Pelvic wall involvement denotes a poor prognosis in T4 rectal cancer

PURPOSE: An aggressive surgical approach with en bloc resection of involved structures is often possible with anterior rectal cancers that invade adjacent visceral organs, but is rarely possible in tumors that invade the pelvic wall. However, most staging systems include both situations in the same group of T4 rectal cancers. We performed a retrospective study of patients with stage T4 rectal cancer undergoing surgery to assess the influence of different organ involvement on resectability and survival. METHODS: A retrospective review was conducted of 84 patients with T4 rectal cancer treated at the University of Minnesota and affiliated hospitals over a ten-year period. Forty-seven patients (56 percent) were staged for local invasion on the basis of final pathology, 19 (23 percent) on the basis of operative findings, and 18 (21 percent) on the basis of ultrasound images. Patients were divided into two groups, those with or without pelvic wall involvement. Resectability, local control, and overall survival were compared between groups. Survival curves were estimated by the Kaplan-Meier method and compared by log-rank test. Multivariate analysis was performed with Cox proportional and logistic regression. RESULTS: Thirty-one patients (37 percent) had involvement of the pelvic wall, whereas 53 patients (63 percent) had visceral involvement only. All 29 patients with distant metastasis died of their disease. Forty-seven of the 55 patients without distant metastasis underwent tumor resection. Age and pelvic wall involvement were the only two factors independently associated with the probability of resection in logistic regression analysis (P = 0.0067 and P = 0.037, respectively). The only factor that affected median survival in patients without distant metastasis was tumor resection (49.1 months for resection vs. 6.1 months for no resection, P = 0.017). Patients with visceral involvement had a longer median survival (49.2 months) than those with pelvic wall involvement (13.2 months), but the difference did not reach statistical significance (P = 0.058). CONCLUSION: Rectal cancers with pelvic and visceral involvement have different rates of resectability and median survival. These differences should be reflected in the TNM classification system.     

Advances in rectal cancer surgery in Japan

A review of advancement of rectal cancer surgery in Japan is presented. The standard operation for rectal cancer was altered in the 1960s from abdominoperineal resection to the pull-through technique and the handsewn anterior resection in the 1970s, and it became the stapled anterior resection in the 1980s. Today, more than 75 percent of rectal cancers are treated with sphincter-preserving anterior resections, and the remaining 20 percent by abdominoperineal resections. Colonic J-pouch is used with anastomoses involving very low anterior rectal resection for cancers. In the late 1970s, a method of dissecting extended pelvic nodes was adopted to decrease local recurrence. However, extended dissection has been applied to only T3 and T4 cancers of the lower rectum because of postoperative dysfunction of pelvic organs. This was caused by injury to the pelvic nerve plexus, thus lowering the quality of life of the patients. Since the middle of the 1980s, the autonomic nerve-preserving operation attracted surgeons' attention because it prevented these dysfunctions from occurring as a result of the treatment of cancer in the upper rectum and for T1 or T2 cancers in the lower rectum. In this article, recent advances in rectal cancer surgery in Japan are reviewed.     

Accuracy of Magnetic Resonance Imaging in Rectal Cancer Depends on Location of the Tumor

PURPOSE This study was designed to evaluate prospectively magnetic resonance imaging for the prediction of the circumferential resection margin in rectal cancer to identify in which patient magnetic resonance imaging could accurately assess the circumferential resection margin before surgery and in which patients it could not.METHODS During a 17-month period, a preoperative magnetic resonance imaging for the assessment of circumferential resection margin was obtained prospectively in 38 patients with mid or low rectal cancer. The agreement of magnetic resonance imaging and pathologic examination for assessment of circumferential resection margin was analyzed.RESULTS Overall, magnetic resonance imaging agreed with histologic examination of the circumferential resection margin assessment in 28 patients (73 percent; κ = 0.47). In all cases of disagreement between magnetic resonance imaging and pathology, magnetic resonance imaging overestimated the circumferential resection margin involvement. For the 11 patients with mid rectal cancer, circumferential resection margin was well predicted by magnetic resonance imaging in all cases (κ = 1). For 27 patients with low rectal tumor, overall agreement between magnetic resonance imaging and histologic assessment was 63 percent (κ = 0.35). Agreement was 22 percent (κ = 0.03) for the 9 patients with low anterior and 83 percent (κ = 0.67) for the 18 patients with low posterior rectal tumor. Univariate analysis revealed that only low and anterior rectal tumor was risk factor of overestimation of the circumferential resection margin by magnetic resonance imaging.CONCLUSIONS Although magnetic resonance imaging remains the best imaging tool for the preoperative assessment of the circumferential resection margin in patients with rectal cancer, it can overestimate the circumferential resection margin involvement in low and anterior tumor with the risk of overtreating the patients.Presented at the meeting of the French Society of Digestive Surgery, Paris, France, March 29 to April 2, 2003.     

