A case of pancreatic adenosquamous cell carcinoma with a pseudocyst following curative surgery

BACKGROUND

Pancreatic adenosquamous cell carcinoma (PASC) is a relatively rare histological type of pancreatic malignancy, and preoperative diagnosis is difficult because of its rarity. PASC accounts for 1-4% of all pancreatic cancers, and even after curative surgery, its prognosis is poorer than that of ordinary pancreatic adenocarcinoma. Pathologically, it shows glandular and squamous differentiation of cells. Complete resection is the only method to achieve a good long-term prognosis, and an increasing doubling time of PASC is considered to indicate early recurrence after surgery. Here, we report a rare case of PASC with an infected pancreatic cyst that was difficult to treat, along with a review of the literature.

CASE PRESENTATION

A woman in her 80s with a history of breast cancer presented with pericardial pain. Computed tomography revealed a 20-mm hypovascular tumor in the body of the pancreas and a 27-mm pseudocyst. Endoscopic retrograde cholangiopancreatography showed a severe main pancreatic duct stenosis in the body of the pancreas that made cannulation impossible, and contrast media extravasation was due to pancreatic duct disruption in the pancreatic tail. Endoscopic fine-needle aspiration revealed that the tumor was a PASC. Because the patient had an infected pancreatic cyst, central intravenous nutrition and antibiotics were administered, which stabilized her general condition. She was diagnosed with resectable PASC and underwent distal pancreatectomy with lymphadenectomy. The postoperative course was uneventful. Immunohistochemical analysis of the resected specimen confirmed T2N0M0 stage IB. Systemic adjuvant chemotherapy with S-1 is ongoing.

CONCLUSION

Appropriate preoperative management and preoperative accurate staging (T2N0M0 stage IB) of PASC with curative surgery can ensure predictable outcomes.

Weekday Surgery Associated With Short-Term Outcomes in Patients With Colorectal Cancers

INTRODUCTION

The "weekday effect" on elective surgery remains controversial. We aimed to examine the association between the day of surgery and short-term outcomes after elective surgery for stage I-III colorectal cancer (CRC).

METHODS

We performed a multicenter retrospective analysis of 2574 patients who underwent primary colorectal resection for CRC between January 2017 and December 2019 at 15 institutions belonging to the Hiroshima Surgical Study Group of Clinical Oncology. Patients were divided into two groups according to the day of surgery: Friday and non-Friday (Monday to Thursday). After propensity score matching (PSM), we compared 30-day mortality and postoperative outcomes.

RESULTS

Out of the total, 368 patients underwent surgery on Fridays, and the remaining 2206 underwent surgery on non-Fridays. The overall mortality rate was 0.04% (n = 1). In 1685 patients with colon cancer, the proportion of American Society of Anesthesiologists scores was significantly lower in the Friday group than in the non-Friday group before PSM. After PSM of patient, tumor, and operative characteristics, operative time was slightly more prolonged and blood loss was slightly greater in the Friday group; however, these differences were not clinically meaningful. In the 889 patients with rectal cancer, the proportion of patients with abnormal respiratory patterns was significantly lower in the Friday group than in the non-Friday group before PSM. After PSM, the Friday group had a higher incidence of morbidity (≥ Clavien-Dindo 3a), higher incidence of digestive complications, and prolonged postoperative hospital stay.

CONCLUSIONS

The results may be useful in determining the day of the week for CRC surgery, which requires more advanced techniques and higher skills.

Survival outcomes of patients with stage III colorectal cancer aged ≥ 80 years who underwent curative resection: the HiSCO-04 prospective cohort study

BACKGROUND

The efficacy of adjuvant chemotherapy in elderly patients aged ≥ 80 years with stage III colorectal cancer remains unclear. In parallel with a multicenter prospective phase II trial evaluating the efficacy of uracil-tegafur and leucovorin as adjuvant chemotherapy (HiSCO-03), we conducted a prospective observational study of these patients to assess survival outcomes, including those ineligible for chemotherapy.

METHODS

This multi-institutional prospective cohort study included 17 institutions in Hiroshima, Japan. Patients aged ≥ 80 years with stage III colorectal cancer who underwent curative resection were enrolled. The primary endpoint was 3-year disease-free survival, and the secondary endpoints were 3-year overall and relapse-free survival. Propensity score matching was used to assess the effects of adjuvant chemotherapy on survival outcomes.

RESULTS

A total of 214 patients were analyzed between 2013 and 2018, including 99 males and 115 females with a median age of 84 years (range 80-101 years). Recurrence occurred in 58 patients and secondary cancers were observed in 17. The 3-year disease-free, overall, and relapse-free survival rates were 63.3%, 76.9%, and 62.9%, respectively. Adjuvant chemotherapy was administered to 65 patients with a completion rate of 52%. In a study of 80 patients that adjusted for background factors using propensity score matching, patients who completed the planned treatment showed improved disease-free survival (3-year disease-free survival: completed, 80.0%; not received, 65.5%; and discontinued, 56.3%; p = 0.029).

CONCLUSIONS

Completion of adjuvant chemotherapy may improve the prognosis of patients with colorectal cancer aged ≥ 80 years, although the number of patients who would benefit from it is limited.

Association between social background and implementation of postoperative adjuvant chemotherapy for older patients undergoing curative resection of colorectal cancers, sub-analysis of the HiSCO-04 study

PURPOSE

Adjuvant chemotherapy is recommended following colorectal cancer resection based on risk of recurrence. In older patients, treatment decisions should consider recurrence rates and tolerability, as well as functional prognosis, residual disease, and social factors. This study aims to investigate factors, including social background, influencing implementation of postoperative adjuvant chemotherapy in older patients undergoing curative resection for colorectal cancer.

METHODS

This multi-institutional prospective cohort study included 15 institutions belonging to the Hiroshima Surgical study group for Clinical Oncology. We analyzed 159 older patients aged ≥ 80 years, who underwent curative resection for stage III colorectal cancer between December 2013 and June 2018, as sub-analysis of the HiSCO-04 study.

RESULTS

In total, 62 (39.0%) patients underwent postoperative adjuvant chemotherapy. Four factors were significantly associated with its implementation: performance status < 2, Charlson Comorbidity Index < 2, prognostic nutritional index ≥ 40, and presence of a spouse or siblings as lifestyle supporters. No significant difference was found in the backgrounds between complete and incomplete postoperative adjuvant chemotherapy patients.

CONCLUSION

Performance status, Charlson Comorbidity Index, nutritional status, and presence of a spouse or siblings as lifestyle supporters are possible factors influencing the implementation of postoperative adjuvant chemotherapy in older patients. To select appropriate treatment options, including postoperative adjuvant chemotherapy, it is essential to consider physical condition and comorbidities of older patients, thoroughly explain the situation to their families, and establish a support system to enhance understanding of the available treatment options.

Clinical Phase I Study of TAS102/Irinotecan/Bevacizumab Combination Therapy in Japanese Patients With Unresectable Metastatic Colorectal Cancer (mCRC)

BACKGROUND

In this phase I study, we aimed to examine the safety of a triple combination (TAS-102/irinotecan/bevacizumab) therapy in patients with previously treated metastatic colorectal cancer (mCRC).

METHODS

In the TAS-102 dose-escalation phase, we determined dose-limiting toxicity (DLT), estimated the maximum tolerated dose (MTD), and determined the recommended dose (RD); in the expansion phase, we evaluated safety. The RD was administered in advance for 10 patients. The TAS-102 dose was increased to 25-35 mg/m2 and administered orally twice on days 1-5 and 8-12. Irinotecan (100 mg/m2) and bevacizumab (5 mg/m2) were administered on days 1 and 15 of the treatment, respectively.

RESULTS

Fifteen patients were enrolled in dose-escalation Levels 1-3, and ten in the expansion phase. A 30 mg/m2 TAS-102 dose at Level 2 was administered to three patients, with one presenting grade 4 neutropenia. A 35 mg/m2 TAS-102 dose at Level 3 was administered to five patients, with three patients presenting grade 4 neutropenia and grade 3 DLTs. We added three patients at Level 2 and set the MTD at 30 mg/m2, with no DLTs. The RD was fixed at 25 mg/m2, with no DLTs (N = 10) or treatment-related deaths. One patient showed complete response at Level 2, four presented partial response, and eleven individuals maintained stable disease for over four months. The median progression-free survival duration was 7.6 months, while the median overall survival period was 16.9 months.

