New Scale Predicting Distant Recurrence in Locally Advanced Lower Rectal Cancer Patients After Neoadjuvant Chemoradiotherapy.

BACKGROUND/AIM: Neoadjuvant chemoradiotherapy (nCRT) for locally advanced lower rectal cancer (LALRC) is effective in preventing locoregional recurrence; however, it is less effective for preventing distant recurrence. This study aimed to evaluate a new scale for predicting distant recurrence before administering nCRT. PATIENTS AND METHODS: Sixty-three patients underwent nCRT for LALRC between 2009 and 2016 at the Tokyo Women's Medical University. Of these, 51 consecutive patients who underwent curative surgery were enrolled in this study. Patients with ≥cT3 status or cN-positive LALRC were classified into three groups before nCRT based on the neutrophil-to-lymphocyte ratio (NLR) and lymphocyte-to-monocyte ratio (LMR): high-risk, NLR ≥3.2 and LMR <5.0; intermediate-risk, NLR <3.2 and LMR ≥5.0 or NLR ≥3.2 and LMR <5.0; and low-risk, NLR <3.2 and LMR ≥5.0. Independent risk factors associated with distant relapse-free survival were analysed using the Cox proportional hazards model. Relapse-free survival from distant metastasis was evaluated using the log-rank test. RESULTS: Patient characteristics and tumour-associated factors were not significantly different between the groups. Distant recurrence in the high-, intermediate-, and low-risk groups was 61.5%, 42.9%, and 20.8% (p=0.046), respectively. In the multivariate analysis, the new scale was an independent risk factor for distant relapse-free survival (high-risk vs. low-risk groups, p=0.004 and intermediate-risk vs. low-risk groups, p=0.055). The 3-year distant relapse-free survival rate in the high-, intermediate-, and low-risk groups was 38.5%, 56.3%, and 81.7% (p=0.028), respectively. CONCLUSION: A new scale combining the pre-nCRT NLR and LMR was independently associated with distant relapse-free survival. The new scale for LALRC may aid selection for total neoadjuvant chemotherapy.

Prognostic risk factors for pT4 colon cancer: A retrospective cohort study.

The present study aimed to clarify the prognostic risk factors for pathological T4 (pT4) colon cancer and provide a basis for improved treatment in affected patients. The current retrospective cohort study included 83 consecutively enrolled patients who underwent curative surgery for primary pT4 colon cancer between January 2014 and December 2021 at Tokyo Medical Women's University (Tokyo, Japan). Oncological outcomes, including recurrence pattern, were compared between patients with pT4a and pT4b colon cancer. Independent risk factors associated with overall survival (OS) and relapse-free survival (RFS) were analyzed using a multivariate Cox regression model. The 3-year OS rates were 85.1 and 95.0% in the pT4a and pT4b groups (P=0.089) and 3-year RFS rates were 64.1 and 60.5% (P=0.589), respectively. Moreover, the 3-year peritoneal recurrence-free survival was 71.0 and 90.2% (P=0.085) in these groups, respectively. Independent risk factors for OS were histology (mucinous or poorly differentiated adenocarcinoma), tumor location (right-sided) and pN status (positive). The risk factors for RFS were histology and pN status. Patients with pT4b colon cancer and R0 resection may not have a poorer prognosis compared with those with pT4a colon cancer. However, patients with pT4a colon cancer tended to have more peritoneal recurrence patterns. Histology and pN status were associated with OS and RFS, and right-sided colon cancer was also a risk factor for OS.

Automated recognition of objects and types of forceps in surgical images using deep learning.

Analysis of operative data with convolutional neural networks (CNNs) is expected to improve the knowledge and professional skills of surgeons. Identification of objects in videos recorded during surgery can be used for surgical skill assessment and surgical navigation. The objectives of this study were to recognize objects and types of forceps in surgical videos acquired during colorectal surgeries and evaluate detection accuracy. Images (n = 1818) were extracted from 11 surgical videos for model training, and another 500 images were extracted from 6 additional videos for validation. The following 5 types of forceps were selected for annotation: ultrasonic scalpel, grasping, clip, angled (Maryland and right-angled), and spatula. IBM Visual Insights software was used, which incorporates the most popular open-source deep-learning CNN frameworks. In total, 1039/1062 (97.8%) forceps were correctly identified among 500 test images. Calculated recall and precision values were as follows: grasping forceps, 98.1% and 98.0%; ultrasonic scalpel, 99.4% and 93.9%; clip forceps, 96.2% and 92.7%; angled forceps, 94.9% and 100%; and spatula forceps, 98.1% and 94.5%, respectively. Forceps recognition can be achieved with high accuracy using deep-learning models, providing the opportunity to evaluate how forceps are used in various operations.

