tumor downstaging for bulky tumors.
For colon cancer, at least 12 lymph nodes are required for adequate staging, though many surgeons aim for at least 16.
High ligation of the inferior mesenteric artery (above the takeoff of the left colic artery) is standard for sigmoid colectomy, with protection of autonomic nerves to preserve sexual function.
Total mesocolic excision for colon cancer should be performed with about 5 mL of blood loss in the embryological plane between retroperitoneal peritoneum (Toldt's fascia) and mesocolic peritoneum.
Scandinavian data showed local recurrence rates for colon cancer were even higher than for rectal cancer (high 20s%) before focus on complete mesocolic excision technique.
For cecal or ileocecal valve tumors, 10 cm of small bowel should be resected; for mid-ascending colon tumors, 5 cm of small bowel is adequate.
Extracorporeal stapled anastomosis for right hemicolectomy achieved a leak rate of 0.8% over 1000 cases at Cleveland Clinic.
Genetic assessment is indicated for colorectal cancer patients with Bethesda criteria risk factors, cancer under age 40, first-degree relatives with cancer, or multiple cancers in the family.
Genetic diagnosis affects both family screening recommendations and surgical approach; patients with hereditary syndromes may require subtotal colectomy or proctocolectomy rather than segmental resection.