CONCLUSION

The TAS-102/irinotecan/bevacizumab combination therapy was safe, effective, and well-tolerated in patients previously treated with mCRC.

Intracystic papillary neoplasm diagnosis following an extended cholecystectomy: a case report … and literature review

We report a case of intracystic papillary neoplasms (ICPN) that was difficult to differentiate from adenocarcinoma of the gallbladder. A 64-year-old man visited our hospital for an examination of gallbladder tumors. At the preoperative examination, the tumor was revealed a papillary type of tumor in the body of the gallbladder without the findings that without the findings that suggested the tumor invasion into the deep subserosal layer. The patient underwent an extended cholecystectomy. Papillary lesions were observed mainly in the body of the gallbladder, with flattened elevated lesions at the gallbladder fundus. Within each of these tumors, cells corresponding to intraepithelial adenocarcinoma were irregularly interspersed, leading to a diagnosis of ICPN. The patient is currently undergoing follow-up with no recurrence postoperatively. The prognosis of ICPN is generally good; however, preoperative diagnosis remains challenging. Therefore, a treatment plan for gallbladder cancer should be applied.

Small bowel cancer arising from a scar site more than 60 years after ileostomy closure: a case report

Although small bowel cancer is rare, cases of carcinoma arising from the abdominal wall have not been reported. We report a case of a tumor arising from a stoma scar site, following ileostomy closure that was performed 60 years earlier. The tumor was resected for both therapeutic and diagnostic purposes and was found to be a primary cancer of the small intestine. The small intestinal mucosa survived long-term at the stoma scar site and developed carcinoma. No similar reports of small bowel cancer arising from the mucosa at the stoma scar site (on the abdominal wall) exist. After tumor resection, the patient received chemotherapy for lung metastases and has survived, thus far, for 2 years since the surgery.

Surgical treatment of hepatic xanthogranuloma arising from a giant hepatic cyst causing gastrointestinal obstruction: a case report

Hepatic cysts are benign liver lesions and are often asymptomatic. Large hepatic cysts may cause jaundice and portal hypertension; however, they rarely cause gastrointestinal obstruction. Symptomatic cysts require treatment, and when malignancy is suspected, cyst puncture for pathological examination of the fluid may pose a risk of dissemination. Herein, we describe a case of xanthogranuloma arising from a large hepatic cyst that was causing duodenal obstruction. Thus, cyst puncture was performed for emergency decompression. Cytological examination of the puncture fluid revealed no malignant findings. Hence, laparoscopic deroofing was performed to treat the hepatic cyst. As the cyst and duodenal wall were firmly adherent, the cyst wall was left behind without dissection from the duodenum. A two-stage approach of cyst puncture followed by surgery may be an option for patients requiring urgent treatment for potentially malignant hepatic cysts.

The characteristics of residual pneumoperitoneum after laparoscopic colorectal surgery

INTRODUCTION

Despite the popularity of laparoscopic surgery, it remains unclear whether residual pneumoperitoneum influences the patient's postoperative course. This study aimed to evaluate the characteristics of residual pneumoperitoneum.

METHODS

This retrospective study included 201 Japanese patients who had undergone elective laparoscopic colorectal surgery. The patients were divided into groups, with and without anastomotic failure; the non-anastomotic failure group was further divided into subgroups, with and without residual pneumoperitoneum. Patient characteristics were compared between the various groups.

RESULTS

The group with residual pneumoperitoneum included 57 patients (30.3%). Percutaneous drainage was required for one patient with residual pneumoperitoneum. Univariate analyses revealed that residual pneumoperitoneum was associated with low values for body mass index (BMI) and subcutaneous fat area (SFA). Furthermore, relative to the group with anastomotic failure, the group without anastomotic failure but with residual pneumoperitoneum had lower values for inflammatory markers.

CONCLUSION

Low BMI and SFA values were identified as risk factors for residual pneumoperitoneum. Inflammatory markers may be useful as indicators for avoiding emergent surgery when it is difficult to differentiate between asymptomatic residual pneumoperitoneum and free air related to anastomotic failure.

A case of effective Delorme's procedure for colonic mucosal prolapse after intersphincteric resection

Recent surgical technical improvements, such as endoscopic surgery with intersphincteric resection (ISR), could help avoid a permanent colostomy for patients with low-lying rectal tumors. However, the problems associated with anal dysfunction following ISR remain unresolved. We performed ISR and temporary ileostomy in a patient with low-lying rectal cancer. After evaluating the stability of the anastomosis, we planned to close the ileostomy, but the patient developed post-operative colonic mucosal prolapse (CMP). Although there are treatment methods available for CMP, there is no consensus on the treatment for post-operative CMP. In this case, we performed Delorme’s procedure because the method has been reported to have advantages in terms of improving post-operative anal function. Post-operative anorectal manometry showed improvement in maximum squeeze pressure, and the patient’s anal function improved; subsequently, ileostomy closure was performed. Delorme’s procedure may be useful for patients with CMP after ISR to achieve good post-operative anal function.

Tumor budding as a predictive marker for 5-fluorouracil response in adjuvant-treated stage III colorectal cancer

BACKGROUND

Tumor budding (TB) has been described as an adverse prognostic marker for operable colorectal cancer (CRC); however, a limited number of studies have demonstrated the prognostic significance of TB in patients with drug therapy. This study was conducted to determine the predictive power of TB in stage III CRC patients who received adjuvant chemotherapy.

METHODS

We retrospectively collected clinicopathological data including TB of 237 stage III colorectal cancer patients at Hiroshima University Hospital between July 1, 2006 and June 31, 2019. Differential disease-free survival (DFS) was investigated according to TB status.

RESULTS

This study included 237 patients with a median age of 67 years, comprising patients who underwent surgery alone (n = 65), 5-fluorouracil (5-FU) monotherapy (n = 129), and oxaliplatin-based chemotherapy (n = 43). Overall, 81 patients developed disease recurrence, and 33 patients died of cancer-related causes. The TB status was categorized into two groups: 99 with low budding (< 5 buds) and 138 with high budding (≥ 5 buds). Overall, the low budding cases demonstrated significantly better DFS. In the 5-FU monotherapy group, low-risk patients (T1, T2, or T3 and N1) with low budding showed a remarkably higher 3-year DFS (91%) compared to high budding (55%).

CONCLUSION

Our results indicate that TB could play a subsidiary role in selecting patients who could maintain a favorable prognosis with 5-FU monotherapy in stage III CRC.

Efficacy and tolerability of preoperative chemoradiotherapy with S-1 alone for locally advanced rectal cancer

Preoperative chemoradiotherapy with capecitabine or 5-fluorouracil is a standard treatment for locally advanced rectal cancer (LARC). S-1, a prodrug of 5-fluorouracil, is a candidate for this chemoradiotherapy regimen in Japan; however, treatment outcomes after S-1 treatment alone are not clear. This study aimed to assess the efficacy and tolerability of preoperative chemoradiotherapy with S-1 alone for LARC. We retrospectively evaluated 54 LARC patients who underwent preoperative chemoradiotherapy with S-1 alone in our institution between 2005 and 2017. The clinical tumor stage was cT2-3 in 31 patients and cT4 in 23 patients, and lymph node metastases were clinically evident in 31 patients. S-1, at a dose of 80 mg/m2/day, was orally administered during radiotherapy. A total dose of 45-50.4 Gy was delivered in 25-28 fractions (median: 50.4 Gy). Surgical resections were scheduled 6-10 weeks after chemoradiotherapy completion. The 3- and 5-year overall survival rates were 92.4 and 72.8%, respectively, with a median follow-up time of 51 months. The 3- and 5-year local control rates were 96.2 and 85.9%, respectively. A pathological complete response was observed in 7 patients (13.0%) at the time of surgery. Ten patients (18.5%) had grade 3 acute toxicities and 5 patients (9.3%) had grade 3 late toxicities. No grade 4 or 5 toxicities were observed. Preoperative chemoradiotherapy with S-1 alone followed by total mesorectal excision resulted in a low incidence of toxicities and comparable clinical results. Therefore, S-1 alone can be a treatment option for preoperative chemoradiotherapy in LARC patients.