Lateral pelvic lymph nodes for rectal cancer: A review of diagnosis and management.

The current status and future prospects for diagnosis and treatment of lateral pelvic lymph node (LPLN) metastasis of rectal cancer are described in this review. Magnetic resonance imaging (MRI) is recommended for the diagnosis of LPLN metastasis. A LPLN-positive status on MRI is a strong risk factor for metastasis, and evaluation by MRI is important for deciding treatment strategy. LPLN dissection (LPLD) has an advantage of reducing recurrence in the lateral pelvis but also has a disadvantage of complications; therefore, LPLD may not be appropriate for cases that are less likely to have LPLN metastasis. Radiation therapy (RT) and chemoradiation therapy (CRT) have limited effects in cases with suspected LPLN metastasis, but a combination of preoperative CRT and LPLD may improve the treatment outcome. Thus, RT and CRT plus selective LPLD may be a rational strategy to omit unnecessary LPLD and produce a favorable treatment outcome.

Pedunculated early colorectal cancer with nodal metastasis: a case report.

BACKGROUND: Pedunculated polyps are more likely to be amenable to complete resection than non-pedunculated early colorectal cancers and rarely require additional surgery. We encountered a patient with a pedunculated early colorectal cancer that consisted of poorly differentiated adenocarcinoma with lymphatic invasion. We performed an additional bowel resection and found nodal metastasis. CASE PRESENTATION: A 43-year-old woman underwent colonoscopy after a positive fecal occult blood test. The colonoscopist found a 20-mm pedunculated polyp in the descending colon and performed endoscopic resection. Histopathologic examination revealed non-solid type poorly differentiated adenocarcinoma. The lesion invaded the submucosa (3500 µm from the muscularis mucosa) and demonstrated lymphatic invasion. In spite of the early stage of this cancer, the patient was considered at high risk for nodal metastasis. She was referred to our institution, where she underwent bowel resection. Although there was no residual cancer after her endoscopic resection, a metastatic lesion was found in one regional lymph node. The patient is undergoing postoperative adjuvant chemotherapy, and there has been no evidence of recurrence 3 months after the second surgery. CONCLUSIONS: Additional bowel resection is indicated for patients with pedunculated polyps and multiple risk factors for nodal metastasis, such as poorly differentiated adenocarcinoma and lymphatic invasion. We encountered just such a patient who did have a nodal metastasis; herein, we report her case history with a review of the literature.

Stage II colon cancer staging using the number of retrieved lymph nodes may be superior to current TNM staging for prognosis stratification: the Japanese study group for postoperative follow-up of colorectal cancer.

PURPOSE: The purpose of the study was to compare staging of stage II colon cancer using the number of retrieved lymph nodes (RN) to current TNM staging for stratification of prognosis. METHODS: The subjects were 6307 patients with stage II colon cancer who underwent curative resection at 24 Japanese institutions. The cutoff for the number of RN was established using Akaike information criterion (AIC) values for relapse-free survival (RFS) and overall survival (OS). Comparison of survival using TNM and T + RN (TRN) staging was performed using a Cox proportional hazards regression model. RESULTS: AIC was lowest for 14 retrieved lymph nodes for RFS and OS. This number was used as the cutoff. In multivariate analysis, age (≥ 69), male gender, V1, CEA (> 5), pT (T4a, T4b), and RN-L were independent factors associated with RFS and OS. Six combinations of pT and RN categories were used to establish three subgroups: TRN stages IIA, IIB, and IIC. The 5-year RFS was 83.9%, 72.3%, and 71.8% in TNM stages IIA, IIB, and IIC; and 86.0%, 76.9%, and 60.3% in TRN stages IIA, IIB, and IIC. The 5-year OS was 90.0%, 81.3%, and 82.6% for the TNM stages; and 91.6%, 85.0%, and 71.9% for the TRN stages. The AIC for RFS was lower for TRN (22,318.2) than for TNM (22,390.6), and that for OS was also lower for TRN (16,285.3) than for TNM (16,355.1). CONCLUSION: Stage II colon cancer staging using the number of retrieved lymph nodes may be superior to current TNM staging for prognosis stratification.

