# Colon Cancer — GCMD Library living collection

Everything in the library about colon cancer — built automatically from dossiers that name it.

Updated: n/a · 2 episodes · 60 cited statements

## Episodes
### In-Depth Reviews
- [Colon Cancer with Conor Delaney](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443) — podcast · 26:50 · [machine version](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443.md)
- [Colorectal Cancer](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749) — podcast · 26:42 · [machine version](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749.md)

## Chapters
- [0:00](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=0) Introduction and Serrated Adenomas in Colonoscopy (Ep 1)
- [3:03](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=183) Rectal Cancer Location and Surgical Margins (Ep 1)
- [7:00](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=420) Rectal Cancer Staging with MRI and Circumferential Resection Margin (Ep 1)
- [11:33](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=693) Neoadjuvant Therapy Indications and Transanal Resection (Ep 1)
- [15:58](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=958) ESD vs Full-Thickness Excision for Rectal Lesions (Ep 1)
- [17:18](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=1038) Sigmoid and Colon Cancer Surgical Principles (Ep 1)
- [21:22](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=1282) Right Hemicolectomy Technique and Anastomosis (Ep 1)
- [24:12](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=1452) Genetic Assessment and Hereditary Cancer Syndromes (Ep 1)
- [0:00](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=0) Introduction and colonoscopy screening (Ep 2)
- [2:03](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=123) Serrated adenomas: recognition and management (Ep 2)
- [4:16](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=256) Rectal cancer: location and surgical margins (Ep 2)
- [9:03](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=543) Rectal cancer staging: MRI versus ultrasound (Ep 2)
- [14:07](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=847) Transanal resection: indications and limitations (Ep 2)
- [16:58](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=1018) Neoadjuvant therapy for rectal cancer (Ep 2)
- [19:22](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=1162) Sigmoid and left colon cancer surgery (Ep 2)
- [22:29](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=1349) Right colon and cecal cancer surgery (Ep 2)
- [24:13](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=1453) Genetic assessment and hereditary syndromes (Ep 2)

