Cytoreductive surgery for synchronous and metachronous colorectal peritoneal dissemination: Japanese P classification and peritoneal cancer index.

Aim: The outcomes of cytoreductive surgery (CRS) for synchronous and metachronous colorectal peritoneal dissemination were investigated using the Japanese P classification and peritoneal cancer index (PCI). Methods: CRS was performed in 111 cases of synchronous peritoneal dissemination and 115 cases of metachronous peritoneal dissemination. The P classification and PCI were determined at the time of laparotomy. Results: In the synchronous dissemination group, the 5-year overall survival rates after CRS in P1/P2 and P3 cases were 51% and 13%, respectively. Even for P3, 51% of the patients achieved macroscopic cytoreductive complete resection (CC-0), with a 5-year survival rate of 40%. When P3 cases were classified into PCI 0-9, 10-19, 20-29, and 30-39, CC-0 was achieved in 93%, 70%, 6%, and 0% of the cases, respectively, and the 5-year survival rate of PCI 0-9 was 41%. In the metachronous dissemination group, the 5-year survival rates were 62% for PCI 0-9 and 22% for PCI 10-19; 5-year survival was not observed in patients with a PCI ≥ 20. CC-0 was significantly associated with the postoperative prognosis in both synchronous and metachronous peritoneal dissemination. Conclusion: In cases of synchronous dissemination, CRS must be performed for P1 and P2 cases or those with a PCI < 10, while detailed examination using PCI is required for P3 cases. In cases of metachronous dissemination, CRS should be considered when the PCI score is <20.

Analysis of the characteristics and outcomes of patients with pseudomyxoma peritonei of appendiceal origin treated with curative-intent surgery.

BACKGROUND: There are no previous studies on pseudomyxoma peritonei regarding the details of surgical procedures included in cytoreductive surgery and quantitative evaluation for peritoneal metastases by region in the abdominal cavity. This study aimed to describe the characteristics and procedural details involved in cytoreductive surgery, and survival outcomes of patients with pseudomyxoma peritonei originating from appendiceal mucinous neoplasm, and identify differences in the difficulty of cytoreductive surgery based on tumor location. METHODS: Patient characteristics and survival outcomes were studied through a retrospective review. The complete cytoreduction rate (i), the 5-year survival rate for patients with complete cytoreduction (ii), and an index as a complement (i × ii × 100) were described for patients who had tumors larger than 50 mm in one of the 13 regions of the abdominal cavity. RESULTS: A total of 989 patients were treated with curative-intent cytoreductive surgery. The median peritoneal cancer index was 18 (interquartile range, 6-29), with complete cytoreduction achieved in 702 patients (71%); the major complication rate was 17%. The median overall survival was 92.9 months, compared to 53.8 months for patients who underwent total gastrectomy and 30.4 months for those who underwent total colectomy. In the 13 abdominal regions, the index scores indicating cytoreduction difficulty were categorized into three risk groups: upper and mid-abdominal (>20), lateral abdominal (10-20), and small bowel (<10). CONCLUSIONS: Cytoreductive surgery offered favorable survival outcomes, even in cases involving total gastrectomy. The difficulty of achieving complete cytoreduction varied across abdominal regions and was classified into three levels.

A rare case of pseudomyxoma peritonei with Morgagni hernia.

Both pseudomyxoma peritonei and Morgagni hernias in adults are rare clinical conditions. A 70-year-old woman who was diagnosed with pseudomyxoma peritonei with Morgagni hernia underwent cytoreductive surgery and primary repair. Pseudomyxoma peritonei causes increased intra-abdominal pressure that may lead to acquired congenital diaphragmatic hernia when there is a local fragility in the diaphragmatic musculature. Parietal peritonectomy of the right diaphragmatic peritoneum can safely remove the hernia sac. The high rate of infections associated with cytoreductive surgery causes hesitation for concurrent mesh repair for Morgagni hernia. This is the first report of pseudomyxoma peritonei with Morgagni hernia. Cytoreductive surgery including parietal peritonectomy of the right diaphragmatic peritoneum plus primary repair of hernial defect was performed safely and successfully, which achieved positive short-term results for patients with pseudomyxoma peritonei-associated Morgagni hernia.