Object and anatomical feature recognition in surgical video images based on a convolutional neural network.

PURPOSE: Artificial intelligence-enabled techniques can process large amounts of surgical data and may be utilized for clinical decision support to recognize or forecast adverse events in an actual intraoperative scenario. To develop an image-guided navigation technology that will help in surgical education, we explored the performance of a convolutional neural network (CNN)-based computer vision system in detecting intraoperative objects. METHODS: The surgical videos used for annotation were recorded during surgeries conducted in the Department of Surgery of Tokyo Women's Medical University from 2019 to 2020. Abdominal endoscopic images were cut out from manually captured surgical videos. An open-source programming framework for CNN was used to design a model that could recognize and segment objects in real time through IBM Visual Insights. The model was used to detect the GI tract, blood, vessels, uterus, forceps, ports, gauze and clips in the surgical images. RESULTS: The accuracy, precision and recall of the model were 83%, 80% and 92%, respectively. The mean average precision (mAP), the calculated mean of the precision for each object, was 91%. Among surgical tools, the highest recall and precision of 96.3% and 97.9%, respectively, were achieved for forceps. Among the anatomical structures, the highest recall and precision of 92.9% and 91.3%, respectively, were achieved for the GI tract. CONCLUSION: The proposed model could detect objects in operative images with high accuracy, highlighting the possibility of using AI-based object recognition techniques for intraoperative navigation. Real-time object recognition will play a major role in navigation surgery and surgical education.

Superior prognosis stratification for stage III colon cancer using log odds of positive lymph nodes (LODDS) compared to TNM stage classification: the Japanese study group for postoperative follow-up of colorectal cancer.

OBJECTIVES: The aim of this study is to examine whether prognosis stratification in staging of Stage III colon cancer using T factor and log odds of positive lymph nodes (LODDS) categories is superior to that of the TNM staging system. MATERIALS AND METHODS: The subjects were 5,919 patients with Stage III colon cancer who underwent curative resection at 24 Japanese institutions. Univariate analysis of LODDS categories and clinicopathologic factors was conducted using a Cox proportional hazards regression model for cancer-specific survival (CSS). Independent prognostic factors for CSS were extracted in multivariate analysis using factors with significance in univariate analysis. Effect sizes of risk factors for CSS were compared using the LogWorth statistic. Combinations of T factor and LODDS categories were used to create L-stage subgroups A, B and C. Stratification of prognosis with L-stage and TNM was compared using the Akaike information criterion (AIC). RESULTS: In multivariate analysis, LODDS was identified as an independent prognostic factor, together with age, maximum tumor diameter, histopathological grade, L, V, pT, and pN. The LogWorth of LODDS was 17.149, which was the second highest after pT (31.562), and that of pN was 7.434. The 5-year CSS was 96.5%, 88.5%, and 66.6% in TNM stages IIIA, IIIB, and IIIC, respectively, and 96.0%, 87.6%, and 59.3% in L-stage A, B, and C, respectively (p < 0.0001). AICs for TNM and L-stage were 14,795.5 and 14,707.8, respectively. CONCLUSIONS: Prognosis stratification of the stage classification for Stage III colon cancer was superior with L-stage compared to TNM stage classification.

Successful treatment of recurrent volvulus in the afferent limb of the pouch following proctocolectomy for ulcerative colitis: a case report.

