A conservative approach to adenomas containing invasive carcinoma removed colonoscopically

Rate of residual disease after complete endoscopic resection of malignant colonic polyp

BACKGROUND

Following polypectomy, colectomy is performed selectively to ensure complete clearance of neoplasia.

OBJECTIVE

This study aimed to determine the risk factors associated with residual disease at colectomy following malignant polypectomy.

DESIGN

This is a retrospective study.

SETTING

This investigation took place at a tertiary teaching cancer center.

PATIENTS

Consecutive patients undergoing polypectomy followed by colectomy from 1990 to 2007 were identified from a prospective database.

MAIN OUTCOME MEASURES

Factors associated with residual disease at colectomy were associated with clinicopathologic features.

RESULTS

Colectomy following polypectomy was performed in 143 patients: 127 with clear invasion of polyp submucosa (invasive disease), and 16 suspicious for submucosal invasion. Residual disease after colectomy was diagnosed in 27 (19%) of 143 patients. Disease was present in the colonic wall in 19 patients (13%): invasive in 16 (11%), and noninvasive in 3 (2.1%). Of the 16 patients with residual invasive disease at colectomy, 15 had clearly invasive disease at polypectomy and 1 was suspicious for invasive disease at polypectomy. Lymph node metastasis was noted in 10 (7.0%) patients. When analyzing patients with clearly invasive disease at polypectomy by margin status, residual invasive disease in the colon wall was noted in 8 of 50 (16%) with <1 mm (positive) polypectomy margin, 7 of 33 (21%) with indeterminate polypectomy margin, and 0 of 44 with ≥1 mm (negative) polypectomy margin (p = 0.009). Nodal metastasis was associated with the presence of lymphovascular invasion (p = 0.01).

LIMITATIONS

This study is limited by its retrospective nature and selection bias.

CONCLUSIONS

Following malignant polypectomy, colectomy should be considered in medically fit patients if the polypectomy margin is positive (≤1 mm) or unknown, or if lymphovascular invasion is present.

The colorectal malignant polyp: scoping a dilemma

Colorectal adenomas containing invasive carcinoma represent the majority of early colorectal cancers. The malignant polyp carries a significant risk of lympho-haematic metastasis and mortality due to the penetration of cancerous cells into the submucosal layer. The therapeutic dilemma is whether to perform endoscopic or surgical resection. A thorough assessment of the endoscopic, histological and clinical variables is needed to unravel the best treatment for each patient. In particular, a unique staging of such lesions, based on certain histopathological features, has been deeply implicated in the therapeutic choice. Aim of this article is to review the main endoscopic, histological and clinical features of the malignant polyp in order to propose a systematic management of this lesion.

Histologic risk factors and clinical outcome in colorectal malignant polyp: a pooled-data analysis

PURPOSE

The malignant polyp carries a significant risk of lymphohematic metastasis and mortality. Clinical usefulness of histologic risk factors is still controversial. The study was designed to compute the association between the main histologic risk factors and the occurrence of unfavorable outcomes in patients with malignant polyps.

METHODS

A MEDLINE search regarding malignant polyps was performed. Three histologic risk factors (positive resection margin, poor differentiation of carcinoma, vascular invasion) and five (residual disease, recurrent disease, lymph node metastasis, hematogenous metastasis, mortality) unfavorable clinical outcomes were evaluated. Further analysis was performed by subgrouping polyps in high-risk and low-risk groups.

RESULTS

Thirty-one studies enrolling 1,900 patients with malignant polyp were selected. Positivity of resection margin was significantly predictive of the presence of residual disease (odds ratio, 22; P < 0.0001), poorly differentiated carcinoma was associated with an increased mortality (odds ratio, 9.2; P < 0.05), and vascular invasion with a higher lymph node metastasis risk (odds ratio, 7; P < 0.05). Patients with high-risk polyps showed a significantly worse outcome than those with low-risk, especially for mortality (odds ratio, 11; P < 0.05). Surgical-related death was as low as 0.8 percent.

CONCLUSIONS

All three histologic risk factors are significantly associated with the clinical outcome. Classification in low-risk and high-risk patients may be regarded as a meaningful staging procedure.