[Pseudomyxoma Peritonei Caused by Intraductal Papillary Mucinous Neoplasm-A Three Case Series].

Pseudomyxoma peritonei(PMP)is a rare condition caused by intraductal papillary mucinous neoplasm(IPMN). At our institution, 3 cases, along with literature review, of PMP caused by IPMN were treated with cytoreductive surgery. In case 1, a 70-year-old man was pathologically diagnosed with low-grade PMP with intraductal papillary mucinous carcinoma. Recurrence was discovered 68 months after surgery, and the patient died after 78 months. In case 2, a 69-year-old man was pathologically diagnosed with high-grade PMP with signet-ring cell carcinoma caused by intraductal papillary mucinous carcinoma. The patient died 8 months post-surgery. In case 3, a 77-year-old woman was pathologically diagnosed with low- grade(partially high-grade)PMP with intraductal papillary mucinous adenoma. There was a recurrence 14 months post- surgery. The patient is still alive because of systemic chemotherapy 32 months after surgery.

A desmoid-type fibromatosis in the retroperitoneum of the gastro-pancreatic region that was resected with a distal pancreatomy: a case report.

An 80-year-old man was referred to our hospital because of epigastric pain. Abdominal computed tomography revealed a well-defined circular intra-abdominal mass in the gastro-pancreatic region measuring 15 mm in diameter. After 6 months, the mass lesion was growing with mild enhancement, and weaker enhancement was found in the lower half of the mass on contrast-enhanced computed tomography. The mass lesion touched the stomach, whereas adipose tissue appeared to intervene between the mass and pancreas. On magnetic resonance imaging, the well-defined mass lesion had isointensity to muscle on T1-weighted imaging, slight hyperintensity to muscle on T2-weighted imaging, which indicated a rich fibrous tumor. Under general anesthesia, the patient underwent open surgery. Intraoperatively, the tumor was separated from the stomach and firmly attached to the pancreas. Therefore, we performed a distal pancreatomy with splenic resection. Pathological diagnosis was desmoid-type fibromatosis in the retroperitoneum, and the tumor margin was attached to the pancreas, splenic artery, and splenic vein. Since there are few reports of desmoid-type fibromatosis occurring in the retroperitoneum of the gastropancreatic region, it is difficult to distinguish from other soft tissue tumors and to identify the tumor origin. Close observation by radiological re-valuation was a useful option. Magnetic resonance imaging signals and an enhanced pattern may help distinguish a desmoid-type fibromatosis from other soft tissue tumors. A desmoid-type fibromatosis that is well-defined in radiological findings may infiltrate the surrounding organs with gross or pathological analyses.

The Development of Peritoneal Metastasis from Gastric Cancer and Rationale of Treatment According to the Mechanism.

In the present article, we describe the normal structure of the peritoneum and review the mechanisms of peritoneal metastasis (PM) from gastric cancer (GC). The structure of the peritoneum was studied by a double-enzyme staining method using alkaline-phosphatase and 5'-nucreotidase, scanning electron microscopy, and immunohistological methods. The fundamental structure consists of three layers, mesothelial cells and a basement membrane (layer 1), macula cribriformis (MC) (layer 2), and submesothelial connective tissue containing blood vessels and initial lymphatic vessels, attached to holes in the MC (layer 3). Macro molecules and macrophages migrate from mesothelial stomata to the initial lymphatic vessels through holes in the MC. These structures are characteristically found in the diaphragm, omentum, paracolic gutter, pelvic peritoneum, and falciform ligament. The first step of PM is spillage of cancer cells (peritoneal free cancer cells; PFCCs) into the peritoneal cavity from the serosal surface of the primary tumor or cancer cell contamination from lymphatic and blood vessels torn during surgical procedures. After PFCCs adhere to the peritoneal surface, PMs form by three processes, i.e., (1) trans-mesothelial metastasis, (2) trans-lymphatic metastasis, and (3) superficial growing metastasis. Because the intraperitoneal (IP) dose intensity is significantly higher when generated by IP chemotherapy than by systemic chemotherapy, IP chemotherapy has a great role in the treatment of PFCCs, superficial growing metastasis, trans-lymphatic metastasis and in the early stages of trans-mesothelial metastasis. However, an established trans-mesothelial metastasis has its own interstitial tissue and vasculature which generate high interstitial pressure. Accordingly, it is reasonable to treat established trans-mesothelial metastasis by bidirectional chemotherapy from both IP and systemic chemotherapy.

