Prognostic factors in colorectal carcinomas arising in adenomas: implications for lesions removed by endoscopic polypectomy

Prognostic factors in colorectal cancer. College of American Pathologists Consensus Statement 1999

BACKGROUND

Under the auspices of the College of American Pathologists, the current state of knowledge regarding pathologic prognostic factors (factors linked to outcome) and predictive factors (factors predicting response to therapy) in colorectal carcinoma was evaluated. A multidisciplinary group of clinical (including the disciplines of medical oncology, surgical oncology, and radiation oncology), pathologic, and statistical experts in colorectal cancer reviewed all relevant medical literature and stratified the reported prognostic factors into categories that reflected the strength of the published evidence demonstrating their prognostic value. Accordingly, the following categories of prognostic factors were defined. Category I includes factors definitively proven to be of prognostic import based on evidence from multiple statistically robust published trials and generally used in patient management. Category IIA includes factors extensively studied biologically and/or clinically and repeatedly shown to have prognostic value for outcome and/or predictive value for therapy that is of sufficient import to be included in the pathology report but that remains to be validated in statistically robust studies. Category IIB includes factors shown to be promising in multiple studies but lacking sufficient data for inclusion in category I or IIA. Category III includes factors not yet sufficiently studied to determine their prognostic value. Category IV includes factors well studied and shown to have no prognostic significance.

MATERIALS AND METHODS

The medical literature was critically reviewed, and the analysis revealed specific points of variability in approach that prevented direct comparisons among published studies and compromised the quality of the collective data. Categories of variability recognized included the following: (1) methods of analysis, (2) interpretation of findings, (3) reporting of data, and (4) statistical evaluation. Additional points of variability within these categories were defined from the collective experience of the group. Reasons for the assignment of an individual prognostic factor to category I, II, III, or IV (categories defined by the level of scientific validation) were outlined with reference to the specific types of variability associated with the supportive data. For each factor and category of variability related to that factor, detailed recommendations for improvement were made. The recommendations were based on the following aims: (1) to increase the uniformity and completeness of pathologic evaluation of tumor specimens, (2) to enhance the quality of the data needed for definitive evaluation of the prognostic value of individual prognostic factors, and (3) ultimately, to improve patient care.

RESULTS AND CONCLUSIONS

Factors that were determined to merit inclusion in category I were as follows: the local extent of tumor assessed pathologically (the pT category of the TNM staging system of the American Joint Committee on Cancer and the Union Internationale Contre le Cancer [AJCC/UICC]); regional lymph node metastasis (the pN category of the TNM staging system); blood or lymphatic vessel invasion; residual tumor following surgery with curative intent (the R classification of the AJCC/UICC staging system), especially as it relates to positive surgical margins; and preoperative elevation of carcinoembryonic antigen elevation (a factor established by laboratory medicine methods rather than anatomic pathology). Factors in category IIA included the following: tumor grade, radial margin status (for resection specimens with nonperitonealized surfaces), and residual tumor in the resection specimen following neoadjuvant therapy (the ypTNM category of the TNM staging system of the AJCC/UICC). (ABSTRACT TRUNCATED)

Clinicopathological management of the patient with a malignant colorectal adenoma

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.

N-myristoyltransferase

Myristoylation refers to the co-translational addition of a myristoyl group to an amino-terminal glycine residue of a protein by an ubiquitously distributed enzyme myristoyl-CoA:protein N-myristoyltransferase (NMT, EC 2.3.1.97). This review describes the basic enzymology, molecular cloning and regulation of NMT activity in various pathophysiological processes such as colon cancer and diabetes.

Accuracy of pathologic interpretation of colorectal polyps by general pathologists in community practice

BACKGROUND

The histologic features of colorectal polyps often guide colonoscopic surveillance and the need for surgical intervention. Our objective was to evaluate the pathologic interpretation of colorectal polyps by general pathologists in community practice.

METHODS

Twenty histologic slides of colorectal polyps were reviewed by 20 randomly selected general pathologists in community practice. There were 5 malignant polyps, 9 adenomas, and 6 miscellaneous polyps.

RESULTS

Cancer was correctly identified in 91% of readings and adenoma in 94%. The grade of differentiation of cancer was provided in 55% of readings, and comment regarding whether the resection margin was free of cancer was made by 50% of pathologists. Tubular adenoma was called tubulovillous or villous in 35% of readings, but tubulovillous or villous adenoma was seldom (2%) called tubular. High-grade dysplasia was correctly identified in 47% of 60 readings, was called invasive cancer in 22%, and was missed in 31%. Among miscellaneous polyps, hyperplastic polyp was correctly recognized in 75% of cases, and inflammatory polyp and juvenile polyp each were recognized by 16 of 20 pathologists (80%). Peutz-Jeghers hamartoma was identified by 4 of 20 pathologists (20%), and the polypoid phase of solitary rectal ulcer syndrome was recognized by 2 pathologists (10%).

CONCLUSION

Areas of strength with regard to interpretation of colon polyps by general pathologists in community practice included identification of cancer, adenoma, and certain non-neoplastic polyps (e.g., inflammatory and juvenile polyps). Areas of weakness included lack of comment on cancer differentiation and proximity to the resection line, erroneous identification of high-grade dysplasia, and identification of rare lesions. The results of this study suggest areas on which to focus continuing education and continuous quality improvement efforts with regard to polyp interpretation.

Correlation of lifting versus non-lifting and microscopic depth of invasion in early colorectal cancer

BACKGROUND

The non-lifting sign is considered a contraindication to endoscopic resection. Our objective was to investigate whether lifting or nonlifting of a lesion is determined by the volume of normal submucosal tissue.

