Survival benefit of adjuvant chemotherapy based on molecular residual disease detection in resected colorectal liver metastases: subgroup analysis from CIRCULATE-Japan GALAXY.

BACKGROUND: The prognostic role of circulating tumor DNA (ctDNA)-based molecular residual disease (MRD) detection and its utility for postsurgical risk stratification has been reported in colorectal cancer. In this study, we explored the use of ctDNA-based MRD detection in patients with colorectal liver metastases (CLM), for whom the survival benefit of adjuvant chemotherapy (ACT) after surgical resection remains unclear. METHODS: Patients with CLM without extrahepatic disease from the GALAXY study (UMIN000039205) were included. The disease-free survival (DFS) benefit of ACT was evaluated in MRD-positive and -negative groups after adjusting for age, gender, number, and size of liver metastases, RAS status, and previous history of oxaliplatin for primary cancer. ctDNA was detected using a personalized, tumor-informed 16-plex polymerase chain reaction-next-generation sequencing (mPCR-NGS) assay. ctDNA-based MRD status was evaluated 2-10 weeks after curative surgery, before the start of ACT. RESULTS: Among 6061 patients registered in GALAXY, 190 surgically resected CLM patients without any preoperative chemotherapy were included with a median follow-up of 24 months (1-48 months). ctDNA positivity in the MRD window was 32.1% (61/190). ACT was administered to 25.1% (48/190) of patients. In the MRD-positive group, 24-month DFS was higher for patients treated with ACT [33.3% versus not reached, adjusted hazard ratio (HR): 0.07, P < 0.0001]; whereas no benefit of ACT was seen in the MRD-negative group (24-month DFS: 72.3% versus 62.2%, adjusted HR: 0.68, P = 0.371). Multivariate analysis showed that the size of liver metastases (HR: 3.94, P = 0.031) was prognostic of DFS in the MRD-positive group. In the MRD-negative group, however, none of the clinicopathological factors were prognostic of DFS. CONCLUSIONS: Our data suggest that ACT may offer notable clinical benefits in MRD-positive patients with CLM. MRD status-based risk stratification could be potentially incorporated in future clinical trials for CLM.

Outcomes of robot-assisted versus conventional laparoscopic low anterior resection in patients with rectal cancer: propensity-matched analysis of the National Clinical Database in Japan.

BACKGROUND: Robot-assisted laparoscopic surgery has several advantages over conventional laparoscopy. However, population-based comparative studies for low anterior resection are limited. This article aimed to compare peri-operative results of robot-assisted low anterior resection (RALAR) and laparoscopy. METHODS: This retrospective cohort study used data from patients treated with RALAR or conventional laparoscopic low anterior resection (CLLAR) between October 2018 and December 2019, as recorded in the Japanese National Clinical Database, a data set registering clinical information, perioperative outcomes, and mortality. Of note, the registry does not include information on the tumour location (centimetres from the anal verge) and diverting stoma creation. Perioperative outcomes, including rate of conversion to open surgery, were compared between RALAR and CLLAR groups. Confounding factors were adjusted for using propensity score matching. RESULTS: Of 21 415 patients treated during the study interval, 20 220 were reviewed. Two homogeneous groups of 2843 patients were created by propensity score matching. The conversion rate to open surgery was significantly lower in the RALAR group than in the CLLAR group (0.7 versus 2.0 per cent; P < 0.001). The RALAR group had a longer operating time (median: 352 versus 283 min; P < 0.001), less intraoperative blood loss (15 versus 20 ml; P < 0.001), a lower in-hospital mortality rate (0.1 versus 0.5 per cent; P = 0.007), and a shorter postoperative hospital stay (median: 13 versus 14 days; P < 0.001) compared with the CLLAR group. The CLLAR group had a lower rate of readmission within 30 days (2.4 versus 3.3 per cent; P = 0.045). CONCLUSION: These data highlight the reduced conversion rate, in-hospital mortality rate, intraoperative blood loss, and length of postoperative hospital stay for rectal cancer surgery in patients treated using robot-assisted laparoscopic surgery compared with laparoscopic low anterior resection.