Prognostic significance of extranodal microscopic foci discontinuous with primary lesion in rectal cancer

PURPOSE: The most common recurrence after curative resection of rectal carcinoma originates from tiny, undetectable residual foci within the pelvic cavity. The significance and methods used to predict the presence of extramural and extranodal microscopic cancer foci discontinuous with the main lesion of rectal cancers were investigated. METHODS: Four hundred twenty-seven patients who underwent resection of rectal carcinoma were studied. All resected specimens were examined for histologic evidence of extramural cancer separate from the main lesion. RESULTS: Extramural cancers not in continuity with the main rectal lesion were classified as follows: 1) extranodal microscopic cancers; 2) large tumor nodules; 3) lymph node metastases. Each classification was found to influence long-term prognosis. Among them, microscopic cancer was thought to be especially relevant because, by virtue of its microscopic nature, it may be left in the pelvic cavity, causing local recurrence. The existence of large tumor nodules and metastatic lymph nodes correlated closely with the presence of microscopic cancer. Because large tumor nodules and lymph node metastases are possibly detectable during the operation by palpation and may be analyzed by microscopic frozen sections, they might be useful predictors of the presence of microscopic cancers. CONCLUSIONS: In cases with extensive local rectal cancer spread, the nerve-sparing rectal resection that omits lateral dissection may be insufficient for local control because of incomplete removal of occult microscopic cancer, resulting in local recurrence. Presence of microscopic cancer correlates closely with large tumor nodules and metastatic lymph nodes. Intraoperative frozen section investigations may, thus, help in deciding on extent of location resection.     

Dynamic magnetic resonance imaging defecography: a diagnostic alternative in the assessment of pelvic floor disorders in proctology

PURPOSE: Standard diagnostic proctologic procedures in the assessment of pelvic floor disorders include clinical evaluation and endoscopy. Particular aspects of combined pelvic floor disorders, especially those involving more than one pelvic compartment, may remain undetected without additional technical diagnostic procedures such as videoproctoscopy, cinedefecography, or colpocystodefecography. The aim of the study was to review the potentials of dynamic magnetic resonance imaging defecography to elucidate the underlying anatomic and pathophysiologic background of pelvic floor disorders in proctologic patients. PATIENTS AND METHODS: Dynamic magnetic resonance imaging defecography was performed in 20 Patients (13 females) with main diagnoses such as rectal prolapse or intussusception, rectocele, descending perineum, fecal incontinence, outlet obstruction, and dyskinetic puborectalis muscle after clinical evaluation. The investigation was performed on a 1.5 T-magnetic resonance imaging machine in supine position. The rectum was filled with Gd-DTPA enriched ultrasound gel. First a T1/T2 weighted investigation of the pelvis was performed, followed by defecography with evacuation of the rectum. Images were obtained in a sagittal plane in a frequency of 1 image/second (true FISP) at rest and during straining. The obtained magnetic resonance imaging video tapes were analyzed off-line with cinematographic evaluation of bladder base, uterus, and anal canal position in relation to the pubococcygeal line by a blinded radiologist. Investigation time was 20 minutes. RESULTS: In dynamic magnetic resonance imaging defecography of the pelvic floor, 12 patients with descending perineum, 10 rectoceles (10 females), 6 cystoceles (6 females), 4 enteroceles (4 females), 8 intussusceptions (5 females), and a dyskinetic puborectalis muscle in 3 males were detected. In 11 females and 3 males multifocal disorders were found, involving more than one compartment in females, whereas in males complex defects were restricted to the posterior compartment. Magnetic resonance imaging defecography revealed diagnoses consistent with clinical results in 77.3 percent and defects in addition to clinical diagnoses in combined pelvic floor disorders in 34 percent. CONCLUSIONS: In complex pelvic floor disorders, involving more than a single defect, dynamic magnetic resonance imaging represents a convenient diagnostic procedure in females and to a lesser extent in males, in particular in terms of dynamic imaging of pelvic floor organs during defecation. In addition to the clinical assessment, dynamic magnetic resonance imaging had clinical impact in proctologic and interdisciplinary treatment.Presented in part at the 116th German Congress of Surgery, 1999     