METHODS

We measured the thickness of the submucosa and examined the relation between submucosal invasion and lesion elevation induced by submucosal injection in 60 patients with colorectal cancer with evidence of submucosal invasion. Extent of tumor elevation was classified into two groups: A, lifting; B, non-lifting. Submucosal invasion was classified as sm1, sm2, or sm3. The distance between the carcinoma and the line of resection and that between the carcinoma and the muscularis propria were measured.

RESULTS

Of 31 sm1 lesions, 29 (93.5%) were group A. All 6 sm3 lesions were group B. All lesions in group A had a value for the distance between carcinoma and muscularis propria of more than 1000 microm. Group B lesions with sm3 invasion had distances of only 105 to 750 microm.

CONCLUSION

Lesions classified as sm3 do not elevate in response to submucosal injection, and lesions that become elevated on injection can be resected endoscopically because they are sm1 or sm2 and have a thickness of normal submucosa of more than 1000 microm.

Clinicopathological features of superficial depressed-type colorectal neoplastic lesions

OBJECTIVE

We performed this study to analyze the endoscopic findings, dissecting microscopic features, and p53 immunostaining in superficial depressed-type (depressed) colorectal neoplastic lesions.

METHODS

Dissecting stereomicroscopy was used to ascertain the size and pit pattern of lesions removed by endoscopic snare polypectomy. Immunohistochemical staining of p53 was performed with an antigen retrieval system using a monoclonal antibody to p53.

RESULTS

All depressed neoplastic lesions (submucosal carcinoma, n = 6; high-grade dysplasia, n = 14; and adenoma, n = 30) were small (< 1 cm in diameter) and were detected as a depression with or without a marginal elevation on colonoscopic examination. In the dissecting microscopic study, submucosal carcinomas and lesions of high-grade dysplasia almost exclusively showed irregular small pits, with the exception of four malignant lesions with moderate submucosal invasion in which the pit structure was absent. In contrast, adenomas had either regular small (29/30 lesions) or oval pits (1/30 lesions). Rates of p53 positivity were 100%, 64%, and 7% in depressed submucosal carcinomas, lesions of high-grade dysplasia, and adenomas, respectively, thus the prevalence of p53 positivity was significantly higher in the former two groups than in the adenoma group.

CONCLUSIONS

The high frequency of invasive carcinoma and high-grade dysplasia found in depressed colorectal neoplastic tumors, despite their small size, indicates that these lesions may be a subtype of colorectal tumor with more aggressive malignant potential at an earlier stage.

Malignant Colorectal Polyps

When a patient undergoes colonoscopic resection of a colorectal polyp found to contain invasive cancer, I carefully analyze a number of pathologic and clinical features of the case to formulate an effective management plan. I usually consider colonoscopic treatment alone to be definitive therapy when the malignant polyp has favorable prognostic features. I find that the risk of residual colonic cancer or lymph node metastases usually is less than the risk of further cancer surgery when the polyp is considered to be completely resected by the endoscopist; and on pathologic examination, the resection margins are negative; and no evidence of vascular invasion, lymphatic invasion, or high-grade cancer exists. When unfavorable criteria are found and the patient is a good risk for surgery, I find that surgical resection of the involved colonic segment and draining lymphatic system usually is indicated. When formulating a management plan, I individualize treatment according to the location of the malignant polyp, risk of surgery, and wishes of an informed patient. I urge patients to adopt a healthy diet and lifestyle to reduce the risk of colorectal neoplasia. I cannot make specific recommendations for preventive dietary supplements such as vitamins, minerals, or drugs such as aspirin because efficacy and risk-benefit chemopreventive trials are ongoing.

CD44 expression in benign and malignant colorectal polyps

PURPOSE

This retrospective study was undertaken to evaluate immunohistochemically the expression of CD44 standard protein and CD44v5 and CD44v6 isoforms in colorectal adenomas and early invasive cancers developing within adenomas as possible markers characterizing colorectal polyps with a more aggressive biologic potential.

METHODS

Archival tissues of 81 consecutive locally resected colorectal polyps, comprising 57 colorectal adenomas and 24 carcinomas-in-adenomas, were stained immunohistochemically with the use of commercially available mouse monoclonal antibodies: SFF-2 for CD44 standard protein, VFF-8 for CD44v5, and VFF-7 for CD44v6.

RESULTS

Sixty-three percent of the colorectal polyps were positive for CD44 standard protein, 59 percent were positive for CD44v5, and 27 percent were positive for CD44v6. Ninety-three percent of the low-grade adenomas were CD44 standard protein-positive, in contrast to 50 percent of the high-grade adenomas and only 42 percent of the carcinomas-in-adenomas (Kendall's Tau = -0.42; P < 0.0001). CD44v6 expression was more frequently found in early invasive cancers (54 percent) than in high-grade adenomas (25 percent) and low-grade adenomas (7 percent). This difference also was statistically significant (Kendall's Tau-b = 0.39; P = 0.00003). Surprisingly, a downregulation of CD44 standard protein expression was observed in the adenoma tissue adjacent to carcinomas (62 percent) and areas with high-grade atypia (71 percent), compared with low-grade adenomas (93 percent; Kendall's Tau-b = -0.28; P = 0.004).

CONCLUSIONS

Our data suggest that CD44 standard protein and CD44 isoform v6 expression differs considerably in benign and malignant colorectal polyps. Clinical studies with larger patient groups could clarify the prognostic potential of CD44 further.

Invasion depth diagnosis of depressed type early colorectal cancers by combined use of videoendoscopy and chromoendoscopy

BACKGROUND

Depressed type early colorectal cancers are found less frequently than other polypoid cancers although they have a higher submucosal invasion rate. Recently videocolonoscopy and chromoendoscopy have become available and precise descriptions of these lesions are now routine. Because endoscopic mucosal resection is designated for intramucosal and focally extended submucosal (m-sm1) cancers, an evaluation of the characteristic findings indicating invasion depth with these modalities is important.

