Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for peritoneal malignancies: How,to whom,and is centralization needed?

Cytoreductive surgery (CRS) with or without hyperthermic intraperitoneal chemotherapy (HIPEC) are treatment options for selected patients with peritoneal metastases from colorectal cancer (PM-CRC), and for rare peritoneal surface malignancies like pseudomyxoma peritonei (PMP) and malignant abdominal mesothelioma. ¹ Given the rarity of relevant cases, reporting outcomes like complications and long-term oncological results should be a requisite for all centers providing such services. Two current articles in Scandinavian Journal of Surgery from low to medium volume centers in Sweden and Finland highlight the importance of publishing such data, contributing to ongoing centralization debates. Despite volumes of 15–30 procedures per year, both centers achieved results in line with previously published literature.^2,3

Optimal treatment strategies for peritoneal malignancies require a dedicated multidisciplinary approach including radiology, oncology, surgery, and pathology. The robustness of complex decision-making in tumor boards and optimal perioperative management depend on in-depth experience. One example of this complexity is the management of appendiceal malignancies, which encompass a wide range of subtypes with different prognoses and recommendations. ⁴ Another example is the discussion raised by PRODIGE 7 trial, which found no survival benefit when comparing CRS-HIPEC to CRS alone in PM-CRC. ⁵ However, given the heterogeneous tumor biology, the great variance in disease burden as well as the diversity of HIPEC and systemic oncologic treatment regimens, the generalizability of these findings is questionable. Several confounders are inborn features of such trials and results should therefore be interpreted with caution. Current guidelines still include HIPEC as a treatment option for PM-CRC. Likewise, most guidelines clearly and homogeneously recommend CRS-HIPEC in the treatment for rare peritoneal malignancies including PMP and mesothelioma, ⁶ mainly based on clinical series and expert opinions.

The sparse populations of the Nordic countries make a discussion of centralization inevitable. While Norway has a centralized CRS-HIPEC service in one national center, ⁷ Sweden has four centers and Finland two. In Denmark two centers offer CRS alone for PM-CRC, whereas CRS-HIPEC is only performed for peritoneal surface malignancies in one of these two centers. Up-to-date surgical decision-making, treatment strategies, training, and research require robust volumes and dedicated teams. Education and meetings offered by organizations like Peritoneal Surface Oncology Group International and Nordic Peritoneal Oncology Group help to facilitate high quality services. Nevertheless, ongoing debates with respect to center volumes for a range of diseases should include the highly specialized CRS-HIPEC service. Closer collaboration between Nordic centers and further centralization should be discussed openly to best benefit the patients.