Dynamic magnetic resonance imaging used in evaluation of female pelvic prolapse: experience from nine cases

Prolapse of pelvic organs in a female can be simple or complex. To make a definite diagnosis of pelvic prolapse preoperatively, dynamic magnetic resonance (MR) is an alternative to conventional fluoroscopic or sonographic examination, with the advantage of providing greater details, and thus helping the surgeon to have a good preoperative plan. Nine women suffering from pelvic prolapse with or without urinary stress incontinence underwent dynamic MR imaging examination (1.0T Magnex100/HP, Shimadzu, Kyoto, Japan) before surgery. All patients were examined in the supine position. A single-shot ultra-high speed scan (FE/8/3.02-20 degrees, 128, 100%-100% 1 NEX 1 slice 10 mm L1.0 second) was used to obtain midline sagittal images, with the patients at rest and during pelvic strain. MR images were then obtained every 4 seconds. Each examination was analyzed, based on specific measurements, to determine the presence and extent of prolapse of pelvic organs. The pubococcygeal, levator hiatus width and muscular pelvic floor relaxation lines, and the angle of the levator plate were identified. Based on these measurements, multicompartment involvement in the pelvic prolapse was confirmed in five patients (5/9). Four patients (4/9) had single compartment involvement. Seven patients underwent surgery. All patients reported significant improvement in their symptoms and signs after surgical intervention. Two patients had an almost complete recovery. MR demonstrated simple or complex organ descent in all pelvic compartments, and may become a standard preoperative examination for pelvic floor abnormalities. The MR images facilitated comprehensive planning by the surgeon; thus, they can increase the success rate and help to accurately predict the outcome of the surgical intervention. The surgeons also expressed high postsurgical satisfaction with the information provided by dynamic MR.     

Assessment of T staging and mesorectal fascia status using high-resolution MRI in rectal cancer with rectal distention

AIM： To determine the accuracy of high-resolution magnetic resonance imaging （MRI） using phasedarray coil for preoperative assessment of T staging and mesorectal fascia infiltration in rectal cancer with rectal distention.
METHODS： In a prospective study of 67 patients with primary rectal cancer, high-resolution magnetic resonance imaging （in-plane resolution, 0.66 × 0.56） with phased-array coil were performed for T-staging and measurement of distance between the tumor and the mesorectal fascia. The assessment of MRI was compared with postoperative histopathologic findings. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were evaluated.
RESULTS： The overall magnetic resonance accuracy was 85.1% for Tstaging and 88% for predicting mesorectal fascia involvement. Magnetic resonance sensitivity, specificity, accuracy, positive predictive value, and negative predictive value was 70%, 97.9%, 89.6%, 93.3% and 88.5% for ≤ T2 tumors, 90.5% , 76% , 85.1%, 86.4% and 82.6% for T3 tumors, 100%, 95.2%, 95.5% , 62.5% and 100% for T4 tumors, and 80% , 90.4%, 88%, 70.6% and 9d% for predicting mesorectal fascia involvement, respectively.
CONCLUSION： High-resolution MRI enables accurate preoperative assessment for T staging and mesorectal fascia infiltration in rectal cancer with rectal distention.     

Cost-effectiveness of endoscopic ultrasonography in the evaluation of proximal rectal cancer