METHODS

Between January 1991 and March 1996, 64 depressed type early colorectal cancers were detected and treated. When a faint abnormality of the mucosa was suspected by routine videocolonoscopy, 0.1% of indigo carmine solution was sprayed on the mucosal surface (chromoendoscopy). Colonoscopic findings of m-sm1 cancers and moderately and massively extended submucosal (sm2-3) cancers were retrospectively reviewed and compared with confirmed histologic findings.

RESULTS

Characteristic colonoscopic findings needed for surgical operation were as follows: (1) expansion appearance, (2) deep depression surface, (3) irregular bottom of depression surface, and (4) folds converging toward the tumor. By using these findings, the invasion depth of depressed type early colorectal cancers could be correctly determined in 58 of 64 lesions (91%).

CONCLUSIONS

Characteristic colonoscopic findings obtained by a combination of videocolonoscopy and chromoendoscopy are useful for determination of the invasion depth of depressed type colorectal cancers, an essential factor in choosing a treatment modality.

A clinicopathological investigation on superficial early invasive carcinomas of the colon and rectum

Due to recent advances in endoscopic surgical techniques, it has now become possible to perform endoscopic resection of most early invasive carcinomas of the colon and rectum (EIC) even if the lesions have invaded the submucosa. In the present study, we investigated the microscopic characteristics of superficial EIC compared with protruding-type EIC, focusing particular attention on histological type, the presence or absence of vascular invasion, the extent of submucosal invasion, and other adverse prognostic factors, to establish appropriate treatment strategies. Our findings led us to conclude that: (1) most cases of EIC can be cured by endoscopic resection if their gross aspects are classified as type IIc, superficial depressed, or type IIa, superficial elevated; (2) colorectal resection with lymph node dissection should be performed first for type IIa + IIc EIC because these lesions are apt to be associated with a large number of adverse prognostic factors; (3) subsequent colorectal resection should be performed after initial endoscopic treatment of EIC if there are adverse prognostic indicators of metastasis in the endoscopically resected specimen, such as moderately or poorly differentiated adenocarcinoma, lymphatic invasion, venous invasion, or extensive submucosal invasion.

Desmoplastic response in biopsy specimens of early colorectal carcinoma is predictive of deep submucosal invasion

PURPOSE

The aim of this study was to evaluate the role of histopathology of biopsy specimens in predicting depth of infiltration in early colorectal carcinomas before treatment.

METHODS

Early colorectal carcinomas that had been resected surgically or endoscopically between 1984 and 1995 were analyzed. Histopathologic findings, including differentiation of adenocarcinoma and a desmoplastic response were investigated.

RESULTS

One hundred nine early colorectal carcinomas consisted of 73 lesions of carcinoma in situ, 13 submucosal carcinomas with minimum invasion, 8 lesions with moderate invasion, and 15 lesions with deep invasion. Of 73 carcinoma in situ lesions, 72 (approximately 99 percent) showed well-differentiated adenocarcinomas and no desmoplastic response. Twelve (92 percent) of 13 submucosal carcinomas with minimum invasion also revealed well-differentiated adenocarcinoma without a desmoplastic response. Sixty-three percent (5/8) of lesions with moderate invasion revealed well-differentiated adenocarcinoma. None of the lesions had a desmoplastic response. Among lesions with deep invasion, 73 percent (11/15) demonstrated moderately differentiated adenocarcinoma, and 11 lesions had a prominent desmoplastic response (73 percent; P < 0.01).

CONCLUSIONS

These results suggest that if histopathologic findings of biopsy specimens taken from them before treatment demonstrated adenocarcinoma associated with a desmoplastic response, the lesions had at least deep invasion carcinomas. These lesions should be resected surgically. Submucosal carcinomas with minimum invasion, which have no desmoplastic response, could be treated endoscopically.

Early colorectal cancer: recognition, classification and treatment

BACKGROUND

With the introduction of colorectal cancer screening and improvements in endoscopic technology, the recognition and management of early colorectal cancer assumes increasing importance.

METHODS

A literature review was undertaken using Medline (National Library of Medicine, Washington DC, USA) searches of the headings early colonic, colorectal and rectal cancer, carcinoma and adenocarcinoma up to and including 1997. All relevant references were examined.

RESULTS AND CONCLUSION

The diagnosis, classification and treatment options are described. Accurate diagnosis, preoperative and histopathological staging is crucial in the management of early colorectal cancer.

Significance of histologic criteria for the management of patients with malignant colorectal polyps and polypectomy

BACKGROUND

The management of invasive cancer in colorectal polyps (malignant polyps) is controversial, particularly with regard to the different sets of histologic criteria for deciding whether malignant colorectal polyps should be treated by polypectomy alone or be followed by surgical resection. We report on the outcome of patients in accordance with the histologic assessment of their malignant polyps.

METHODS

Malignant polyps were defined as having favourable histology (free margin, grade I or II, and no angiolymphatic invasion) or unfavorable histology (no free margin, grade III, or angiolymphatic invasion). Malignant polyps with favourable histology were treated by endoscopic polypectomy alone, whereas further therapy was recommended for malignant polyps with unfavourable histology. Residual cancer in a resection specimen and local or metastatic recurrence during the follow-up period (mean, 60 months; range, 12 - 120) were defined as adverse outcome.

RESULTS

Thirty-seven malignant polyps were detected in 35 (0.5%) of 6605 patients. Five of these 35 patients were treated by primary bowel resection and analysed separately. In the other 30 patients the following unfavourable histologic signs were detected in 20 (62.5%) of 32 malignant polyps; no free margin in 16, grade III in 1, and angiolymphatic invasion in 3 polyps. Twelve polyps with favourable histology had no adverse outcome; in contrast, 5 of 20 polyps with unfavourable histology had an average outcome (P < 0.05).

CONCLUSIONS

Locally excised malignant polyps without unfavourable histologic signs may not need further surgical treatment; for all other malignant polyps an ensuing bowel resection is recommended.

