Analysis of regional lymph node metastases from rectal carcinoma by the clearing method. Justification of the use of sigmoid in J-pouch construction after low anterior resection

Clinical impact of fat clearing technique in nodal staging of rectal cancer after preoperative chemoradiotherapy

Purpose

This study was designed to evaluate the efficacy of a fat clearing technique for accurate nodal staging of rectal cancer patients after preoperative chemoradiotherapy (CRT).

Methods

A total of 19 patients with rectal cancer within 10 cm from anal verge were divided into two groups: non-CRT group (n = 10) and CRT group (n = 9). For pathologic assessment, lymph node (LN) harvest was performed using conventional manual dissection followed by a fat clearing technique.

Results

A median of 3.0 additional LNs in non-CRT group and 3.8 LNs in CRT group were identified by the fat clearing technique. When subanalysis was performed in patients with fewer than 12 retrieved LNs, a median of 4.0 extra LNs in non-CRT group and 3.5 extra LNs in CRT group were identified after the fat clearing technique. None of additionally identified nodes were metastatic. In both groups, the median size of retrieved LNs following the fat clearing technique was smaller than that obtained by manual dissection (2.0 mm vs. 3.0 mm, P < 0.001).

Conclusion

The fat clearing technique allowed detection of additional LNs that were missed by the manual method, but these detected LNs were not proven to be metastatic.

Pouch operation for rectal cancer

Many retrospective studies have found that the functional outcome after a low anterior resection for rectal cancer is better with colonic J-pouch reconstruction than with conventional straight anastomosis. This advantage was demonstrated in prospective, randomized trials and meta-analyses. However, despite its increasing popularity there are several areas of controversy about the use of the colonic J-pouch reconstruction. These issues include anastomotic leaks, the part of the colon used for the pouch, the pouch size, causes of difficulty in evacuation, indications (the optimum level of anastomosis), appropriateness for the elderly, and long-term (2 years or more after surgery) functional outcome. All relevant articles identified from MEDLINE databases were reviewed. The incidence of anastomotic leaks is apparently reduced by colonic J-pouch reconstruction. A 5-cm colonic J-pouch using the sigmoid colon increases the reservoir function without compromising evacuation, and provides better functional outcome than straight anastomosis, even 2 years or more after surgery, in patients whose anastomosis is less than 8 cm from the anal verge. Patients with ultralow anastomoses, less than 4 cm from the verge, appear to benefit the most. At a time when the indications for abdominoperineal excision appear to be reduced for low rectal cancer, the demand for colonic J-pouch reconstruction (the best technique in pouch operations) is therefore likely to increase.

Metastasis to the sigmoid or sigmoid mesenteric lymph nodes from rectal cancer

OBJECTIVE

We analyzed metastases to the sigmoid and sigmoid mesenteric lymph nodes from rectal cancer.

BACKGROUND

It has been reported that rectal cancer spreads upward and lateral. However, metastasis to the sigmoid mesenteric or sigmoid nodes from rectal cancer has been rarely reported.

METHODS

We enrolled 347 patients who underwent curative resection for rectal cancer with proven lymph node metastases and dissection of the sigmoid and sigmoid mesenteric lymph nodes. Lymph node classification was performed by the colorectal surgeon and the lymph nodes were sent to pathology. Two hundred ninety sigmoid mesenteric and 248 sigmoid lymph node dissections were confirmed by pathologic examination.

RESULTS

There were 185 and 162 patients with extraperitoneal and intraperitoneal rectal cancers, respectively. The T categories were T1 in 4 patients (1.2%), T2 in 25 patients (7.2%), T3 in 252 patients (72.6%), and T4 in 66 patients (18.8%). The N categories were N1 in 216 patients (62.2%) and N2 in 131 patients (37.8%). Metastases to the sigmoid and sigmoid mesenteric lymph nodes occurred in 60 (20.7%) and 28 patients (11.3%), respectively. Metastases to the sigmoid or sigmoid mesenteric lymph nodes, without metastases to the superior rectal and inferior mesenteric lymph nodes, developed in 18 patients (5.2%). Compared with patients without sigmoid mesenteric lymph node metastases, N2 category disease, and poor differentiation, overall recurrence was more common in patients with sigmoid mesenteric lymph node metastases. Patients with sigmoid lymph node metastases were common in the N2 category of disease. However, the number of retrieved lymph nodes, and the overall and local recurrence rates were not significantly different. Seventeen of 18 patients with only sigmoid mesenteric or sigmoid lymph node metastases had N1 category disease; 8 and 10 patients had extraperitoenal and intraperitoneal rectal cancers, respectively. For patients with N1 category disease, there was no difference in the overall and local disease recurrence rates among the patients.