Endorectal ultrasound in the management of patients with malignant rectal polyps

PURPOSE

This study was designed to determine the efficacy of endorectal ultrasound in the management of patients with malignant rectal polyps removed by snare excision during colonoscopy.

METHODS

A retrospective review of the medical records and endorectal ultrasound images of 63 patients with endoscopically removed rectal polyps containing invasive adenocarcinoma subsequently staged by endorectal ultrasound. Patients underwent surgery or were followed at a single institution. The polyp characteristics and ultrasound images were compared with the presence of residual tumor in the surgical specimen in patients who underwent further surgery or with recurrence in patients who did not.

RESULTS

The morphology of the polyps was described in 31 patients (49 percent); they were sessile in 26 (41 percent) and pedunculated in 6 (9 percent). The margins were positive in 22 patients (35 percent), negative in 19 (30 percent), and not specified in 22 (35 percent). Most tumors were well or moderately differentiated; only 3 (5 percent) were poorly differentiated. Thirty-three patients underwent further surgery (3 low anterior resection, and 30 transanal excision); 30 had no further surgery. The accuracy of endorectal ultrasound in assessing the presence of residual cancer in the rectal wall in patients who had surgery was 54 percent, with a 39 percent positive predictive value and 65 percent negative predictive value. Endorectal ultrasound accurately identified metastatic lymph nodes in two of three patients who had radical surgery. Endorectal ultrasound was more useful than polyp morphologic or histologic criteria to determine the presence of residual cancer in the rectal wall.

CONCLUSIONS

Endorectal ultrasound does not definitely exclude the possibility of residual tumor in the rectal wall or mesenteric nodes of patients who had a malignant polyp snared endoscopically. Consequently, decisions regarding the definitive management of these patients cannot be based exclusively on the endorectal ultrasound images of the polypectomy site.

New indication for endoscopic treatment of colorectal carcinoma with submucosal invasion

BACKGROUND AND AIMS

Although an increasing number of early colorectal cancers (CRC) have been curatively treated by endoscopy, there have been no definitive criteria to decide the effectiveness of such therapy. We retrospectively analyzed clinicopathological factors to establish criteria for curative endoscopic treatment of early CRC.

METHODS

First, risk factors of lymph node metastasis were analyzed in 171 patients who received surgery with postoperative histology of CRC submucosal invasion. The resultant new criteria were evaluated in another 60 patients who experienced endoscopic resection of CRC and surgery according to the current criteria most often used in Japan.

RESULTS

In the first substudy, lymph node metastasis was present in 18 of 171 patients (10.5%). Lymphatic permeation, sprouting and infiltrative growth of cancer cells were identified as histological factors significantly related to lymph node metastasis, and observed in much higher rates when the depth of submucosal invasion was beyond 1,500 micron. The minimum depth with positive lymph nodes was 1,075 micron. In the second group of 60 patients, lymph node metastasis was recorded in none of nine patients who met our new criteria of complete endoscopic treatment: submucosal invasion below 1,500 micron in depth, and no lymphatic permeation, sprouting or infiltrative growth pattern on tumor histology. Lymph node metastasis was positive in three of the other cases who did not meet our new criteria.

CONCLUSIONS

The present study showed that endoscopic treatment of early CRC may be considered complete when submucosal invasion beyond 1,500 micron, lymphatic permeation, sprouting, and infiltrating growth are all denied.

MUC-1 expression as a predictor of the curative endoscopic treatment of submucosally invasive colorectal carcinoma

PURPOSE

This study was undertaken to clarify the clinical significance of MUC-1 expression in the endoscopic treatment of colorectal carcinoma with submucosal invasion.

METHODS

One hundred eighty-four colorectal carcinomas with submucosal invasion were examined. The depth of submucosal invasion was classified as scanty or massive. The histologic subclassification at the deepest invasive portion was defined as well-differentiated, moderately well-differentiated, moderately to poorly differentiated, poorly differentiated, or mucinous adenocarcinoma. MUC-1 expression was examined immunohistochemically at the deepest invasive portion. In addition, the Ki67 labeling index was also examined immunohistochemically.