BACKGROUND: Pouch volvulus after proctocolectomy for ulcerative colitis is a very rare postoperative complication. The common site of pouch volvulus has been reported to be the ileal pouch-anal anastomosis and the middle part of the pouch, but no reports on pouch volvulus in the afferent limb of the pouch have been observed. Here, we report the case of a patient with afferent limb volvulus who underwent afferent limbpexy, but required reoperation 7 months later. CASE PRESENTATION: A 38-year-old man with refractory ulcerative colitis had undergone open proctocolectomy 10 years ago at another hospital. He had been aware of lower abdominal pain and bowel movement difficulty for 2 years. After repeated bowel obstruction, he was referred to our hospital for surgery. Based on the radiographic findings, we diagnosed a pouch volvulus and performed an operation. Laparoscopically, counterclockwise rotation of the afferent limb of the pouch was recognized. Moreover, the ileal mesentery was adhered and fixed to the presacral space 20 cm from the oral side of the pouch. The antimesenteric side of the afferent limb was fixed using interrupted stiches on the left peritoneal wall of the pelvis. He was discharged uneventfully 18 days after surgery, and defecation improved immediately. However, he was readmitted 7 months after surgery with the same abdominal pain and defecation difficulty. A similar finding was found and diagnosed as recurrent volvulus. Therefore, we performed a laparoscopic surgery. The same volvulus as in the previous surgery was confirmed. The site fixed during the previous surgery showed scars, but the afferent limb was free. The dilated ileum that contained the volvulus was excised only on the oral side of the pouch and an intraluminal anastomosis was performed on the anterior wall of the pouch. He had a good postoperative course and was discharged. CONCLUSION: Proper diagnosis of volvulus based on the characteristic imaging findings is important. In principle, bilateral row fixation of the rotated ileum is the basic procedure for volvulus. However, fixation with this technique is sometimes difficult. Therefore, this procedure is one of the useful options for the fixation of difficult or recurrent cases.

Diagnosis of lateral pelvic lymph node metastasis of T1 lower rectal cancer using diffusion-weighted magnetic resonance imaging: A case report with lateral pelvic lymph node dissection of lower rectal cancer.

The present study presented a 35-year-old female patient in whom fecal occult blood was detected in a medical check-up. Colonoscopy revealed a superficial elevated-type tumor with central depression in the lower rectum. The tumor was diagnosed as T1 deep invasive cancer. No swollen lymph nodes or distant metastasis were found on computed tomography or [18F]-fluorodeoxyglucose-positron emission tomography with computed tomography. However, a swollen right lateral pelvic lymph node (LPLN; short axis 4 mm) was revealed on magnetic resonance imaging (MRI). This lymph node exhibited high intensity on diffusion-weighted imaging (DWI), suggesting metastasis. Low anterior resection, regional lymph node dissection and right LPLN dissection (LPLD) were performed. Histological analysis revealed metastasis in the right LPLN, as suggested by the high DWI intensity. The indication for LPLD in the current Japanese guidelines is based on the tumor location and depth of invasion (≥T3), however, not on the status of LPLN metastasis in pre-operative evaluation. The present case was cT1, which is not included in this indication. DWI is sensitive for the diagnosis of lymph node metastasis of colorectal cancer, although inflammation-induced swelling of lymph nodes in advanced rectal cancer may cause a false-positive result, which is uncommon in T1 cases. Therefore, an LPLN with a high intensity DWI signal in T1 cases is likely to be metastasis-positive. Pre-operative DWI-MRI may be useful for identifying LPLN metastasis when planning the treatment strategy in these cases. The present study suggested reinvestigation of the indication for LPLD with inclusion of LPLN status on pre-operative imaging.

A logistic model including risk factors for lymph node metastasis can improve the accuracy of magnetic resonance imaging diagnosis of rectal cancer.

BACKGROUND: To evaluate use of magnetic resonance imaging (MRI) and a logistic model including risk factors for lymph node metastasis for improved diagnosis. MATERIALS AND METHODS: The subjects were 176 patients with rectal cancer who underwent preoperative MRI. The longest lymph node diameter was measured and a cut-off value for positive lymph node metastasis was established based on a receiver operating characteristic (ROC) curve. A logistic model was constructed based on MRI findings and risk factors for lymph node metastasis extracted from logistic-regression analysis. The diagnostic capabilities of MRI alone and those of the logistic model were compared using the area under the curve (AUC) of the ROC curve. RESULTS: The cut-off value was a diameter of 5.47 mm. Diagnosis using MRI had an accuracy of 65.9%, sensitivity 73.5%, specificity 61.3%, positive predictive value (PPV) 62.9%, and negative predictive value (NPV) 72.2% [AUC: 0.6739 (95%CI: 0.6016-0.7388)]. Age (<59) (p=0.0163), pT (T3+T4) (p=0.0001), and BMI (<23.5) (p=0.0003) were extracted as independent risk factors for lymph node metastasis. Diagnosis using MRI with the logistic model had an accuracy of 75.0%, sensitivity 72.3%, specificity 77.4%, PPV 74.1%, and NPV 75.8% [AUC: 0.7853 (95%CI: 0.7098-0.8454)], showing a significantly improved diagnostic capacity using the logistic model (p=0.0002). CONCLUSIONS: A logistic model including risk factors for lymph node metastasis can improve the accuracy of MRI diagnosis of rectal cancer.