The prognostic value of organ/space surgical site infection in stage I colorectal cancer recurrence

PURPOSE

Evidence on risk factors for postoperative recurrence in patients with colorectal cancer (CRC) confined to pathological stage I is limited. Therefore, this study aimed to identify the risk factors for recurrence in patients with stage I CRC.

METHODS

Data on clinicopathological factors and blood tests of patients diagnosed with pathological stage I CRC at Hiroshima University Hospital between April 1, 2010, and December 31, 2018, were retrospectively obtained. The statistical significance between the clinical factors and postoperative recurrence was also investigated.

RESULTS

A total of 244 patients were included. The median observation period was 45 months. There were 17 patients (6.6%) with a postoperative recurrence (8 local and 9 distant recurrences). In the log-lank test, rectal cancer (p = 0.004), pT2 (p = 0.020) and organ/space surgical site infection (SSI) (p = 0.008) were significantly associated with postoperative recurrence. In a multivariate analysis, rectal cancer (hazard ratio [HR] 3.678, 95% confidence interval [CI] 1.184-11.425, p = 0.024) and organ/space SSI (HR 3.137, 95% CI 1.013-9.713, p = 0.047) were independently associated with a higher recurrence rate. Among 18 patients with organ/space SSI, 4 recurrences occurred, all of which were distant metastases.

CONCLUSION

Organ/space SSI significantly affects the postoperative recurrence in patients with stage I CRC.

Oncogenic mutation in RAS-RAF axis leads to increased expression of GREB1, resulting in tumor proliferation in colorectal cancer

BRAF^V600E mutation accounts for up to 90% of all BRAF mutations in human colorectal cancer (CRC), and constitutively activates the MEK‐MAPK pathway. It is recognized that neutralizing mAbs for epidermal growth factor receptor alone are not effective for CRC with BRAF^V600E mutation. Therefore, there is increasing interest in identification of the possible therapeutic targets in downstream of BRAF mutation in CRCs. To address this, we studied genome engineered mouse models for colonic neoplasia that has Braf^V600E mutation on the basis of Apc inactivation, induced in 2 distinct Cre mouse models, CDX2P‐G22Cre and CDX2P‐CreER^T2 mice. We carried out oligonucleotide microarray analysis for colonic neoplasia generated in these mouse models, and compared gene expression profiles among Kras/Braf WT, Kras‐mutated, and Braf‐mutated mouse colon tumors to seek new molecular targets corresponding to the KRAS‐BRAF‐MAPK axis. We found that the expression of the growth regulation by estrogen in breast cancer protein 1 (Greb1) was the most upregulated gene in Braf‐mutated mouse tumors compared to Kras/Braf WT counterparts. The silencing of GREB1 significantly reduced the proliferation and tumorigenesis of CRC cell lines, whereas the overexpression of GREB1 promoted cell proliferation. Although GREB1 was first identified as a hormone‐responsive gene mediating estrogen‐stimulated cell proliferation in endometriosis, breast, and ovarian cancers, these results suggest that RAS‐RAF‐MAPK signaling upregulates GREB1 expression in CRC, resulting in cellular proliferation. Thus, GREB1 is a possible therapeutic target for CRCs with Braf^V600E mutation.

A Case of Isolated Adrenocorticotropic Hormone Deficiency Caused by Pembrolizumab

Pembrolizumab (Keytruda®) is an anti-programmed cell death 1-specific monoclonal antibody that has become the standard second-line chemotherapy for unresectable advanced microsatellite instability-high colorectal cancer. Several immune-related adverse events (irAEs), particularly endocrinopathy, are linked to the administration of pembrolizumab. We report here a case of pembrolizumab-induced isolated adrenocorticotropic hormone deficiency in a patient with metastatic colon cancer. A 65-year-old woman visited our hospital for complaints of fatigue with a recent history of primary resection of cecal mucinous cancer and hepatectomy for liver metastasis 3 years ago. Peritoneal dissemination was detected 2 years after surgery. Several chemotherapeutic regimens of cytotoxic and molecular targeted drugs were administered; however, the metastases progressed gradually. Pembrolizumab monotherapy was started because of resistance to treatment. After 2 cycles of pembrolizumab, the patient was severely fatigued. Laboratory data demonstrated that the cortisol level was extremely low. All the other values were within the normal range. Magnetic resonance imaging indicated no mass in the pituitary gland. From multiple tolerance tests, we diagnosed isolated adrenocorticotropic hormone deficiency caused by pembrolizumab. The patient's symptoms improved promptly with cortisol treatment. An abdominal contrast-enhanced computed tomography scan after 5 cycles of pembrolizumab demonstrated that the size of the peritoneal dissemination remained unchanged. However, her serum level of carcinoembryonic antigen had decreased to normal levels. Endocrine disorders are very rarely seen as irAEs. Careful laboratory data follow-up is required to inhibit the progression of severe endocrine disorders.

Case report of hepatic pseudocyst: A rare manifestation of liver metastasis from an anal squamous cell carcinoma

•

Liver metastasis of anal squamous cell carcinoma with a presented pseudocyst is very rare.

•

Some hepatic diseases such as infections, simple biliary cysts, and neoplasms demonstrate a cystic change of the liver.

•

Metastasis should be suspected when CT findings in patients with a history of gastrointestinal cancer show cystic changes involving the liver.

Introduction

Liver metastasis of an anal squamous cell carcinoma (SCC) with a pseudocyst is uncommon. There are many diseases which form hepatic cystic lesions and sometimes it is difficult to arrive at an accurate diagnosis.

Presentation of case

A 69-year-old woman visited our hospital with complaints of bloody stool and difficult defecation. A palpable mass in the anal canal was found on digital examination. The laboratory tests revealed anemia and raised levels of SCC antigen. On endoscopy a type 2 tumor was identified in the anal canal and biopsy revealed SCC. The patient was diagnosed with advanced anal SCC (cT2N1aM0, cStage IIIA) as a result of the examination and underwent chemoradiotherapy (CRT); unfortunately the tumor persisted after CRT. A salvage abdominoperineal resection with D2 and left lateral lymph node dissection was conducted. Histopathologically, the tumor was diagnosed as poorly differentiated SCC. She was readmitted for fever 3 weeks after surgery, and the abdominal CT showed multiple low density areas with enhancement at the edge of the liver, suggesting abscess or metastasis. The metastatic SCC was revealed by cytology of liver drainage and liver biopsy.

Discussion

Anal cancers are sometimes encountered however; a pseudo cystic presentation of a liver metastasis is very rare which makes it difficult to distinguish from other diseases.

Conclusion

We present a case of SCC in the anal canal with liver metastasis presenting as a hepatic pseudocyst.

Perioperative management of a bleeding jejunal tumor in a patient with erythropoietic protoporphyria: A case report and literature review

Introduction

Erythropoietic protoporphyria (EPP) is a rare disorder caused by reduced ferrochelatase activity and shows incomplete autosomal dominant inheritance. Meticulous perioperative management can avoid characteristic complications. This report describes a case of a bleeding jejunal tumor in a patient with EPP.

Presentation of case

A 49-year-old man with a history of EPP was admitted to our department with abdominal distention and severe anemia. Contrast-enhanced computed tomography revealed an abdominal tumor measuring 5 cm, originating from the small bowel wall or mesentery. Tumor resection was planned after correction of anemia. Red blood cell transfusion restored his hemoglobin to acceptable levels; however, his liver function worsened. Institution of liver support therapy achieved gradual reduction in his elevated liver enzymes; however, hyperbilirubinemia persisted. He underwent tumor resection on the 12^th day of hospitalization. Yellow filters were used to avoid operating room light-induced tissue injury. The tumor was located in the jejunum 30 cm from the Treitz ligament toward the anal aspect. The histopathological diagnosis was desmoid-type fibromatosis of the jejunum. Postoperatively, his hemoglobin levels were stabilized; however, his serum bilirubin level remained high. His serum bilirubin level gradually decreased following hemin injections (150 mg/day).