PRDM14 promotes malignant phenotype and correlates with poor prognosis in colorectal cancer.

BACKGROUND: Emerging evidence suggests that stemness in cancer cells is a cause of drug resistance or metastasis and is an important therapeutic target. PR [positive regulatory domain I-binding factor 1 (PRDI-BF1) and retinoblastoma protein-interacting zinc finger gene (RIZ1)] domain containing 14 (PRDM14), that regulates pluripotency in primordial germ cell, has reported the overexpression and function of stemness in various malignancies, suggesting it as the possible therapeutic target. However, to our knowledge, there have been no reports on the expression and function of PRDM14 in colorectal cancer (CRC). Therefore, we investigated the expression and the role of PRDM14 in CRC. METHODS: We performed immunohistochemistry evaluations and assessed PRDM14 expression on 414 primary CRC specimens. Colon cancer cell lines were subjected to functional and stemness assays in vitro and in vivo. RESULTS: We found that PRDM14 positive staining exhibited heterogeneity in the CRC primary tumor, especially at the tumor invasion front. The aberrant expression of PRDM14 at the invasion front was associated with lymph node metastasis and disease stage in patients with CRC. Furthermore, the multivariate analysis revealed high PRDM14 expression as an independent prognostic factor in the patients with Stage III CRC. Overexpression of PRDM14 enhanced the invasive, drug-resistant and stem-like properties in colon cancer cells in vitro and tumorigenicity in vivo. CONCLUSION: Our findings suggest that PRDM14 is involved in progression and chemoresistance of CRC, and is a potential prognostic biomarker and therapeutic target in the CRC patients.

Tumour-suppressive function of SIRT4 in human colorectal cancer.

BACKGROUND: SIRT4, which is localised in the mitochondria, is one of the least characterised members of the sirtuin family of nicotinamide adenine dinucleotide-dependent enzymes that play key roles in multiple cellular processes such as metabolism, stress response and longevity. There are only a few studies that have characterised its function and assessed its clinical significance in human cancers. METHODS: We established colorectal cancer cell lines (SW480, HCT116, and HT29) overexpressing SIRT4 and investigated their effects on proliferation, migration and invasion, as well as E-cadherin expression, that negatively regulates tumour invasion and metastases. The associations between SIRT4 expression in colorectal cancer specimens and clinicopathological features including prognosis were assessed by immunohistochemistry. RESULTS: SIRT4 upregulated E-cadherin expression and suppressed proliferation, migration and invasion through inhibition of glutamine metabolism in colorectal cancer cells. Moreover, SIRT4 expression in colorectal cancer decreased with the progression of invasion and metastasis, and a low expression level of SIRT4 was correlated with a worse prognosis. CONCLUSIONS: SIRT4 has a tumour-suppressive function and may serve as a novel therapeutic target in colorectal cancer.

Heterogeneity of colorectal cancers and extraction of discriminator gene signatures for personalized prediction of prognosis.

Dissected specimens of colorectal cancer (CRC) have been intensively studied using molecular sketches (gene signatures) to obtain a set of discriminator gene signatures for accurate prognosis prediction in individual patients. The discriminators obtained so far are not universally applicable, as the gene sets reflect the method and site of the study. In this study, we show that dissected stage II and III CRC samples are significantly heterogeneous in molecular sketches, and are not appropriate sources for discriminator extraction unless handled individually. To search for an accurate discriminator gene set for prediction of metastases, we need to start with less heterogeneous stage II CRC. We examined 198 (92 stage II and 106 stage III) CRC dissected samples for the predictability of discriminator gene signatures by analyzing stage II CRC alone, stage III alone, or in combination. The best predictive power of discriminator genes was obtained only when these genes were extracted and validated with stage II CRC samples. An accurate discriminator gene set for the prediction of CRC metastases can be obtained by focusing on stage II CRC samples.

