Presentation on theme: "The Adenoma/Carcinoma Sequence in the Colon A colon with an adenoma is A colon with an adenoma is at increased risk to develop at increased risk to develop."— Presentation transcript:
The Adenoma/Carcinoma Sequence in the Colon A colon with an adenoma is A colon with an adenoma is at increased risk to develop at increased risk to develop a carcinoma a carcinoma n The more adenomas there are, the greater the risk the greater the risk
The Adenoma/Carcinoma Sequence in the Colon removing adenomas decreases the incidence of colorectal carcinoma removing adenomas decreases the incidence of colorectal carcinoma n big adenomas are at risk to contain carcinomas and are also markers of cancer risk for the rest of the colon
The Sporadic Adenoma-Carcinoma Sequence in the Colon Endoscopy with removal of adenomas can prevent colorectal carcinoma. Endoscopy with removal of adenomas can prevent colorectal carcinoma. n A ton of adenomas are removed every year n Few small cancers are picked up during routine endoscopy n The number of colorectal carcinomas isn’t decreasing, but the deaths are!
Colorectal carcinoma (USA) American Cancer Society Estimates New cases 145, , ,920 Deaths 56,290 55,170 49,920 Males and females about equal Cancers are stable while the population at risk is increasing. Cancer deaths are down. Why???
From , the age adjusted colorectal cancer incidence decreased by 13% and the mortality decreased by 12%. Screening increased by 13% from Data from the CDC, 7/5/11
We know which adenomas are at risk to contain invasive carcinoma we have no idea which adenomas are the precursors of most ordinary colorectal carcinomas but
Small Adenoma with Highest-GD: the real cancer precursor?
Case based practical approaches to adenomas using the information taken from the adenoma-carcinoma sequence to make clinical decisions
Polyp with a stalk
Sure looks like carcinoma, but is it?
The key is the lymphatics. Normal colonic mucosa has very few
Metastatic carcinoma outlines lymphatics at the very base of the mucosa and in the submucosa Muscularis mucosae
the diagnosis of “adenocarcinoma” is limited to dysplastic epithelium that invades into the submucosa. The same epithelium confined to the mucosa is called “high-grade dysplasia ” Therefore, “carcinoma-in-situ” and “intramucosal carcinoma” do not exist in the colon! This is our approach at the U of M. Recommendation: In the colon:
Endo:2 cm pedunculated polyp Proc:Polypectomy Micro:Adenoma; it has multifocal high-grade dysplasia multifocal high-grade dysplasia Dx: Adenoma (at the U of M we do not diagnose high-grade dysplasia) Rx:None further F-U: Surveillance Summary of this adenoma
Same polyp Different findings
Desmoplasia, with or without inflammation The stroma of invasive colorectal carcinoma
Risk of metastasis from invasive carcinoma in pedunculated adenomas Depth of invasion% mets submucosa2 muscularis20 pericolic adipose 40 source: accumulated literature
Haggitt levels Invasive carcinoma in a pedunculated adenoma involves expanded submucosa submucosa submucosa
Cautery marks the resection margin No carcinoma in the cauterized tissue
Endo:2 cm pedunculated polyp Proc:Polypectomy Micro:Superficial invasive carcinoma in an adenoma, margin free No adverse prognostic features Dx:Same Rx:None further F-U:Surveillance Summary of this adenoma
adverse prognostic features? What are adverse prognostic features? Those features that have been associated with an adverse outcome after polypectomy, such as residual carcinoma at the polypectomy site and nodal metastases. These are likely to be indications for resection after the polypectomy
Adenomas with Carcinoma Indications for Resection, 3 studies St Marks* GIPS Clev Clin Margininvolved <1mm <2mm CA Gradehigh highhigh Lymphaticssubjective yes no Blood vascno yes no * both sessile and pedunc and must be removed in one piece. Geraghty, Williams, Talbot. Gut, 32 : Cooper, et al, Gastroenterol, 108: , 1995 Volk, et al, Gastroenterol, 109: , 1995