Discussion

Reducing heme synthesis and minimizing protoporphyrin generation are important perioperatively. Additionally, preventing operating room light-induced tissue burns and selecting appropriate anesthestic agents are important during surgery.

Conclusion

The institution of appropriate treatment and adequate intra- and perioperative measures can ensure safe surgery in patients with EPP even under emergency conditions.

Synbiotics suppress colitis-induced tumorigenesis in a colon-specific cancer mouse model

Although synbiotics may be effective in maintaining remission of inflammatory bowel disease, their anticarcinogenic effects are still debated. To address this issue, we evaluated the effects of synbiotics, probiotics, and prebiotics on tumorigenesis using a CDX2P-Cre; Apc^+/flox mouse model harboring a colon-specific Apc knock out, which develops adenoma and adenocarcinoma of the colon. Dextran sodium sulfate (DSS)-administration promoted colonic tumor development in CDX2P-Cre; Apc^+/flox mice, and these tumors were associated with loss of Apc heterozygosity, as confirmed by observation of well-differentiated adenocarcinomas with β-catenin accumulation in tumor cell cytoplasm. Synbiotics-treatment suppressed dextran sodium sulfate-induced colitis in CDX2P-Cre; Apc^+/flox mice, thereby reducing mortality, and inhibited tumorigenesis accelerated by DSS-administration. Conversely, neither probiotics nor prebiotics had any effect on inflammation and tumorigenesis. Lactobacillus casei and Bifidobacterium breve were detected in the fecal microbiota of probiotics-treated mice. Synbiotics-treatment suppressed DSS-induced expression of IL-6, STAT-3, COX-2, and TNF-α gene transcripts in normal colonic epithelium, indicating the possibility of suppressing tumor development. Importantly, these genes may be potential therapeutic targets in inflammation-associated colon cancer.

Is laparoscopic colorectal surgery with continuation of antiplatelet therapy safe without increasing bleeding complications?

PURPOSE

The number of patients on antiplatelet therapy (APT) who need surgery is increasing; however, it is unclear whether APT should be continued for abdominal surgery, particularly laparoscopic colorectal surgery. We investigated the safety of continuing APT for patients undergoing laparoscopic colorectal surgery.

METHODS

We collected retrospective data from 529 patients who underwent laparoscopic colorectal surgery at Hiroshima University between January, 2013 and December, 2018. We analyzed information related to APT. Thirty-six pairs were matched by the propensity score method between patients on APT (APT+) and those not on APT (APT-). We compared the surgical outcomes of both groups.

RESULTS

Among 463 patients eligible for the study, 48 were on APT for cerebrovascular or cardiovascular disease, and 36 continued to take aspirin. In the case-matched comparison, the amount of intraoperative blood loss in the APT+ group was not significantly higher than that in the APT- group, and the incidences of bleeding complications, thromboembolic complications, and other complications were not significantly different between the groups.

CONCLUSION

In a case-matched comparison, continuation of aspirin during laparoscopic colorectal surgery did not increase perioperative complications. In laparoscopic colorectal surgery, continuation of aspirin is an acceptable strategy for patients with thromboembolic risk caused by interruption of APT.

Successful Resection of Solitary Abdominal Wall Metastasis of Sarcomatous Intrahepatic Cholangiocarcinoma

Sarcomatous intrahepatic cholangiocarcinoma (ICC) is a rare histological variant of ICC that is composed of both adenocarcinoma (ICC component) and sarcomatous components. Surgery is believed to be the primary treatment, and some reports describe primary resection. However, due to the aggressive malignancy of sarcomatous ICC, there is no report regarding resection of a metastatic lesion. In this report, we present the case of a 75-year-old woman admitted to our hospital with the chief complaint of weight loss. Various imaging techniques demonstrated a single mass in the liver and cecum. A cecal gastrointestinal stromal tumor accompanied by liver metastasis was suspected, and ileocecal resection was performed for diagnostic purposes. However, the tumor was present in the abdominal wall rather than in the cecum. The tumor was resected and diagnosed as undifferentiated sarcoma. We suspected the liver tumor was a series of lesions, so we performed hepatectomy. As the tumor was composed of both adenocarcinoma and sarcomatous components, it was diagnosed as sarcomatous ICC. The histological findings of the abdominal wall tumor were similar to those of sarcomatous ICC, so we diagnosed the abdominal wall tumor as a solitary metastasis of sarcomatous ICC. In this case, solitary metastasis was observed, and we were able to resect both the primary and metastatic lesions. This case illustrates that when solitary metastasis can be seen in sarcomatous ICC, radical resection is possible.

Abstract P4-08-19: Progression-free survival or time to progression in comparative clinical trials of metastatic breast cancer as a potential surrogate for overall survival: A systematic review of 49 trials focusing on breast cancer subtype

Background: Overall survival (OS) is the established endpoint to evaluate the effects of drug treatment in comparative clinical trials of metastatic breast cancer. But assessing OS requires long follow-up periods and large sample size, which raise costs and create long delays in the drug approval process. Progression-free survival (PFS) or time to progression (TTP) is considered as a surrogate for OS and is often used as an alternative to OS. In some cancers the two endpoints are highly correlated, but in others they are not. Furthermore, the effect of breast cancer (BC) subtypes on the surrogacy of PFS/TTP for OS has not been completely defined.

Method: A systematic literature review of randomized control trials was conducted to identify studies that reported both the hazard ratio (HR) of PFS/TTP and OS for BC subtypes {i.e. estrogen receptor (ER) positive, HER2 positive, and triple negative (TN)}. The correlation between the HR of PFS/TTP and OS was evaluated using weighted Spearman's rank correlation.

Results: A total of 49 trials (34 phase III trials and 15 phase II trials) were selected for analysis. Among these trials, there were 8 comparison trials between one chemotherapy and another chemotherapy regimen, 18 comparison trials between chemotherapy and chemotherapy plus molecularly-targeted therapy, 9 comparison trials between one endocrine therapy and another endocrine therapy, and 5 comparison trials between endocrine therapy and endocrine therapy plus molecularly-targeted therapy. There were 17 trials reporting the HR of PFS/TTP and OS for ER positive, 16 trials for HER2 positive, and 9 trials for TN BC. Weighted Spearman's rank correlation revealed that coefficient between the HR of PFS/TTP and OS was 0.721(p&lt;.0001) for all trials, 0.873(p&lt; .0001) for ER positive, 0.642(p=0.0055) for HER2 positive, and 0.615(p=0.078)for TN BC.

Conclusion: There was a strong correlation between the HR of PFS/TTP and OS for ER positive BC, and a weak correlation between the HR of PFS/TTP and OS for HER2 positive and TN BC. The validity of using PFS/TTP as an OS surrogate marker was shown for metastatic BC, especially for ER positive BC.

Citation Format: Tsukioki T, Taira N, Sakamaki K, Suzuki Y, Kajiwara Y, Hatono M, Takahashi Y, Kawata K, Kochi M, Iwamoto T, Ikeda H, Shien T, Doihara H. Progression-free survival or time to progression in comparative clinical trials of metastatic breast cancer as a potential surrogate for overall survival: A systematic review of 49 trials focusing on breast cancer subtype [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-19.

Abstract P2-05-06: Effects of a soy isoflavone in breast cancer treatment

Background : Isoflavones are phytoestrogens that may be effective in preventing osteoporosis, reducing cardiovascular events, and improving menopausal symptoms such as hot flash due to their estrogen-like actions. Isoflavones are currently used as a supplement for improving symptoms of menopause. Epidemiological studies have shown that ingestion of soy products may also reduce the risk of breast cancer, and antitumor effects on hormone receptor (HR)-positive breast cancer cells have been shown in vitro for equol, an isoflavone metabolite. Equol binds to estrogen receptors (ERα, β) and is thought to antagonize ERα-estradiol binding in the presence of estradiol. Since equol shows an antiestrogenic effect, similar to that of the hormonal agent tamoxifen, it is thought that equol acts as a selective estrogen receptor modulator (SERM), but the mechanism is still unclear. In this study, we evaluated the antitumor effects of equol alone and in combination with existing therapeutic agents in HR-positive breast cancer cells, and examined the mechanism of these effects.