OBJECTIVE: Clinical trials demonstrate the superiority of preoperative over postoperative radiotherapy (XRT) in diminishing rates of local recurrence of transmurally infiltrating (T3/4) rectal tumors. The dosage and cost of preoperative XRT are less than postoperative XRT. The economic and health impact of transrectal endoscopic ultrasound (EUS) on rectal cancer management has not been described. The aim of this study was to apply a decision analysis model to compare the cost-effectiveness of three staging strategies in the evaluation of nonmetastatic proximal rectal cancer: abdominal and pelvic CT versus abdominal CT plus EUS versus abdominal CT plus pelvic magnetic resonance imaging. METHODS: A decision model was designed using DATA Version 3.5 (TreeAge Software, Williamstown, MA), taking as entry criteria nonmetastatic proximal rectal cancer as determined by abdominal CT. In each arm, detection of transmural invasion prompted preoperative XRT. Baseline probabilities were varied through plausible ranges using sensitivity analysis. Cost inputs were based on Medicare professional plus facility fees. Endpoints were cost of treatment per patient and tumor recurrence-free rates. Cost-effectiveness (cost per prevention of local recurrence) and incremental cost-effectiveness ratios were calculated. RESULTS: For proximal rectal tumors, evaluation with abdominal CT plus EUS is the most cost-effective approach ($24,468/yr) compared with abdominal CT plus pelvic magnetic resonance imaging ($24,870) and CT alone ($26,076). Both the magnetic resonance imaging- and CT-only approaches were dominated (i.e., more costly and less effective). CONCLUSIONS: Abdominal CT plus EUS is the most cost-effective staging strategy for nonmetastatic proximal rectal cancer. Staging strategies incorporating EUS improve treatment allocation by achieving more accurate T staging, thereby optimizing the benefit of preoperative XRT to more advanced tumors.     

Surgical Salvage of Recurrent Rectal Cancer After Transanal Excision

PURPOSE This study examines surgical salvage of locally recurrent rectal cancer following transanal excision of early tumors.METHODS Through retrospective review of a colorectal database we identified 50 patients who underwent attempted surgical salvage for local recurrence following initial transanal excision of T1 or T2 rectal cancer. Eight patients had resectable synchronous distant disease. Clinicopathologic variables were associated with extent of surgery required for salvage and outcome.RESULTS Salvage procedures included abdominoperineal resection (31), low anterior resection (11), total pelvic exenteration (4), and transanal excision (3). One patient had unresectable disease at exploration, requiring diverting ostomy. Of the 49 patients who underwent successful salvage, 27 (55 percent) required an extended pelvic dissection with en bloc resection of one or more of the following structures: pelvic sidewall and autonomic nerves (18); coccyx or portion of sacrum (6); prostate (5); seminal vesicle (5); bladder (4); portion of the vagina (3); ureter (2); ovary (1); and uterus (1). Complete pathologic resection (R0) was accomplished in 47 of 49 patients. Of the eight patients with distant and local recurrence, two underwent synchronous resection and six had delayed metastasectomy. With a median follow-up of 33 months, 29 patients had recurred or died of disease at the time of this analysis. Five-year disease-specific survival was 53 percent. Factors predictive of survival included evidence of any mucosal recurrence on endoscopy, low presalvage carcinoembryonic antigen, and absence of poor pathologic features (lymphovascular and perineural invasion). Patients who required an extended pelvic resection had a worse survival rate.CONCLUSION Pelvic recurrence following transanal excision of early rectal cancer is often locally advanced, requiring an extended pelvic dissection with en bloc resection of adjacent pelvic organs to achieve salvage. The long-term outcome in patients undergoing resection is less than expected, considering the early stage of their initial disease. When contemplating local excision for early rectal cancer, the risk of local recurrence, the extent and morbidity of surgery required for salvage, and the modest cure rate following salvage should be considered.Read at the meeting of The American Society of Colon and Rectal Surgeons, Dallas, Texas, May 8 to 13, 2004.Reprints are not available.     

Immediate Radical Resection After Local Excision of Rectal Cancer: An Oncologic Compromise?