Significance of RRM1 and ERCC1 expression in resectable pancreatic adenocarcinoma.

The identification of molecular markers, useful for therapeutic decisions in pancreatic cancer patients, is crucial for advances in disease management. Gemcitabine, although a cornerstone of current therapy, has limited efficacy. RRM1 is a key molecule for gemcitabine efficacy and is also involved in tumor progression. We determined in situ RRM1 and excision repair cross complementation group 1 (ERCC1) protein levels in 68 pancreatic cancer patients. All had R0 resections without preoperative therapy. Protein levels were determined by automated quantitative analysis (AQUA), a fluorescence-based immunohistochemical method. The relationship between protein expressions and clinical outcomes, including response to gemcitabine at the time of disease recurrence, was determined. Patients with high RRM1 showed significantly better overall survival than patients with low expression (P=0.0196). There was a trend toward better overall survival for patient with high ERCC1 (P=0.0552). When both markers were considered together, patients with both high RRM1 and ERCC1 faired the best in terms of overall and disease-free survival (P=0.0066, P=0.0127). In addition, treatment benefit from gemcitabine in patients with disease recurrence was observed only in patients with low RRM1. The combination of RRM1 and ERCC1 expression is prognostic in pancreatic cancer patients after a complete resection. On disease recurrence, only patients with low RRM1 derive benefit from gemcitabine.

Activation of Wnt/beta-catenin signalling pathway induces chemoresistance to interferon-alpha/5-fluorouracil combination therapy for hepatocellular carcinoma.

Type I IFN receptor type 2 (IFNAR2) expression correlates significantly with clinical response to interferon (IFN)-alpha/5-fluorouracil (5-FU) combination therapy for hepatocellular carcinoma (HCC). However, some IFNAR2-positive patients show no response to the therapy. This result suggests the possibility of other factors, which would be responsible for resistance to IFN-alpha/5-FU therapy. The aim of this study was to examine the mechanism of anti-proliferative effects of IFN-alpha/5-FU therapy and search for a biological marker of chemoresistance to such therapy. Gene expression profiling and molecular network analysis were used in the analysis of non-responders and responders with IFNAR2-positive HCC. The Wnt/beta-catenin signalling pathway contributed to resistance to IFN-alpha/5-FU therapy. Immunohistochemical analysis showed positive epithelial cell adhesion molecule (Ep-CAM) expression, the target molecule of Wnt/beta-catenin signalling, only in non-responders. In vitro studies showed that activation of Wnt/beta-catenin signalling by glycogen synthesis kinase-3 inhibitor (6-bromoindirubin-3'-oxime (BIO)) induced chemoresistance to IFN-alpha/5-FU. BrdU-based cell proliferation ELISA and cell cycle analysis showed that concurrent addition of BIO and IFN-alpha/5-FU significantly to hepatoma cell cultures reduced the inhibitory effects of the latter two on DNA synthesis and accumulation of cells in the S-phase. The results indicate that activation of Wnt/beta-catenin signalling pathway induces chemoresistance to IFN-alpha/5-FU therapy and suggest that Ep-CAM is a potentially useful marker for resistance to such therapy, especially in IFNAR2-positive cases.

Integrative approach for differentially overexpressed genes in gastric cancer by combining large-scale gene expression profiling and network analysis.