Methods : The antitumor effects of equol alone and in combination with hormone drugs (4-hydroxytamoxifen (Tam), fulvestrant (Ful)) and chemotherapeutic agents (paclitaxel (Ptx), doxorubicin (Dox)) were examined using a MTS assay. Combination indexes (CIs) were determined in HR-positive MCF-7, T-47D, and ZR-75-1 cell lines. The mechanisms of the drug effects were evaluated by Western blot for assessment of changes in chemoresistance factors at the protein level.

Results : In MCF-7, T-47D and ZR-75-1 cells, there was a concentration-dependent antitumor effect of equol and of the other hormonal agents. CIs showed an antagonistic effect of equol with Tam and a synergistic effect with Ful in all cell lines. Equol also had an antagonistic effect with the two chemotherapeutic agents, with the strongest antagonism occurring at a low dose of equol. Western blot showed that ER, PgR, Cyclin D1 and Bcl-2 were upregulated via ER at a low concentration of equol, similarly to the effect of 17-β-estradiol (E2), and ER, PgR, Cyclin D1 and Bcl-2 were downregulated at a high concentration, similarly to the effect of Tam. In addition, ER, PgR and cyclin D1 were downregulated with the combination of equol and Tam, while the expression of Bcl-2, a chemoresistance factor, increased.

Conclusion : These results suggest that equol has a concentration-dependent antitumor effect in HR-positive breast cancer cell lines and may antagonize the effect of existing therapeutic agents (hormone drugs and chemotherapeutic agents). In particular, it was considered that in combination of equol and Tam, the apoptosis inducing action of each drug was attenuated and antagonistic effect was shown.

Citation Format: Hatono M, Ikeda H, Taira N, Suzuki Y, Kajiwara Y, Kawata K, Takahashi Y, Tsukioki T, Kochi M, Iwamoto T, Shien T, Doihara H. Effects of a soy isoflavone in breast cancer treatment [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-05-06.

Abstract 4074: Pten haploinsufficiency promotes tumor invasion and carcinogenesis in mouse colon epithelium with Apc deficiency

Background and Aim: The loss of PTEN (phosphatase and tensin homologue) expression in human colorectal cancer (CRC) is found in approximately 40% of cases, and its functional contribution is not fully understood. To address this question, the colon tumors from the Pten-deficient mice with a disruption of the Adenomatous polyposis coli (Apc) were compared with those from the mice with Apc deficiency alone.

Method: To recapitulate human CRC, mouse models carrying transgenes regulated by a 9.5-kb fragment containing sequences from the human CDX2 promoter (CDX2P9.5), which were previously shown to have tightly restricted transgene expression in the colon epithelium, were prepared. CDX2P9.5-NLSCre;Apcflox/+;Ptenflox/+ (referred to as CPC;Apc+Pten mouse) and CDX2P9.5-NLSCre;Apcflox/+(;Pten+/+) mice (referred to as CPC;Apc mouse) were generated, and the overall survival and tumor phenotypes (number, size and severity) at 4, 6, 9, 12 and 15 weeks of age were compared between the two models. In addition, the loss of heterozygosity status of the Apc and Pten wild-type alleles in tumor tissue and normal mucosa in the two mouse models were compared with multiplex polymerase chain reaction (PCR), and Pten transcripts and protein expression were evaluated by quantitative reverse transcription PCR and immunohistochemistry, respectively.

Results: CPC;Apc+Pten mice had a significantly shorter life span than CPC;Apc mice (median survival time of CPC;Apc+Pten mice and CPC;Apc mice: 14.4 weeks [n=20] vs. 21.6 weeks [n=20], respectively). The CPC;Apc+Pten mice had more tumors than CPC;Apc mice at all time points measured, but the tumor size in CPC;Apc+Pten mice was significantly larger than that in CPC;Apc mice only at 9 weeks of age. Invasion into the submucosa was more frequently observed in CPC;Apc+Pten mice than in CPC;Apc mice (CPC;Apc+Pten mice and CPC;Apc mice: 36.3%/58.3% and 4.9%/10% at 12/15 weeks of age, respectively). Regarding the findings on multiplex PCR, while the tumors from both models showed biallelic Apc inactivation, the tumors from CPC;Apc+Pten mice showed no loss of the wild-type allele of Pten. Regarding the Pten transcript levels, the levels in the tumors and mucosa from CPC;Apc+Pten mice were almost half of those in CPC;Apc mice. The Pten protein expression level in tumors from CPC;Apc+Pten mice was lower than that in tumors from CPC;Apc mice but not completely suppressed.

Conclusion: Pten promotes tumor invasion and carcinogenesis without two hits on the gene. Consistent with the previous finding that two hits on the PTEN gene was a rare event in human CRC with PTEN loss, our data strongly suggest the haploinsufficient tumor-suppressive activity of Pten. These findings show that this CPC;Apc+Pten mouse model recapitulates human CRC with PTEN loss.

Citation Format: Haruki Sada, Takao Hinoi, Hiroaki Niitsu, Masatoshi Kochi, Naoya Sakamoto, Kazuhiro Sentani, Naohide Oue, Wataru Yasui, Hideki Ohdan. Pten haploinsufficiency promotes tumor invasion and carcinogenesis in mouse colon epithelium with Apc deficiency [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4074.

Left colic artery-preserving D3 lymphadenectomy using near-infrared spectroscopy was effective for double advanced cancers of the transverse colon and rectum: A case report

INTRODUCTION

Exact assessment of intestinal viability is necessary, since the risk of anastomotic complications increases due to the reduction in anastomotic blood supply. Near-infrared spectroscopy is useful in assessing blood flow because it allows real-time monitoring and quantifying of tissue oxygen saturation. Herein, we report a case in which two intestinal resections were performed safely by using near-infrared spectroscopy to evaluate the blood flow at the anastomotic sites.

PRESENTATION OF CASE

A 67-year-old man was diagnosed with multiple cancers of the transverse colon and rectum. Laparoscopic transverse colon resection and low anterior resection were performed along with left colic artery-preserving lymphadenectomy, including tissues around the origin of the inferior mesenteric artery. After mesenteric dissection, the tissue oxygen saturation of the proximal side and distal side stumps were 93% and 87%, respectively. The tissue oxygen saturation of the anastomotic proximal side after mesenteric dissection was 76%, thus confirming sufficient blood flow.

DISCUSSION

Performance of transverse colon resection and low anterior resection for multiple cancers of the transverse colon and rectum resulted in blockage of the blood flow to the descending colon; therefore, it was necessary to preserve the blood flow to the descending colon by preserving the left colic artery. Near-infrared spectroscopy was used to evaluate blood flow to the anastomotic sites, in order to perform the surgery safely.

CONCLUSION

Near-infrared spectroscopy is a safe, simple and low-cost method for assessing blood flow intraoperatively in conjunction with left colic artery-preserving surgery.

Laparoscopic management of refractory chylous ascites using fluorescence navigation with indocyanine green: A case report

INTRODUCTION

Postoperative chylous ascites is a rare complication of colorectal surgery. Conservative management is usually effective in most cases of the postoperative chylous ascites. However, surgical intervention is performed for refractory cases.

PRESENTATION OF CASE

A 31-year-old man with neuroendocrine carcinoma developed chylous ascites after laparoscopic descending colectomy with D3 lymphadenectomy. Conservative treatment including total parenteral nutrition and somatostatin analogue failed and surgical intervention via laparoscopy was performed for the refractory chylous ascites. Lymphatic leakage was detected at the upper part of the inferior mesenteric artery during the laparoscopic exploration and was reconfirmed by intraoperative indocyanine green injection with an infrared camera system. Moreover, we injected the ICG into the other sites of the lymphadenectomy performed and identified the lymphatic flow. We confirmed there was no other lymphatic leakage. The lesion was ligated and closed with fibrin glue. Five months after the surgical intervention, no symptom was noted.