RESULTS

Lymph node metastases were detected in 28 (15.2 percent) of 184 lesions. Lesions with both scanty submucosal invasion and well-differentiated or moderately well-differentiated adenocarcinomas had no lymph node metastases. MUC-1 expression was detected in 88 (47.8 percent) of 184 lesions and correlated significantly with the presence of lymph node metastases. The Ki67 labeling index also correlated significantly with lymph node metastases. Furthermore, lesions with both MUC-1-negative and low Ki67 labeling index showed no lymph node metastases, even in lesions with massive submucosal invasion. Multivariate analysis indicated that MUC-1 expression was one of the most important risk factors for lymph node metastases and histologic grade among the clinicopathologic factors usually examined.

CONCLUSION

MUC-1 expression is one of the accurate predictors of the presence of lymph node metastases among the clinicopathologic factors commonly used. Combined analysis of MUC-1 expression and Ki67 labeling index may be a useful indicator of lymph node metastases and may broaden the indications for the curative endoscopic treatment of carcinoma with massive submucosal invasion.

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.

Clinicopathologic features of early rectal carcinoma and indications for endoscopic treatment

PURPOSE

This study was undertaken to clarify the indications for endoscopic treatment.

METHODS

Clinical and pathologic features of 191 lesions in 180 patients with early rectal carcinoma were examined, including 110 intramucosal carcinomas and 81 carcinomas with submucosal invasion (submucosal carcinomas). All lesions had been endoscopically or surgically resected at the National Cancer Center Hospital between 1976 and 1990.

RESULTS

Metastasis to regional lymph nodes (LN metastasis) was seen in 0 percent (0/39) of intramucosal carcinomas and 9.2 percent (6/65) of submucosal carcinomas in the surgically treated patients. The incidence of LN metastasis was higher for lesions larger than 10 mm in diameter, for those showing massive submucosal invasion, and for moderately differentiated adenocarcinomas. LN metastases were associated significantly with lymphatic invasion.

CONCLUSIONS

These results suggest that early rectal carcinomas should be resected surgically if they 1) show massive submucosal invasion, 2) are classified as moderately differentiated adenocarcinomas, and 3) are larger than 10 mm in diameter. In patients with both scanty submucosal invasion and features of well-differentiated adenocarcinoma or intramucosal carcinoma and if no other risk factors for LN metastasis are present, such as lymphatic invasion by the primary lesion, surveillance may suffice after endoscopic resection.

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.

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.

Treatment of carcinoma in adenomas

Invasive carcinomas in polyps removed during endoscopy are described. Most of them can be treated adequately by polypectomy alone, but some need additional surgical treatment. Incomplete excision, poorly-differentiated carcinoma, and lymphatic invasion are associated with increased risk of residual carcinoma and lymph node metastases, making colorectal resection more attractive; however, in elderly patients and poor-risk patients, the risks of surgery should be balanced against the possible advantage of curative surgery. Rectal polyps may be large but sphincter preservation can usually be achieved by different types of local excision. Recently described flat adenomas may contain carcinoma, but may also be treated by polypectomy using snare or hot biopsy.

Invasive colorectal adenomas: surgery versus colonoscopic polypectomy

Of 6,426 colonoscopies performed in 1978-1987, 66 invasive colorectal adenomatous polyps were removed in 58 examinations. The study group included 36 (62%) men and 22 (38%) women with an age range of 42-96 years. Forty-three patients had invasive pedunculated polyps and 15 had invasive sessile polyps. Following the colonoscopic polypectomy, secondary surgical resection was done in 19 patients with pedunculated polyps and in 13 patients with sessile polyps. The operative specimens showed that the colonoscopic polypectomy removed the entire cancerous focus in all patients with pedunculated polyps, including those with stalk invasion. In contrast, most cases with sessile polyps turned out on operation to be Dukes' B or C carcinoma. Follow-up (mean 4.4 years) was available for 53 (93%) patients: none of 24 unoperated patients with pedunculated polyps suffered from local recurrence. We conclude that colonoscopic polypectomy is sufficient for invasive pedunculated polyps, provided that histology shows that the resection margins are free of tumoral cells. Surgery is recommended for all invasive sessile polyps.