Surgical aspects of colorectal carcinoma

Colorectal surgery remains the cornerstone of curative therapy for colorectal carcinoma. The development of new instruments permitting technical advances, however, as well as the advent of effective adjuvant therapies and the progress in staging and early detection, have changed some of the indications for surgery as well as surgical methods. Even so, emphasis has always been placed on thorough preoperative evaluation and staging. This article explores the current state of standard surgical care of the colorectal cancer patient with special attention given to preoperative evaluation, standard and controversial surgical therapies, and postoperative surveillance.

Long-term survival after treatment of malignant colonic polyps

PURPOSE

This study was designed to evaluate the long-term outcome and survival of patients treated for malignant colonic polyps.

METHODS

A retrospective review of 15,975 cases of colonoscopies with 8,685 endoscopic polypectomies performed between 1972 and 1990 was undertaken. In 65 patients, the polypectomy specimens contained invasive carcinoma. Six patients were excluded (follow-up, <6 months). Polyp data, operative findings, and follow-up on the remaining 59 patients were recorded.

RESULTS

Malignant polyps were found in 35 males and 24 females who had an average age of 64 (range, 39-81) years. Follow-up ranged from 12 to 202 (mean, 90) months. Tumor differentiation was poor in one and well or moderately differentiated in 58 patients. Positive or indeterminate margins were found in 13 patients. Thirty-seven (63 percent) patients were managed with polypectomy and surveillance. Four of these (with rectal tumors) also had an additional local excision for questionable margins. One recurrence was noted in a patient who refused surgery, which was recommended because of indeterminate margins. Twenty-two patients (37 percent) underwent colectomy. Indications included Haggitt Level 3 or 4 invasion (19), inadequate margins (7), patient preference (1), and poor differentiation (1). Residual disease was found in colectomy specimens of three patients (14 percent). There were no cancer-related deaths in either treatment group. Life table analysis demonstrated a five-year survival of 82 percent for the colectomy group and 95 percent for the polypectomy group (P = 0.15).

CONCLUSION

Treatment of patients with malignant polyps must be individualized based on evolving criteria. Patients in whom polypectomy margins are inadequate should undergo colectomy. With appropriate selection criteria, patients selected for colectomy had a five-year survival rate similar to the rate of those treated by polypectomy alone.

Flat cancers do develop in the polyp-free large intestine

PURPOSE AND BACKGROUND

Qualitative and quantitative analysis of many flat early cancers that have been discovered during the last decade led us to recognize that a flat route of cancer development de novo is as important a route as the polypoid one. We aim to prove through a longitudinal study that these flat early cancers indeed develop in flat mucosa and not in an adenomatous polyp.

METHODS

From January 1, 1990, to July 31, 1994, 554 patients underwent at least two colonoscopies. These patients consisted of 364 males, and average age was 59 years. We searched for flat early cancers developing in polyp-free colorectal mucosa on or after a second colonoscopy. Polyp-free mucosa here means an intestinal segment proved to possess no adenomatous polyp during the preceding colonoscopies, irrespective of the presence of polyps elsewhere.

RESULTS

Four flat early cancers were found developing in polyp-free colonic mucosa in four patients. Average age of the patients was 67 years. Locations of the cancers were the transverse (3) and descending colons (1). The shapes were all depressed, and average size of the lesions was 11 mm. Two lesions were endoscopically resected, and two by surgery.

CONCLUSION

These four depressed cancers developing in polyp-free mucosa show that flat early colorectal cancers do arise de novo and not from an adenomatous polyp having collapsed on itself.

Correlation between macroscopic morphologic features and malignant potential of colorectal sessile adenomas

PURPOSE AND METHODS

To clarify malignant potential of colorectal sessile adenomas, we investigated 46 colorectal sessile adenomas surgically resected from 44 patients. Lesions were divided into three types according to their macroscopic morphologic features: nodular-type (19 adenomas), villous-type (7), and creeping-type (20). Clinicopathologic features were investigated and compared among these three types.

RESULTS

Frequency of focal carcinoma in the nodular-type, villous-type, and creeping-type adenoma was 37, 29, and 55 percent, respectively. Frequency of submucosal invasion in these three types were 11, 14, and 20 percent, respectively. Irrespective of the type, large lesions (> 3 cm) tended to have a higher frequency of submucosal invasion than did smaller ones (60 vs. 20 percent; P = 0.063). Large creeping-type adenomas (> 3 cm) had a definitely higher frequency of submucosal invasion than smaller ones (36 vs. 0 percent; P < 0.05). Lymphatic or vascular invasion of carcinoma was present only in the lesion with submucosal invasion: 5 percent in the nodular-type; 14 percent in the villous-type; 20 percent in the creeping-type. Lymph node metastasis was present only in the creeping-type lesion.

CONCLUSIONS

The large creeping-type adenomas (> 3 cm) have a definitely high frequency of submucosal invasive carcinoma. Endoscopic polypectomy or local resection may be adequate for most sessile adenomas. However, we recommend segmental resection of the colon with regional lymph node dissection for a creeping-type adenoma that is larger than 3 cm because of increased risk of submucosal carcinomatous invasion and lymph node involvement.

Management and outcome of patients with invasive carcinoma arising in colorectal polyps

BACKGROUND & AIMS

Treatment for invasive adenocarcinoma in colorectal polyps (malignant polyps) is controversial. The aim of this study was to evaluate our institutional treatment strategy for malignant polyps.

METHODS

Malignant polyps were designated as having favorable histology (grade I or II carcinoma with at least a 2-mm free margin) or unfavorable histology (grade III invasive adenocarcinoma, invasive adenocarcinoma with an unassessable margin, or a margin of < 2 mm). Malignant polyps with favorable histology were considered treated adequately by endoscopic polypectomy, whereas further therapy was recommended for malignant polyps with unfavorable histology. Recurrence, residual adenocarcinoma in a follow-up resection specimen, or metastasis during follow-up were considered adverse outcomes.