DISCUSSION

It is frequently difficult to detect the site of lymphatic leakage intraoperatively. Intraoperative indocyanine green injection is useful for detecting a lymphatic leakage site and especially making sure without other leakages. Additionally, laparoscopic surgery seems safe and effective for refractory chylous ascites.

CONCLUSION

we reported successful laparoscopic management of refractory chylous ascites using fluorescence navigation with indocyanine green.

Risk factors for postoperative pneumonia in elderly patients with colorectal cancer: a sub-analysis of a large, multicenter, case-control study in Japan

PURPOSE

Postoperative pneumonia affects the length of stay and mortality after surgery in elderly patients with colorectal cancer (CRC). We aimed to determine the risk factors of postoperative pneumonia in elderly patients with CRC, and to evaluate the impact of laparoscopic surgery on elderly patients with CRC.

METHODS

We retrospectively investigated 1473 patients ≥ 80 years of age who underwent surgery for stage 0-III CRC between 2003 and 2007. Using a multivariate analysis, we determined the risk factors for pneumonia occurrence from each baseline characteristic.

RESULTS

Among all included patients, 26 (1.8%) experienced postoperative pneumonia, and restrictive respiratory impairment, obstructive respiratory impairment, history of cerebrovascular events, and open surgery were determined as risk factors (odds ratio [95% confidence interval], 2.78 [1.22-6.20], 2.71 [1.22-6.30], 3.60 [1.37-8.55], and 3.57 [1.22-15.2], respectively). Furthermore, postoperative pneumonia was more frequently accompanied by increasing cumulative numbers of these risk factors (area under the receiver operating characteristic curve = 0.763).

CONCLUSIONS

Laparoscopic surgery may be safely performed in elderly CRC patients, even those with respiratory impairment and a history of cerebrovascular events.

possible role of soluble fibrin monomer complex after gastroenterological surgery

AIM

To examine the role of soluble fibrin monomer complex (SFMC) in the prediction of hypercoagulable state after gastroenterological surgery.

METHODS

We collected data on the clinical risk factors and fibrin-related makers from patients who underwent gastroenterological surgery at Hiroshima University Hospital between April 1, 2014 and March 31, 2015. We investigated the clinical significance of SFMC, which is known to reflect the early plasmatic activation of coagulation, in the view of these fibrin related markers.

RESULTS

A total of 123 patients were included in the present study. There were no patients with symptomatic VTE. Thirty-five (28%) patients received postoperative anticoagulant therapy. In the multivariate analysis, a high SFMC level on POD 1 was independently associated with D-dimer elevation on POD 7 (OR = 4.31, 95%CI: 1.10-18.30, P = 0.03). The cutoff SFMC level was 3.8 μg/mL (AUC = 0.78, sensitivity, 63%, specificity, 89%). The D-dimer level on POD 7 was significantly reduced in high-SFMC patients who received anticoagulant therapy in comparison to high-SFMC patients who did not.

CONCLUSION

The SFMC on POD 1 strongly predicted the hypercoagulable state after gastroenterological surgery than the clinical risk factors and the other fibrin related markers.

Clinical Significance of Pharmacological Prophylaxis based on the Original Risk Classification of Venous Thromboembolism after Lower Abdominal Surgery

Pharmacological prophylaxis was not routinely administrated following gastroenterological surgery because of concerns about bleeding complications. We tried to establish the original risk classification to determine the indication for pharmacological prophylaxis for selected patients at high risk of venous thromboembolism (VTE). One hundred and fifty-six consecutive patients who underwent lower abdominal elective surgery were divided into three groups (highest, high, and low risk groups) based on the original risk classification. Pharmacological prophylaxis was indicated for patients in the highest and high risk groups. We investigated safety and efficacy of the pharmacological prophylaxis based on this classification. Sixteen patients were classified in the highest, 50 in the high, and 90 in the low risk groups. Pharmacological prophylaxis was used for 59 cases (37.8%). There was no symptomatic pulmonary embolism or major bleeding complications. There were no significant differences in the occurrence of postoperative complications, analgesia use, and median postoperative pain scores for the three groups. In the highest and high risk groups administrated pharmacological prophylaxis, fibrin degradation products (FDP) and D-dimer did not change between postoperative day 1 and day 7. These data suggested the clinical significance of the pharmacological prophylaxis based on the original risk classification.

Increased Calcineurin A Expression Is Associated with a Lower Relapse-Free Survival Rate after Colorectal Cancer Surgery

OBJECTIVE

Increased expression of calcineurin in colorectal cancer (CRC) has been reported. Although the oncogenic function has been suggested, the clinical relevance is still unclear. We herein studied calcineurin expression as a prognostic biomarker in patients receiving curative surgery for stages I-III CRC.

METHODS

In 121 patients with stages I-III CRC treated at Hiroshima University between 1997 and 2003, calcineurin A expression was examined using immunohistochemistry (IHC) staining of surgical specimens. Specimens were considered positive for calcineurin A if any IHC-stained cells were observed within the carcinomatous area, and clinicopathological characteristics and survival outcomes were compared between IHC-positive and -negative groups.

RESULTS

Calcineurin A was preferentially expressed in the cytoplasm of cancer cells, and a median of 8% of the cells (range: 0-80%; interquartile range: 0-22.5%) were stained within the carcinomatous areas. Of 121 cases, 81 were determined as IHC positive while 40 were determined to be negative. Positive expression of calcineurin A, as well UICC-TNM stage, was associated with low relapse-free survival (RFS) rates in multivariate analyses (hazard ratio = 2.92; 95% CI: 1.27-7.92; p = 0.010).

CONCLUSION

Increased calcineurin A expression is associated with lower RFS rates and may have clinical value in predicting recurrence.

Abstract P5-08-14: Tumor Infiltrating lymphocytes (TIL) related genomic signature associated with chemotherapy response and prognosis in subtypes of breast cancer

Background: Tumor infiltrating lymphocytes (TIL) in subtypes of breast cancer may provide clinically important information on chemotherapy response and prognosis. However, the standardized methodology for immunohistochemical (IHC)-TIL has not yet been established, reproducible and objective method of evaluation of TIL such as gene expression profiles is warranted. We evaluated whether IHC-TIL level was associated with gene expression profiles and whether such profiles could be used to predict chemotherapy response and prognosis according to subtypes of breast cancers.

Methods: To select TIL associated genes, we used 40 samples with both IHC-TIL information and gene expression profiling data. The degree of TIL at the edges of the tumor mass, in the tumor mass, or in the stroma surrounding the expanding mammary ducts packed by carcinoma cells was evaluated as score 0, 1, and 2, when TIL was not unrecognizable (0%), sparse (0 &lt;&lt; 50%) and dense (50% ≤), respectively. We selected 22 genes as the TIL-gene signature (GS), by comparing expression profiles between TIL score 2 and 0 tumors. We showed the associations between the TIL-GS levels and subtypes of breast cancers (Estrogen receptor: ER / Human Epidermal growth factor 2: HER2). The chemotherapy sensitivity analysis was performed on cohorts of 625 patients with stage I–III breast cancer who received neo adjuvant chemotherapy (NAC) based on Anthracycline and Taxane containing regimen. Data from 1,586 tumors were used to evaluate the association between distant metastasis free survival (DMFS) and the TIL-GS in a Kaplan-Meier analysis.

Results: The TIL-GS for ER negative (-)/HER2- and HER2 positive (+) cases were significantly higher expression level than luminal types (p-value &lt;0.001). All breast cancer subtypes except luminal-low proliferation had significantly higher differential TIL-GS level in cases with pathological complete response (pCR) after NAC than residual disease (luminal-high: p-value = 0.013, HER2+: 0.005, and ER-/HER2-: 0.016). With no adjuvant chemo or only tamoxifen treated breast cancer data set, the TIL-GS had no prognostic power in luminal cases regardless of proliferative level. In HER2+ breast cancers, cases with the high TIL-GS had significantly better prognosis than low cases (p-value =0.001), but no significance in ER-/HER2- cases (p-value = 0.621).