CONCLUSION

Sigmoid mesenteric or sigmoid lymph node metastases developed in 23.2% of patients in the present study. But, there were no differences in the cancer-specific survival, overall and local disease recurrence rates in the patients with sigmoid mesenteric or sigmoid lymph node metastases.

Tumor invasion of lymph node capsules in patients with Dukes C colorectal adenocarcinoma

PURPOSE

The objective of this study was to investigate the correlation between the microscopic findings of positive lymph nodes, especially focusing on capsular invasion, and the outcome after curative surgical resection of colorectal cancer.

METHODS

We analyzed 480 positive lymph nodes from 155 consecutive patients with Stage III colorectal cancer to determine the frequency and significance of lymph node capsular invasion. Recurrence-free and cancer-specific survival rates were assessed in the patients with and without lymph node capsular invasion.

RESULTS

Between April 1995 and December 2000, 406 consecutive patients with primary colorectal cancer underwent curative resection. Regional lymph node metastases were present in 155 cases (38.2 percent). During the median follow-up period of 4.8 years, 41 patients (26.5 percent) developed recurrent disease and 28 patients died of cancer. Lymph node capsular invasion was detected in one or more lymph nodes from 75 cases (48.3 percent). The five-year recurrence-free rate was 56.1 percent in this group, whereas in the 80 patients without lymph node capsular invasion the rate was 88 percent (P<0.01). Features that were associated with recurrent disease were greater number of positive lymph nodes, venous invasion in primary tumor, infiltrative growth pattern of intranodal tumor, and presence of lymph node capsular invasion. Multivariate analysis identified lymph node capsular invasion as the only significant prognostic factor for recurrence. In multivariate analysis with regard to survival, lymph node capsular invasion, venous invasion, and number of positive nodes remained as significant prognostic factors.

CONCLUSIONS

Lymph node capsular invasion, determined by routine hematoxylin-eosin staining, is a potent prognostic factor in Stage III colorectal cancer.

Definition and delineation of the clinical target volume for rectal cancer

PURPOSE

Optimization of radiation techniques to maximize local tumor control and to minimize small bowel toxicity in locally advanced rectal cancer requires proper definition and delineation guidelines for the clinical target volume (CTV). The purpose of this investigation was to analyze reported data on the predominant locations and frequency of local recurrences and lymph node involvement in rectal cancer, to propose a definition of the CTV for rectal cancer and guidelines for its delineation.

METHODS AND MATERIALS

Seven reports were analyzed to assess the incidence and predominant location of local recurrences in rectal cancer. The distribution of lymphatic spread was analyzed in another 10 reports to record the relative frequency and location of metastatic lymph nodes in rectal cancer, according to the stage and level of the primary tumor.

RESULTS

The mesorectal, posterior, and inferior pelvic subsites are most at risk for local recurrences, whereas lymphatic tumor spread occurs mainly in three directions: upward into the inferior mesenteric nodes; lateral into the internal iliac lymph nodes; and, in a few cases, downward into the external iliac and inguinal lymph nodes. The risk for recurrence or lymph node involvement is related to the stage and the level of the primary lesion.

CONCLUSION

Based on a review of articles reporting on the incidence and predominant location of local recurrences and the distribution of lymphatic spread in rectal cancer, we defined guidelines for CTV delineation including the pelvic subsites and lymph node groups at risk for microscopic involvement. We propose to include the primary tumor, the mesorectal subsite, and the posterior pelvic subsite in the CTV in all patients. Moreover, the lateral lymph nodes are at high risk for microscopic involvement and should also be added in the CTV.

The colonic J-pouch in colo-anal anastomosis

Anastomosis of the colon to the anal canal is now an accepted technique in the surgical management of low and mid rectal cancers. Although significant postoperative bowel disturbance is often seen with straight colo-anal anastomosis, controversy exists over the benefit of adding a colonic pouch for low anastomoses. Several short and long-term studies have demonstrated the early functional superiority of pouch-anal over straight anastomosis. Pouch construction does not compromise anal physiological parameters. It is recommended the pouch be constructed from a length of descending colon and be small (5 cm) in size to adequately act as a neo-rectum; long-term evacuatory difficulties are encountered with the construction of large pouches (10 cm). Anastomotic complications appear to be less frequent with pouch surgery; construction of a pouch does not significantly add to operative time, patient morbidity and mortality. At present there is no compromise to long-term oncological survival. The data supporting these statements is weak and based largely upon retrospective studies. Furthermore the impact of improved function with pouch-anal anastomosis on overall quality of life has been poorly investigated. Further prospective randomized studies are required to ascertain whether the potential benefits of a colonic pouch are realized in the randomized setting.