Rationale of Treatment for Peritoneal Metastasis.

In 1998, the Peritoneal Surface Oncology Group International(PSOGI)proposed a novel treatment referred to as comprehensive treatment(COMPT). COMPT involves the complete removal of macroscopic tumors(cytoreductive surgery: CRS) and eradication of micrometastasis(MM)with neoadjuvant chemotherapy(NAC)plus intraoperative hyperthermic intraperitoneal chemotherapy(HIPEC). This article provides a rationale for curative COMPT. Additionally, based on our experience, the selection criteria for treatment will be clarified. RATIONALE: The residual cancer cell burden is lowest immediately following CRS, and intraoperative HIPEC plays a crucial role in the treatment of patients with peritoneal surface malignancy (PSM). COMPT will fail if the number of the MM remaining after CRS exceeds the limit of complete eradication by intraoperative HIPEC(threshold). However, if the residual number of MM is less than the threshold, patients will respond positively to treatment. PATIENTS AND METHODS: To validate the direct effect of HIPEC, laparoscopic HIPEC(LHIPEC)was performed, and changes in the peritoneal cancer index(PCI)were then evaluated. Complete cytoreduction and HIPEC carried out based on the concept of COMPT was performed in 171 gastric cancer(GC)patients with PCI≤12, 183 colorectal cancer(CRC)with PCI≤21 and 460 pseudomyxoma peritonei(PMP)patients with PCI≤28. The postoperative survivals rates were then analyzed. RESULTS: After 1 cycle of LHIPEC, PCIs in GC and PMP were significantly reduced by 1.85 and 2.7 1 month after LHIPEC. However, PCI of CRC increased. Positive cytology at LHIPEC became negative in 57.6%, 42.9% and 60.9% of patients with GC, CRC and PMP, respectively. Median survival time(MST)for GC and CRC was 21.2 and 71.5 months, respectively MST of PMP was not reached. MST of PMP was not reached. Ten-year survival rates were 12.6%, 21.7% and 81.6%, respectively. Grade 5 complications for each disease were 0.8%, 1.0% and 1.1%, respectively. CONCLUSIONS: Complete cytoreductive surgery combined with intraoperative HIPEC may improve the long-term survival of patients with PSM who have PCIs less than the threshold levels, by keeping the mortality rates after CRS plus intraoperative HIPEC within acceptable levels.

Thirty-three long-term survivors after cytoreductive surgery in patients with peritoneal metastases from colorectal cancer: a retrospective descriptive study.

BACKGROUND: Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) improves survival in selected patients with peritoneal metastasis (PM) from colorectal cancer (CRC). However, little has been reported on characteristics and clinical course of long-term survivors with CRC-PM beyond 5 years. The objective of this study was to identify the clinical and oncological features affecting long-term survival of CRC-PM after comprehensive treatment. METHODS: Between January 1990 and April 2015, CRC-PM patients who underwent CRS with or without HIPEC in two Japanese tertiary hospitals were analyzed. Clinicopathological parameters and therapeutic details for long-term survivors (patients surviving ≥ 5 years after CRS) were described and compared with those for non-survivors (patients surviving < 5 years). RESULTS: The study identified 236 patients with CRC-PM who underwent CRS, with a median follow-up period of 2.5 years. Thirty-three patients (14.0%) were considered as long-term survivors. Compared with non-survivors, long-term survivors had a lower median peritoneal cancer index (PCI) [4 (1-27) vs 9 (0-39), p < 0.001]. Complete cytoreduction (CCR-0) was achieved in all long-term survivors, with a significantly higher rate [33/33 (100%) vs 141/203 (69.8%), p < 0.001]. Metachronous onsets of PM were more frequently observed in the long-term survivor group [26/33 (78.8%) vs 103/203 (50.3%), p = 0.018]. Regarding histopathology, long-term survivors more frequently had mucinous adenocarcinoma than non-survivors [8/33 (24.2%) vs 27/203 (13.3%)] and less likely exhibited poorly differentiated or signet ring cell carcinoma [2/33 (6.1%) vs 48/203 (23.7%)] (p < 0.001). CONCLUSIONS: One in seven patients with CRC-PM achieved the long-term milestone after CRS. A long-term survival was associated with the presence of low PCI, CCR-0, metachronous onset, and mucinous histology.