RESULTS

Of the 47 patients identified, 17 (36%) had favorable histology. Sixteen patients (94%) were treated with polypectomy alone. None had an adverse outcome (median follow-up, 70 months). Thirty patients (64%) had unfavorable histology, and 21 patients (70%) underwent colectomy. Five patients underwent radiation therapy alone. Four patients underwent no additional therapy. Ten of 30 patients with unfavorable histology had adverse outcomes that differed significantly from the favorable histology group (P = 0.03).

CONCLUSIONS

Endoscopic polypectomy alone is adequate therapy for malignant polyps with favorable histology.

Management of early invasive colorectal cancer. Risk of recurrence and clinical guidelines

PURPOSE

The purpose of this study was the evaluation of various factors in the formulation of guidelines for treatment of early invasive colorectal cancer, in which malignant cells extend through the muscularis mucosa into the submucosa but do not deeply invade the muscularis propria.

METHOD

A total of 182 patients were followed for at least five years or until death, with early invasive cancer diagnosed between 1982 and 1989. Patients were grouped according to the level of invasion, as follows: 64 patients with slight carcinoma invasion of the muscularis mucosa (200-300 microns; sm1), 82 with intermediate invasion (sm2), and 36 with carcinoma invasion extending to the inner surface of the muscularis propria (sm3).

RESULT

The configuration, diameter, and histologic grade of adenocarcinoma and lymphovascular invasion were correlated with level of invasion. After endoscopic polypectomy or local resection, 4 patients showed local recurrence and 13 patients showed lymph node metastasis. None of these 17 patients had sm1 disease. The level of invasion, configuration, and location were significant risk factors for development of lymph node metastasis or local recurrence (P < 0.05), but lymphovascular invasion, histologic grade, and diameter were not risk factors.

CONCLUSIONS

Preoperative assessment of the level of invasion using this classification, in which the submucosa is divided into three depths, may decrease the incidence of unnecessary surgery for sessile polyps. Assessment according to the level of invasion is useful in the formulation of appropriate guidelines for the treatment of early invasive cancer.

Endoscopic treatment of submucosal invasive colorectal carcinoma with special reference to risk factors for lymph node metastasis

A clinicopathological analysis of the risk factors for lymph node metastasis was performed in 177 patients with submucosal invasive colorectal carcinoma (CRC). The submucosal deepest invasive portion was histologically subclassified as well (W), moderately (M), or poorly (Por) differentiated. M type was further subdivided into moderately-well (Mw) and moderately-poorly (Mp) differentiated. The pattern of tumor growth was classified as polypoid growth (PG) and non-polypoid growth (NPG). Lymph node metastasis was detected in 21 (12%) of the 177 patients. Macroscopically, type IIc and IIa + IIc lesions showed a significantly higher incidence of lymph node metastasis (44% and 30%) than type IIa and I (4% and 8%). Regarding the histologic subclassification, Por and Mp lesions showed a significantly higher incidence of lymph node metastasis (67% and 37%) than W and Mw lesions (4% and 14%). NPG tumors showed a significantly higher incidence of lymph node metastasis (29%) than PG tumors (7%). The depth of submucosal invasion and lymphatic invasion (ly) were also significantly correlated with the incidence of lymph node metastasis (submucosal scanty (sm-s) invasion 4%, massive invasion 20%; ly(+) 23%, ly(-) 5%). None of the lesions with both sm-s invasion and of W or Mw type showed lymph node metastasis. These results indicate that submucosal invasive CRC with both sm-s invasion and of W or Mw type, which shows no ly, is the appropriate indication for endoscopic curative treatment.

Polyps: the pathologist's perspective

Adenomas of the colon and rectum are perhaps the most commonly encountered of human benign epithelial neoplasms. Evidence of their relationship to the development of colorectal carcinoma has mounted over the years. They represent a phase present for significant duration in many fated to develop colon cancer. Because of this, and because of the technical advances in endoscopy, a great deal of effort has been expended on identifying and removing these lesions. Subsequent care of the patient is heavily dependent on the pathologic analysis of these lesions. they must be properly classified; the presence of cancer must be carefully sought. If present, the character and location of the cancer arising in the polyp must be carefully described. Communication between clinician and pathologist if of paramount importance. Attention must be paid to the precise meaning of such terms as dysplasia, carcinoma, and invasion. The pathologist's report needs to detail parameters important in determining prognosis and further therapy.

Endorectal ultrasonic detection of malignancy within rectal villous lesions

PURPOSE

The ability of endorectal ultrasonography (EU) to detect the presence of a malignant focus within rectal villous adenomas was studied.

METHODS

Clinical charts were reviewed of 62 consecutive patients undergoing EU of rectal villous adenomas, in whom histologic confirmation was available.

RESULTS

Twelve lesions were found to contain cancer, of which only two demonstrated clinical signs of induration. Positive predictive value of EU for detecting a malignant focus was 66.7 percent, negative predictive value was 88.7 percent, sensitivity was 50 percent, and specificity was 94 percent. There was moderate overall agreement between pathologic and ultrasound staging (kappa statistic, 0.48). When an optimal image was obtained, all cancers that penetrated the submucosa were detected. Sensitivity of the technique was compromised in some large exophytic lesions and those at the level of the anal sphincter because of artefacts produced in the ultrasonographic image.

CONCLUSION

A clear EU image can detect a malignant focus within a villous adenoma and direct the surgeon to the appropriate plane of surgical resection. In lesions with an ambiguous image, a malignancy cannot be excluded.

