**5. Treatment**

yps with lymphatic invasion have been reported, and most of them have had positive mar‐

The presence of vascular invasion is defined as cancer in an endothelial-lined channel sur‐ rounded by a smooth muscle wall [35]. However, it is difficult to recognise it. Vascular markers (CD31, CD34 and factor VIII) may help. These markers strongly stain blood vessel endothelium, and to a lesser extent lymphatic endothelium [14].The prevalence of venous invasion in malignant polyps varies greatly, ranging from 3.5% to 39% [37].Often venous in‐ vasion is associated with lymphatic invasion and/or tumours which have a resection margin of less than 2 mm and/or are poorly differentiated. In contrast, Talbot et al. [38] observed

**4.7. Risk of residual disease or recurrent carcinoma in favourable and unfavourable**

Favourable histology is defined as grade 1 or 2 differentiated adenocarcinoma in which car‐ cinoma cells are at least 1 mm from a clearly visualized margin, resection is carried out en

Unfavourable histology is defined as polyps with biopsy margin ≤1 mm, tumour within the cauterized region constitutes a positive margin, piecemeal removal, poorly differentiated tu‐ mour (grade 3) or lymphatic or vascular invasion.In these cases, surgical resection is indicat‐ ed because of the increased risk of lymph node metastasis or residual disease [14]. On the other hand, in the absence of unfavourable features, polypectomy is considered curative. Sometimes, specimens do not lend themselves to proper analysis for any reason (piecemeal

In 1995, Volk et al [5] reviewed 20 studies in which 858 malignant polyps were analysed. They observed residual disease or recurrent carcinoma in 89 patients (10%). However, there were relapses or tumours in the area of the resection in only 8 (1%) patients with favourable histological criteria. Subsequent studies have also reported an incidence of less than 1% [37,39]. Only one study described incidence higher than 5% in malignant polyps with fa‐ vourable histology [40] and the study itself has been widely criticized from subsequent re‐ views [5]. By contrast, in malignant polyps with unfavourable histology, the risk of relapse

In 1975, Ponsky and King [41] published the first case in which marking with India ink was used with the purpose of locating the polyp during the surgical procedure. Sometimes to lo‐

All the endoscopicallyunresectable polyps in patients in whom surgery would be consid‐ ered, should be tattooed. Endoscopicallyresectable polyps that could have become malig‐

cate the base of the polyp after polypectomy or during surgery is extremely difficult.

gins, grade 3 invasive adenocarcinoma (as defined above), or both [5].

130 Colonoscopy and Colorectal Cancer Screening - Future Directions

that venous invasion was not associated with poorer prognosis.

bloc and there is an absence of vascular or lymphatic invasion.

removal or poor orientation) result in a default decision to resect.

or residual lesions ranges between 10% and 39% [5,14,29,39].

**4.8. Marking with India Ink**

**4.6. Vascular invasion**

**histology**

Prior to removal of the polyp, it is difficult to know whether the polyp is malignant or not. Some features, as we have mentioned earlier, can give some indication of the degree of ma‐ lignancy. Regardless of the morphological characteristics, a polyp is normally removed when detected.

Polypectomy should be performed en bloc, since this is essential to establish and define fa‐ vourable or unfavourable histological criteria. In just a few cases, only polyp biopsies are performed, such a lack of coagulation data, polyp could be difficult to remove at that point in time, or the patient being on antiplatelet drugs or anticoagulants.

The indication for a malignant polyp with sessile morphology, regardless of favourable his‐ tological criteria, is surgery [10], especially in patients younger than 50 years old, who tend to present fewer surgical complications [59]. Surgical treatment is recommended for malig‐ nant polyps with pedunculated morphology which have unfavourable histological criteria (partial polyp resection, poorly differentiated carcinoma, vascular or lymphatic invasion, or lesions ≤1 mm from the polypectomy) [10]. On the other hand, for malignant polyps with pedunculated morphology but with favourable histological criteria, polypectomy is consid‐ ered to be curative (Figure 7). Non-invasive high grade neoplasia regardless of their mor‐ phology, are considered to be cured with polypectomy. Indeed, according to some authors, polyps harbouring "in situ" or "intramucosal" cancer should not be regarded or treated as malignant polyps [59].

