Multicystic Peritoneal Mesothelioma Treated by Surgical Cytoreduction and Hyperthermic Intra-peritoneal Chemotherapy (HIPEC) D. BARATTI 1, S. KUSAMURA 1, A. SIRONI 2, A. CABRAS 3, L. FUMAGALLI 4, B. LATERZA 1 and M. DERACO 1 Departments of 1 Surgery, 3 Pathology and 4 Anestesiology, and 2 The Nutritional Care Unit, National Cancer Institute, Milan, Italy Abstract. Background: Multicystic peritoneal mesothelioma (MPM) is an extremely uncommon lesion with uncertain malignant potential. Multiple recurrences after surgical interventions and transition to aggressive malignancies have been reported. Here, we review our experience with cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC) in the management of MPM. Patients and Methods: Five women with MPM underwent 6 procedures of cytoreduction and close-abdomen HIPEC with cisplatin and doxorubicin. Three patients had recurrent disease after 1, 2 and 4 previous debulkings, respectively. Results: Optimal cytoreduction (residual tumor nodules 2.5 mm) was performed in all the procedures. One grade 4 postoperative complication (NCI/ CTCAE v.3.0) and no operative mortality occurred. Median follow-up was 31 months (range 3-102). MPM recurred in two patients: one is presently disease-free after a second cytoreduction with HIPEC and the other is alive with minimal stable disease. Conclusion: Definitive eradication by means of cytoreduction and HIPEC seems a safe and effective therapeutic option for MPM. To date, approximately 130 cases of multicystic peritoneal mesothelioma (MPM) have been reported in the literature (1-5). According to information coming from single case reports, small series or relatively larger pathological reviews with incomplete follow-up, MPM generally affects women of reproductive age with no history of asbestos exposure and shows an indolent clinical behaviour. However, uncertainty still exists on its natural history and no uniform treatment strategy has been established (3-5). Correspondence to: Marcello Deraco, MD, Fondazione IRCCS Istituto Nazionale Tumori Milano, Via Venezian n.1, 20133 Milano, Italy. Tel: +3902 23902362, Fax: +3902 3902404, e-mail: marcello.deraco@istitutotumori.mi.it Key Words: Multicystic peritoneal mesothelioma, peritonectomy, hyperthermic intra-peritoneal chemotherapy, HIPEC. In recent years, the combination of surgical cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC) has reportedly resulted in a considerable outcome improvement for selected patients with diffuse malignant peritoneal mesothelioma (6-9). Considering its known potentiality to relapse and to evolve into an aggressive malignant tumour (10-11), MPM may represent a potential indication to multimodality treatment. To date, however, the disease has been treated by means of cytoreduction and HIPEC in only a few patients (12). In the present paper we present our experience with cytoreduction and HIPEC in the management of MPM, attempting to evaluate feasibility and effectiveness of such a combined modality approach in this controversial clinical setting. Patients and Methods Data for the present analysis derived from a prospective database including 301 individuals treated with cytoreduction and HIPEC at the National Cancer Institute (Milan, Italy). Additional clinical information were collected from the medical charts. All the patients included in the present study were treated according to a protocol approved by the Institutional Ethics Committee and gave their written informed consent. Diagnosis of MPM was based on hematoxylin/eosin slides and immunohistochemical studies. Morphological criteria to diagnose MPM were the presence of multiple variably sized cysts separated by fibrous/adipose septa and lined by single layers of flattened to cuboidal mesothelial cells with no or little atypia. The following immunohistochemistry tests were used for confirmation: positive calretinin, cytokeratins 5/6, Wilms' tumor 1/antigen and negative CEA, B72.3 and Ber-Ep4. The available slides from previous operations were also reviewed. Additional eligibility criteria were age 75 years, performance status 2 according to the Eastern Cooperative Oncology Group (ECOG), no significant co-morbidities, potentially resectable peritoneal disease and no hepatic or extra-abdominal metastases at preoperative CT-scan. The details of the operative technique adopted in our centre were described previously (8). Briefly, the goal of cytoreduction was to remove all the visible tumour by means of pelvic and parietal 0258-851X/2008 $2.00+.40 153