PURPOSE Local excision for early-staged rectal cancers is controversial. Preoperative understaging is not uncommon and radical resection after local resection may be needed for a curative treatment. The aim of this study was to determine the frequency and outcome of radical resection (within 30 days) after local excision for rectal adenocarcinoma.METHODS All locally excised rectal cancers (curative intent) that required radical surgery within 30 days were reviewed (1980–2000). T2–3N0–1 stage cancers were each matched to three primary radical surgery controls for stage, age (±5 years), gender, date (±1 years), and type (abdominoperineal resection or low anterior resection) of operation. T1N0–1 cancers were compared with stage-matched rectal cancers treated by either primary radical surgery (n = 78) or local excision alone (n = 77).RESULTS Fifty-two locally excised rectal adenocarcinomas (29 transanal and 23 polypectomies) were followed by radical surgery (24 abdominoperineal resection and 28 low anterior resection) within 7 (range, 1–29) days. Radical surgery was performed because of a cancerous polyp (n = 42), positive margins (5), lymphovascular invasion (3), and T3-staged cancer (2). Twelve of 52 cancers (23 percent) were found to have nodal involvement and 15 of 52 (29 percent) showed residual cancer in the resected specimen. The T2–3N0–1 stage controls were well matched. No significant difference in tumor location, size, adjuvant therapy, or length of follow-up was noted. Local and distant recurrence occurred in 2 of 4 T2–3N1 tumors and in 2 of 11 T2–3N0 cancers and were comparable to the matched controls, as was survival, with the exception of shorter survival in T3N1 cases, but numbers were too small for a definitive conclusion. Length of follow-up was not different. For T1 cancers, the controls were also comparable regarding patient and tumor demographics and adjuvant therapy. Nodal involvement was 21 percent in T1 study cases and 15 percent in T1 primary radical-surgery controls, with a trend toward location in the lower third of the rectum in both groups (58 percent and 50 percent, respectively). Local recurrence rates were 3 percent in the study group, 5 percent for patients undergoing primary radical surgery, and 8 percent for local excision alone. Distant metastasis (11 percent, 12 percent, and 13 percent, respectively) and overall five-year survival were also not significantly different (78 percent, 89 percent, and 73 percent, respectively).CONCLUSIONS Nodal involvement in attempted locally excised rectal cancers is not uncommon. Local excision of rectal tumors followed by radical surgery within 30 days in cancer patients does not compromise outcome compared with primary radical surgery. Even after radical surgery for superficial T1 rectal cancers, recurrence rates are not insignificant. Future improvements in preoperative staging may be helpful in selecting tumors for local excision only.Read at the meeting of The American Society of Colon and Rectal Surgeons, Dallas, Texas, May 8 to 13, 2004.D. Hahnlosers current address is: Visceral and Transplantation Surgery, University Hospital Zurich, Switzerland.     

Pelvic Floor Images: Anatomy of the Levator Ani Muscle

Purpose The levator ani has been divided into many functional portions based on necropic observation. Our objective was to use a combination of CT and magnetic resonance images to show a complete levator ani. Methods Normal magnetic resonance images of the pelvis were obtained at rest in 22 volunteers while in the lying position (10 males, aged 21–23 yr). The pelvic floor images of ten cadavers (5 males) were obtained while in the supine position by CT. Source magnetic resonance images were used to measure the heights of the transverse portion of the levator ani and the area of the genital hiatus. Source magnetic resonance images and CT reconstructed images were used to study the anatomy of the levator ani. Results The levator ani had a transverse portion and a vertical portion. The anterior transverse portion was found to be basin-shaped, the middle transverse portion was funnel-shaped, and the posterior transverse portion was dome-shaped. The transverse portion sloped sharply downward to form the vertical portion at the puborectalis plane. The vertical portion was a muscular tube outside the intrahiatal structures. The puborectalis was a u-shaped muscle outside the vertical portion. One case of the deep transverse perineal muscle was found in 22 volunteers. The volume of the ischioanal fossa influenced the anatomic appearance of the pelvic floor in cadavers. Conclusions The transverse portion of the levator ani has five kinds of shapes in the different-coronal sections of the pelvis, which changes from basin to dome in a lying position. The puborectalis is outside the vertical portion and not part of the levator ani.     

Prognostic factors in Stage T2NO rectal cancer

PURPOSE: To further define the indications for postoperative pelvic irradiation and chemotherapy, an analysis of the influence of extent of tumor invasion into perirectal fat, lymphatic or venous vessel invasion, and tumor grade on the clinical course of patients with Stage T2NO rectal cancer undergoing surgery was undertaken. METHODS: From 1968 to 1985, 117 patients with Stage T3NO rectal cancer underwent resection with curative intent. No patient received neoadjuvant or adjuvant irradiation or chemotherapy. Surgical specimens were assessed for maximum depth of tumor invasion into perirectal fat, lymphatic or venous involvement, and tumor grade. After surgery the clinical course of these patients was assessed for local control, distant metastases, and survival rate. RESULTS: For 25 patients with tumors exhibiting favorable histologic features (well-differentiated or moderately well-differentiated carcinomas invading less than 2 mm into perirectal fat, without lymphatic or venous vessel involvement), the ten-year actuarial rates of local control and recurrence-free survival were 95 and 87 percent, respectively. In contrast, the ten-year actuarial rates of local control and recurrence-free survival were inferior (71 and 55 percent, respectively) for 88 patients with tumors exhibiting moderate to deep perirectal fat invasion, vessel involvement, or poor differentiation. CONCLUSIONS: In the design of future trials of rectal cancer, selection of patients with rectal cancer for postoperative adjuvant therapy should be based not only on stage, but also on depth of invasion into the perirectal fat, vessel involvement, tumor grade, and integrity of the radial resection margin. For subsets of patients with Stage T3NO rectal cancer, there may be little benefit to adjuvant therapy after surgery.     