Transanal endoscopic microsurgery in large, sessile adenomas of the rectum. A 10-year experience

The clinical and long-term results of 286 cases encountered from 1983 to 1993 in our Department of Surgery regarding the local excision of large, sessile rectal adenomas (> 2 cm2) by the endoscopic surgical method and the influence of this selected series of adenomas on age, sex, size, grade of dysplasia, and architecture are subjects of this study. Histologically proven rectal carcinomas as well as non-neoplastic polyps were excluded from this trial. Early postoperative complications amounted to 3.4%. The 1-year and 5-year recurrence rates +/- SE of adenomas were 1.2 +/- 0.7% and 7.0 +/- 1.9%, respectively. Remarkably, there was no significant relationship between the histological type of the adenoma and the grade of dysplasia nor between the size and grade of dysplasia. However, there was a significant relationship between the size and histological type of the adenoma (P < 0.01). With the endoscopic minimal-invasive system, we are able to achieve a superior rate of recurrence compared to any other local treatment as well as a more favorable operative result compared to extensive surgical procedures.

Polyps and polypectomy surveillance--role of the histopathologist

The traditional roles of the pathologist are those of diagnostician, and being able to communicate these diagnoses back to the clinician in a clear unambiguous form so that subsequent therapy can be planned. Important findings may require more direct communication, particularly when the implications involve a choice between therapeutic options. Some diagnoses have implications that require an educational role for the pathologist; these in turn may evolve into a research role, based on clinico-pathological correlation, active basic science research or simply supplying tissue for research. Clinicians must also be aware that the same biopsy can be interpreted in numerous ways, depending upon the clinical situation.

Endoscopically removed malignant colorectal polyps: clinicopathologic correlations

BACKGROUND/AIMS

Treatment options for patients with endoscopically removed malignant colorectal polyps are polypectomy alone vs. polypectomy followed by surgery. The aim of this study was to define histopathologic parameters that can be used for clinically relevant treatment decisions.

METHODS

Five pathologists evaluated 140 polyps for the presence or absence of unfavorable histology. Unfavorable histology was tumor at or near (< or = 1.0 mm) the margin and/or grade III and/or lymphatic and/or venous invasion. Adverse outcome was recurrent and/or local cancer and/or lymph node metastasis.

RESULTS

Adverse outcome was 19.7% (14 of 71), 8.6% (2 of 23), and 0% (0 of 46) when unfavorable histology was present, indefinite (lack of agreement), and absent, respectively (P < 0.0005, present vs. absent). Four patients with cancer > 1.0 mm from the margin had an adverse outcome (2 with lymphatic invasion and 2 indefinite for lymphatic invasion). Four patients with negative resections later developed distant metastases. Eight patients (6.3%) died of disease, and 2 of 69 without unfavorable histology (both indefinite for lymphatic invasion) had an adverse outcome. Interobserver strength of agreement was substantial to almost perfect for margin, grade, and venous invasion and fair to substantial for lymphatic invasion.

CONCLUSIONS

This system is usable clinically. Patients with unfavorable histology are probably best managed by resection postpolypectomy, whereas in the absence of unfavorable histology, they probably can be treated by polypectomy only.

Long-term results of curative resection of "minimally invasive" colorectal cancer

PURPOSE

The aim of this study was to determine the long-term outcome after curative resection of colorectal cancers that extend only into the submucosa ("minimally invasive") and to evaluate potential histologic predictors of lymph node metastases.

METHODS

Seventy-nine patients who underwent curative resection of minimally invasive colorectal cancer and were followed for at least five years were studied retrospectively.

RESULTS

The series was comprised of 53 men and 26 women, with a mean age of 61 years. The lesion was in the colon in 47 patients and the rectosigmoid or rectum in 32 patients. Open surgery followed attempted endoscopic tumor removal in 25 patients. Lymph node metastasis, found in 11/79 patients (13.9 percent), was associated with worse outcome: 36.4 percent of node(+) patients developed recurrence, vs. only 5.9 percent of node(-) patients (P < 0.005). The cumulative survival rate was also worse in node(+) vs. node(-) patients: 72.7 percent vs. 91.1 percent at five years (P < 0.05) and 45.5 percent vs. 65.3 percent at ten years (P < 0.05). Five histopathologic characteristics were identified as risk factors for lymph node metastasis: 1) small clusters of undifferentiated cancer cells ahead of the invasive front of the lesion ("tumor budding"); 2) a poorly demarcated invasive front; 3) moderately or poorly differentiated cancer cells in the invasive front; 4) extension of the tumor to the middle or deep submucosal layer; 5) cancer cells in lymphatics. Whereas patients with three or fewer risk factors had no nodal spread, the rate of lymph node involvement with four or more risk factors was 33.3 percent and 66.7 percent, respectively.

CONCLUSIONS

Metastasis is not infrequent in "minimally invasive" colorectal cancer. Appropriate bowel resection with lymph node dissection is indicated if such a lesion exhibits more than three histologic risk factors for metastasis.

Dysplasia and early carcinoma in inflammatory bowel disease and colorectal adenomas

The control of colorectal cancer is currently dependent on early detection, and its prevention requires the recognition and treatment of its precursor lesions. The adenoma has been established as the precursor of colorectal carcinoma in the general population. Among patients with inflammatory bowel disease (IBD), dysplasia is associated with, and precedes, invasive carcinoma. In this section criteria are described for the histological detection of preinvasive and early invasive neoplasia in the large intestine of patients with and without IBD. The therapeutic implications of these diagnoses are stressed. A brief review of subcellular changes, including genetic alterations, in colorectal neoplasia is included.