Table I. Six procedures of surgical cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC). No. Age at Presenting Diagnosis Previous treatment (outcome) Cytoreductive surgery PCI CC Outcome (therapy) diagnosis symptoms procedures 1 37 Ileus Laparotomy TAH, BSO (PRO 11 months) TPP 9 1 NED 102 months Debulking (PRO 18 months) Debulking (PRO 24 months) Debulking (PRO 31 months) 2 50 Incidental Laparotomy TAH (PRO 22 months) TPP, splenectomy, BSO 26 0 PRO 18 months (2nd cyt.+ HIPEC) NED 46 months 3 39 Incidental Laproscopy TPP, appendectomy, 10 0 NED 31 months TAH+BSO 4 22 Abdominal pain Laparotomy Debulking (PRO 27 months) TPP 8 0 PRO 23 months Complete excision AWD 27 months (PRO 28 months) (waiting for 2nd cyt. + HIPEC) 5* TPP, splenectomy 19 0 NED 25 months 6 40 Umbilical hernia Laparotomy Hernia repair, omental biopsy TPP, sigmoidectomy, 20 0 NED 3 months Abdominal pain right-colectomy, splenectomy, TAH+BSO *Submitted to the procedure for the second time. TAH: Total abdominal hysterectomy; BSO: bilateral salpingo-oophorectomy; TPP: total parietal peritonectomy; PCI: peritoneal cancer index; CC: completeness of cytoreduction score; cyt.: surgical cytoreduction; NED: no evidence of disease; AWD: alive with disease; PRO: disease progression. peritonectomy, greater and lesser omentectomy. Due to the low invasiveness of MPM, small tumor deposits on visceral serosa were preferably removed by electrosurgical dissection. Organ resections were performed only if massive disease involvement precluded a conservative approach. HIPEC was performed according to the closed abdomen technique for 60 minutes, at a temperature of 42.5ÆC, with cisplatin (43 mg/l) plus doxorubicin (15.25 mg/l). The perfusate volume was 4-6 L and average flow 700 ml/min. For one patient submitted to the procedure for the second time due to disease recurrence drug schedule was cisplatin (25 ml/m 2 /L) plus mitomycin-c (3.3 mg/m 2 /L). The extent of peritoneal involvement was scored at surgical exploration according to the Peritoneal Cancer Index (PCI) (13). The completeness of cytoreduction (CC) was classified at the end of the cytoreduction according to Sugarbaker criteria (13): CC- 0=no residual disease; CC-1=residual disease nodules 2.5 mm; CC-2= residual disease nodules >2.5 mm but 25 mm; CC- 3=residual disease nodules >25 mm. Postoperative complications occurring within 30 days from the procedure were scored according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 3.0 (NCI CTCAE v.3.0) (14). All the patients underwent postoperative follow-up. Clinical evaluation and thoracic/abdominal CT-scan were performed every 3 months during the first 2 years and every 6 months afterward. Postoperative disease progression was confirmed at surgical exploration, by CT-scan/ultrasound guided biopsy or according to the Response Evaluation Criteria in Solid Tumour Group (RECIST) (15). Overall (OS) and progression-free survival (PFS) were calculated from the day of surgery to the time of death due to any cause or postoperative disease progression, according to the Kaplan-Meier method. Patients with an uneventful postoperative course were censored at the time of their last follow-up visit. Results From August 1995 to September 2007, 5 patients with multicystic mesothelioma underwent 6 procedures of cytoreduction and HIPEC. Patient characteristics and clinical history before comprehensive treatment are summarized in Table I. All the patients were females with no documented history of asbestos exposure; median age at diagnosis was 38 years (range 22-50 years). Diagnosis of MPM was established by means of laparotomy in 3 patients and laparoscopy in 2. All the patients complained of abdominal distension and/or pain at the time of comprehensive treatment. Before cytoreduction and HIPEC, three patients underwent to 1, 2 and 4 surgical resections of their disease, respectively. Disease extent and completeness of cytoreduction were retrospectively reviewed. The mean PCI was 12 (range 8-14). Only one patient underwent macroscopically complete surgical cytoreduction (and no HIPEC) in our institution before the initiation of our peritoneal malignancy treatment program; the remaining operations performed elsewhere were all considered as debulking surgery. Disease progression invariably followed all these 7 surgical attempts, with an overall median time-to-progression of 24 months (range 11-31 months). By the time of cytoreduction and HIPEC, the mean PCI was 15.3 (range 8-26). Optimal cytoreduction with no or minimal ( 2.5 mm) residual disease was accomplished in all six procedures. In addition to complete parietal 154