Treatment strategy for preventing pouchitis as a postoperative complication of ulcerative colitis: the significance of the management of cuffitis.

PURPOSE: The aim of this study was to examine the risk factors for and to evaluate strategies for preventing pouchitis as a postoperative complication of ulcerative colitis (UC). METHODS: A total of 119 cases of UC in which restorative proctocolectomy with an ileal pouch-anal anastomosis (IPAA) was performed at our institution between 2000 and 2012 was investigated; nine patients in whom it was impossible to close the ileostomy due to an intractable anal fistula or pelvic abscess were excluded. RESULTS: The cumulative risk of developing pouchitis 5 years after IPAA with stoma closure was 31.0%. Significant relationships with pouchitis were found for the surgical indication (p = 0.0126) and surgical method (p = 0.0214). A significant correlation was found between pouchitis and cuffitis. Pouchitis was significantly more common in the cases with cuffitis than in those without (p = 0.0002). There was also a significantly different cumulative incidence observed between the cases with and without cuffitis (p < 0.0001). In addition, pouchitis had a greater tendency to recur in the cases with cuffitis than in those without (p = 0.2730). CONCLUSION: The cumulative incidence rate of pouchitis was 10.6% at 1 year, 15.1% at 2 years and 31.0% at 5 years. Controlling cuffitis is important to prevent pouchitis.

Sub-classification of Stage II colorectal cancer based on clinicopathological risk factors for recurrence.

PURPOSE: To make a Stage II colorectal cancer (CRC) sub-classification based on clinicopathological factors. METHODS: The subjects of this study were 422 patients with Stage II CRC, who underwent curative surgery with dissection of more than 12 lymph nodes. We used the logistic regression analysis or model and Cox's proportional hazard regression model for analysis. RESULTS: Preoperative carcinoembryonic antigen (CEA) level (p = 0.0057), macroscopic type (p = 0.0316), and depth of invasion (p = 0.0401) were extracted as independent risk factors for recurrence, whereas the preoperative CEA level (p = 0.0045) and depth of invasion (p = 0.0395) were extracted as independent predictors of 5-year disease-free survival. We defined depth of invasion (pT4) and the preoperative CEA level (abnormal) as risk factors for recurrence, and classified Grade A as a normal CEA level regardless of depth invasion, Grade B as depth of invasion to pT3 and an elevated CEA level, and Grade C as depth of invasion to pT4 and an elevated CEA level. There were significant differences in cumulative 5-year disease-free survival rates among each grade (Grade A vs. Grade B, p = 0.0474; Grade A vs. Grade C, p < 0.0001; Grade B vs. Grade C, p = 0.0134). CONCLUSION: The sub-classification of Stage II CRC, according not only to depth of invasion but also to preoperative CEA level, is important for predicting the prognosis.

Lateral pelvic lymph node dissection can be omitted in lower rectal cancer in which the longest lateral pelvic and perirectal lymph node is less than 5 mm on MRI.

BACKGROUND AND OBJECTIVES: The goal of the study was to examine the use of magnetic resonance imaging (MRI) for identification of patients with lower rectal cancer who may benefit from lateral pelvic lymph node dissection (LPLD). METHODS: Diagnoses and oncological outcomes were examined in 160 cases. Patients in whom the long-axis diameter of the longest detected lymph node was < 5 mm or ≥ 5 mm were classified as LPLN(-) (n = 102) and LPLN(+) (n = 58), respectively. RESULTS: Diagnostic results gave a 21.6% positive predictive value (PPV) and a 95.0% negative predictive value (NPV) for the LPLN. These values were 59.6% and 91.5%, respectively, for the perirectal lymph node (PRLN). Multivariate analysis showed that a pathologic PRLN (pPRLN)(+) status was an independent prognostic factor for relapse-free survival (RFS) (P = 0.0424) in the LPLN(-) group. The 5-year RFS did not differ significantly between cases that did not and did undergo LPLD (90.0% vs. 83.8%) in the LPLN(-) and pPRLN(-) groups. CONCLUSIONS: The low PPV and high NPV indicate that it is difficult to identify patients who may benefit from LPLD. However, the results show that LPLD has no benefit in LPLN(-) and PRLN(-) cases and that these cases can be identified based on MRI findings.