Long-term prognosis of well-differentiated adenocarcinoma in endoscopically removed colorectal adenomas

Thirty-six malignant polyps were identified that met the following criteria: well-differentiated adenocarcinoma and complete excision endoscopically. Location, type, size, distance of the cancer to the cautery mark, and lymphovascular involvement were analyzed to determine if they affected findings at surgery or risk of recurrent cancer. There were 20 patients and 21 polyps in the nonsurgical group, and 15 patients and polyps in the surgical group. One patient from each group had residual cancer after endoscopic removal of the polyp. The only factor that had an adverse effect on outcome was the distance of the cancer to the cautery mark (< 1 mm). Although rectal location was associated with the residual cancer, poor prognosis could have been predicted by the inadequate margins. This long-term follow-up (65 months average) study supports previous observations that an adequate margin is the most important factor in predicting the prognosis of endoscopically resected colorectal adenomas containing well-differentiated adenocarcinomas.

Superficial-type adenomas and adenocarcinomas of the colon and rectum: a comparative morphological study

BACKGROUND/AIMS

It has been uncertain whether colorectal carcinomas preferentially arise on preexisting adenomas or de novo. However, from a morphological viewpoint, it seems unlikely that pedunculated or exophytic malignant polyps progress to the deeply ulcerated advanced carcinomas usually found clinically.

METHODS

The morphological features of 26 nonpolypoid, superficial-type colorectal tumors (17 adenomas and 9 adenocarcinomas) were compared to clarify the developmental route of colorectal carcinomas.

RESULTS

The adenomas and adenocarcinomas were very similar in size and gross appearance; however, examination of the surface appearances of unsectioned tumors by dissecting microscopy was helpful for distinguishing the two. Histologically, no adenomatous tissue was found in any case of superficial-type adenocarcinoma. Five of the nine adenocarcinomas, even including those of small size, invaded the submucosal layer, and two showed lymph node metastasis.

CONCLUSIONS

These findings suggest that superficial-type adenocarcinomas show rapid growth and aggressive behavior. We suggest that this type of carcinoma may not progress by the adenoma-to-carcinoma pathway but that it may arise from a very small superficial-type adenoma.

Management of the malignant colorectal polyp: the importance of clinicopathological correlation

The results of management of colorectal adenomas removed endoscopically and found to contain invasive cancer seen in a single institution over a 10 year period are presented. Clinical data were obtained retrospectively from patient case notes and all specimens were reviewed by one pathologist. Fifty-four patients with malignant polyps were studied after exclusion of others with polypoid carcinomas, epithelial misplacement and cases managed by primary segmental resection. Of the various considered predictors of adverse outcome, only histologically incomplete excision proved significant. However, when excision was considered macroscopically complete there was no significant association between incomplete histological excision and adverse outcome. Consideration should be given to conservative management of such cases.

Patient characteristics and pathology in colorectal adenomas removed by colonoscopic polypectomy

Between September 1981 and August 1987 420 patients with 565 adenomas underwent colonoscopic polypectomy to produce a 'clean colon'. Data from these patients were analysed to identify associations between patient characteristics (age and sex), polyp characteristics (site, size, shape, multiplicity and villous content) and the degree of dysplasia in the index adenoma. In univariate analysis, severe dysplasia in the index adenoma was significantly but weakly associated with size (> or = 10 mm), peduncular shape and villous architecture. Logistic regression confirmed an independent effect only from villous architecture. These findings suggest that it is unlikely that strong predictors of a patient developing a metachronous adenoma or colorectal cancer can be identified on the basis of an index adenoma found at initial colonoscopy. These patients will continue to be followed to investigate this question.

Management of malignant colorectal polyps

The optimal management of patients with adenomatous polyps that contain invasive adenocarcinoma remains controversial. The independent factors of margins of resection, level of invasion, differentiation, grade, and vascular invasion are examined as prognostic indicators for outcome. The literature is reviewed with regard to the management of patients with polyp-containing invasive adenocarcinoma with standard operative resection versus endoscopic treatment alone.

Recent advances in surgery for colon and rectal cancer

Surgery is the mainstay of therapy for colon and rectal cancer. Over the past several decades, there have been important advances both in the understanding of the biology of colon and rectal cancer and in the preoperative and operative techniques for treating this disease. Although it appears in some studies that we have made a difference in the survival rates in the treatment of colon and rectal cancer, in actual fact, this phenomenon may only be secondary to better staging and, therefore, a greater ability to prognosticate a particular patient's chance of cure. What has been learned in the past 20 to 30 years is that most colon and rectal carcinomas start as polyps of the colon and rectum. Most often, polyps are sporadic, but there are certain high-risk groups that produce polyps and, consequently, colon and rectal cancer at a much higher rate. The goal of a practicing physician is to identify these high-risk individuals and to recommend frequent screenings so as to intervene before a polyp has had a chance to become a deeply invasive cancer. These high-risk groups are best typified by familial adenomatous polyposis, which if left untreated will, in 100% of cases, lead to the death of a patient from colon or rectal cancer. Other diseases that lead to an increase in colon and rectal cancer but may not go through the usual adenoma-to-carcinoma sequence include inflammatory bowel disease such as Crohn's colitis and ulcerative colitis. Most patients with colorectal carcinoma are asymptomatic at the time of diagnosis. This phenomenon has led to efforts to screen the general population for polyps and for cancer. Screening techniques such as the detection of occult blood in the stool and endoscopic procedures are currently the most popular. It is unclear at this time exactly what the efficacy of these techniques is in improving the survival of the general population from colorectal carcinoma. The surgical techniques to remove colon and rectal carcinomas have recently expanded to include a more aggressive local excision policy for small tumors of the rectum and the application of laparoscopic techniques, new stapling techniques, and new anastomosing techniques for tumors of the colon and rectum. These techniques have become possible in part through advances in surgical instrumentation and also in part from our increasing understanding of the biology of the disease. Both have allowed for more creative approaches to diagnosing and treating colon and rectal cancer.(ABSTRACT TRUNCATED AT 400 WORDS)

The care of patients with colorectal polyps that contain invasive adenocarcinoma. Endoscopic polypectomy or colectomy?

BACKGROUND

The appropriateness of resection in patients from whom polyps with invasive adenocarcinoma were excised has been questioned.