Gene expression profiling is a valuable tool for identifying differentially expressed genes in studies of disease subtype and patient outcome for various cancers. However, it remains difficult to assign biological significance to the vast number of genes. There is an increasing awareness of gene expression profile as an important part of the contextual molecular network at play in complex biological processes such as cancer initiation and progression. This study analysed the transcriptional profiles commonly activated at different stages of gastric cancers using an integrated approach combining gene expression profiling of 222 human tissues and gene regulatory dynamic mapping. We focused on an inferred core network with CDKN1A (p21(WAF1/CIP1)) as the hub, and extracted seven candidates for gastric carcinogenesis (MMP7, SPARC, SOD2, INHBA, IGFBP7, NEK6, LUM). They were classified into two groups based on the correlation between expression level and stage. The seven genes were commonly activated and their expression levels tended to increase as disease progressed. NEK6 and INHBA are particularly promising candidate genes overexpressed at the protein level, as confirmed by immunohistochemistry and western blotting. This integrated approach could help to identify candidate players in gastric carcinogenesis and progression. These genes are potential markers of gastric cancer regardless of stage.

Quantitative evaluation of vimentin expression in tumour stroma of colorectal cancer.

Recent studies have identified vimentin, a type III intermediate filament, among genes differentially expressed in tumours with more invasive features, suggesting an association between vimentin and tumour progression. The aim of this study, was to investigate whether vimentin expression in colon cancer tissue is of clinical relevance. We performed immunostaining in 142 colorectal cancer (CRC) samples and quantified the amount of vimentin expression using computer-assisted image analysis. Vimentin expression in the tumour stroma of CRC was associated with shorter survival. Overall survival in the high vimentin expression group was 71.2% compared with 90.4% in the low-expression group (P=0.002), whereas disease-free survival for the high-expression group was 62.7% compared with 86.7% for the low-expression group (P=0.001). Furthermore, the prognostic power of vimentin for disease recurrence was maintained in both stage II and III CRC. Multivariate analysis suggested that vimentin was a better prognostic indicator for disease recurrence (risk ratio=3.5) than the widely used lymph node status (risk ratio=2.2). Vimentin expression in the tumour stroma may reflect a higher malignant potential of the tumour and may be a useful predictive marker for disease recurrence in CRC patients.

Evaluation of the technical difficulty performing laparoscopic resection of a rectosigmoid carcinoma: visceral fat reflects technical difficulty more accurately than body mass index.

BACKGROUND: In general, visceral fat and adhesion greatly influence the technical difficulty in performing abdominal surgery. Body mass index (BMI) has been widely used to express the degree of obesity, but it does not always properly reflect the degree of visceral fat. This retrospective study investigated the impact of visceral fat on the operation time to examine whether a quantified visceral fat area (VFA) could be used as a sensitive predictor of technical difficulty in performing a laparoscopic resection of rectosigmoid carcinoma. METHODS: Between February 1999 and April 2004, 58 consecutive patients underwent a laparoscopically assisted sigmoidectomy or anterior resection. After a review of the medical charts, the relationship between the operation time and the following variables was analyzed: sex, depth of invasion, approach (medial-to-lateral, lateral-to-medial), subjectively graded degree of visceral fat and adhesion, history of previous abdominal surgery, and BMI. The correlations between VFA, VFA/body surface area (BSA) measured by the "FatScan," software package for quantifying the VFA from the preoperative CT images, and operation time were investigated. Next, the impact of the VFA amount on the early surgical outcome was examined. RESULTS: According to the intraoperative findings, two patients with a severe adhesion required a significantly longer operation time. A history of previous abdominal surgery was not a significant factor in the operation time. Instead, the VFA/BSA had a stronger correlation with the operation time than the BMI. A significantly longer operation time (209 +/- 42 vs 179 +/- 37 min; p = 0.031) was observed for the patients in the high VFA/BSA group (> or =85 cm(2)/m(2)) group than in the normal VFA/BSA group (<85 cm(2)/m(2)). CONCLUSION: For predicting the technical difficulty of performing a laparoscopic resection of rectosigmoid carcinoma, VFA/BSA may be a more useful index than BMI.

Expression and mutation of SMAD4 in poorly differentiated carcinoma and signet-ring cell carcinoma of the colorectum.

