Cost-effectiveness of surveillance intervals after curative resection of colorectal cancer.

BACKGROUND: Major guidelines consistently recommend 5 years of postoperative surveillance for patients with colorectal cancer. However, they differ in their recommendations for examination intervals and whether they should vary according to disease stage. Furthermore, there are no reports on the cost-effectiveness of the different surveillance schedules. The objective of this study is to identify the most cost-effective surveillance intervals after curative resection of colorectal cancer. METHODS: A total of 3701 patients who underwent curative surgery for colorectal cancer at the National Cancer Center Hospital were included. A cost-effectiveness analysis was conducted for the five surveillance strategies with reference to the guidelines. Expected medical costs and quality-adjusted life years after colorectal cancer resection were calculated using a state-transition model by Monte Carlo simulation. The incremental cost-effectiveness ratio per quality-adjusted life years gained was calculated for each strategy, with a maximum acceptable value of 43 500-52 200 USD (5-6 million JPY). RESULTS: Stages I, II and III included 1316, 1082 and 1303 patients, respectively, with 45, 140 and 338 relapsed cases. For patients with stage I disease, strategy 4 (incremental cost-effectiveness ratio $26 555/quality-adjusted life year) was considered to be the most cost-effective, while strategies 3 ($83 071/quality-adjusted life year) and 2 ($289 642/quality-adjusted life year) exceeded the threshold value. In stages II and III, the incremental cost-effectiveness ratio for strategy 3 was the most cost-effective option, with an incremental cost-effectiveness ratio of $18 358-22 230/quality-adjusted life year. CONCLUSIONS: In stage I, the cost-effectiveness of intensive surveillance is very poor and strategy 4 is the most cost-effective. Strategy 3 is the most cost-effective in stages II and III.

A postoperative body weight increase is a novel risk factor for incisional hernia of midline abdominal incision after elective gastroenterological surgery.

PURPOSE: Midline abdominal incisions (MAIs) are widely used in both open and minimally invasive surgery. Incisional hernia (IH) accounts for most long-term postoperative wound complications. This study explored the risk factors for IH due to MAI in patients with clean-contaminated wounds after elective gastroenterological surgery. METHODS: The present study targeted patients enrolled in 2 randomized controlled trials to evaluate the efficacy of intraoperative interventions for incisional SSI prevention after gastroenterological surgery for clean-contaminated wounds. The patients were reassessed, and pre- and intraoperative variables and postoperative outcomes were collected. IH was defined as any abdominal wall gap, regardless of bulge, in the area of a postoperative scar that was perceptible or palpable on clinical examination or computed tomography according to the European Hernia Society guidelines. The risk factors for IH were identified using univariate and multivariate analyses. RESULTS: The study population included 1,281 patients, of whom 273 (21.3%) developed IH. Seventy-four (5.8%) patients developed incisional SSI. Multivariate logistic regression analysis revealed that female sex (odds ratio [OR], 1.39; 95% confidence interval [CI] 1.03-1.86, p = 0.031), high preoperative body mass index (OR, 1.81; 95% CI 1.19-2.77, p = 0.006), incisional SSI (OR, 2.29; 95% CI 1.34-3.93, p = 0.003), and postoperative body weight increase (OR, 1.49; 95% CI 1.09-2.04, p = 0.012) were independent risk factors for IH due to MAI in patients who underwent elective gastroenterological surgery. CONCLUSION: We identified postoperative body weight increase at one year as a novel risk factor for IH in patients with MAI after elective gastroenterological surgery.

Contrasting seasonality of the incidence of incisional surgical site infection after general and gastroenterological surgery: An analysis of 8,436 patients in a single institute.