Importance of the Postoperative Carcinoembryonic Antigen Level during Follow-Up after Curative Resection in Patients with Liver Metastatic Colorectal Carcinoma.

BACKGROUND/AIMS: To validate the conventional Japanese grading of liver metastasis for no residual tumor resection in Stage IV colorectal cancer (CRC) with liver metastasis and to identify risk factors for postoperative recurrence. METHODOLOGY: The subjects of this study were 1792 Stage IV CRC patients with liver metastasis. RESULTS: In 1792 cases, including unresectable cases, there was a significantly different prognosis by grade (P < 0.0001). In 421 R0 cases, there was no significant difference between Grade A and Grade B (P = 0.8527). In 381 cases without extra-hepatic metastasis, the prognosis was not significantly different among three grades. On multivariate analysis, carcinoembryonic antigen within 3 months from R0 operation (3M-CEA) was an independent risk factor regardless of extrahepatic metastasis. There was a significantly different prognosis (P < 0.0001) among Grade A', defined as a normal 3M-CEA level, Grade B', defined as Grade A or B and an abnormal 3M-CEA level, and Grade C', defined as Grade C and an abnormal 3M-CEA level. CONCLUSIONS: The postoperative CEA level is an important risk factor during follow-up after curative resection in patients with liver metastatic colorectal carcinoma. The combination of the 3M-CEA level and conventional grading of liver metastasis is useful for follow-up of R0 resection cases.

Clinical use of PET/CT in peritoneal carcinomatosis from colorectal cancer.

BACKGROUND/AIMS: Peritoneal carcinomatosis (PC) from colorectal cancer has been associated with poor survival but new approaches and postoperative chemotherapy have improved survival. The purpose of this study was to evaluate the clinical utility of imaging in cases of PC from colorectal cancer. METHODOLOGY: This is a retrospective single-institution study which examined 23 patients with colorectal cancer who underwent positron emission tomography (PET), computed tomography (CT) and received a final diagnosis PC in our institute between 2005 and 2010. RESULTS: PET/CT detected PC in 19 of 23 cases (82.6%), whereas CT detected PC in 6 of 20 cases (30%). Four cases of PC were FDG-negative, all with maximal size <10mm, representing smaller tumors. FDG-negative PC was diffuse in 3 cases and nodular in 1. The distributed spotty uptake of FDG-negative PC was harder to detect. Diagnostic detection of PC was only achieved in 3 of 23 cases (13%). In the remaining cases, clinical diagnosis was metastasis to lymph nodes, recurrence, or normal FDG uptake by intestine. CONCLUSIONS: PET/CT offers efficient detection of PC and has the potential to improve clinical diagnosis when coupled with an understanding of the pathways of flow for ascitic fluid and peritoneal seeding.

Preoperative evaluation of the depth of anal canal invasion in very low rectal cancer by magnetic resonance imaging and surgical indications for intersphincteric resection.

PURPOSE: The present study was performed to evaluate the depth of anal canal invasion (DACI), and determine whether magnetic resonance imaging (MRI) assessment of the conjoined longitudinal muscle (CLM) can be used to identify the surgical indication for intersphincteric resection. METHODS: Sixty-six patients with T1 (n = 2), T2 (n = 20), T3 (n = 39), and T4 (n = 5) lower rectal cancer were included. Depth of anal canal invasion was defined as extension of the tumor to the anal canal. The outline of the CLM on MRI was assessed as clear, unclear, or absent (indicating invasion). RESULTS: A comparison of overall T-stage and DACI of 22 pT1-pT2 tumors revealed that none had a higher T-stage within the anal canal, and 16 of 39 pT3 tumors had only pT0-pT2 invasion within the anal canal. The CLM was clear in 30 cases of T0-T2 DACI, unclear in 5 cases of T0-T2 DACI, and 3 cases of T3-T4 DACI, and showed invasion in 3 cases of T2 DACI and 25 cases of T3-T4 DACI. The sensitivity, specificity, positive predictive value, and negative predictive value of using a clear CLM outline for determining T0-T2 DACI was 78.9, 91.9, 100, and 77.8%, respectively. CONCLUSIONS: Preoperative evaluation of DACI was compatible with the surgical indications. A clear CLM accurately indicates T0-T2 DACI.