## Statements
Every statement is attributed, typed, and timestamped; the link is the citation.
- "Colonoscopy is still the best test for colon cancer detection, finding the vast majority of cancers and polyps, though not perfect." — Conor Delaney (clinical) [Ep 1 · 1:16](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=76)
- "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." — Conor Delaney (clinical) [Ep 1 · 2:05](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=125)
- "Finding serrated adenomas requires family assessment for hereditary cancer syndromes and may necessitate changes in colonoscopy frequency and family member screening." — Conor Delaney (guideline) [Ep 1 · 2:42](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=162)
- "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." — Conor Delaney (clinical) [Ep 1 · 3:27](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=207)
- "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." — Conor Delaney (clinical) [Ep 1 · 6:13](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=373)
- "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)." — Conor Delaney (clinical) [Ep 1 · 7:25](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=445)
- "Distant staging for rectal cancer is best performed with CT abdomen (for liver metastases) and CT chest (replacing chest X-ray per current guidelines)." — Conor Delaney (guideline) [Ep 1 · 9:31](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=571)
- "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." — Conor Delaney (clinical) [Ep 1 · 9:50](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=590)
- "MRI is 90 to mid-90s percent accurate for T-staging and high 80s to 90% accurate for nodal staging of rectal cancer." — Conor Delaney (clinical) [Ep 1 · 13:37](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=817)
- "Endoscopic ultrasound is only about 70% accurate for predicting nodal involvement in rectal cancer and is much more operator-dependent than MRI." — Conor Delaney (clinical) [Ep 1 · 13:56](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=836)
- "MRI is particularly good at distinguishing T3 and T4 tumors and assessing circumferential resection margins, though less accurate at distinguishing T1 from T2." — Conor Delaney (clinical) [Ep 1 · 10:27](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=627)
- "Historical local recurrence rates for rectal cancer from good institutions were 20–38%, with some series up to 50%." — Conor Delaney (epidemiological) [Ep 1 · 10:51](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=651)
- "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%." — Conor Delaney (epidemiological) [Ep 1 · 11:04](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=664)
- "Circumferential resection margin is the most important margin (or many think more important than distal margin) for preventing local recurrence in rectal cancer." — Conor Delaney (clinical) [Ep 1 · 10:39](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=639)
- "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." — Conor Delaney (clinical) [Ep 1 · 12:24](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=744)
- "Neoadjuvant therapy for rectal cancer is indicated for T3 tumors (outside the rectal wall) or node-positive disease." — Conor Delaney (guideline) [Ep 1 · 12:54](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=774)
- "Stage 1 rectal cancer (node-negative, T1 or T2), particularly in the upper third of the rectum, does not require neoadjuvant therapy." — Conor Delaney (guideline) [Ep 1 · 13:18](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=798)
- "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." — Conor Delaney (guideline) [Ep 1 · 18:04](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=1084)
- "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." — Conor Delaney (clinical) [Ep 1 · 18:26](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=1106)
- "Transanal resection for rectal cancer is generally limited to T1 tumors less than one-third circumference and ideally less than 2 cm." — Conor Delaney (guideline) [Ep 1 · 14:35](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=875)
- "Historical local recurrence rates for transanally excised rectal cancers were about 18%, remarkably consistent across multiple centers." — Conor Delaney (epidemiological) [Ep 1 · 14:51](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=891)
- "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." — Conor Delaney (opinion) [Ep 1 · 15:05](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=905)
- "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." — Conor Delaney (guideline) [Ep 1 · 15:27](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=927)
- "For rectal cancer, full-thickness excision is required; ESD or EMR is never appropriate for proven cancer, only for benign polyps." — Conor Delaney (clinical) [Ep 1 · 16:24](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=984)
- "For colon cancer, at least 12 lymph nodes are required for adequate staging, though many surgeons aim for at least 16." — Conor Delaney (guideline) [Ep 1 · 19:51](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=1191)
- "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." — Conor Delaney (clinical) [Ep 1 · 19:59](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=1199)
- "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." — Conor Delaney (clinical) [Ep 1 · 20:18](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=1218)
- "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." — Conor Delaney (epidemiological) [Ep 1 · 20:48](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=1248)
- "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." — Conor Delaney (clinical) [Ep 1 · 23:12](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=1392)
- "Extracorporeal stapled anastomosis for right hemicolectomy achieved a leak rate of 0.8% over 1000 cases at Cleveland Clinic." — Conor Delaney (epidemiological) [Ep 1 · 24:00](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=1440)
- "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." — Conor Delaney (guideline) [Ep 1 · 24:56](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=1496)
- "Genetic diagnosis affects both family screening recommendations and surgical approach; patients with hereditary syndromes may require subtotal colectomy or proctocolectomy rather than segmental resection." — Conor Delaney (clinical) [Ep 1 · 25:33](https://qa.library.globalcastmd.com/watch/colon-cancer-with-conor-delaney-3443?t=1533)
- "Colonoscopy is still the best test available for colon cancer detection, finding the vast majority of cancers and polyps, though not perfect." — Conor Delaney (clinical) [Ep 2 · 1:15](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=75)
- "Serrated adenomas (previously misclassified as hyperplastic polyps) have good evidence of genetic predisposition and tie into many family cancer syndromes." — Conor Delaney (clinical) [Ep 2 · 2:03](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=123)