Poorly differentiated adenocarcinoma (Por) and signet-ring cell carcinoma (Sig) are rare but highly malignant types of colorectal cancer. To explore their genetic backgrounds we investigated TGF-beta type II receptor (TGF-beta RII) and SMAD4 in the TGF-beta signaling pathway, and to identify their mutator phenotype we examined microsatellite instability (MSI) status. Loss of SMAD4 expression was significantly more frequent in Por (12 of 38; 31%) and Sig (4 of 5; 80%) tumors than in well (Well) and moderately differentiated (Mod) carcinomas (p = 0.04, 0.003, respectively). Mutation of the SMAD4 gene was detected in 2 of 26 Por tumors. MSI was positive in 14 of the 38 Por tumors and in 1 of the 5 Sig tumors, but in none of the Well or Mod tumors examined. We also found mutation of TGF-beta RII, a putative target of MSI, in 10 of 35 Por tumors (28.6%), but in none of 3 Sig tumors. As a whole, about 50% of the Por tumors and 80% of the Sig tumors showed abnormalities of either TGF-beta RII or SMAD4 expression. This suggests that disruption of the TGF-beta signaling pathway may play a central role in the pathogenesis of Por and Sig tumors of the colorectum.

Expression of PPARdelta in multistage carcinogenesis of the colorectum: implications of malignant cancer morphology.

Whether peroxisome proliferator-activated receptor (PPAR) delta is a good target for the chemoprevention and/or treatment of colorectal cancer (CRC) remains controversial. Our goal was to examine PPARdelta expression in multistage carcinogenesis of the colorectum and to assess the relevance of PPARdelta in CRC. Immunohistochemical analysis indicated that PPARdelta expression increased from normal mucosa to adenomatous polyps to CRC. In cancer tissues, the PPARdelta protein was accumulated only in those cancer cells with highly malignant morphology, as represented by a large-sized nucleus, round-shaped nucleus, and presence of clear nucleoli. Interestingly, the cancer tissue often contained both PPARdelta-positive and -negative areas, each retaining their respective specific morphological features. Moreover, this pattern persisted even when PPARdelta-positive and -negative cells were aligned next to each other within a single cancer nest or gland and was present in the majority of CRC cases. Immunohistochemistry for Ki-67 proliferation marker showed no significant correlation between Ki-67 and PPARdelta in CRC samples. Based on Western blot analysis and quantitative RT-PCR, high PPARdelta protein expression correlated with high PPARdelta mRNA levels. Peroxisome proliferator-activated receptor delta may have a supporting role in tumorigenesis, and the close association between PPARdelta expression and malignant morphology of CRC cells suggests a pivotal role in cancer tissue.

Identification of differentially expressed genes involved in colorectal carcinogenesis using a cDNA microarray.

To identify candidate genes involved in human colorectal carcinogenesis, we constructed the gene expression profiles of 50 colorectal cancers (CRCs) and 12 normal colorectal epithelia using a cDNA microarray specially constructed for CRC. Hierarchical clustering analysis and principal component analysis could clearly distinguish the gene profiles of cancer tissues from those of normal tissues. Our results confirm there are indeed differences in gene expression between cancer and normal mucosa. Our cDNA microarray identified 22 up-regulated genes and 32 down-regulated genes in CRC. Many of these genes have been previously identified in relation to human carcinogenesis, 68% and 78%, respectively. Subsequent validation of selected genes by serial analysis of gene expression and reverse transcription polymerase chain reaction, demonstrated expression patterns that were almost identical to our microarray analysis. Using a four-fold larger sample relative to that used in our previous study, candidate genes involved in human colorectal carcinogenesis were reproducibly identified. Further studies of comprehensive gene expression using our technique may elucidate the mechanism of CRC tumorigenesis.

PCR-array gene expression profiling of hepatocellular carcinoma.