Value of PET/CT imaging for diagnosing pulmonary metastasis of colorectal cancer.

BACKGROUND/AIMS: Several types of cancer can be clinically diagnosed by PET/CT, which can also perform whole-body imaging based on 18F-fluorodeoxyglucose (FDG) uptake. The present study assesses the value of PET/CT for diagnosing of pulmonary metastasis of colorectal cancer. METHODOLOGY: We staged or restaged 256 patients with colorectal cancer by PET/CT. Actual and suspected pulmonary metastases were detected in 37 (male, n=23; female, n=14) patients with primary or recurrent colorectal cancer. Among them, 35 (21 males, 14 females) patients had extant homochronous (n=7) and metachronous (n=28) pulmonary metastasis. RESULTS: The sensitivity and specificity of FDG-PET/CT for pulmonary metastasis were 57.1% and 99.1%, respectively, and the positive and negative predictive values were 90.1% and 93.6%, respectively. The uptake of FDG was affected by the size of the metastatic nodules; uptake was positive and negative in pulmonary metastases with an average size of 14.9mm and 5.75mm, respectively. The limit of positive FDG uptake was reached in pulmonary metastases of about 9mm. CONCLUSIONS: Pulmonary metastasis of colorectal cancer can be accurately and conveniently diagnosed by PET/CT, especially when nodules are >9mm.

Management of local recurrence of colorectal cancer: the role of PET/CT.

AIM: The aim was to examine the clinical applicability of positron-emission tomography/computed tomography (PET/CT) for diagnosing local recurrence of colorectal cancer. METHODS: From August 2003 to August 2008, 256 patients with colorectal cancer underwent PET/CT scanning for staging or restaging. Local recurrence was detected in 22 patients (18 men, 4 women) postsurgically. RESULTS: Of the 22 patients, 21 (95.5%) underwent positive 2-[fluorine-18]-fluoro-2-deoxy-D: -glucose uptake and were diagnosed with local recurrence by PET/CT; the results were negative in one case (4.5%). The sensitivity, specificity, positive predictive value, and negative predictive value for local recurrence were 95.5%, 100%, 100%, and 99.6%, respectively. CT/MRI scans yielded the following results: positive, 10 cases (45.5%); suspected positive, 11 cases (50.0%); negative, 1 case (4.5%). In the suspected positive cases, not only imaging but also colonoscopy and tumor markers among other techniques were used for definitive diagnosis. CONCLUSION: PET/CT has high sensitivity and specificity for diagnosing local recurrence of colorectal cancer and would be useful especially in the case of locally recurrent colorectal cancer suspected to be positive by CT/MRI.

[Roles of positron emission tomography/computed tomography (PET/CT) in the management of colorectal cancer].

In diagnosis and treatment of colorectal cancer, PET/CT has high sensitivity and specificity in comparison to other modalities, and in the near future is expected to play important roles in these areas. However, because of the high cost, PET/CT must be used cost-effectively. In the diagnosis of colorectal cancer with PET/CT, evaluation of cancer growth is possible, but evaluation of tumor invasion is inadequate. In the diagnosis of lymph node metastases, PET/CT provides higher sensitivity of evaluation in distant lymph nodes. The reason for difficulty in proximal lymph node evaluation is due to the close proximity of the main cancer tumor. In the diagnosis of liver metastases, meta-analysis indicates the need for higher sensitivity and specificity compared to CT and MRI. In the diagnosis of pulmonary metastases, chest CT should be obtained in very early pulmonary metastases because of the tiny tumor size in the early stage. In the diagnosis of local recurrence, discrimination between postoperative change and recurrence is difficult, but PET/CT is very useful as a qualitative diagnostic tool. Recent reports have also indicated the usefulness of PET/CT in the evaluation of treatment efficacy in chemotherapy or radiotherapy.