Invasive carcinoma in a pedunculated adenoma: indications for colectomy 1. Invasive carcinoma at the margin solid data solid data 2. High-grade carcinoma: definition not clear; data limited data limited 3. Lymphatic invasion: data conflicting; overlaps with other indications overlaps with other indications
The best indicator for colectomy: Involvement of the margin Tumor in the cautery artifact at the margin
A bias cut of the cauterized margin Carcinoma in the cautery artifact: margin involved
Invasive carcinoma in a pedunculated adenoma: indications for colectomy 1. Invasive carcinoma at the margin solid data solid data 2. High-grade carcinoma: definition not clear; data limited definition not clear; data limited 3. Lymphatic invasion: data conflicting; overlaps with other indications overlaps with other indications
This is a high-grade carcinoma
Invasive carcinoma in a pedunculated adenoma: indications for colectomy 1. Invasive carcinoma at the margin solid data solid data 2. High-grade carcinoma: definition not clear; data limited data limited 3. Lymphatic invasion: data conflicting; overlaps with other indications. This is also a very subjective determination overlaps with other indications. This is also a very subjective determination
The least reproducible indicator: lymphatic tumor thromboemboli
Unfavorable histopathologic factors associated with a high risk of node metastasis or local recurrence after endoscopic resection include 1. poorly differentiated histology, 2. vascular or lymphatic invasion, 3. cancer at the resection margin 4. incomplete endoscopic resection. ASGE guideline: endoscopy for colorectal cancer GASTROINTESTINAL ENDOSCOPY 61z:
Pedunculated adenomas with carcinoma confined to the submucosa can be considered to be adequately treated by endoscopic resection if 1. removed completely and 2. there are no unfavorable histologic features.
Surveillance after the endoscopic removal of a malignant polyp should consist of a follow-up colonoscopy within 3 to 6 months after resection.
Next scenario Huge, sessile polyp
Biopsy before polypectomy
Lots of villous surface Dysplasias Dysplasias LowHigh
Adenomas at risk to contain invasive carcinoma are 1. Large 2. Villous and have 3. High-grade dysplasia
Big sessile adenoma Big carcinoma at the base
Endo:7 cm sessile polyp Proc:Biopsy Micro:Adenoma with lots of villi, high-grade dysplasia high-grade dysplasia Dx:Adenoma Rx:It has to come out: possibilities: If proximal: local resection If proximal: local resection If rectal: ± mucosal resection Summary of this adenoma
Treatment of GI Adenomas Adenomas must be removed in toto Endoscopic polypectomy, that is, gross total resection, is definitive, regardless if we see adenoma at a margin After biopsy of a large adenoma, removal is necessary, regardless of degree of dysplasia
What you need to say about a colonic adenoma in the pathology report Architecture: tubular, villous, tubulovillous, flat, serrated: Maybe villi High-grade dysplasia: Maybe Pseudoinvasion: NO Adenoma at the margin:NO The word “adenoma” YES! Invasive carcinoma:YES! This is when we mention the margin. This is when we mention the margin.
In the 2006 guidelines for patients with adenomas, the most important determinants of interval to the next colonoscopy are 1.Number of adenomas: 3 or more 2.Size: if any polyp containing adenoma is at least 1 cm (polyp size, not adenoma size) 3.High grade dysplasia (no published criteria) 4.Villous features (no published criteria) Winawer et al: Gastroenterol, 130:1872, 2006
At the U of M, the gastroenterologists with whom we work do not find either high-grade dysplasia or villous features to be useful for determining surveillance intervals. They use size of the initial adenoma and the number of adenomas at the initial colonoscopy to make that decision.
Some gastroenterologists want to know the architecture, generally tubular, villous, or tubulovillous, and/or if high-grade dysplasia is present There is no reason not to tell them what they want. After all, we pathologists are a service organization!!! They don’t know that there are no hard criteria as to what is a villous component and what is HGD