BACKGROUND: While seasonality of hospital-acquired infections, including incisional SSI after orthopaedic surgery, is recognized, the seasonality of incisional SSI after general and gastroenterological surgeries remains unclear. STUDY DESIGN: This retrospective single-institute observational study analysed the seasonality and risk factors of incisional SSI after general and gastroenterological surgeries using univariate and multivariable analyses. The evaluated variables included age, sex, surgical approach, surgical urgency, operation time, wound classification, and the American Society of Anesthesiologists physical status (ASA-PS). RESULTS: 8,436 patients were enrolled. General surgeries (n=2,241) showed a pronounced SSI incidence in summer (3.9%; odds ratio [OR] 1.87; 95% confidence interval [CI] 1.05-3.27; p=0.025) compared to other seasons (2.1%). Conversely, gastroenterological surgeries (n=6,195) showed a higher incidence in winter (8.3%; OR 1.38; 95% CI 1.10-1.73; p=0.005) than in other seasons (6.1%). Summer for general surgery (OR 1.90; 95% CI 1.12-3.24; p=0.018) and winter for gastroenterological surgery (OR 1.46; 95% CI 1.17-1.82; p=0.001) emerged as independent risk factors for incisional SSI. Open surgery (OR, 2.72; 95% CI 1.73-4.29, p<0.001) and an ASA-PS score ≥3 (OR, 1.64; 95% CI 1.08-2.50, p=0.021) were independent risk factors for incisional SSI in patients undergoing gastroenterological surgery during winter. CONCLUSION: Seasonality exists in the incisional SSI incidence following general and gastroenterological surgeries. Recognizing these trends may help enhance preventive strategies, highlighting the elevated risk in summer for general surgery and in winter for gastroenterological surgery.

Superiority trial for the development of an ideal method for the closure of midline abdominal wall incisions to reduce the incidence of wound complications after elective gastroenterological surgery: study protocol for a randomized controlled trial.

BACKGROUND: The recent guidelines from the European and American Hernia Societies recommend a continuous small-bite suturing technique with slowly absorbable sutures for fascial closure of midline abdominal wall incisions to reduce the incidence of wound complications, especially for incisional hernia. However, this is based on low-certainty evidence. We could not find any recommendations for skin closure. The wound closure technique is an important determinant of the risk of wound complications, and a comprehensive approach to prevent wound complications should be developed. METHODS: We propose a single-institute, prospective, randomized, blinded-endpoint trial to assess the superiority of the combination of continuous suturing of the fascia without peritoneal closure and continuous suturing of the subcuticular tissue (study group) over that of interrupted suturing of the fascia together with the peritoneum and interrupted suturing of the subcuticular tissue (control group) for reducing the incidence of midline abdominal wall incision wound complications after elective gastroenterological surgery with a clean-contaminated wound. Permuted-block randomization with an allocation ratio of 1:1 and blocking will be used. We hypothesize that the study group will show a 50% reduction in the incidence of wound complications. The target number of cases is set at 284. The primary outcome is the incidence of wound complications, including incisional surgical site infection, hemorrhage, seroma, wound dehiscence within 30 days after surgery, and incisional hernia at approximately 1 year after surgery. DISCUSSION: This trial will provide initial evidence on the ideal combination of fascial and skin closure for midline abdominal wall incision to reduce the incidence of overall postoperative wound complications after gastroenterological surgery with a clean-contaminated wound. This trial is expected to generate high-quality evidence that supports the current guidelines for the closure of abdominal wall incisions from the European and American Hernia Societies and to contribute to their next updates. TRIAL REGISTRATION: UMIN-CTR UMIN000048442. Registered on 1 August 2022. https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000055205.

Circulating tumor DNA in molecular assessment feasibly predicts early progression of pancreatic cancer that cannot be identified via initial imaging.

Molecular assessment using circulating tumor DNA (ctDNA) has not been well-defined. We recruited 61 pancreatic cancer (PC) patients who underwent initial computed tomography (CT) imaging study during first-line chemotherapy. Initial molecular assessment was performed using droplet digital PCR and defined as the change in KRAS-mutated ctDNA before and after treatments, which was classified into five categories: mNT, molecular negative; mCR, complete response; mPR, partial response; mSD, stable disease; mPD, progressive disease. Of 61 patients, 14 diagnosed with PD after initial CT imaging showed significantly worse therapeutic outcomes than 47 patients with disease control. In these 47 patients, initial molecular assessment exhibited significant differences in therapeutic outcomes between patients with and without ctDNA (mPD + mSD vs. mCR + mNT; 13.2 M vs. 21.7 M, P = 0.0029) but no difference between those with mPD and mSD + mCR + mNT, suggesting that the presence of ctDNA had more impact on the therapeutic outcomes than change in its number. Multivariate analysis revealed that it was the only independent prognostic factor (P = 0.0405). The presence of ctDNA in initial molecular assessment predicted early tumor progression and identified PC patients more likely to benefit from chemotherapy.