Retrospective Analysis of Patients with Signet Ring Subtype of Colorectal Cancer with Peritoneal Metastasis Treated with CRS & HIPEC.

Signet ring cell subtype (SRC) of colorectal cancer (CRC) is a rare subtype and occurs in approximately 1% of all patients with CRC. Patients with peritoneal metastasis (PM) of SRC have a poor prognosis, and this subtype is frequently considered as a contra-indication for extensive surgical treatment. This retrospective study from two dedicated peritoneal surface malignancy centers in Japan included all patients treated with CRS ± hyperthermic intraperitoneal chemotherapy (HIPEC) between July 1994 and December 2017 from a prospectively maintained database. Preoperative, operative, and postoperative parameters were recorded, including complication rates and follow-up. Sixty of the 320 patients treated with CRS due to CRC were diagnosed with SRC subtype. The mean age of the patients was 51.4 years, and the mean peritoneal carcinomatosis index (PCI) was 13.1. Complete cytoreduction was achieved in 61.7% of cases. The postoperative morbidity rate was 25% and the mortality rate was 1.7%. The median overall survival (OS) was 14.4 months. Cox regression analysis revealed small bowel PCI > 2 (hazard ratio (HR) 6.5; p = 0.008) as the most important factor for OS. With accurate patient selection (e.g., PCI ≤ 12 or small bowel PCI ≤ 2), even patients with PM of CRC with SRC subtype may benefit from CRS and HIPEC, with median OS from 17.8 to 20.8 months and 5-year OS of 11.6%.

Neoadjuvant Intraperitoneal Chemotherapy in Patients with Pseudomyxoma Peritonei-A Novel Treatment Approach.

Neoadjuvant intravenous chemotherapy in patients with pseudomyxoma peritonei (PMP) has not shown convincing results. The effectiveness of neoadjuvant intraperitoneal (IP) chemotherapy has never been reported. This prospective, non-randomized phase II study included patients with PMP treated between May 2017 and December 2018, who were not considered suitable for primary cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). The majority of patients were treated with laparoscopic HIPEC (oxaliplatin 200 mg/m2, 60 min, 43 °C). IP chemotherapy was started 2 weeks after docetaxel 40 mg/m2 + cisplatin 40 mg/m2, accompanied by oral S1 (tegafur, gimeracil, and oteracil) (50 mg/m2) for 14 days, followed by one week rest. Clinical parameters and complications were recorded. In total, 22/27 patients qualified for CRS and HIPEC after neoadjuvant treatment. A complete cytoreduction (Completeness of cytoreduction Score 0/1) could be achieved in 54.5%. The postoperative morbidity rate was 13.6% and mortality was rate 4.5%. In total, 20/22 patients had major pathological tumor responses. The mean drop in CEA was 28.2% and in the peritoneal carcinomatosis index (PCI) was 2.6. Positive or suspicious cytology turned negative in 69.2% of patients. Thus, for PMP patients who were not amenable for primary surgery, the majority received complete cytoreduction after treatment with neoadjuvant IP chemotherapy, with satisfying tumor regression and with low complication rates. The oncological benefit in terms of survival with this new treatment regimen needs to be proven.

Advances with pharmacotherapy for peritoneal metastasis.

