Diagnostic and therapeutic algorithm for colorectal peritoneal metastases. A consensus of the peritoneal surface malignancies onco-team of the Italian society of surgical oncology

INDEPSO-ISPSM Consensus on Peritoneal Malignancies: Management of Colorectal Peritoneal Metastases

PURPOSE

This manuscript reports the results of the Indian Network for Development of Peritoneal Surface Oncology and Indian Society of Peritoneal Surface Malignancies (INDEPSO-ISPSM) consensus that aimed to provide recommendations for some important aspects management of patients with colorectal peritoneal metastases (CPM) and address some issues unique to India.

METHODS

The modified Delphi technique was used with two rounds of voting. There were 29 questions on nine main topics-the role of cytoreductive surgery (CRS), patient selection for CRS, preoperative workup, role of systemic chemotherapy (SC), CPM with other visceral metastases, molecular profile, hyperthermic intraperitoneal chemotherapy (HIPEC) and other modalities of intraperitoneal chemotherapy (IPC), prophylactic/preventive strategies, and surveillances after CRS. A consensus was achieved if anyone option received >70 votes (strong consensus >90%).

RESULTS

Forty-eight surgical (n = 41) and gastrointestinal (n = 7) oncologists were invited; 44 agreed to participate. The response rate was 95.4% (42/44) in round 1 and 93.1% (41/44) in round 2. Overall, a consensus was achieved on 23/29 (79.3%) questions (strong consensus on 6/29 [20.6%]). The panel strongly recommended considering surgery for limited CPM with limited liver metastases (92.5%), not altering the surgical approach in patients with KRAS mutations (91.67%), and limiting the use of IPC for unresectable CPM outside clinical trials (95%). Adjuvant SC was recommended for all patients undergoing CRS (89.47%). CRS is a therapeutic option for selected patients with CPM including those with metachronous CPM (79.49) and signet ring cell cancers (76.92%). HIPEC was recommended outside clinical trials only for patients with peritoneal cancer index 11-15(80%).

CONCLUSION

The panel recommended CRS for most indications but was very selective in recommending HIPEC and IPC outside clinical trials. These recommendations should be a useful resource in clinical decision making for clinicians treating CPM in India and regions with a similar sociodemographic background.

Colorectal Cancer with Peritoneal Metastases: The Impact of the Results of PROPHYLOCHIP, COLOPEC, and PRODIGE 7 Trials on Peritoneal Disease Management

HIPEC is a potentially useful locoregional treatment combined with cytoreduction in patients with peritoneal colorectal metastases. Despite being widely used in several cancer centers around the world, its role had never been investigated before the results of three important RCTs appeared on this topic. The PRODIGE 7 trial clarified the role of oxaliplatin-based HIPEC in patients treated with radical surgery. Conversely, the PROPHYLOCHIP and the COLOPEC were designed to chair the role of HIPEC in patients at high risk of developing peritoneal metastases. Although all three trials demonstrated the relative ineffectiveness of HIPEC for treating or preventing peritoneal metastases, these results are not sufficient to abandon this technique. In addition to some criticisms relating to the design of the trials and their statistical value, the oxaliplatin-based HIPEC was found to be ineffective in preventing or treating peritoneal colorectal metastases, especially in patients already treated with systemic platinum-based chemotherapy. Several studies are ongoing investigating further HIPEC drugs and regimens. The review deeply discussed all the aspects and relapses of this new evidence.

Treatment Strategies and Prognosis of Patients With Synchronous or Metachronous Colorectal Peritoneal Metastases: A Population-Based Study

BACKGROUND

This study aimed to compare treatment strategies and survival of patients with synchronous colorectal peritoneal metastases (CPM) and patients with metachronous CPM in a nationwide cohort.

METHODS

All patients from the Netherlands Cancer Registry with synchronous or metachronous CPM whose primary colorectal cancer (CRC) was diagnosed between 1 January and 30 June 2015 were included in the study. Treatments were categorized as (A) cytoreductive surgery and hyperthermic intraperitoneal chemotherapy [CRS-HIPEC]; (B) palliative treatment; or (C) best supportive care. Overall survival (OS) for all the patients and disease-free survival (DFS) for those who underwent CRS-HIPEC were compared between the two groups.

RESULTS

Of 7233 patients, 743 had a diagnosis of CPM, including 409 patients with synchronous CPM and 334 patients with metachronous CPM. The median OS was 8.1 months for the patients with synchronous CPM versus 12 months for the patients with metachronous CPM (p = 0.003). After multivariable correction, OS no longer differed between the patients with synchronous CPM and those with metachronous CPM (HR 1.03 [0.83-1.27]). The patients with metachronous CPM more often underwent CRS-HIPEC than the patients with synchronous CPM (16 % vs 8 %; p = 0.001). The two groups did not differ statistically in terms of DFS and OS (median DFS, 21.5 vs 14.1 months, respectively; p = 0.094; median OS, 37.8 vs. 35.8 months, respectively; p = 0.553).

CONCLUSION

This population-based study showed that survival for the patients with synchronous CPM and patients with metachronous CPM did not significantly differ. This suggests that a similar prognosis may be expected for patients selected for treatment regardless of the onset of CPM.