Baratti et al: Multicystic Peritoneal Mesothelioma Figure 1. Overall (heavy line) and progression-free survival (light line) in 5 patients treated with cytoreduction and HIPEC for multicystic peritoneal mesothelioma. Figure 2. Progression-free survival after cytoreduction with HIPEC for multicystic peritoneal mesothelioma (heavy line) and after 7 debulking procedures performed in 3 patients during their previous clinical history (light line). peritonectomy, 8 visceral resections were made during 4 operations. Splenectomy, followed by hysterectomy with bilateral salpingo-oophorectomy, was the most commonly performed procedure. Two colon resections were performed in one patient; no small bowel resection were performed. The uterus and ovaries were spared in a reproductive age woman, according to patient will and limited disease involvement (see Table I). One grade 4 complication occurred within the first 30 postoperative days in a patient who required re-intervention and jejunostomy for a colorectal anastomosis dehiscence. No operative death occurred. The median follow-up was 31 months (range 3-102 months) for the overall series. At the end of the study period, postoperative disease progression occurred in two patients. In the first patient, MPM recurred 18 months after macroscopically complete cytoreduction and HIPEC; the patient underwent a second cytoreduction with HIPEC and she is presently disease-free after 25 months from reintervention. Histological features and immunochemistry staining pattern at recurrence were similar to those seen at initial cytoreduction. Additionally, disease recurrence involving the pelvis developed in the woman who underwent complete cytoreduction with sparing of uterus and ovaries. The patient is presently waiting to undergo a second cytoreduction with HIPEC. Overall and progression-free survival in the whole series are displayed in Figure 1. Progression-free survival after cytoreduction with HIPEC and after debulking procedures previously performed in the patients included in the present series are displayed in Figure 2. All the patients are presently free of symptoms related to the disease. Discussion Multicystic mesothelioma is a mesothelial neoplasm which occupies an intermediate position between the truly benign adenomatoid tumour and the rapidly lethal diffuse malignant mesothelioma (5). Although its histological features have been extensively described, disagreement still exists regarding the natural history of the disease (2-5). The nature of MPM as a benign or border-line lesion is still discussed (5). Furthermore, some authors suggest that MPM may be a simple reactive process, since the association with previous abdominal surgery, inflammation or endometriosis has been described (5). Nevertheless, disease recurrence is frequently reported in the literature and invariably occurred also in patients who underwent traditional debulking surgery before referral to our centre (3). One patient who did not receive any treatment died 12 years after the diagnosis of MPM (2). Transformation of MPM into malignant epithelial mesothelioma was reported in two patients by De Stephano and Gonzalez-Moreno, respectively (10-11). The first was a 6- month-old infant who died 11 months after partial resection. The second underwent cytoreduction and HIPEC and was alive with persistent macroscopic disease 25 months later. The optimal treatment for MPM is still a matter of debate. Most authors recommend complete surgical resection, although long-term treatment outcome is generally poor (3-5). Due to the risk of infertility related to pelvic surgery in women, more conservative treatment approaches, such as laparoscopic debulking, radiation, systemic or intraperitoneal chemotherapy, laser vaporization, percutaneous cyst drainage, hormone-therapy, sclero-therapy with anthracycline or simple observation have been attempted with uncertain results (4-5). 155