INTRODUCTION: A new treatment strategy involving cytoreductive surgery (CRS) combined with perioperative intraperitoneal (IP) chemotherapy was proposed in 1999 by the Peritoneal Surface Oncology Group International, and the strategy is now justified as a state-of-the-art treatment to improve the long-term survival of patients with peritoneal metastasis (PM). To achieve cure in the patients with PM, complete removal of macroscopic tumors and eradication of micrometastasis on the peritoneum, left after CRS are essential. Systemic chemotherapy is not indicated for the treatment of PM. In contrast, intraperitoneal (IP) chemotherapy brings about significantly higher locoregional dose intensity in the peritoneal cavity and subperitoneal tissues. In combination with anticancer drugs, hyperthermia enhances cytotoxicity against cancer cells. AREA COVERED: This article provides a systematic overview of PM from various cancers including gastric, colorectal, small bowel, appendiceal cancer, and mesothelioma. It also includes all the essential aspects of therapy. EXPERT OPINION: CRS plus perioperative intraperitoneal chemotherapy is safe with acceptable morbidity and mortality. It is justified as a standard treatment to improve the long-term survival of patients with PM and is now performed with curative intent for PM from various malignancies.

Long Term Survival after Cytoreductive Surgery Combined with Perioperative Chemotherapy in Gastric Cancer Patients with Peritoneal Metastasis.

The present study demonstrated prognostic factors for long-term survival in patients after a comprehensive treatment (CHT) for peritoneal metastasis (PM) from gastric cancer (GC). MATERIALS AND METHODS: Among 419 patients treated with neoadjuvant intraperitoneal/systemic chemotherapy (NIPS), 266 (63.5%) patients received complete resection (CC-0) of the macroscopic tumors. In total, 184 (43.9%) patients were treated with postoperative systemic chemotherapy. RESULTS: All patients treated who received incomplete cytoreduction (CC-1) died of GC within 6 years. In contrast, 10- year survival rates (-YSR) of CC-0 resection were 8.3% with median survival time (MST) of 20.5 months. Post-NIPS peritoneal cancer index (PCI) ≤11, and pre-NIPS PCI ≤13 were the significant favorable prognostic factors. Patients with numbers of involved peritoneal sectors ≤5 survived significant longer than those with ≥6. Both negative pre- and post-NIPS cytology was associated with significant favorable prognosis. Multivariate analyses identified pre-PCI (≤13 vs. ≥14), and cytology after NIPS (negative cytology vs. positive cytology) as independent prognostic factors. Ten year-survivors were found in patients with involvement of the greater omentum (9%), pelvic peritoneum (3%), para-colic gutter (13.9%), upper jejunum (5.6%), lower jejunum (5.5%), spermatic cord (21.9%), rectum (9.5%), ureter (6.3%), ovary (6.7%), and diaphragm (7.0%) at the time of cytoreduction. Twenty-one patients survived longer than 5 years, and 17 patients are still alive without recurrence. CONCLUSIONS: GC-PM should be removed aggressively, in patients with PCI after NIPS ≤11, PCI before NIPS ≤13, mall bowel PCI ≤2, and complete cytoreduction should be performed for metastasis in ≤5 peritoneal sectors.

Hyperthermic intraperitoneal chemotherapy in management of malignant intraductal papillary mucinous neoplasm with peritoneal dissemination: Case report.

INTRODUCTION: Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are treatment to deal with peritoneal dissemination that has excellent result for various cancer especially pseudomyxoma peritonei (PMP), mesothelioma. For now, this combination of treatment is still running for pancreatic adenocarcinoma but no description for pancreatic cystic tumor like malignant Intraductal papillary mucinous neoplasm (IPMN). PRESENTATION OF CASES: We report 3 cases of malignant IPMN with peritoneal dissemination that treated with CRS and HIPEC. Two cases have atypical presentation of malignant IPMN with PMP. HIPEC was performed using cisplatin-based regimen. The longest survival in this study is 93 months, compared to the median survival of 44.3 months without HIPEC. DISCUSSION: CRS and HIPEC have not proven to treat in patient with pancreatic cystic tumor with peritoneal dissemination. But these treatments can be improved survival outcome in selected patient. CONCLUSION: CRS and HIPEC trend to improve survival. More studies need, not only to evaluate the role of HIPEC on malignant IPMN, but also prognosis and outcome.

