Peritoneal carcinomatosis has long been considered incurable. Despite the development of new, more effective chemotherapeutic agents and combinations, the results of systemic chemotherapy treatment remain disappointing, with a limited impact on survival. Patients with peritoneal carcinomatosis have long been considered as a terminal condition with no curative options. The natural history of untreated patients with this condition showed a median survival ranging between 3 and 9 months depending on the primary tumor involved.^1–4 There is a renewed interest in peritoneal surface malignancies with a new therapeutic strategy towards peritoneal carcinomatosis being developed over the past 20 years combining maximum radical cytoreductive surgery and perioperative intraperitoneal chemotherapy. Some interesting results have been reported although a majority of oncologists remains skeptical regarding this combined therapeutic approach.⁵⁶ To provide further data, a collaborative effort of the Spanish institutions involved in the treatment of peritoneal surface malignancies gathered information on a large number of patients to evaluate the efficacy of this treatment, and to identify principal prognostic indicators. The aim of this study is to present the preliminary results of the Spanish national experience of the main groups involved in this new treatment alternative.#

A retrospective multicenter study was performed to evaluate the national experience with this combined treatment strategy and to identify the principal prognostic indicators.#

During the months of April and June 2004, a questionnaire was sent out nationally to all the General Surgery and Digestive Tract departments of the hospital centers in Spain interested in this problem.#

A data sheet was enclosed, with the date of July 31, 2004 as the limit for including patients and September 30 as the limit for collecting data. The inclusion criteria were peritoneal carcinomatoses from different malignancies confirmed by pathologic examination. All patients had their cytoreductive surgery before July 2004 and had to have received perioperative intraperitoneal chemotherapy defined as heated intraperitoneal intraoperative chemohyperthermia (HIIC) or early postoperative intraperitoneal chemotherapy (EPIC), or both, administered within 7 days of their surgery. Excluded were patients not treated with intraperitoneal chemotherapy or intraperitoneal chemotherapy performed more than 7 days after surgery. Patients with extra-abdominal metastases were excluded. Standardized clinical data on consecutive patients from each institution were entered into a central database. One institution recorded more than 50 patients, 3 institutions recorded 30–50 patients, 3 institutions recorded 10–30 patients, and 2 institutions recorded fewer than 10 patients. Each institution recorded all consecutive procedures performed in the study period. One author (AGP) reviewed all data sheets before their entry in the database in an effort to make this a uniform interpretation.#

A standard data form was created to retrieve information on the primary tumor including its location, the presence or absence of hepatic or lymphatic metastases, and the differentiation of the primary tumor. The form also recorded information on the status of the patient before undergoing the combined procedure, including the sex, the age, the extent of peritoneal carcinomatosis, and the previous treatment with systemic chemotherapy. The extent of peritoneal carcinomatosis was assessed by intraoperative exploration. Individual institutions used 2 different tools to assess the extent of carcinomatosis, the Lyon classification and the Peritoneal Cancer Index (PCI).⁷⁸ Information recorded about the combined procedure included the date, the completeness of cytoreductive surgery, the simultaneous resection of the primary tumor, the presence or absence of lymph node metastases or liver metastases, the type of perioperative intraperitoneal chemotherapy (HIIC, EPIC, or both) and treatment with adjuvant systemic chemotherapy, including the drugs used. Information was obtained regarding the postoperative course including postoperative death (within 30 postoperative days) and its etiology, major complications, and reoperations. Follow-up data recorded included the data of the most recent follow-up, the status of the patient (alive with disease, alive without disease, dead with disease, dead without disease), the location of the initial site recurrence, and all other sites of recurrence after the initial site recurrence.#

Analysis was performed up to July 2004. Data were recorded and analyzed with a commercially available computer program (SPSS 12.0 for Windows. The Apache Software Foundation, USA). To study relationships between variables, standard tests have been used: Chi-square with 2 variables, Pearson's correlation (or Spearman's ranks correlation) if quantitative, and analysis of variance, Student's t-test, otherwise Kruskall–Wallis H-test, depending on the number of distributions, normality, and differences of variances. A Kaplan–Meier survival curve was fitted to the data and log-rank testing was used to identify differences between curves.⁹ Cox's regression model was used for multivariate survival analysis. Continuous variables were analyzed with an unpaired Student's t-test.¹⁰ Fischer's exact test was used to analyze categorical variables. P≤0.05 was considered statistically significant. The postoperative deaths were not excluded from the survival analysis.#

From the study of the database which draws on the cases reported by the 9 Spanish centers interested in the implementation and development of this treatment program for peritoneal carcinomatosis, it can be concluded that considering cancer management as a national problem few centers are at present offering this type of treatment, with experiences that are limited in time and number of cases. There is a progressive increase in interest that can be detected and there are already more than 6 groups with experience of more than 25 cytoreductions.#

The pathology most often treated is carcinomatosis of ovarian and appendiceal origin. The best results are obtained by performing an almost always radical cytoreduction in both pathologies and in the case of the ovarian cancer, treatment with systemic postoperative chemotherapy.#

The guidelines for chemotherapy are not homogenous, even though the majority of the patients (61%) received hyperthermic intraoperative intraperitoneal chemotherapy with hyperthermia with a time range of between 30 and 90min, and reaching temperatures between 40 and 43°C. In Spain this radical treatment also entails a raised morbidity and mortality rate. It has a postoperative mortality of 7.8%. The serious morbidity was 37.5% with reintervention in 18% of the patients.#

From this contribution to worldwide experience we may conclude that the Spanish carcinomatosis treatment group has laid its foundations, developing the program in more than 9 hospital centers throughout Spain, with encouraging results. These are comparable in terms of morbidity and mortality and survival with those being published in the world literature, although numerically the contribution is small.#

We propose to establish a Spanish Peritoneal Surface Oncology Group to develop a national register of patients treated with this therapeutic alternative. This should include standards for registering the disease, description of the treatment with intraperitoneal chemotherapy, a register of complications and survival rates.#