Update of risk factors for surgical site infection in clean-contaminated wounds after gastroenterological surgery: An analysis of 1,878 participants enrolled in 2 recent randomized control trials for the prevention of surgical site infection.

BACKGROUND: Clean-contaminated wounds should be the main target for reducing the burden of harm caused by surgical site infection after gastroenterological surgery. METHODS: The present study targeted 1,973 patients enrolled in 2 randomized controlled trials to evaluate the efficacy of intraoperative interventions for incisional surgical site infection prevention after gastroenterological surgery with clean-contaminated wounds. Patients were reassessed, and preoperative and postoperative variables were collected. Risk factors for surgical site infection were identified by univariate and multivariate analyses. RESULTS: The study population included 1,878 patients, among whom 213 (11.3%) developed overall surgical site infection and 119 (6.3%) developed incisional surgical site infection. A multivariate analysis revealed that steroid or immunosuppressant use (odds ratio 3.03; 95% confidence interval 1.37-6.73, P = .0064), open surgery (odds ratio 1.77; 95% confidence interval 1.11-2.83, P = .0167), and long operative time (odds ratio 2.31; 95% confidence interval 1.5-3.56, P < .001) were independent risk factors for incisional surgical site infection. Steroid or immunosuppressant use (odds ratio 2.62; 95% confidence interval 1.29-5.33, P = .0078), open surgery (odds ratio 2.13; 95% confidence interval 1.44-3.16, P < .001), and long operative time (odds ratio 2.92; 95% confidence interval 2.08-4.10, P < .001) were also independent risk factors for overall surgical site infection in the multivariate analysis. Furthermore, a multivariate analysis revealed that a long operative time (odds ratio 3.21; 95% confidence interval 1.69-6.1, P = .00378) was an independent risk factor for incisional surgical site infection in patients who underwent laparoscopic surgery. CONCLUSION: Even under current measures for surgical site infection prevention, surgeons should continue to make efforts to appropriately expand the indication of laparoscopic surgery and to reduce operative times even when performing laparoscopic surgery.

Synthesis of nucleoside 5'-boranophosphorothioate derivatives using an H-boranophosphonate monoester as a precursor.

We developed a method to convert a nucleoside 5'-H-boranophosphonate monoester into the corresponding nucleoside 5'-boranophosphorothioate monoester through temporary protection of the H-boranophosphonate monoester moiety as a diester with 9-fluorenylmethanol, subsequent sulfurization of the P-H group and removal of the 9-fluorenylmethyl group. Although the isolation of the resultant boranophosphorothioate monoester was found to be difficult due to instability of the compound, this new method proved to be useful to synthesize some conjugates of the nucleoside 5'-boranophosphorothioate with other biomolecules, such as cholesterol and an amino acid.

Laparoscopic resection of a solitary fibrous tumor in the mesentery of the small intestine: a case report.

Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms that are usually localized in the mesothelium of soft tissues. Although SFTs of pleural origin are common, SFTs arising in the small intestine are extremely rare, and there are few reports of laparoscopic resection of these tumors. A 74-year-old woman presented to her local physician with intermittent pain in the lower abdomen. Computed tomography showed a 25 mm mass in the ileum with extramural protrusion and small intestine capsule endoscopy showed a submucosal tumor-like elevation covered by normal mucosa. The diagnosis was ileal tumor, which was removed by laparoscopic partial resection of the small intestine. Macroscopically, the tumor was found to be a substantial mass within subplasmalemmal fatty tissue that had no continuity with the muscular layer. Histological analysis showed proliferation of homogeneous spindle-shaped cells against a background of fibrous stroma. Immunostaining was positive for STAT6 and negative for KIT, Dog1, and S100, and SFT was diagnosed. The tumor was low risk according to Demicco's risk classification. In conclusion, a less invasive laparoscopic procedure is preferable if the tumor can be resected completely without applying excessive external force that results in seeding of tumor cells in the abdominal cavity.

Mid-term Efficacy of Local Repair Using Modified Altemeier Technique for Stomal Prolapse: A Case Series.

