LAUSR

The Regional Cancer Therapies article series marks the fourth anniversary of the relationship between the Society of Surgical Oncology (SSO) and the International Symposium of Regional Therapies via the Annals of Surgical Oncology. The remarkable success and alignment has led to a closer association between the two groups, with a resulting joint SSO-International Symposium of Regional Therapies at Jacksonville in 2018. We celebrate this association and the remarkable advances in regional therapies with this very special supplement. Last year was a key year in cancer care and the use of regional therapies. Several ongoing clinical trials have accrued successfully, and we look forward to the results of the recent few U.S. and International trials examining the role of regional therapies in peritoneal metastases. The field of hepatic and limb regional therapies have been punctuated with advances in regional therapies including immunotherapy, oncolytic virus therapy and catheter-based therapies. This year saw the National Comprehensive Cancer Network (NCCN) guidelines and the European Society for Medical Oncology (ESMO) guidelines endorse the use of intraperitoneal chemotherapy for colorectal metastases. Additionally, the 8th-edition American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) classification now identifies patients with peritoneal disease (M1c). This supplement collates some of the remarkable work presented at the International Symposium of Regional Therapies, in Snow Bird, Utah 2017. The first two articles examine appendiceal epithelial neoplasms (AENs) with peritoneal dissemination and an attempt to validate the Peritoneal Surface Oncology Group International (PSOGI) classification of AEN. Baratti et al. examined 265 patients with mucinous peritoneal disease and found that the 10 years survival rate for patients with acellular mucin was 90%, 63% for low-grade disease, 40% for high-grade disease, and 0% for signet ring cell disease. Similarly, after examining 310 patients, Choudry et al., found that the 5-year progression-free survival rate was 100% for patients with acellular mucin, 83% for those with scant cellularity, and only 27% for those with moderate cellularity. Although these articles corroborate the discrimination of the new classification, they point to the importance of cellularity in the extra-appendiceal mucin. Extra-appendiceal epithelial cells have been suggested to indicate a high risk of recurrence. Guaglio et al. present a prospective series that challenges this paradigm and suggest that any low-grade appendiceal neoplasm (LAMN) with pelvic or right lower quadrant acellular mucin or cells can be treated with a radical appendectomy. They also suggest that this group of patients might not have a high risk of recurrence and can be safely surveilled. Although these data are intriguing, larger and longer series are necessary to define the risk of recurrence better. The technique for the delivery of hyperthermic intraperitoneal chemotherapy (HIPEC) has been understudied, and this series includes four articles that attempt to understand several physiologic components of the technique and its effects on the host. Franko et al. identify antimicrobial properties of the perfusate, whereas Stewart Society of Surgical Oncology 2018