The variability of the clinical target volume for rectal cancer due to internal organ motion during adjuvant treatment

PURPOSE

This study defined the clinical target volume (CTV) for the adjuvant treatment of rectal cancer and applied this definition to multiple CT scans obtained during the typical 5-week course of treatment to measure the modification to the CTV due to internal organ motion that would be needed to define the planning target volume (PTV).

METHODS AND MATERIALS

Ten patients with rectal cancer had weekly treatment planning CT scans during adjuvant radiation therapy. All patients were given oral contrast, placed prone on a rigid foam cradle with a depressed area for small bowel exclusion, and instructed to have a full bladder. The CT scans were registered according to the bones of the pelvis, and the CTV was outlined on each CT slice. Movement of the CTV in all dimensions was measured. The CT scan with the lowest and highest bladder volume for each patient was used to calculate the CTV movement due to bladder filling.

RESULTS

The largest difference in the CTV occurred 10 cm caudal to the anus, with a standard deviation of 1 cm. Bladder filling displaced the anterior border of the CTV an average of 7 mm over a cranial to caudal length of 2.5 cm. Other borders of the CTV were based on muscle, bone, or major blood vessels and were stable.

CONCLUSION

Modification of the CTV to design a PTV can be unequal, with the largest change at the anterior border of the inferior pelvis.

Preservation of rectal function after low anterior resection with formation of a neorectum

Recent advances in surgery have enabled low rectal cancers to be resected, while at the same time restoring bowel continuity and preserving the anal sphincter. Although a permanent stoma is avoided and the operation is oncologically sound, function may be compromised. Many patients with a straight coloanal anstomosis suffer from urgency, incontinence, and bowel frequency-the so-called anterior resection syndrome. Over the last 15 years, surgical developments have aimed at improving function after restoration of bowel continuity, essentially by creating a neorectum. The best known and most widely practiced operation involves formation of a colonic J-pouch. The physiological and functional outcomes of the colonic J-pouch are discussed, along with controversies surrounding construction. Although a J-pouch improves some aspects of function, the results are not perfect. Alternatives to the colonic J-pouch are appraised, indicating future areas of development.

Clinicopathological study of intrapelvic cancer spread to the iliac area in lower rectal adenocarcinoma by serial sectioning

BACKGROUND

The role of iliac lymphadenectomy in surgery for rectal cancer remains unknown. Detailed clinicopathological data on lateral cancer extension may be needed to determine the true role of this procedure.

METHODS

Seventy consecutive patients with low rectal cancer who underwent systematic iliac lymphadenectomy between 1991 and 1995 were reviewed. The iliac area was divided into five regions: (1) middle rectal root, (2) internal iliac, (3) obturator, (4) common iliac and (5) external iliac. Iliac lymph nodes that were cancer-free based on conventional pathological examination were serially sectioned at 100-microm intervals and re-examined for occult microscopic involvement.

RESULTS

Occult microscopic foci were detected in five (7 per cent) of the 70 patients, and the overall incidence of lateral cancer spread was 24 per cent (17 of 70). Among patients without other sites of distant metastasis or circumferential involvement of the margin, the 5-year survival rate of those with lateral spread was 35 per cent. Although the prognosis of patients with cancer involving multiple iliac regions was poor, three of six patients with metastasis to only a single region were alive without disease at 3 years.

CONCLUSION

Surgeons should be aware of the possibility of localized lateral spread, including microscopic metastasis, when determining the optimum procedure for iliac lymphadenectomy in patients with rectal cancer.

Physiological and functional outcome following ultra-low anterior resection with colon pouch-anal anastomosis

BACKGROUND

Low rectal cancer is usually managed by ultra-low anterior resection (ULAR) with total mesorectal excision and straight coloanal anastomosis. However, following this procedure patients often suffer from frequency, urgency of bowel action and, occasionally, faecal incontinence. To overcome such problems, a colon pouch may be fashioned and a subsequent colon pouch-anal anastomosis performed. The physiological and functional outcome following the use of a colon pouch are appraised.

METHODS

All relevant papers identified from a Medline search and papers from cross-referencing were reviewed.

RESULTS AND CONCLUSION

Creation of a colon pouch following ULAR results in reduced bowel frequency, and a lower incidence of urgency and faecal incontinence. Although there is a slightly increased incidence of evacuatory disorder and need for enemas or suppositories, this appears to be a minor problem which may possibly be overcome by using a smaller colon pouch. Compared with straight coloanal anastomosis following ULAR, the creation of a colon pouch produced a superior functional outcome.