Appendiceal Adenocarcinoma (APAD)

Overview

Appendiceal Adenocarcinoma (AC) is an Appendiceal Cancer (parent BOWEL). Subtypes in the corpus include mucinous appendiceal adenocarcinoma (MAAP), goblet cell adenocarcinoma (GCA), and colonic-type appendiceal adenocarcinoma (CTAAP) PMID:36493333.

Cohorts in the corpus

• appendiceal_msk_2022: retrospective MSK cohort sequenced on MSK-IMPACT (April 2015–October 2020); molecular subtype analysis focused on 164 MAAP tumors PMID:36493333.

Recurrent alterations

• GNAS, KRAS/NRAS, and TP53 co-mutations define three molecular subtypes of MAAP PMID:36493333.
• TP53-mut predominant tumors are highly aneuploid; aneuploidy is an independent predictor of poor OS (P=.001) PMID:36493333.

Subtypes

• RAS-mut predominant (RAS-mut/GNAS-wt/TP53-wt, n=24): lowest mutational and chromosomal burden, best overall survival, 50% first-line chemotherapy response rate PMID:36493333.
• GNAS-mut predominant: chemotherapy-resistant (6% first-line response); intermediate survival PMID:36493333.
• TP53-mut predominant: highly aneuploid, invasive, worst prognosis PMID:36493333.
• Subtype-associated clinical behavior conserved across MAAP, GCA, and CTAAP histologies PMID:36493333.

Therapeutic landscape

• First-line regimens include FOLFOX/FOLFIRI/FOLFIRINOX (fluorouracil, leucovorin, oxaliplatin, irinotecan) and capecitabine; GNAS-mut predominant tumors appear unlikely to benefit from standard colorectal-style regimens PMID:36493333.
• Findings challenge the default of managing AC with colorectal cancer treatment paradigms PMID:36493333.

Sources

• PMID:36493333

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