Prognostic significance of the presence of epithelial cell clusters in the ascites of patients with pseudomyxoma peritonei.

BACKGROUND: Pseudomyxoma peritonei (PMP) is a rare condition characterized by intraperitoneal accumulation of mucus due to mucinous neoplasia. The characteristic cytological feature of PMP in the ascites is abundant mucus with or without epithelial cell clusters. However, the prognostic significance of the presence of epithelial cell clusters has not been determined. This study aimed to determine the prognostic significance of epithelial cell clusters in the ascites of patients with PMP. METHODS: Patients who were clinically and histopathologically diagnosed with PMP and who underwent intraoperative cytological examination of their ascites were included in this study. Cytological characteristics including mucus and epithelial cell clusters, nuclear atypia, and the presence of signet ring cells were investigated. Overall survival was compared based on the presence of epithelial cell clusters or nuclear atypia. RESULTS: A total of 283 patients (199 women and 84 men) were investigated. The most common original site was the appendix (244 patients). Ninety patients (31.8%) had mucus without epithelial cell clusters (acellular mucin) while 193 (68.2%) had mucus with such clusters; 134 (69.4%) and 44 (22.8%) of these patients showed low-grade and high-grade nuclear features, respectively. Signet ring cells were detected in 15 patients (7.8%). The presence of epithelial cell clusters did not influence overall survival (P = .28); however, high-grade nuclear features and signet ring cell presence were significant negative prognostic factors (P < .001). CONCLUSION: The presence of high-grade nuclear features or of signet ring cells should be carefully investigated in the cytological specimens of patients with PMP.

History of Peritoneal Surface Malignancy Treatment in Japan.

In this review, Japanese experience of cytoreductive surgery and perioperative chemotherapy is described. The new concept of peritoneal metastasis (PM) type, i.e., trans-mesothelial, trans-lymphatic, and superficial growing metastasis type was proposed in 2012. Surgeons should perform peritonectomy according to the type of PM. Since 1980, Japanese surgical oncologists have been spearheading the use of cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemoperfusion (HIPEC) as treatment for PM from gastric cancer. Two RCTs were conducted to verify the effect of HIPEC for the prophylaxis of peritoneal recurrence after curative resection of advanced gastric cancer. These two studies indicated that HIPEC is effective in preventing peritoneal recurrence of gastric cancer with serosal invasion. In 2002, intraperitoneal chemotherapy using taxans was developed for the treatment of PM from gastric cancer and led to the development of neoadjuvant intraperitoneal/systemic chemotherapy (NIPS), which was reported in 2006. In 2009, extensive intra-operative peritoneal lavage (EIPL) was developed, and contributed to the remarkable improvement in survival of patients with positive lavage cytology as demonstrated by prospective randomized clinical trials. In 2017, the Peritoneal Surface Oncology Group International proposed the value of complete cytoreduction and peritoneal cancer index cut-off as independent prognostic factors after CRS for gastric cancer with PM. Founded in 2016, the Japanese/Asian School of Peritoneal Surface Oncology (JASPSO) trains beginners to perform CRS and HIPEC safely. Sixteen students have already graduated from JASPSO and started to perform the treatment in their home countries.

Prognostic Factors of Malignant Peritoneal Mesothelioma Experienced in Japanese Peritoneal Metastasis Center.

BACKGROUND AND OBJECTIVES: The current standard of treatment for malignant peritoneal mesothelioma(MPM)is cytoreductive surgery(CRS)plus perioperative intraperitoneal or systemic chemotherapy(comprehensive treatment), The present study was performed to clarify the prognostic factors of PMP after comprehensive treatment. METHODS: Among 63 patients with MPM, male and female patients were 34 and 29. CRSwas performed in 47 patients and complete cytoreduction(CC-0) was performed in 14(22%)patients. Mean numbers of resected peritoneal sectors and organs were 5.2(1-13), and 2.9(0- 9), respectively. Hyperthermic intraperitoneal chemoperfusion(HIPEC)was performed in 27 patients. Grade 1/2, Grade 3, and Grade 4 complications were experienced in 5, 6, and 3 patients, respectively. One patient died of sepsis, and the mortality rate was 2.3%. Independent prognostic factors for favorable prognosis were performance of HIPEC, peritoneal cancer index (PCI)score C12, no distant metastasis and histologic epithelial type. Relative risk of no HIPEC, PCI score B13, presence of distant metastasis and non epithelial type were 7.69, 22.1, 3.6 and 3.9, respectively. CONCLUSIONS: Risk factors for death after comprehensive treatment were no HIPEC, PCI score B13, and non epithelial type. However, only 11(17%)patients showed PCI score C12. Accordingly, PCI score should be reducedC12 before CRSby neoadjuvant chemotherapy.