Circumferential resection margins of rectal tumours post-radiotherapy: how can MRI aid surgical planning?

Background

Magnetic resonance imaging (MRI) is known to have high predictive accuracy for circumferential resection margin (CRM) involvement of pre-treatment rectal tumours. This study aims to assess predictive accuracy of MRI for CRM involvement in rectal cancers post-long-course chemoradiotherapy (CRT) and in particular to understand how this information can influence surgical planning.

Methods

Forty-seven rectal cancers treated with CRT followed by bowel resection in one hospital since 2005 were reviewed for clinical, radiological and pathological characteristics. Using a validated pro forma, a radiologist blinded to final histology and original MRI report predicted CRM status from post-CRT MRI images. Results were compared to histological CRM status of final specimen, and differential analysis by type of surgical operation was performed.

Results

Overall accuracy of MRI for CRM involvement post-CRT was 72 % with a negative predictive value of 92 %. Abdominoperineal excision (APE) post-CRT was associated with non-significantly higher rates of histologically involved CRM than anterior resection (AR; 41 vs. 21 %) as were mucinous adenocarcinomas when compared to non-mucinous (56 vs. 21 %). Overall accuracy and positive predictive value were non-significantly higher for cancer treated with a standard APE than AR, and negative predictive value was high for both groups.

Conclusions

MRI post-CRT has high negative predictive value for CRM status. Such information is of particular clinical relevance in low rectal cancers treated with APE as it can indicate when a standard surgical approach is likely to be sufficient.     

Klassifikation der Beckenbodeninsuffizienz mit Hilfe der Magnetresonanztomographie (MRT) — ein Schritt zur rationalen Therapie

56 patients suffering from descending perineum syndrome (DPS) were investigated protocologically and by dynamic magnetic resonance imaging (dMRI), that was performed after filling the rectum with contrast media. Dynamic magnetic resonance imaging allowed the accurate evaluation of cystoceles, genital prolapses, rectoceles, enteroceles and external rectal prolapses. However, internal rectal prolapses and mucosal prolapses were diagnosed only in 2 of 10 patients. Based on the findings in dMRI, a new classification of descending perineum syndrome was developed dividing DPS in 4 disease stages. Each of these stages is characterized by a typical constellation of MRI results which facilitates the selection of the adequate treatment. In conclusion, dMRI of the pelvic floor is the most important imaging procedure in planning the correct therapy of DPS, thereby making cystography and defaecography dispensable.     

Indication and Benefit of Pelvic Sidewall Dissection for Rectal Cancer

Purpose This study was designed to clarify indication and benefit of pelvic sidewall dissection for rectal cancer. Methods The retrospective, multicenter study collected the data of rectal cancer patients who underwent surgery between 1991 and 1998 and were prospectively followed. Results Of 1,977 patients with rectal cancers, 930 underwent pelvic sidewall dissection without adjuvant radiotherapy. Positive lateral lymph nodes were found in 129. Multivariate analysis disclosed a significantly increased incidence of positive lateral lymph nodes in female gender, lower rectal cancers, non-well-differentiated adenocarcinoma, tumor size of ≥4 cm and T3-T4. The five-year survival rate for 1,977 patients was 79.7 percent. The survival of patients with positive lateral lymph nodes was significantly worse than that of Stage III patients with negative lateral lymph nodes (45.8 vs. 71.2 percent, P<0.0001). Multivariate analysis showed significantly worse prognosis in male gender, pelvic sidewall dissection, lower rectal cancers, T3-T4, perirectal lymph node metastasis, and positive lateral lymph nodes. During the median follow-up time of 57 months, recurrence developed in 19.7 percent: 17 percent in negative and 58.1 percent in positive lateral lymph nodes (P<0.0001). Local recurrence was found in 8 percent: 6.8 percent in negative and 25.6 percent in positive lateral lymph nodes (P<0.0001). Multivariate analysis disclosed that lower rectal cancers, non-well-differentiated adenocarcinoma, T3-T4, perirectal lymph node metastasis, and positive lateral lymph nodes were significantly associated with an increased local recurrence. Conclusions Positive lateral lymph node was the strongest predictor in both survival and local recurrence. Pelvic sidewall dissection may be indicated for patients with T3-T4 lower rectal cancers because of the greater provability of positive lateral lymph nodes. Study Group for Rectal Cancer Surgery of the Japanese Society for Cancer of the Colon and Rectum. Presented at the United States-Japan Clinical Trial Summit Meeting, Maui, Hawaii, February 10–13, 2005.     