INTRODUCTION:  Stomal prolapse (SP) is characterized by full-thickness protrusion of the bowel through the stoma site. The surgical procedures for SP include local repair, abdominal wall fixation, and stoma relocation. However, previous reports were mostly case reports or case series with a small number of patients and lacked long-term results. A modified Altemeier technique (MAT) has been used for the local repair of SP in our institution, and this study aimed to evaluate its mid-term efficacy. METHODS:  We reviewed patients who underwent MAT for SP between August 2013 and December 2020. The variables included patient characteristics, type of stoma, indications of stoma creation, the time interval from stoma creation to prolapse, site of prolapse, reasons for SP surgery, perioperative variables, complications during SP surgery, and length of follow-up. Recurrence of SP was defined as the need for change in stoma care or re-protrusion of the stoma by more than 5 cm in length. RESULTS:  Ten patients were included in this study. The median age at the time of SP surgery was 71.5 years. The indications of stoma creation included unresectable or recurrent intra-abdominal malignancies in four patients, diverting ileostomy with rectal cancer surgery in two, transverse colon cancer in one, gastric and rectal cancer in one, rectovaginal fistula in one, and non-occlusive mesenteric ischemia in one. The median interval from stoma creation to prolapse was 2.5 months. Six patients underwent elective SP surgery, and four patients underwent emergency surgery for incarcerated prolapse. The median operative time was 75.5 min. Postoperative complications that included transient mucosal ischemia and subcutaneous abscess occurred in one patient. There were four recurrences (40%), and the median time interval from surgery to recurrence was 4.5 months. Two patients underwent repeated MAT, one of whom underwent stomal reversal with laparotomy for re-recurrence. The median follow-up duration was 19 months. CONCLUSION:  MAT for SP is associated with a high recurrence rate in mid-term follow-up.

The advantage of laparoscopic surgery in the treatment of Spigelian hernia: A report of two cases.

INTRODUCTION AND IMPORTANCE: The usefulness of laparoscopic surgery in the treatment of Spigelian hernias and the appropriate insufflation pressure remains unclear. CASE PRESENTATION: Case 1 involved an 81-year-old woman presented with a right abdominal protrusion. CT scan demonstrated a defect in the abdominal wall at the lateral edge of the right rectus abdominis muscle. We diagnosed as Spigelian hernia and performed laparoscopic hernia repair. The insufflation pressure was set at 10 cm H 2 O, and the IPOM method was selected as the repair method. Case 2 involved a 74-year-old male presented with a right abdominal painful bulging. Strangulation was released and CT scan demonstrated a defect in the abdominal wall at the lateral edge of the right rectus abdominis muscle. We diagnosed as Spigelian hernia and performed laparoscopic hernia repair. The insufflation pressure was set at 10 cmH 2 O, and the repair was performed by the hybrid method. CLINICAL DISCUSSION: In both cases, the positions of the hernia portals marked preoperatively based on the tender areas and confirmed laparoscopically were not accurate. Although Spigelian hernia is a rare disease and various laparoscopic techniques have been reported in recent years, laparoscopic surgery is very useful to obtain an accurate diagnosis and to observe the abdominal wall from inside the abdominal cavity under insufflation, and it is better to decide the repair method according to the situation of each case and institution. CONCLUSION: Laparoscopic surgery is important for accurate diagnosis in surgery of Spiegel's hernia, and insufflation pressure of 10 cmH2O was sufficient.

Intestinal perforation secondary to intestinal Burkitt lymphoma.

INTRODUCTION AND IMPORTANCE: Small intestinal perforation in patients with Burkitt lymphoma is extremely rare. We present the first report of such a case. CASE PRESENTATION: A 53-year-old woman was admitted with abdominal pain and vomiting. Abdominal examination revealed rigidity and tenderness in the upper abdomen. Computed tomography scan showed thickening of the wall of the jejunum, intra-abdominal free gas, and ascites; the patient was diagnosed with small intestinal perforation, and underwent emergency surgery on the same day. Laparoscopic findings were a 50 mm jejunal perforation and perforation in the transverse mesocolon. A partial jejunal resection of the perforated area, partial transverse colectomy, temporary colostomy, and intra-abdominal drainage were performed. Histological examination showed diffuse infiltration of medium-sized atypical lymphocytes in the perforated area, exhibiting a "starry sky" appearance. Immunostaining results showed that the atypical lymphocytes were CD20 and virtually 100% Ki-67 positive, and CD56, CD30, and EBER negative. The lesion was identified as Burkitt lymphoma (BL). The postoperative course was favorable. On postoperative day 18 the patient began chemotherapy through the hematology department. Currently, the patient is in remission. CLINICAL DISCUSSION: The majority of the malignant lymphomas occurring in the digestive tract are identified in the stomach; over 90% are B-cell lymphomas and mucosa-associated lymphoid tissue lymphoma Nakamura et al. BL originating from the small intestine accounts for only about 9%. CONCLUSION: The incidence of BL in the small intestine is low. Pretreatment BL can lead to bowel perforation. Prompt involvement of the hemato-oncologist after definitive diagnosis, and commencing chemotherapy as early as possible after surgery, are thought to improve prognosis.

