Clinicopathological management of the patient with a malignant colorectal adenoma

Abstract

A malignant adenoma of the colorectum is defined as an adenoma in which cancer has invaded by direct continuity through the muscularis mucosae into the submucosa [ 1]. The biological basement membrane of the colon is the muscularis mucosae. Thus the term 'cancer' cannot be applied to a neoplastic polyp which is confined to the mucosa and does not have the potential to metastases [ 2-4]. The term polypoid carcinoma is reserved for a polyp which is entirely replaced by carcinoma. There is however no practical benefit in distinguishing between the terms malignant adenoma and polypoid carcinoma [ 1, 4, 5]. The term carcinoma-in-situ is used by some to describe an adenoma containing severe dysplasia. Not having invaded through the muscularis mucosa, it is not a carcinoma. When the diagnosis of malignant polyp is presented by the clinician to the patient, a decision is needed as to whether the polypectomy on its own is sufficient therapy or whether the patient should be subjected to surgical resection. What are the pathological and clinical factors that contribute to this decision? This review examines the issues that require consideration to arrive at a balanced view of this difficult dilemma and to allow the patient to give informed consent to the management option decided upon.

Pathology of Staging of Early Colorectal Lesions During Surveillance Programmes

“…The bowel cancer screening programme will generate many early cancers (pT1) for which there is poor management protocols as opposed to pT2 tumours which they need a definite surgical excision (Haboubi, 2010;. The preferred care for patients with polypectomy specimens which contain invasive carcinoma is controversial (Haboubi and Scott, 2000). Taking into considerations all factors involved, the issue of polypectomy for malignant polyps versus surgical resection is best resolved by a multidisciplinary team involving the surgeon, pathologist and endoscopist, taking the patient's condition and wishes into account (Mitchell and Haboubi, 2008).…”

“…If the polypectomy has been performed in piecemeal, it may be impossible to determine the true margin of resection, therefore precluding an accurate reporting on the status of completeness of excision (Cooper, 2007). The presence of multiple adenomas in the same segment as the malignant polyp might be an argument for resection, particularly if the other polyps subsequently show high grade dysplasia (Haboubi and Scott, 2000). Similarly, the presence of a malignant adenoma in association with a strong family history of large bowel cancer would also be in favour of resection (Haboubi and Scott, 2000).…”

“…The presence of multiple adenomas in the same segment as the malignant polyp might be an argument for resection, particularly if the other polyps subsequently show high grade dysplasia (Haboubi and Scott, 2000). Similarly, the presence of a malignant adenoma in association with a strong family history of large bowel cancer would also be in favour of resection (Haboubi and Scott, 2000).…”

“…Surgical resection is associated with a significant risk of mortality and morbidity with the risk of diarrhea after extensive colonic resection, particularly in the elderly (Haboubi and Scott, 2000) with an overall mortality of 5% (Scott et al, 1995). In practice, any individual patient with a histologically unfavourable malignant polyp has either a 10% chance of cancer-specific treatment failure or a 3-5% risk of postoperative death (Haboubi and Scott, 2000).…”

“…In practice, any individual patient with a histologically unfavourable malignant polyp has either a 10% chance of cancer-specific treatment failure or a 3-5% risk of postoperative death (Haboubi and Scott, 2000).…”