Total pelvic exenteration for locally advanced rectal carcinoma

Total pelvic exenteration was performed in 31 patients (30 males and 1 female) who had rectal cancers involving adjoining pelvic structures. Twenty-nine patients had primary tumors and two had recurrent diseases after previous abdominoperineal resection. Preoperative irradiation was used in nine patients with fixed tumors. When performing the surgical procedure, we also actively employed lateral node dissection to make the operation more radical. Three patients (one with primary tumor and two with recurrent) underwent the exenteration with partial sacrectomy because of the sacral involvement and they all died of local failure within 15 months. The overall 5-year survival rate was 52 percent for all patients and 56 percent for those who had primary tumors. The results suggest that total pelvic exenteration with lateral node dissection should be performed for locally advanced rectal cancer if the tumor is not completely fixed to the pelvic wall and preoperative irradiation should be used to convert a fixed tumor to a resectable one.     

Magnetic resonance imaging in rectal cancer:A surgeon’s perspective

Magnetic resonance imaging(MRI)in rectal cancer was first investigated in 1999 and has become almost mandatory in planning rectal cancer treatment.MRI has a high accuracy in predicting circumferential resection margin involvement and is used to plan neoadjuvant therapy.The accuracy of MRI in assessing mesorectal lymph nodes remains moderate,as there are no reliable criteria to assess nodal involvement.MRI seems to be good in assessing peritoneal involvement in upper rectal cancer;this however has been assessed in only a few studies and needs further research.For low rectal cancers,mesorectum is thin at the level of levator ani especially in relation to prostate;so predicting circumferential resection margin involvement is not easy.However high spatial resolution coronal imaging shows levator muscles,sphincter complex and intersphincteric plane accurately.This is used to stage low rectal tumors and plan plane of surgery(standard surgery,intersphincteric resection,Extralevator abdominoperineal resection).While most centres perform MRI post chemoradiotherapy,its role in accurate staging post neoadjuvant therapy remains debatable.THe role of Diffusion weighted MRI post neoadjuvant therapy is being evaluated in research settings.     

Prediction of different stages of rectal cancer: Texture analysis based on diffusion-weighted images and apparent diffusion coefficient maps

BACKGROUND It is evident that an accurate evaluation of T and N stage rectal cancer is essential for treatment planning. It has not been extensively investigated whether texture features derived from diffusion-weighted imaging(DWI) images and apparent diffusion coefficient(ADC) maps are associated with the extent of local invasion(pathological stage T1-2 vs T3-4) and nodal involvement(pathological stage N0 vs N1-2) in rectal cancer.AIM To predict different stages of rectal cancer using texture analysis based on DWI images and ADC maps.METHODS One hundred and fifteen patients with pathologically proven rectal cancer, who underwent preoperative magnetic resonance imaging, including DWI, were enrolled, retrospectively. The ADC measurements(ADC_(mean), ADC_(min), ADC_(max)) as well as texture features, including the gray level co-occurrence matrix parameters, the gray level run-length matrix parameters and wavelet parameters were calculated based on DWI(b = 0 and b = 1000) images and the ADC maps.Independent sample t-tests or Mann-Whitney U tests were used for statistical analysis. Multivariate logistic regression analysis was conducted to establish the models. The predictive performance was validated by receiver operating characteristic curve analysis.RESULTS Dissimilarity, sum average, information correlation and run-length nonuniformity from DWI_(b=0) images, gray level nonuniformity, run percentage and run-length nonuniformity from DWI_(b=1000) images, and dissimilarity and run percentage from ADC maps were found to be independent predictors of local invasion(stage T3-4). The area under the operating characteristic curve of the model reached 0.793 with a sensitivity of 78.57% and a specificity of 74.19%. Sum average, gray level nonuniformity and the horizontal components of symlet transform(SymletH) from DWI_(b=0) images, sum average, information correlation,long run low gray level emphasis and SymletH from DWI_(b=1000) images, and ADC_(max), ADC_(mean) and information correlation from ADC maps were identified as independent predictors of nodal involvement. The area under the operating characteristic curve of the model reached 0.802 with a sensitivity of 80.77% and a specificity of 68.25%.,CONCLUSION Texture features extracted from DWI images and ADC maps are useful clues for predicting pathological T and N stages in rectal cancer.     