Optimal value of CA19-9 determined by KRAS-mutated circulating tumor DNA contributes to the prediction of prognosis in pancreatic cancer patients.

Despite the acceptance of carbohydrate antigen 19-9 (CA19-9) as a valuable predictor for the prognosis of pancreatic ductal adenocarcinoma (PDAC), its cutoff value remains controversial. Our previous study showed a significant correlation between CA19-9 levels and the presence of KRAS-mutated ctDNA in the blood of patients with PDAC. Based on this correlation, we investigated the optimal cutoff value of CA19-9 before surgery. Continuous CA19-9 values and KRAS-mutated ctDNAs were monitored in 22 patients with unresectable PDAC who underwent chemotherapy between 2015 and 2017. Receiver operating characteristic curve analysis identified 949.7 U/mL of CA19-9 as the cutoff value corresponding to the presence of KRAS-mutated ctDNA. The median value of CA19-9 was 221.1 U/mL. Subsequently, these values were verified for their prognostic values of recurrence-free survival (RFS) and overall survival (OS) in 60 patients who underwent surgery between 2005 and 2013. Multivariate analysis revealed that 949.7 U/mL of CA19-9 was an independent risk factor for OS and RFS in these patients (P = 0.001 and P = 0.010, respectively), along with lymph node metastasis (P = 0.008 and P = 0.017), unlike the median CA19-9 level (P = 0.150 and P = 0.210). The optimal CA19-9 level contributes to the prediction of prognosis in patients with PDAC before surgery.

Multiple primary malignancies of six organs in a Japanese male patient: A case report.

As a result of recent advances in diagnostic techniques and treatment modalities, the number of patients diagnosed with multiple primary malignancies has been increasing. We report the case of a 79-year-old male with multiple primary malignancies of three histological types in six different organs: Stomach, prostate, colon, urinary bladder, facial skin and pancreas, in chronological order. The first malignancy was upper gastric cancer diagnosed in 1998. The second and third malignancies were prostate cancer and ascending colon cancer, which were diagnosed in 2010. The fourth malignancy was bladder cancer diagnosed in 2011. The fifth and sixth malignancies were squamous cell skin cancer of the right cheek and intraductal papillary mucinous carcinoma (IPMC), respectively, diagnosed in 2014. The gastric cancer, colon cancer, bladder cancer, skin cancer and IPMC were surgically resected. The prostate cancer was treated by anti-androgen therapy. The patient died of local recurrence of IPMC in August 2016. Although multiple primary malignancies are not uncommon, diagnosis of six primary malignancies in a single patient, as reported in the present study, is extremely rare. It is important to understand the characteristics of multiple primary malignancies in order to administer suitable treatment and determine relevant follow-up plans for patients with cancer.

Longitudinal monitoring of KRAS-mutated circulating tumor DNA enables the prediction of prognosis and therapeutic responses in patients with pancreatic cancer.