- "Serrated polyps have a very high risk of cancer and require family assessment to determine if patients have a family cancer syndrome." — Conor Delaney (clinical) [Ep 2 · 2:03](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=123)
- "Serrated adenomas are often flat and difficult to see; retroflexion in the cecum is useful because they are often on the inferior or superior side of the valve or on folds." — Conor Delaney (clinical) [Ep 2 · 3:26](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=206)
- "Six centimeters from the anal verge can be mid-rectum in a small patient (90-pound, 80-year-old female) or close to the dentate line in a large patient (6'6", 300 pounds)." — Conor Delaney (clinical) [Ep 2 · 4:59](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=299)
- "Distal margin requirements for rectal resection: 5 centimeters if possible, 2 centimeters if possible, and for very lowest tumors perhaps 1 centimeter as long as they are not poorly differentiated." — Conor Delaney (guideline) [Ep 2 · 4:59](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=299)
- "MRI is probably 90 to mid-90s percent accurate at T staging and high 80s to 90% accurate for nodal staging in rectal cancer." — Conor Delaney (clinical) [Ep 2 · 13:18](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=798)
- "Endoscopic ultrasound is much more operator dependent and probably only 70% accurate for predicting nodal involvement in rectal cancer." — Conor Delaney (clinical) [Ep 2 · 13:18](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=798)
- "Historical local recurrence rates for rectal cancer from good institutions were 20 to 38 percent, with some up to 50 percent." — Conor Delaney (epidemiological) [Ep 2 · 9:03](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=543)
- "With optimized surgery, imaging, and patient selection, local recurrence rates for rectal cancer should be under 10 percent; Cleveland Clinic's rate over the last 10 years was about 3 percent." — Conor Delaney (epidemiological) [Ep 2 · 9:03](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=543)
- "For total mesorectal excision, the circumferential resection margin should be one to two millimeters; if threatened, this is an indication for neoadjuvant therapy or extended resection." — Conor Delaney (guideline) [Ep 2 · 9:03](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=543)
- "A total mesorectal excision can be performed with about 5 milliliters of blood loss because it is a bloodless plane; bleeding indicates being outside that plane or in the wrong plane." — Conor Delaney (clinical) [Ep 2 · 9:03](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=543)
- "Most accepted guidelines for neoadjuvant therapy in rectal cancer are for tumors that are T3 (outside the wall of the rectum) or node positive." — Conor Delaney (guideline) [Ep 2 · 9:03](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=543)
- "For node-negative T1 or T2 rectal tumors (stage one), particularly if upper third, neoadjuvant therapy can be omitted." — Conor Delaney (guideline) [Ep 2 · 13:11](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=791)
- "Historical local recurrence rates for transanally excised rectal cancers were about 18%, remarkably consistent across outcome data from several big centers." — Conor Delaney (epidemiological) [Ep 2 · 14:07](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=847)
- "Transanal resection is generally appropriate for tumors less than a third of the circumference, ideally less than two centimeters, that are T1." — Conor Delaney (guideline) [Ep 2 · 14:07](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=847)
- "For young, curable patients, most surgeons favor radical resection over transanal resection; transanal resection is generally kept for patients unfit for rectal resection or those whose tumor is so close to the dentate line that a permanent stoma would be required." — Conor Delaney (opinion) [Ep 2 · 14:07](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=847)
- "For rectal cancer, full-thickness excision is required; ESD (endoscopic submucosal dissection) would never be done for a proven cancer, only for benign polyps." — Conor Delaney (clinical) [Ep 2 · 16:23](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=983)
- "In Europe, short-course radiation is five times five gray given over five days, with surgery about one to two weeks later." — Conor Delaney (guideline) [Ep 2 · 17:25](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=1045)
- "In the U.S., long-course radiation is 40 to 45 gray given with chemotherapy over six weeks, followed by a six to eight week waiting period." — Conor Delaney (guideline) [Ep 2 · 17:25](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=1045)
- "Twenty-five gray over a short period is radiotherapeutically equivalent to 40 to 45 gray over a longer period, but longer course can make a big difference for tumor response and physical downstaging." — Conor Delaney (clinical) [Ep 2 · 17:25](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=1045)
- "For colon cancer surgery, goals include at least a 5 centimeter proximal and distal margin (usually determined by blood supply) and at least 12 lymph nodes, with many surgeons hoping for at least 16." — Conor Delaney (guideline) [Ep 2 · 19:22](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=1162)
- "Total mesocolic excision should be performed in the plane between the embryological peritoneum of the retroperitoneum (Toldt's fascia) and the embryological peritoneum on the mesocolon, keeping the mesocolon complete." — Conor Delaney (clinical) [Ep 2 · 19:22](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=1162)
- "Scandinavian data showed local recurrence rates for colon cancer were even higher than for rectal cancer (which was high 20s percent) because they realized they weren't doing adequate colon cancer surgery." — Conor Delaney (epidemiological) [Ep 2 · 19:22](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=1162)
- "For a cecal tumor or lesion near the ileocecal valve, 10 centimeters of small bowel should be taken; for mid-ascending colon, 5 centimeters should be taken." — Conor Delaney (guideline) [Ep 2 · 22:44](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=1364)
- "Extracorporeal stapled anastomosis for right colectomy has reported leak rates of 0.8% over 1,000 cases at Cleveland Clinic." — Conor Delaney (epidemiological) [Ep 2 · 23:59](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=1439)
- "Genetic workup should be considered for patients with cancer under age 40, first-degree relatives with cancer, multiple cancers in a family, or non-GI cancers in a family." — Conor Delaney (guideline) [Ep 2 · 24:32](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=1472)
- "Genetic findings may change the surgical operation: a patient with a right colon cancer plus multiple polyps or significant family history may be better served with a subtotal colectomy rather than segmental resection." — Conor Delaney (clinical) [Ep 2 · 24:32](https://qa.library.globalcastmd.com/watch/colorectal-cancer-13749?t=1472)

## Changelog
- Sep 7: 4 items added automatically

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