Phenotypic variation in functional disorders of defecation

BACKGROUND & AIMS: Although obstructed defecation is generally attributed to pelvic floor dyssynergia, clinical observations suggest a wider spectrum of anorectal disturbances. Our aim was to characterize phenotypic variability in constipated patients by anorectal assessments. METHODS: Anal pressures, rectal balloon expulsion, rectal sensation, and pelvic floor structure (by endoanal magnetic resonance imaging) and motion (by dynamic magnetic resonance imaging) were assessed in 52 constipated women and 41 age-matched asymptomatic women. Phenotypes were characterized in patients by principal components analysis of these measurements. RESULTS: Among patients, 16 had a hypertensive anal sphincter, 41 had an abnormal rectal balloon expulsion test, and 20 had abnormal rectal sensation. Forty-nine patients (94%) had abnormal pelvic floor motion during evacuation and/or squeeze. After correcting for age and body mass index, 3 principal components explained 71% of variance between patients. These factors were weighted most strongly by perineal descent during evacuation (factor 1), anorectal location at rest (factor 2), and anal resting pressure (factor 3). Factors 1 and 3 discriminated between controls and patients. Compared with patients with normal (n = 23) or reduced (n = 18) perineal descent, patients with increased (n = 11) descent were more likely (P < or = .01) to be obese, have an anal resting pressure >90 mm Hg, and have a normal rectal balloon expulsion test result. CONCLUSIONS: These observations demonstrate that functional defecation disorders comprise a heterogeneous entity that can be subcharacterized by perineal descent during defecation, perineal location at rest, and anal resting pressure. Further studies are needed to ascertain if the phenotypes reflect differences in the natural history of these disorders.     

Preoperative diagnosis of gastric cancer using 2‐D magnetic resonance imaging with 3‐D reconstruction techniques

OBJECTIVE: To investigate the clinical value of 2‐D magnetic resonance imaging (MRI) with 3‐D reconstruction techniques for the preoperative diagnosis and TNM‐staging of gastric cancer. METHODS: Using a Philips Gyroscan NT 1.0T superconductive unit, MRI using the water‐filling method was performed in 15 patients with suspected gastric cancers. The 2‐D MRI sequences included TSE‐T1WI, TSE‐T2WI and fat suppression (SPIR). The source images of magnetic resonance hydrography (heavily TSE‐T2WI sequence) were reconstructed using the Philips EasyVision viewing workstation. Four 3‐D postprocessing algorithms, including maximum intensity projection, surface shaded viewing, volume rendering and virtual endoscopy, were performed and compared with the results of a barium study and endoscopy. All 15 patients with 16 gastric cancers had their diagnosis confirmed by postoperative pathological findings. RESULTS: 2‐D MRI and 3‐D reconstruction images were successfully obtained for all 15 patients. The maximum intensity projection, surface shaded viewing, and volume rendering images corresponded to the upper gastrointestinal series findings, and the virtual endoscopy images corresponded to the gastroscopic views. In 16 gastric lesions, MRI correctly diagnosed 14 (87.5%) advanced gastric cancers, and the tumor location, size and classification were also accurately identified. The accuracy of MRI for determining the preoperative TNM stage was 64.3% (9/14), and there was significant correlation between these results and those from the histopathological studies (P < 0.01). Based on T, N and M factors, the staging accuracy of MRI was 71.4% (10/14), 57.1% (8/14) and 85.7% (12/14), respectively. CONCLUSIONS: 2‐D MRI with 3‐D reconstruction is an effective method for the preoperative diagnosis and TNM staging of gastric cancer. However, the detection of early cancers or benign lesions and N‐staging should be further studied.