METHODS

To determine the results of this policy, the authors reviewed the outcome of 42 patients from whom 44 such polyps were removed. Each polyp was categorized for the level of invasion according to the classification of Haggitt.

RESULTS

Level 1 invasion was found in 27%; level 2, in 9%; level 3, in 11%; level 4, in 39%; and uncertain, in 14%. The histologic grade was well differentiated in 48% of patients and moderately differentiated in 52%. No polyps contained poorly differentiated adenocarcinoma; lymphatic and vascular invasion were not encountered. Excision was judged complete in 23 patients; 11 underwent resection, and in none was residual adenocarcinoma identified. In 14 patients, margins could not be evaluated; of 12 patients who underwent resection, residual adenocarcinoma was found in 1. Of the seven patients with positive margins who underwent resection, residual adenocarcinoma was found in only two. In the resected specimens in which residual carcinoma was encountered, all original lesions were designated level 4. None of the patients treated by polypectomy alone has experienced a recurrence at a mean follow-up time of 66 months (range, 12-152 months).

CONCLUSIONS

The authors conclude that only patients with level 4 invasion require resection.

The fate of patients following polypectomy alone for polyps containing invasive carcinoma

Eighty-two patients with colon and rectal polyps containing invasive adenocarcinoma treated by polypectomy alone were studied. Seven of 34 patients (21 percent) with sessile lesions had an adverse outcome, including five local recurrences and two distant metastases. They occurred from 4 to 68 months after the polypectomy. Forty-seven pedunculated polyps with invasion to the head (Level 1) or to the stalk (Level 3) and one polyp to the base of the stalk (Level 4) had no evidence of local recurrence or signs of metastasis. Twenty-eight percent of patients were found to have adenomatous polyps, and 4 percent had malignant polyps during the follow-up examinations (range, 3-119 months; mean, 53 months). The findings suggested that pedunculated polyps with invasion to the head (Level 1), neck (Level 2), or stalk (Level 3) can be safely treated with a complete polypectomy provided that the carcinoma is not undifferentiated. Sessile lesions as well as Level 4 pedunculated lesions should be treated aggressively. If resection is not performed, a long-term follow-up in these patients is essential.

The National Polyp Study. Design, methods, and characteristics of patients with newly diagnosed polyps. The National Polyp Study Workgroup

The National Polyp Study (NPS) is a multicenter prospective randomized trial designed to evaluate follow-up surveillance strategies in patients who have undergone polypectomy for the control of large bowel cancer. The study design was developed by a joint research committee from American Gastroenterological Association, the American Society for Gastrointestinal Endoscopy, and the American College of Gastroenterology. Subjects who met the eligibility criteria were randomized into two different treatment arms. Eligibility criteria included: removal of one or more adenomas; complete colonoscopy; no prior polypectomy, inflammatory bowel disease, or familial polyposis; and no history of colon cancer. The treatment arms consisted of a frequent follow-up (1 and 3 years after initial polypectomy) and a less frequent follow-up (3 years). Follow-up examinations included fecal occult blood tests, air-contrast barium enema, and colonoscopy. The latter was done on 9112 referred patients at the seven participating centers from November 1980 until February 1990 who had no history of polypectomy, colon cancer, familial polyposis, or inflammatory bowel disease. Of these patients, 4763 (52.3%) had no polyps; 549 (6.0%) had an invasive cancer; 776 (8.5%) had nonadenomatous polyps; 208 (2.3%) had incomplete examinations; 184 (2.0%) had other findings; and 2632 (28.9%) had one or more adenomas, of which 1418 (53.9%) were randomized to one of the two treatment arms. This article reports the background, rationale, objectives, methods, and organization of this study and includes patient characteristics on initial presentation. Future data provided by the NPS may help in the development of recommendations for surveillance guidelines for such patients. This study also provides a framework to address questions regarding the natural history of adenomas and their relationship with colorectal cancer.

The value of nuclear morphometry in the management of patients with colorectal polyps that contain invasive adenocarcinoma

Haggitt's classification is a useful guide in the management of patients with large bowel polyps which contain invasive adenocarcinoma in that patients with levels 1 to 3 require no operation. Nuclear morphometry has been shown to be a useful prognostic discriminant for patients with invasive carcinoma of the large bowel. The nuclear shape factor of 44 polyps with invasive carcinoma was studied to determine whether this parameter was of value to define those patients with Haggitt level 4 who should have a resection. The shape factor of 50 interphase nuclei was obtained through the use of image analysis by tracing the nuclear profiles as digitized on a video screen. The nuclear shape factor was defined as the degree of circularity of the nucleus, a perfect circle recorded as 1.0. Our previous experience showed a nuclear shape factor greater than 0.84 was associated with a poor outcome. The overall mean shape factor was 0.71 (0.59-0.85). There was a tendency for the patients with residual disease to have values in the upper range. Our findings suggest that nuclear morphometry fails to add any predictive information in this clinical situation.

Outcome in patients with early colorectal carcinoma

Twenty-four patients seen between 1978 and 1990 with early colorectal carcinoma were reviewed to determine the outcome of surgical treatment. The mean age was 62 (range 35-79) years; there were 16 men and eight women. The site of the tumour was the ascending colon in two patients, sigmoid colon in ten and rectum in 12. The polypoid and flat-elevated ulcerated (IIa+IIc) subtypes were detected in 14 and nine lesions respectively. Restorative colectomy was carried out in 19 patients, and five required Mile's operation. There were no postoperative complications or deaths at a mean follow-up of 71 (range 12-151) months. Neither recurrence nor distant metastasis was found during follow-up. There was a close relationship between the depth of submucosal invasion and presence of flat-elevated ulcerated subtype lesions with lymphatic infiltration. This association may play an important role in the mechanism of metastasis. Major surgical resection is probably required if longer disease-free intervals and better cure rates are desired.