Conclusions: Higher TIL-gene signature of 22 genes appeared to be associated with aggressive subtypes and pCR rate (except luminal-low) of breast cancers. This approach may improve the reproducibility of assessment on tumor TIL level and thus serve the clinical applications for breast cancers.

Citation Format: Kochi M, Niikura N, Iwamoto T, Bianchini G, Mizoo T, Nogami T, Shien T, Motoki T, Taira N, Masuda S, Doihara H, Fujiwara T, Tokuda Y, Matsuoka J. Tumor Infiltrating lymphocytes (TIL) related genomic signature associated with chemotherapy response and prognosis in subtypes of breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-08-14.

Total colectomy for multiple metachronous colon cancers in a patient with Lynch syndrome

Lynch syndrome (LS) is a disorder caused by mismatch repair gene mutations, which have been recognized to be associated with an increased frequency of colorectal and extracolorectal tumors. However, it remains controversial as to whether total or segmental colectomy should be performed to treat colorectal cancer in patients with LS. A 58-year-old male underwent total colectomy with ileostomy for advanced transverse colon cancer. He was also found to have LS based on his characteristic family history and the findings of a preoperative examination, including a microsatellite instability analysis of past multiple metachronous cancers. The postoperative histological findings showed mucinous adenocarcinoma without lymph node metastasis, and the loss of the MSH2 protein expression was confirmed on an immunohistochemical examination. The present case provided important information on the clinical management of multiple developing metachronous colorectal cancers in patients with LS.

Abstract 2301: The generation of colorectal cancer mouse model based on microsatellite instability and the identification of transforming growth factor-beta signal target

Background & Aims:

The transforming growth factor-beta (TGF-beta) signal is a tumor-suppressor pathway that is commonly inactivated in about 90% of microsatellite instability (MSI) colorectal cancer (CRC). However, there was little evidence what gene is regulated by TGF-beta signal in the multistep progression sequence of CRC. The first aim of the present study was to generate a mouse model that is null for Tgfbr2 and Apc in the colon epithelium and forms tumors in the colon. The second aim was to analyze the tumors that arose in the mice model for the purpose to identify the gene regulated by TGF-beta signal.

Method & Result:

Previously we have described the generation of the ‘CDX2P-G19Cre;Apcflox/flox mice’ (called Apc KO mice) which is randomly null for Apc in the colonic epithelium. By mating Tgfbr2flox/flox mice with Apcflox/flox and CDX2P9.5-G19Cre mice, we have finally generated a mouse model ‘CDX2P-G19Cre;Apcflox/flox;Tgfbr2flox/flox mice’ (called Apc+Tgfbr2 KO mice) which is null for Apc and Tgfbr2. In these model, the tumors with well differentiated adenocarcinoma arose mainly in proximal colon and most of mice died at 4 weeks age due to tumor bleeding. Therefore the mice were harvested at 3 weeks age to evaluate the development of colon tumors. Total RNAs of only cancerous tissue areas were extracted from frozen samples by the laser capture microdissection method. We compared gene expression profiles of these mice's tumors (n = 3, respectively) with Mouse Exon 1.0 ST Array (Affymetrix). Gene X expression of Apc+Tgfbr2 KO mice tumors was most highly upregurated by 9.25-fold compared with Apc KO mice (p = 0.045). The array data was validated by quantitative PCR. For human CRC samples, mutations of repetitive mononucleotide tracts in the coding regions of TGFBR2 were identified by direct sequencing. By immunohistochemical analysis, the expression of X was classified according to the percentage of stained cancer cells. The expression was considered to be ‘positive’ if ≥30% of cancer cells were stained. An analysis demonstrated that 11 (100%) of 11 mutated TGFBR2 cases were positive for X, whereas 10 (66.7%) of 15 wild type TGFBR2 cases were positive (P = 0.033), indicating that high expression of X was correlated with TGFBR2 mutation in human CRCs samples. Additionally, the cell proliferation assay revealed that silencing of X led to a significant reduction in CRC cell proliferation. Conversely, forced expression of X enhanced CRC cell proliferation in vitro.

Conclusion:

We have generated an in vivo model system that Apc and Tgfbr2 were inactivated only in the colonic epithelium and tumors with well differentiated adenocarcinoma arose mainly in proximal colon. The analysis of this model revealed that Gene X is regulated by a TGF-beta signal and likely promotes cell proliferation in CRC.

Citation Format: Masashi Miguchi, Takao Hinoi, Manabu Shimomura, Tomohiro Adachi, Yasufumi Saito, Hiroaki Niitsu, Masatoshi Kochi, Yusuke Sotomaru, Hideaki Ijichi, Tsuneo Ikenoue, Kunitoshi Shigeyasu, Kohji Tanakaya, Kazuhiro Sentani, Naohide Oue, Wataru Yasui, Hideki Ohdan. The generation of colorectal cancer mouse model based on microsatellite instability and the identification of transforming growth factor-beta signal target. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2301. doi:10.1158/1538-7445.AM2015-2301

Abstract 823: Gene expression profiling for oncogenic Kras mutation in mice and human colorectal cancer

Purpose: Oncogenic KRAS mutations are found in 40-50% of human colorectal cancers. However, specific therapeutics has not been yet available. We aimed to search new therapeutic molecular targets or biomarkers in KRAS mutated colorectal cancers.

Experimental design: We generated Apcflox/flox; CDX2P9.5-G22Cre and LSL-KrasG12D; Apcflox/flox; CDX2P9.5-G22Cre mice, that had been considered as sporadic colon cancer mouse model with Kras wild and mutant, respectively. We observed the carcinogenesis at the age of 3-4 weeks by necropsy, and harvested the tumors for gene expression profiling. We compared the gene expression by Microarray (GeneChip, Affymetrix) between each 3 tumors from these mice strains. Genes with &gt;5 fold changes between the two groups were selected as candidate genes, and subsequently narrow these down by bibliographic search for further analyses in human colorectal cancers.

Result: In macroscopic findings, extensive polyps were generated in cecum and proximal colon, but not in other site of gastrointestinal tract. Tumors occurred in the both strains were considered as well differentiated adenocarcinomas in hematoxylin-eosin staining. It was confirmed that tumors generated in Apcflox/flox; CDX2P9.5-G22Cre mice had Cre-targeted Apc 580D alleles and wild-type Kras, and that tumors generated in LSL-KrasG12D; Apcflox/flox; CDX2P9.5-G22Cre mice had both Cre-targeted Apc 580D alleles and activated oncogenic KrasG12D. In the subsequent gene expression profiling, we identified 31 genes with &gt;5 fold change in Microarray analyses. Of these, we focused on some genes that showed lower expression in Kras mutant tumor than in Kras wild type tumor. We confirmed the lower expressions of these genes in murine tumors by quantitative RT-PCR, and the lower expression in early-staged human colorectal cancers with oncogenic KRAS mutant by immunohistochemistry staining. To analyze the functions, the retroviral vectors that lead overexpression of these genes were constructed and infected to SW480 and RKO CRC cell lines. Proliferation and migration is being analyzed using these cell lines.

Conclusion: We identified novel genes associated with oncogenic KRAS mutation, using the analyses of gene expression in colon cancer mouse model.

Citation Format: Hiroaki Niitsu, Takao Hinoi, Yasuo Kawaguchi, Kazuhiro Sentani, Naohide Oue, Yusuke Sotomaru, Tomohiro Adachi, Yasufumi Saito, Masashi Miguchi, Masatoshi Kochi, Manabu Shimomura, Wataru Yasui, Hideki Ohdan. Gene expression profiling for oncogenic Kras mutation in mice and human colorectal cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 823. doi:10.1158/1538-7445.AM2015-823

Phase II/III study of second-line chemotherapy comparing irinotecan-alone with S-1 plus irinotecan in advanced gastric cancer refractory to first-line treatment with S-1 (JACCRO GC-05)

BACKGROUND

In Japan, S-1 plus cisplatin has been used as first-line therapy for advanced gastric cancer (AGC). Patients with no response to first-line treatment with S-1 often receive a taxane-alone or irinotecan-alone as second-line treatment. However, second-line treatment with S-1 plus irinotecan is widely used in patients with AGC resistant to first-line S-1-based chemotherapy. The goal of this trial was to determine whether the consecutive use of S-1 plus irinotecan improves survival when compared with irinotecan-alone as second-line treatment for AGC.