Many trials using DNA microarrays have been reported for various human malignancies, but an efficient molecular diagnostic system has yet to be established. Here, we adopted a high throughput quantitative PCR-array system based on adaptor-tagged competitive PCR (ATAC-PCR), as a novel technique for gene expression profiling of hepatocellular carcinoma (HCC). This PCR-array contained 3,072 genes derived from three different cDNA libraries, including 298 additional known genes suspected to be involved in hepatocarcinogenesis. Using this PCR-array with 20 pairs of liver tissues (20 HCC, 20 surrounding nontumor liver), we identified a total of 117 genes differing in expression levels in the two liver tissues. Hierarchical clustering analysis and principal component analysis with these genes revealed distinct gene expression patterns in the HBV-positive group and the HCV-positive groups. Among 117 genes, only 7 (GPAA1, TMEM9, FACL4, ADFP, MAWBP, PACE4, FOS) were common to both groups. In conclusion, this PCR-array analysis with an appropriate set of genes is considered useful for gene expression profiling of HCC, and we identified some genes which may play a common key role in hepatocarcinogenesis.

Construction of preferential cDNA microarray specialized for human colorectal carcinoma: molecular sketch of colorectal cancer.

cDNA microarray analyses can be used to identify candidate genes that play important roles in human carcinogenesis. To gain insight into the molecular sketch of colorectal cancer, we have constructed cDNA microarrays specialized for colorectal cancer, which we named "Colonochip" by selecting genes that are expressed in colorectal cancer, normal colonic mucosa, and liver metastatic cancer tissues. This microarray contained 4608 nonredundant cDNA clones from over 30,000 cDNA clones derived from the three types of human cDNA libraries, as well as clones from 170 additional conventional major genes suspected to be involved in colorectal carcinogenesis, according to literatures. Using this "Colonochip," we were able to identify 59 genes showing twofold or more differential expression between primary cancer and normal colonic mucosa, potent candidates for diagnosis, and therapy of colorectal cancer for further studies.

Expression of second class of KIP protein p57KIP2 in human colorectal carcinoma.

p57KIP2, the second class of KIP family protein, is one of the negative regulators of the cell cycle. To elucidate the role of p57KIP2 in colorectal normal mucosa and cancer, we examined the expression of p57KIP2 protein in 110 pairs of colorectal non-tumor and cancer tissues. Immunohistochemical analysis showed that p57KIP2 was weakly detected in the normal colonic epithelium and lymph follicles. A unique expression pattern of p57KIP2 was exclusively noted in the elastic fibers within the walls of relatively large blood vessels (diameter > 100 microm). In cancer tissues, p57KIP2 protein was localized mainly in nuclei. Using the mean percentage of nuclear p57KIP2 expression (25%) as the cut-off value, we divided our cases into those with high expression (n = 44, 40%) and low expression (n = 66, 60%) of p57KIP2 among 110 colorectal cancer cases tested. The clinical and pathological survey showed a significant correlation between low expression of p57KIP2 and large tumor size (p < 0.05) or the presence of tumors in females (p < 0.01). Survival analysis showed that p57KIP2 expression did not influence prognosis. RT-PCR analysis was also performed using RNA extracts from 6 colorectal cancer tissues. When the levels of p57KIP2 mRNAs were compared with expression of p57KIP2 protein, a clear correlation was found, suggesting that expression of the p57KIP2 protein may be regulated at the transcription level. The present study revealed p57KIP2 expression in colorectal cancer and suggests that p57KIP2 may not play a central role in the progression of colorectal cancer.

Carcinoma of the head of the pancreas after excision of a choledochal cyst.

We here report a 53-year-old woman who had undergone resection of a choledochal cyst and hepaticojejunostomy three years before. She was readmitted because of intermittent fever, and abdominal computed tomography revealed a 4-cm tumor in the head of the pancreas. We performed pancreatoduodenectomy, and examination of the resected specimen showed well-differentiated papillary adenocarcinoma. Only 5 cases of carcinoma occurring after the resection of a choledochal cyst have been reported, and to our knowledge, this is the second case of carcinoma of the head of the pancreas.