BACKGROUND: Liquid biopsies enable the detection of circulating tumor DNA (ctDNA). However, the clinical significance of KRAS-mutated ctDNA for pancreatic cancer has been inconsistent with respect to its prognostic and predictive potential. METHODS AND FINDINGS: A total of 422 blood samples were collected from 78 patients undergoing treatments for localized and metastatic pancreatic ductal adenocarcinoma. KRAS mutation in tissues and KRAS ctDNA levels in plasma were determined by RASKET and droplet digital polymerase chain reaction. Longitudinal monitoring of KRAS ctDNA was performed to assess its significance for predicting recurrence and prognosis and for evaluating therapeutic responses to chemotherapy compared with carbohydrate antigen 19-9 (CA19-9). In 67 tumor tissues, discrepancies in point mutations of KRAS were rarely observed among individual patients, implying that one targeted point mutation of KRAS can be determined in tumor tissues prior to longitudinal blood monitoring. One-time blood assessment of KRAS-mutated ctDNA before surgery or chemotherapy was not clearly associated with recurrence and prognosis. Sequential blood monitoring was performed in 39 patients who underwent surgery for potentially resectable tumors. Increased CA19-9 levels were significantly associated with recurrence, but not prognosis (P<0.001, P = 1.0, respectively), whereas emergence of KRAS ctDNA was significantly associated with prognosis (P<0.001) regardless of recurrence. Furthermore, in 39 patients who did not undergo surgery, detection of KRAS ctDNA was a predictive factor for prognosis (P = 0.005). Multivariate analysis revealed that detection of KRAS ctDNA was the only independent prognostic factor regardless of tumor resection (hazard ratios = 54.5 for patients who underwent surgery and 10.1 for patients who did not undergo surgery; P<0.001 for both). Patients without emergence of KRAS ctDNA within 1 year after surgery showed significantly better prognosis irrespective of recurrence (P<0.001). No detection or disappearance of KRAS ctDNA within 6 months of treatment was significantly correlated with therapeutic responses to first-line chemotherapy (P<0.001). Changes in KRAS status provided critical information for the prediction of therapeutic responses. CONCLUSIONS: Our study showed for the first time that detection of KRAS ctDNA levels within a short period enables the prediction of prognosis and therapeutic responses in patients with pancreatic cancer.

Overexpression of satellite alpha transcripts leads to chromosomal instability via segregation errors at specific chromosomes.

The impairment of the stability of the chromosomal structure facilitates the abnormal segregation of chromosomes, thus increasing the risk of carcinogenesis. Chromosomal stability during segregation is managed by appropriate methylation at the centromere of chromosomes. Insufficient methylation, or hypomethylation, results in chromosomal instability. The centromere consists of satellite alpha repetitive sequences, which are ideal targets for DNA hypomethylation, resulting in the overexpression of satellite alpha transcript (SAT). The overexpression of SAT has been reported to induce the abnormal segregation of chromosomes. In this study, we verified the oncogenic pathway via chromosomal instability involving DNA hypomethylation and the overexpression of SAT. For this purpose, we constructed lentiviral vectors expressing SAT and control viruses and then infected human mammary epithelial cells with these vectors. The copy number alterations and segregation errors of chromosomes were evaluated by microarray-based comparative genomic hybridization (array CGH) and immunocytochemistry, respectively. The levels of hypomethylation of satellite alpha sequences were determined by MethyLight polymerase chain reaction. Clinical specimens from 45 patients with breast cancer were recruited to verify the data in vitro. The results of immunocytochemistry revealed that the incidence of segregation errors was significantly higher in the cells overexpressing SAT than in the controls. An array CGH identified the specific chromosomes of 8q and 20q as frequent sites of copy number alterations in cells with SAT overexpression, although no such sites were noted in the controls, which was consistent with the data from clinical specimens. A regression analysis revealed that the expression of SAT was significantly associated with the levels of hypomethylation of satellite alpha sequences. On the whole, the overexpression of SAT led to chromosomal instability via segregation errors at specific chromosomes in connection with DNA hypomethylation, which was also recognized in clinical specimens of patients with breast cancer. Thus, this oncogenic pathway may be involved in the development of breast cancer.

Monitoring circulating tumor DNA revealed dynamic changes in KRAS status in patients with metastatic colorectal cancer.

