Ultimate Clinical Outcomes of Appendiceal Mucinous Neoplasm of Uncertain Malignant Potential.
BACKGROUND
The clinical outcome of appendiceal mucinous neoplasm (AMN) is not well understood. This study aimed to compare the long-term outcome for the uncertain malignant potential (UMP) subtype of AMNs with those of the mucinous adenoma (MA) and mucinous adenocarcinoma (MAC) subtypes.


METHODS
In this study, AMNs were classified into three groups (MA, UMP, and MAC), and clinical characteristics, overall survival (OS), and progression-free survival (PFS) were compared among the three groups.


RESULTS
The study included 65 AMN patients (26 MA, 20 UMP, and 19 MAC patients). The median follow-up period was 87 months (range 0.3-311.0) months. The symptoms at diagnosis and the presence of pseudomyxoma peritonei were more common in the MAC group than in the MA group (P = 0.012) or the UMP group (P < 0.001). The 5-year OS rates were 95.5% for the MA group, 93.8% for the UMP group, and 78.3% for the MAC group (P < 0.001), and the 5-year PFS rates were 95.2% for the MA group, 95% for the UMP group, and 36.8% for the MAC group (P < 0.001). Thus, OS and PFS did not differ significantly in the MA and UMP groups (P = 0.884 and 0.345, respectively). In contrast, the OS and PFS of the MAC group were worse than in the MA group (P = 0.017 and <0.001, respectively) or the UMP group (P < 0.001 and 0.001, respectively).


CONCLUSIONS
The long-term outcome for UMP tumors is similar to that for MA tumors and significantly better than for MAC tumors.
Department of Surgery, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea.|Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
Rumi
R
Shin
Department of Surgery, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea.|Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
Young Jun
YJ
Chai
Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.|Cancer Research Institute, Seoul National University, Seoul, Korea.|Colorectal Cancer Center, Seoul National University Cancer Hospital, Seoul, Korea.
Ji Won
JW
Park
Department of Pathology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea.
Mee Soo
MS
Chang
Department of Pathology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea.
Jeong Mo
JM
Bae
Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi, Korea.
Min Jung
MJ
Kim
Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi, Korea.
Byung Kwan
BK
Park
Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.|Cancer Research Institute, Seoul National University, Seoul, Korea.|Colorectal Cancer Center, Seoul National University Cancer Hospital, Seoul, Korea.
Kyu Joo
KJ
Park
Department of Surgery, Seoul National University College of Medicine, Seoul, Korea. syjeong@snu.ac.kr.|Cancer Research Institute, Seoul National University, Seoul, Korea. syjeong@snu.ac.kr.|Colorectal Cancer Center, Seoul National University Cancer Hospital, Seoul, Korea. syjeong@snu.ac.kr.
Seung-Yong
SY
Jeong
D002288:Adenocarcinoma, Mucinous / Q000556:secondary* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001063:Appendiceal Neoplasms / Q000473:pathology* / Q000601:surgery; D018291:Cystadenoma, Mucinous / Q000556:secondary* / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D010534:Peritoneal Neoplasms / Q000556:secondary*; D011553:Pseudomyxoma Peritonei / Q000473:pathology*; D012307:Risk Factors; D015996:Survival Rate; D013997:Time Factors