Overexpression of CDC25B phosphatase as a novel marker of poor prognosis of human colorectal carcinoma.

There is evidence to suggest that CDC25B phosphatase is an oncogenic protein. To elucidate the role of CDC25B in colorectal carcinoma, we examined the expression of CDC25B at the mRNA and protein levels. Reverse transcription-PCR assay indicated that CDC25B was overexpressed in tumor tissues relative to normal mucosa in 6 of 10 cases. Using immunohistochemistry, we identified high expression of CDC25B in 77 of 181 colorectal cases (43%). Univariate analysis showed that high expression was a significant predictor for poor prognosis compared with low expression (5-year survival rate; 59% versus 82%, respectively; P < 0.0001). Multivariate analysis indicated that CDC25B was an independent prognostic marker (risk ratio for death, 3.7; P < 0.0001) even after controlling for various factors such as lymph node metastasis, tumor size, degree of differentiation, and depth of invasion. Furthermore, the level of CDC25B expression clearly predicted the outcome of patients with Dukes' B and Dukes' C tumors. On the other hand, CDC25A mRNA was overexpressed in 9 of 10 colorectal cancer cases, and immunohistochemistry for CDC25A showed high expression in 52 of 111 cases (47%), but no significant correlation with prognosis. Our findings suggest that CDC25B is a novel independent prognostic marker of colorectal carcinoma and that it may be clinically useful for selecting patients who could benefit from adjuvant therapy.

[Features of colorectal cancer with fecal-occult-blood tests--comparison with colorectal cancer with no screening].

BACKGROUND: There is now evidence from three randomized controlled trials (from Minnesota, Nottingham and Funen) that screening average-risk individuals for colorectal cancer (CRC) with fecal-occult-blood tests (FOBT) can reduce mortality from CRC. In Japan, mortality rates from CRC have increased and mass screening with FOBT has been performed since 1992. Although there is growing proportion of CRC with FOBT, there is no conclusive evidence that they reduce mortality from this cause. We evaluated the feature of CRC with FOBT, as one of the methods for evaluation of the efficacy of screening with this test. METHODS: Between January, 1982 and December, 1996, 2071 cases with CRC resected in our hospital were considered. We evaluated the clinicopathological findings about age, sex, location of tumor, size depth, incidence of lymph node metastasis, stage and prognosis of CRC with FOBT (376) compared with CRC with no screening (controls; 1695). RESULTS: CRC with FOBT were earlier stage and smaller-sized cancers than controls. No significant difference was found in the incidence of lymph node metastasis at each depth and prognosis in each stage. CONCLUSIONS: By screening with FOBT, we can detect at an earlier stage and with a smaller cancer, with the same biological behavior as controls. Now, we must encourage colon screening, continuing to research ways to improve identification of high-risk subgroups and increase complicance.

[Growth and development of colorectal cancer with subclassification on submucosa and proper muscle infiltrating cancer].

Colorectal cancer (CRC) infiltrating the submucosa (sm cancer) and the proper muscle (mp cancer) represent an early and an intermediate stage in the development of CRC, and sm and mp cancer are therefore appropriate to discuss the natural history of CRC. A total of 337 sm cancers and 291 mp cancers resected in our series were evaluated. We divided sm and mp cancers into three categories, respectively, sm 1, sm 2, sm 3, mp 1, mp 2, and mp 3, according to the depth of infiltration of the submucosa or the proper muscle. The deeper the invasion, the larger of the tumor size, and the proportion of depressed type in their configuration increases. On the contrary, the proportion of tumors with adenomatous component decreases. A larger proportion of tumors in all categories of infiltration showed PG more of ten than that of NPG in their marginal structure. In this study, 17% of sm cancer and 23% of mp cancer might develop not via the adenoma-carcinoma sequence.