Adjuvant chemotherapy for high-grade appendiceal cancer after cytoreductive surgery with hyperthermic intraperitoneal chemotherapy.

Abstract

There are no available data on the efficacy of adjuvant chemotherapy (ACT) in stage IVA/B high-grade mucinous appendiceal cancer treated with CRS/HIPEC. We evaluated the association between ACT and survival in this cohort. A single-institution retrospective cohort study using a prospective database was conducted. Stage IVA/B high-grade mucinous appendiceal cancer patients who underwent CRS/HIPEC with CC-0/1 were included. Survival was compared between ACT and no chemotherapy (NoCT) patients. Subgroup analysis was performed with adjustment for confounding variables. We identified 180 patients: 77 ACT and 103 NoCT. ACT regimens included 5-FU/capecitabine (13%), oxaliplatin-based (63%), and irinotecan-based (21%), combined with bevacizumab in 27% of cases. Median number of cycles was 9 (IQR: 6-12). Median overall survival (OS) did not significantly differ between ACT and NoCT (53 vs 75 months, p=0.566). Multivariable Cox regression showed no OS benefit for ACT vs NoCT in patients with neoadjuvant chemotherapy (HR 1.14; 95%CI: 0.38-3.39) or without it (HR 1.33; 95%CI: 0.69-2.57), with signet ring cell (HR 0.89; 95%CI: 0.38-2.06) or other histologies (HR 1.11; 95%CI: 0.50-2.46), positive lymph nodes (HR 1.60; 95%CI: 0.74-3.49), or peritoneal cancer index ≥20 (HR 1.08; 95%CI: 0.55-2.11) after adjusting for other factors. In our cohort, colon-type ACT was not associated with better OS in stage IVA/B mucinous appendiceal cancer after CRS/HIPEC, even after adjusting for confounders. This may be due to different tumor biology than colon cancer or small sample size. Prospective collaborative studies are needed.