PATIENTS AND METHODS

Patients who had disease progression during first-line S-1-based chemotherapy were randomly assigned to receive S-1 plus irinotecan or irinotecan-alone. The S-1 plus irinotecan group received oral S-1 (40-60 mg/m(2)) on days 1-14 and intravenous irinotecan (150 mg/m(2)) on day 1 of a 21-day cycle. The irinotecan-alone group received the same dose of irinotecan intravenously on day 1 of a 14-day cycle. The primary end point was overall survival (OS).

RESULTS

From February 2008 to May 2011, a total of 304 patients were enrolled. The median OS was 8.8 months in the S-1 plus irinotecan group and 9.5 months in the irinotecan-alone group. This difference was not significant (hazard ratio for death, 0.99; 95% confidence interval 0.78-1.25; P = 0.92). Grade 3 or higher toxicities were more common in the S-1 plus irinotecan group than in the irinotecan-alone group.

CONCLUSION

The consecutive use of S-1 plus irinotecan is not recommended as second-line treatment in patients who are refractory to S-1-based first-line chemotherapy. ClinicalTrials.gov ID: NCT00639327.

Up-front systemic chemotherapy is a feasible option compared to primary tumor resection followed by chemotherapy for colorectal cancer with unresectable synchronous metastases

Background

In stage IV colorectal cancer (CRC) with unresectable metastases, whether or not resection of the primary tumor should be indicated remains controversial. We aim to determine the impact of primary tumor resection on the survival of stage IV CRC patients with unresectable metastases.

Methods

We retrospectively investigated 103 CRC patients with stage IV colorectal cancer with metastases, treated at Hiroshima University Hospital between 2007 and 2013. Of these, those who had resectable primary tumor but unresectable metastases and received any chemotherapy were included in the study. We analyzed the overall survival (OS) and short-term outcomes between the patients who received up-front systemic chemotherapy (USC group) and those who received primary tumor resection followed by chemotherapy (PTR group).

Results

Of the 57 included patients, 15 underwent USC and 42 PTR. The median survival times were 13.4 and 23.9 months in the USC and PTR groups, respectively (P = 0.093), but multivariate analysis for the overall survival showed no significant difference between the two groups (hazard ratio, 1.30; 95% confidence interval (CI), 0.60 to 2.73, P = 0.495). In the USC group, the disease control rate of primary tumor was observed in 12 patients (80.0%), but emergency laparotomy was required for 1 patient. Morbidity in the PTR group was observed in 18 cases (42.9%).

Conclusions

The overall survival did not differ significantly between the USC and PTR groups. USC may help avoid unnecessary resection and consequently the high morbidity rate associated with primary tumor resection for stage IV CRC with unresectable metastases.

Abstract P4-01-05: Utility of Preoperative Routine MRI and PET/CT in Breast Cancer Staging vs. Surgical Staging

Background: Staging of breast cancer is one of the most important factors in determining treatment options. The aim of this study is to assess the utility of routine magnetic resonance imaging (MRI) and positron emission tomography and computed tomography (PET/CT) in preoperative breast cancer staging.

Patients and methods: We examined 616 consecutive patients, who were newly-diagnosed with operable primary breast cancer less than 3 cm, at our institution between 2009 and 2011. They all underwent MRI and PET/CT to assign the clinical stage by TNM classification. Tumor size was measured by contrast MRI examinations and node status and metastases were evaluated on PET/CT. We examined their clinical and pathological T and N status retrospectively to assess the utility and concordance rate of preoperative imaging studies. Patients with tumors more than 3 cm were excluded from this study, since preoperative systemic therapy is the standard therapeutic strategy for those patients.

Results: The concordance rate of T status was 79.9% in clinical T1 patients (366/458) and 55.6% in clinical T2 patients (88/158). The concordance rate of N status was 83.8% in clinical N0 patients (495/591) and 60.0% in clinical N1 patients (15/25). As a result, the concordance rate of clinical stage was 66.5% in clinical stage I patients (296/445) and 55.0% in clinical stage II patients (94/171). In addition, 43 patients were diagnosed as contrary breast cancer by MRI (7.5%) and 31 contrary breast cancer (5.4%) and 12 other malignant disease (1.9%) were found by PET/CT.

Conclusions: MRI and PET/CT are valuable tools to provide information on tumor size, lymph node involvement, distant metastases and other occult primary disease. Preoperative routine MRI and PET/CT studies have a substantial impact on patients with operable primary breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-01-05.

Abstract P1-14-12: Response to neoadjuvant chemotherapy and prognosis of primary breast cancer according to intrinsic subtype

Background: Response to neoadjuvant chemotherapy of primary breast cancer differs across intrinsic subtypes and is considered as a useful surrogate indicator for prognostic prediction, while some subtype populations seems to take different course.

Methods: We classified 364 primary breast cancer patients, who received neoadjuvant chemotherapy after 2002 at our institute, to 5 intrinsic subtype groups; Luminal A type (LA), Luminal B type (LB), Luminal Her2 type (LH), Her2 type (Her2) and triple negative (TN), according to hormonal sensitivity, Her2 status, and cancer proliferation. We evaluated their pathological response to neoadjuvant chemotherapy by response criteria of Japanese Breast Cancer Society. Pathological complete response (pCR) is defined as Necrosis or disappearance of invasive cancer of breast in this study, approving residual non-invasive component of breast or axillary lymph node metastasis. We also examined disease free survival (DFS) and overall survival (OS) by each subtypes statistically, using Kaplan-Meier method and Log-rank test.

Results: Number of patients in each subtype were as follows; LA: 141 patients, LB: 41 patients, LH: 38 patients, Her2: 54 patients, and TN: 90 patients. Surveillance period is 4–105 months (median: 37 months). Most of cases in all subtypes received both anthracycline and taxane. 27 cases in LH (71.1%) and 48 cases in Her2 (88.9%) were treated with trastzumab. 7 cases in LA (5.0%), 4 cases in LB (9.8%), 9 cases in LH (23.7%), 31 cases in Her2 (57.4%), and 26 cases in TN (28.9%) achieved pCR. pCR rate was significantly high in Her2 and TN (p &lt; 0.05). LA, LB, LH showed no significant differences in DFS and OS between pCR group and non-pCR group (LA; DFS p = 0.929 OS p = 0.663, LB; DFS p = 0.189 OS p = 0.552, LH; DFS p = 0.508 OS p = 0.691). In Her2 group, pCR group tended to show better prognosis, but there were no significant differences (Her2; DFS p = 0.107, OS p = 0.343). In TN group, pCR group showed significantly better prognosis (TN; DFS p = 0.046, OS p = 0.040), which indicates the correlation between response to neoadjuvant chemotherapy and prognosis.

Conclusion: Our results indicate the correlation between response to neoadjuvant chemotherapy and prognosis in TN breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-14-12.

Neurofibromatosis 2 gene has novel alternative splicings which controls intracellular protein binding

Three novel isoforms of the neurofibromatosis 2 (NF2) gene transcripts generated from alternative splicing were identified from normal human brain, schwannoma and glioma tissues. The 3 novel transcripts lack exon 2, exons 2 and 3, exons 2-4, respectively. Recombinant isoform proteins encoded by those new transcripts have lost the previously reported ability to bind S-35-methionine labeled cellular proteins. Two of seven glioblastoma tissues expressed significantly high levels of the shorter transcripts whereas low grade astrocytomas expressed levels similar to those found in normal brain, suggesting that genomic mutation or aberrant alternative splicing of the NF2 gene may contribute to the progression of malignant gliomas.