A B

C D

E F

reduce the risk of delayed bleeding

bleeding

rectum cancer patient.

**Figure 6.** Polypectomy of pediculated polyp 0-Ip. Submucosal injection was performed using indigo carmine (A,B), polypectomy was made with electrosurgical knives (C), After polypectomy, a large non bleeding vessel was visualized (D) and cauterized using coagulation forceps (E) and obliterated with an endoclip(F) to

An exception to these guidelines is patients with malignant polyps, with sessile or flat mor‐ phology, that are located in the rectum. The occurence of distant metastases is correlated to T-stage and, after radical resection of T1 tumours, the 5-year rate of metastases is about 10% [62], similar to other locations of malignant polyps. About 50% of the local recurrences fol‐ lowing local resection are curable if the patients are included in an intensive follow-up pro‐ gramme. Local resection should be offered to patients whenever the individually calculated risk of short-term mortality after major surgery exceeds twice the additional risk of local re‐ currence added by local procedures. An adequate preoperative evaluation of the patient's general health is essential before deciding the modality of treatment for the individual T1

In recent years, various serum markers been identified in an effort to establish which pa‐ tients could benefit from surgical treatment and from a more strict follow up. These markers include metalloproteinase 7, vascular adhesion proteins, vascular endothelial growth factors and cytokeratins [63-66]. The majority of markers have been studied in patients operated on for colon cancer with infiltration of the lamina propria (equivalent to or higher than T2), so

these results cannot readily be extrapolated to malignant colorectal polyps.

**Figure 6.** Polypectomy of pediculated polyp 0-Ip. Submucosal injection was performed using indigo carmine (A,B), polypectomy was made with electrosurgical knives (C), After polypectomy, a large non bleeding vessel was visualized (D) and cauterized using coagulation forceps (E) and obliterated with an endoclip (F) to reduce the risk of delayed

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133

**Figure 5.** Endoscopic Mucosal Resection in a 0-IIa + Is polyp in colon (A-E), with control of the base after one month (F). **Figure 5.** Endoscopic Mucosal Resection in a 0-IIa + Is polyp in colon (A-E), with control of the base after one month (F).

However, until now in many pathology reports were not reported histological criteria. For example at the University of Minnesota between 1987 and 2000, 83% of the reports are not angiolymphatic vessel invasion, 69% not reported the depth of invasion by cancer cells and 22% no stated the degree of tumour differentiation [60]. Beside the agreement among experi‐ enced pathologists was poor with respect to histological grade of differentiated carcinoma and angiolymphatic vessel invasion [60].

Endoscopic submucosal dissection (ESD) has emerged as a possible technique to successful‐ ly resect malignant colonic polyps en bloc [26,61]. The technique makes it possible to treat and cure large (>2 cm) sessile and flat polyps enabling pathological evaluation in most pa‐ tients, also can be an alternative to surgery for older patients and for those suffering from associated conditions that contraindicate surgery.

phology, are considered to be cured with polypectomy. Indeed, according to some authors, polyps harbouring "in situ" or "intramucosal" cancer should not be regarded or treated as

A B

132 Colonoscopy and Colorectal Cancer Screening - Future Directions

C D

E F

and angiolymphatic vessel invasion [60].

associated conditions that contraindicate surgery.

**Figure 5.** Endoscopic Mucosal Resection in a 0-IIa + Is polyp in

**Figure 5.** Endoscopic Mucosal Resection in a 0-IIa + Is polyp in colon (A-E), with control of the base after one month (F).

However, until now in many pathology reports were not reported histological criteria. For example at the University of Minnesota between 1987 and 2000, 83% of the reports are not angiolymphatic vessel invasion, 69% not reported the depth of invasion by cancer cells and 22% no stated the degree of tumour differentiation [60]. Beside the agreement among experi‐ enced pathologists was poor with respect to histological grade of differentiated carcinoma

Endoscopic submucosal dissection (ESD) has emerged as a possible technique to successful‐ ly resect malignant colonic polyps en bloc [26,61]. The technique makes it possible to treat and cure large (>2 cm) sessile and flat polyps enabling pathological evaluation in most pa‐ tients, also can be an alternative to surgery for older patients and for those suffering from

colon (A-E), with control of the base after one month (F).

malignant polyps [59].