KRAS mutated circulating tumor DNA (MctDNA) can be monitored in the blood of patients with metastatic colorectal cancer (mCRC), but dynamic changes have not been determined. Four hundred and fifty-seven plasma samples were collected prospectively from 85 mCRC patients who underwent chemotherapy. MctDNA in plasma was detected by droplet digital PCR, and the percentage of MctDNA in total circulating cell-free DNA was calculated. KRAS assessment in tumor tissues showed 29 patients with the mutant-type (MT) and 56 patients with the wild-type (WT). Twenty-three of 29 MT patients (79.3%) and 28 of 56 WT patients (50.0%) showed MctDNA. Emergence of MctDNA was recognized during treatments with various drugs. Regardless of KRAS status in tumor tissues, patients with MctDNA in blood showed poor progression-free survival with first-line treatment. Median percentage of MctDNA accounted for 10.10% in MT patients and 0.22% in WT patients. These differences between MT and WT likely affected patterns of changes in MctDNA. KRAS monitoring identified dynamic changes in MctDNA, such as continuous, intermittent, and transient changes (quick elevation and disappearance). Emergence of MctDNA involved drug resistance, except for transient changes, which were seen in WT patients and likely corresponded with the drug response. Transient changes could be involved in recovery of sensitivity to anti-EGFR antibody in WT patients. Monitoring MctDNA during various treatments showed dynamic changes in KRAS status and could provide useful information for determining treatments for patients with mCRC.

Clinical and molecular assessment of regorafenib monotherapy.

Regorafenib has shown survival benefits in metastatic colorectal cancer patients who were exacerbated after all standard therapies. Some patients, however, exhibit severe adverse events (AEs) resulting in treatment discontinuation. Therefore, the selection of patients likely to benefit from regorafenib is crucial. Twenty patients were treated with regorafenib for metastatic colorectal cancer; 122 plasma samples were taken from 16 of these patients for monitoring of circulating tumor DNA (ctDNA) in the blood. The treatment response, AEs, overall survival (OS), progression-free survival (PFS) and tumor morphologic changes on CT images were evaluated. KRAS mutant ctDNA was determined using digital PCR. Median PFS and OS were 2.5 and 5.9 months, respectively. Treatment was discontinued because of disease progression (PD) in 10 patients, and AEs in another 10 patients. AEs included hyperbilirubinemia, severe fatigue and skin rash. Hyperbilirubinemia was seen in two patients with multiple bilateral liver metastases, and severe fatigue in another 2 patients with poor performance status (PS). These severe AEs resulted in treatment discontinuation. Ten patients had a median PFS of 2.1 months with AE related discontinuation; PD occurred at 3.5 months (p=0.00334). Four patients exhibited a morphologic response, achieving better PFS times of 3.5, 5.3, 5.6 and 14.2 months. Emergence of the KRAS mutation in ctDNA was observed during anti-EGFR antibody treatment in 3 patients among 11 with KRAS wild-type tumors; it was detectable in the blood prior to radiographic detection of PD. Moreover, the KRAS mutation declined in two patients during regorafenib monotherapy. These patients were re-challenged with anti-EGFR antibody. Patients with extensive multiple liver metastases or poor PS are unlikely to benefit from regorafenib. Patients with a morphologic response will probably benefit from regorafenib with adequate management of other AEs. KRAS monitoring in ctDNA could be useful regarding treatment response and in determining treatment strategy.

Sequential administration of XELOX and XELIRI is effective, feasible and well tolerated by patients with metastatic colorectal cancer.

Sequential administration of the chemotherapy regimes capecitabine and oxaliplatin (XELOX) and capecitabine and irinotecan (XELIRI) in the first- to second-line treatment setting would allow patients to be managed more easily in an outpatient unit. However, a small number of studies have raised concerns of cumulative adverse events as a consequence of the continuous use of capecitabine. To investigate this, the present study conducted a retrospective review of 81 consecutive metastatic colorectal cancer (mCRC) patients treated with the oxaliplatin, fluorouracil and leucovorin-irinotecan, fluorouracil and leucovorin (FOLFOX-FOFIRI/F-F) regimen (n=40) or the XELOX-XELIRI (X-X) regimen (n=41) in first- to second-line chemotherapy in Saitama Medical Center between 2006 and 2012. The disease control rate (DCR), the progression free survival (PFS), the overall survival (OS) and the time to failure of strategy (TFS) from first to second-line chemotherapy, as well as adverse events, were assessed and compared between patients receiving X-X or F-F. A total of 10 and 20 patients were additionally treated with bevacizumab in the F-F and X-X regimens, respectively, during first or second-line chemotherapy. There was no significant difference in DCR and the median PFS between the two regimens for first or second-line chemotherapy. There was no significant difference in the median OS and TFS between the two regimens (OS=24.5 and TFS=14 months in the F-F vs. 23.2 and 12.0 months in the X-X). Regarding adverse events, 45.0% of patients (18/40) exhibited grade 3-4 neutropenia throughout treatment with F-F. Whilst, 15.0% of patients (6/41) exhibited grade 3 hypertension throughout treatment with X-X, which was effectively controlled by a single antihypertensive drug. The results show that sequential administration of X-X is as effective and feasible as F-F treatment, while additionally reducing the frequency of infusion visits and eliminating the need for a central venous access device or home infusion pump, thereby offering a more convenient treatment option to patients with mCRC.