Colorectal adenomas containing invasive carcinoma. Pathologic assessment of lymph node metastatic potential

Adenomas that contain early invasive carcinoma (ACIC) represent the earliest form of clinically relevant cancer of the colorectum in most patients. In order to assess the incidence of nodal metastases of ACIC, we studied 31 patients in whom the colon was resected after endoscopic polypectomy (EP) done from 1975 to 1987. We also reviewed the pathologic features reported in individual cases and in literature series of ACIC with lymph node metastases published from 1958 to 1986. The lymph node metastatic potential of ACIC is relatively high, ranging from an average value of 8.5% in the literature of to 16.1% in our own study, and is equivalent to the range of 10%-17% that occurs in colorectal carcinomas that invade the submucosa. When an ACIC is seen in an EP specimen in which the polypectomy margin is normal, the decision as to whether the patient should enter a follow-up protocol or have radical surgical resection is determined by the assessment of the probability of the occurrence of nodal metastases. According to several authors, certain histopathologic features make it possible to distinguish between an ACIC with a high-risk of nodal metastases versus those with a low-risk. The most relevant pathologic parameters include the state of the resection margins, the grade of the invasive carcinoma, and the presence or absence of vascular invasion. Of 351 cases of ACIC that were operated on, derived from 16 literature series, 45.6% were high-risk cases and 8.5% had lymph node metastases. In our group of high-risk ACIC that had surgical resection subsequently, the lymph node metastatic rate was 35.7%. Our results help to estimate the nodal metastatic potential of early colorectal carcinomas and stress the importance of adequate pathologic evaluation in order to assess metastatic risk in these patients accurately.

Management of patients with invasive carcinoma removed by colonoscopic polypectomy

The management of patients with invasive carcinoma removed by colonoscopic polypectomy remains controversial. In order to assess the criteria for subsequent surgery after polypectomy, the histologic findings and outcome of 25 patients with invasive carcinomas treated by polypectomy were analyzed. Subsequent surgery was indicated when removed invasive carcinoma showed at least one of the following findings: 1) carcinoma near the surgical margin, 2) vessel invasion, 3) massive invasion, and 4) poorly differentiated adenocarcinoma. The authors considered those findings to be a risk factor for local residual carcinoma or lymph-node metastases, or both. Of 25 patients, 18 showed risk factors, with 16 receiving surgery. Only one had residual carcinoma in the lymphatic vessel of the surgical specimen. The remaining 15 had no carcinoma in the surgical specimens, however, one died of recurrent disease 55 months later. Two patients with risk factors received no surgery for various reasons. Local recurrent carcinoma developed in one 39 months later and the other had no recurrent carcinoma at autopsy. Seven patients without risk factors were adequately treated by polypectomy without recurrent disease 34 to 96 months later (average, 69 months). Consequently, of 18 patients with risk factors, 3 showed either residual carcinoma in the surgical specimens or recurrent carcinoma was found later. None of 7 patients without risk factors developed recurrent disease. We recommend that patients with risk factors be followed by surgery; however, patients without risk factors can be adequately treated by polypectomy alone.

Large bowel adenomas containing carcinoma--a diagnostic and therapeutic approach

Adenomas containing invasive carcinoma of the large bowel form the majority of early colorectal cancers. Conclusive histological diagnosis of early colorectal cancer depends on two conditions; first, the whole lesion must be examined and second the resection margin must border on healthy tissue. The presence of certain histopathological features makes it possible to distinguish between cases with high and low risk of having lymph node metastases. Sixty-six adenomas containing invasive carcinoma are reported. They comprised 3.15% of 2,095 adenomas removed by colonoscopic polypectomy during the same period. Five cases were lost to follow-up. Forty-nine patients considered to be at low risk of having lymph node metastases have been treated by endoscopic polypectomy only with a rigorous follow-up regime including CEA estimation, ultrasonography and total colonoscopy at regular intervals. In none have distant metastases been found on follow-up examinations at a mean duration of 3 years. Two of these cases have developed a metachronous colorectal carcinoma and 15 (30.5%) have metachronous adenomas. Two low risk patients with no tumour found in the operative specimen have undergone major surgical resection. Ten high risk cases have been referred for major surgery and lymph node metastases have been found in four (40%). The need for careful histological examination for lymphatic and veinous invasion is stressed by the presence of this finding in all four high risk patients with involved lymph nodes.