The aim of our study was to provide population‐based data on incidence and prognosis of synchronous peritoneal carcinomatosis and to evaluate predictors for its development. Diagnosed in 1995–2008, 18,738 cases of primary colorectal cancer were included. Predictors of peritoneal carcinomatosis were analysed by multivariable logistic regression analysis. Median survival in months was calculated by site of metastasis. In the study period, 904 patients were diagnosed with synchronous peritoneal carcinomatosis (4.8% of total, constituting 24% of patients presenting with M1 disease). The risk of peritoneal carcinomatosis was increased in case of advanced T stage [T4 vs. T1,2: odds ratio (OR) 4.7, confidence limits 4.0–5.6), advanced N stage [N0 vs. N1,2: OR 0.2 (0.1–0.2)], poor differentiation grade [OR 2.1 (1.8–2.5)], younger age [<60 years vs. 70–79 years: OR 1.4 (1.1–1.7)], mucinous adenocarcinoma [OR 2.0 (1.6–2.4)] and right‐sided localisation of primary tumour [left vs. right: OR 0.6 (0.5–0.7)]. Median survival of patients with peritoneum as single site of metastasis remained dismal [1995–2001: 7 (6–9) months; 2002–2008: 8 (6–11) months], contrasting the improvement among patients with liver metastases [1995–2001: 8 (7–9) months; 2002–2008: 12 (11–14) months]. To conclude, synchronous peritoneal metastases from colorectal cancer are more frequent among younger patients and among patients with advanced T stage, mucinous adenocarcinoma, right‐sided tumours and tumours that are poorly differentiated. The prognosis of synchronous peritoneal carcinomatosis remains poor with a median survival of 8 months and even worse if concomitant metastases in other organs are present.

No abstract

Prognosis of patients with pancreatic cancer presenting with PC remains extremely poor. Treatment options are scarce and, given the magnitude of the problem, efforts should be undertaken to develop effective treatments in experimental and clinical studies.

Peritoneal carcinomatosis (PC) is one manifestation of metastatic colorectal cancer (CRC). Tumor growth on intestinal surfaces and associated fluid accumulation eventually result in bowel obstruction and incapacitating levels of ascites, which profoundly affect the quality of life for affected patients. PC appears resistant to traditional 5-fluorouracil-based chemotherapy, and surgery was formerly reserved for palliative purposes only. In the absence of effective treatment, the historical prognosis for these patients was extremely poor, with an invariably fatal outcome. These poor outcomes likely explain why PC secondary to CRC has received little attention from oncologic researchers. Thus, data are lacking regarding incidence, clinical disease course, and accurate treatment evaluation for patients with PC. Recently, population-based studies have revealed that PC occurs relatively frequently among patients with CRC. Risk factors for developing PC have been identified: right-sided tumor, advanced T-stage, advanced N-stage, poor differentiation grade, and younger age at diagnosis. During the past decade, both chemotherapeutical and surgical treatments have achieved promising results in these patients. A chance for long-term survival or even cure may now be offered to selected patients by combining radical surgical resection with intraperitoneal instillation of heated chemotherapy. This combined procedure has become known as hyperthermic intraperitoneal chemotherapy. This editorial outlines recent advancements in the medical and surgical treatment of PC and reviews the most recent information on incidence and prognosis of this disease. Given recent progress, treatment should now be considered in every patient presenting with PC.

Despite increasing usage of palliative chemotherapy and availability of new agents, population-based survival of patients with PC did not improve until very recently. Response to palliative chemotherapy in PC should be evaluated separately from haematogenous metastases.

A combination of CS and HIPEC results in longer survival than CS alone in rats with PC of colorectal origin.

The effectiveness of intraoperative intraperitoneal perfusion after CS is highly dependent on the presence of chemotherapeutic agents in the perfusate but not on hyperthermia. The need to include hyperthermia in the adjuvant intraoperative treatment after CS for PC should be further investigated.

Background. Perioperative intraperitoneal chemotherapy is used as an adjunct to cytoreductive surgery (CS) for peritoneal carcinomatosis (PC) in order to prolong survival. Worldwide, hyperthermic intraperitoneal chemotherapy (HIPEC), early postoperative intraperitoneal chemotherapy (EPIC), and combinations of the two are used. It remains unclear which regimen is most beneficial. Methods. The rat colon carcinoma cell line CC-531 was injected into the peritoneal cavity of 80 WAG/Rij rats to induce PC. Animals were randomized into four treatment groups (n = 20): CS only, CS followed by HIPEC (mitomycin 35 mg/m 2 at 41.5°C), CS followed by EPIC during 5 days (i.p. injection of mitomycin on day 1 and 5-fluorouracil on days 2-5), and CS followed by HIPEC plus EPIC. Primary outcome was survival. Results. In rats treated with CS only, median survival was 53 days (95% confidence interval (CI) 49-57 days). In rats treated with CS followed by HIPEC, survival was significantly (P = 0.001) increased (median survival 94 days, 95% CI 51-137 days). In the group treated with EPIC after CS, 12 out of 20 rats were still alive at the end of the experiment (P \ 0.001 as compared with CS only). In the group receiving both treatments, 11 rats died of toxicity, and therefore this group was not included in the survival analysis.Conclusions. Both EPIC and HIPEC were effective in prolonging survival. The beneficial effect of EPIC on survival seemed to be more pronounced than that of HIPEC.Further research is indicated to evaluate and compare the possible benefits and adverse effects associated with both treatments.