**Figure 6.** Polypectomy of pediculated polyp 0-Ip. Submucosal injection was performed using indigo carmine (A,B), polypectomy was made with electrosurgical knives (C), After polypectomy, a **Figure 6.** Polypectomy of pediculated polyp 0-Ip. Submucosal injection was performed using indigo carmine (A,B), polypectomy was made with electrosurgical knives (C), After polypectomy, a large non bleeding vessel was visualized (D) and cauterized using coagulation forceps (E) and obliterated with an endoclip (F) to reduce the risk of delayed bleeding

large non bleeding vessel was visualized (D) and cauterized using coagulation forceps (E) and obliterated with an endoclip(F) to reduce the risk of delayed bleeding An exception to these guidelines is patients with malignant polyps, with sessile or flat mor‐ phology, that are located in the rectum. The occurence of distant metastases is correlated to T-stage and, after radical resection of T1 tumours, the 5-year rate of metastases is about 10% [62], similar to other locations of malignant polyps. About 50% of the local recurrences fol‐ lowing local resection are curable if the patients are included in an intensive follow-up pro‐ gramme. Local resection should be offered to patients whenever the individually calculated risk of short-term mortality after major surgery exceeds twice the additional risk of local re‐ currence added by local procedures. An adequate preoperative evaluation of the patient's general health is essential before deciding the modality of treatment for the individual T1 rectum cancer patient.

In recent years, various serum markers been identified in an effort to establish which pa‐ tients could benefit from surgical treatment and from a more strict follow up. These markers include metalloproteinase 7, vascular adhesion proteins, vascular endothelial growth factors and cytokeratins [63-66]. The majority of markers have been studied in patients operated on for colon cancer with infiltration of the lamina propria (equivalent to or higher than T2), so these results cannot readily be extrapolated to malignant colorectal polyps.

**6. Follow-up**

after surgery [4,5].

**7. Conclusion**

**Acknowledgments**

**Author details**

Luis Bujanda Fernández de Piérola1

(UPV/EHU), San Sebastian, Gipuzcoa, Spain

Fernando Múgica Aguinaga1

Carol Julyssa Cobián Malaver1

In cases of non-invasive high grade neoplasia and malignant polyps with pedunculated morphology and favourable histological criteria, it is recommended that a colonoscopy be carried out three months after taking the biopsy [1,43].If this is normal, a further check-up is advised after one year, three years and five year [43]. Some authors suggest that if the re‐ sults within three months are negative, subsequent monitoring should be the same as that offered to patients with non-malignant adenomas [35,44]. However, recent studies estimate that 11.8% of patients who have undergone polypectomy will develop a metachronic ad‐ vanced adenoma and 0.6% an invasive carcinoma. Associated risk factors include age, num‐ ber of polyps (5 or more), size (greater than 1 cm), villous architecture, proximal location, and being male. Smoking, body mass index, family history of CRC, and degree of dysplasia were not found to be associated with higher risks of advanced adenoma or cancer [45].

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There have been reports of cases of malignant pedunculated polyps with unfavourable his‐ tological criteria which, despite no findings of residual carcinoma in the intestine wall or lymph node involvement, are found on follow up to have distant metastasis, even five years

En brief, the adenoma-carcinoma sequence is well known and polypectomy has proven to reduce the incidence of CRC. However, the success of treatment depends on the complete

CIBERehd is funded by the Instituto de Salud Carlos III (Carlos III Health Institute).

, Joaquin Cubiella Fernández2

, Lander Hijona Muruamendiaraz1

1 Department of Gastroenterology, Donostia Hospital, Centro de Investigación Biomédica en Red en Enfermedades Hepáticas y Digestivas (CIBERehd), University of Basque Country

2 Department of Gastroenterology, Complexo Hospitalario de Ourense, Ourense, Spain

,

and

resection and the future follow up of the base of polypectomy.

**Figure 7.** Therapeutic algorithm of pedunculated (0-Ip) polyps.

<sup>\*</sup> Biopsy margin ≤ 1 mm, piecemeal removal, poorly differentiated tumour, lymphatic or vascular invasion
