Relapse Rare After Appendiceal Adenocarcinoma Resection

TUESDAY, Sept. 15, 2026 (HealthDay News) — Relapse is uncommon after resection of appendiceal adenocarcinoma (AA), according to a study published online Sept. 9 in JAMA Surgery.

Sacha El Khoury, M.D., from the University of Texas MD Anderson Cancer Center in Houston, and colleagues identified clinicopathologic and genomic factors associated with relapse in localized AA in a retrospective cohort study. Participants included 439 patients with stage I to III AA; of these participants, 202 underwent surgery at the University of Texas MD Anderson Cancer Center. A validation cohort of 128 patients with stage II AA from the Memorial Sloan Kettering Cancer Center were also included.

The researchers found that 19 (9.4 percent) of the 202 surgical patients had a relapse, including 6.0 and 19.5 percent of patients with stage II and stage III disease, respectively. Five-year overall survival was 95.7 and 77.2 percent with and without relapse, respectively (hazard ratio, 5.50). Mucinous and enteric-type histologies were independently associated with relapse relative to goblet cell tumors (hazard ratios, 5.60 and 6.60, respectively), as was pathologic T4 (hazard ratio, 3.30). No significant associations with relapse were seen for known risk factors in colorectal cancer: poor differentiation, perforation, lymphovascular invasion, and perineural invasion. Adjuvant chemotherapy was not associated with improved relapse-free survival or overall survival. A greater risk for relapse was seen in association with TP53 mutation in goblet cell tumors and GNAS mutation in nongoblet tumors (hazard ratios, 6.93 and 17.0, respectively).

“Appendiceal cancers are not all the same,” El Khoury said in a statement. “When we consider tumor histology together with its molecular features, we can better identify which patients are truly at a higher risk of recurrence. That”s where tailoring treatment for this disease has to start.”

Several authors disclosed ties to the biopharmaceutical industry; one author has a patent pending for neoadjuvant PD1 for mismatch repair-deficient rectal cancer.

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