A strong rationale supports the management of MPM by means of surgical cytoreduction and HIPEC. Disseminated peritoneal malignancies typically recur unless complete removal by means of peritonectomy procedures is performed; the heated intraoperative locoregional chemotherapy minimizes the risk of residual tumour cell entrapment which could give rise to disease recurrence (16). Pseudomyxoma peritonei is successfully treated by cytoreduction and HIPEC. This disease shares with MPM common clinicopathological features, such as a bland histological aspect, a slow non-infiltrative growth and the tendency to remain confined within the abdominal cavity. Both pseudomyxoma and MPM, however, almost invariably recur after partial excision, resulting in progressive abdominal distension and return of symptoms (16). Our clinical results suggest that surgical cytoreduction combined with HIPEC is an effective and safe treatment option for patients with MPM. Prolonged symptom control was obtained at the price of acceptable morbidity and no mortality, since only one grade 4 complication (NCI CTCAE v.3) was recorded. In the literature, morbidity and mortality rates are 12-55% and 0-12% respectively following cytoreduction with HIPEC; they were 12% and 0.9%, respectively, in a series of 209 consecutive procedures performed in our institution for peritoneal malignancies of different origins (17). Given the uncertain malignant potential of MPM, a less aggressive surgical approach was adopted in this series, compared to the more extensive cytoreductive procedures used with more invasive disease processes (8). Tumour nodules adherent to visceral surfaces were preferably removed by means of local electrosurgical dissection, aiming at preserving postoperative function as much as possible. Colon resections were performed, due to massive disease involvement, only in one procedure. Nevertheless, complete or nearly complete cytoreduction was obtained in all the procedures, these findings likely reflecting the minimally invasive nature of MPM. Macroscopically complete cytoreduction was achieved in a reproductive-age woman although uterus and ovaries were spared according to her desire to preserve her fertility. However, disease recurrences involving the pelvis occurred in this patient, suggesting that the disease capacity to recur in spite of extensive treatment should not be underestimated. Little data are available in the literature regarding MPM treated by cytoreduction and HIPEC. In the series of the Washington Cancer Institute, 5 patients with MPM were alive at 6 to 69 months (median 37 months) after cytoreduction and HIPEC; one of them had persistent gross disease involving the right hemi-diaphragm (12). Brigand and Park included in their series two patients with MPM alive without recurrence at 67 and 31 months, respectively (7, 18). The scarcity of literature hampers the comparison between historical series and the results of comprehensive treatment. For this purpose, we reviewed the past clinical history of our patients: disease recurrence occurred after all the 7 debulking operations performed before referral to our centre, with a median time-to-progression of 24 months. Conversely, after a median follow-up of 31 months disease progression occurred only after 2 of 6 procedures of cytoreduction and HIPEC. Since we compared different treatment modalities in the same subset of patients, no imbalance in potential prognostic factor distribution likely occurred. Analogously, it may be assumed that complete tumor removal was feasible at the time of previous debulking, since it was achieved during the more recent cytoreduction. Therefore, such a striking difference strongly suggests the superiority of an integrated treatment strategy over traditional surgery. A bias, however, could have occurred in this setting. Since the presence of active disease was a condition for the patients to be included in the study, only cases with disease progression after previous surgery were analyzed and no data on patients who did not relapse after tumour excision were available. In conclusion, our data and literature review suggest that MPM are capable of multiple recurrences and transformation into invasive and potentially lethal processes. Hence, the definition of low-malignant potential tumors may be more appropriate. Based on our findings, definitive tumour eradication by means of peritonectomy procedures and HIPEC seems to be the optimal treatment to prevent disease recurrence and transition to a truly aggressive tumour. References 1 Mennemeyer R and Smith M: Multicystic peritoneal mesothelioma: a case report with electron microscopy of a case mimicking intra-abdominal cystic hygroma (lymphangioma). Cancer 44: 629-698, 1979. 2 Weiss SW and Tavassoli FA: Multicystic mesothelioma. 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