Analysis of Treatment Failure after Complete Cytoreductive Surgery for Peritoneal Metastasis from Appendiceal Mucinous Neoplasm at a Japanese High Volume Center for Peritoneal Surface Malignancy.

BACKGROUND AND OBJECTIVES: Treatment failure after complete cytoreduction for appendiceal mucinous carcinoma peritonei (AMCP)has not been fully investigated. The present study was performed to clarify the risk factor for recurrence after complete cytoreduction for AMCP. METHODS: A total of 400 patients with AMCP who underwent complete cytoreductive surgery combined with perioperative chemotherapy were investigated. RESULTS: Documented recurrence was developed in 135 (33.8%)patients. The 5- and 10-year progression-free survival was 51% and 49%, respectively. By multivariate analysis, histological subtype of peritoneal disease(high-grade AMCP[AMCP-H]and AMCP-H with signet ring cells), serum CA19- 9 level, and PCIB20 were significantly associated with reduced progression-free survival. In contrast, histologic subtype of mucin without epithelial cells(MWEC)showed the lowest risk for recurrence. Eighty-six patients had localized intra-abdominal recurrence, and 42 patients had diffuse peritoneal recurrence. Recurrence was found in the various peritoneal sectors. Eighty-one patients underwent complete cytoreduction for the recurrence, and the overall survival 5-year survival rate after secondary cytoreduction was 49%. CONCLUSIONS: Risk factors for recurrence were histologic subtype, PCI cutoff level, and serum CA19-9 levels. Aggressive second attempt of cytoreduction in patients with localized recurrence improved the survival.

Effects of Cytoreductive Surgery Combined with Perioperative Chemotherapy on Long-Term Survivals of Colorectal Cancer Patients with Peritoneal Metastasis, with Special Reference to the Involved Peritoneal Sectors and Organs.

Peritoneal Surface Oncology Group International(PSOGI)proposed a novel treatment, named comprehensive treatment for peritoneal metastasis(PM)from colorectal cancer(CRC). The present study demonstrated the efficacies of the treatment regarding the peritoneal sectors and organs involved with PM from CRC. MATERIALS AND METHODS: Among 365 patients received laparotomy, 278 CRC patients with PM underwent complete cytoreductive surgery(CC-0). RESULTS: After CC-0 resection Grade 3, Grade 4, and Grade 5 postoperative complication were found in 20(7.2%), 26(9.3%), and 6(2.2%). Five- and 10-year survival rate(YSR)of CC-0 resection were 24.5%, and 11.6% with median survival time(MST)of 42.0 months. Regarding the peritoneal cancer index(PCI)of small bowel(SB-PCI), all patients of PCI B3 died of the disease. In contrast, 10-YSR of patients with SB-PCI of 0, 1, and 2 were 26.1%, 19.5%, and 6.2%, respectively. Ten-YSR of patients with the number of involved peritoneal sectors C9 ranged from 6.9% to 29.8%. MST of patients with PM in each peritoneal sector(sector 0 to sector 8)ranged from 26.4 months to 49.2 months, and 10-YSR ranged from 4.2%to 17.2%. Ten-YSR of patients with involvement of rectum, stomach, liver capsule, seminal vesicle, ureter, uterus, or ovary ranged from 0% to 16.9%. CONCLUSIONS: From the present data, PM should be removed aggressively to achieve complete cytoreduction, when the patients with PCIC26, involved peritoneal sectorsC9 and SB-PCIC2 are supposed to receive complete cytoreduction of PM.