Morphological response contributes to patient selection for rescue liver resection in chemotherapy patients with initially un-resectable colorectal liver metastasis.

Morphological response is considered an improved surrogate to the Response Evaluation Criteria in Solid Tumors (RECIST) model with regard to predicting the prognosis for patients with colorectal liver metastases. However, its use as a decision-making tool for surgical intervention has not been examined. The present study assessed the morphological response in 50 patients who underwent chemotherapy with or without bevacizumab for initially un-resectable colorectal liver metastases. Changes in tumor morphology between heterogeneous with uncertain borders and homogeneous with clear borders were defined as an optimal response (OR). Patients were also assessed as having an incomplete response (IR), and an absence of marked changes was assessed as no response (NR). No significant difference was observed in progression-free survival (PFS) between complete response/partial response (CR/PR) and stable disease/progressive disease (SD/PD), according to RECIST. By contrast, PFS for OR/IR patients was significantly improved compared with that for NR patients (13.2 vs. 8.7 months; P=0.0426). Exclusion of PD enhanced the difference in PFS between OR/IR and NR patients (15.1 vs. 9.3 months; P<0.0001), whereas no difference was observed between CR/PR and SD. The rate of OR and IR in patients treated with bevacizumab was 47.4% (9/19), but only 19.4% (6/31) for patients that were not administered bevacizumab. Comparison of the survival curves between OR/IR and NR patients revealed similar survival rates at 6 months after chemotherapy, but the groups exhibited different survival rates subsequent to this period of time. Patients showing OR/IR within 6 months appeared to be oncologically stable and could be considered as candidates for surgical intervention, including rescue liver resection. Comparing the pathological and morphological features of the tumor with representative optimal response, living tumor cells were revealed to be distributed within the area of vascular reconstruction induced by bevacizumab, resulting in a predictive value for prognosis in the patients treated with bevacizumab. The present findings provided the evidence for physicians to consider patients with previously un-resectable metastatic colorectal cancer as candidates for surgical treatment. Morphological response is a useful decision-making tool for evaluating these patients for rescue liver resection following chemotherapy.

Heterogeneous expression of zinc-finger E-box-binding homeobox 1 plays a pivotal role in metastasis via regulation of miR-200c in epithelial-mesenchymal transition.

Although epithelial-mesenchymal transition (EMT) has been implicated as the pivotal event in metastasis, there is insufficient evidence related to EMT in clinical settings. Intratumor heterogeneity may lead to underestimation of gene expression representing EMT. In the present study, we investigated the expression of EMT-associated genes and microRNAs in primary colorectal cancer while considering intratumor heterogeneity. One-hundred and thirty-three multiple spatially separated samples were obtained from 8 patients with metastatic colorectal cancers and 8 with non-metastatic colorectal cancers, from the tumor center (TC), invasive front (IF) and metastasis. Differences in gene and microRNA expression were investigated by microarray and quantitative reverse-transcription PCR. Gene expression microarray analysis detected 7920 sites showing differing levels of gene expression among the TC, IF and metastasis. Expression of the EMT-associated gene zinc-finger E-box-binding homeobox 1 (ZEB1) significantly increased in the IF (p<0.01). To exclude individual differences, the expression ratio between TC and IF in each tumor was applied to analysis. This approach enabled recognition of the activation of the VEGF and Wnt signaling pathways, which were involved in metastasis via promotion of EMT. While no activation of these pathways was seen at the TC, regardless of whether tumors were metastatic or non-metastatic, they were preferentially activated at the IF in metastatic tumors, where high ZEB1 expression was seen in connection with decreased miR-200c expression. Multiple sampling in a tumor revealed that heterogeneous ZEB1 expression induced by EMT-associated signaling pathways played a pivotal role in metastasis via regulation of miR-200c.