Table 5.
Clinical characteristics of the three prognostic categories of AMN.*
| Prognosis + histopathology | Additional findings | Additional treatment after 1st surgery | Status |
|---|---|---|---|
| No potential for recurrence i.e., curative (n = 24) | |||
| LAMN (n = 22) | Free margins + intact appendix (n = 24 cases) | none | Alive with no recurrence |
| Appendiceal adenoma (n = 2) | |||
| Low recurrence risk (n = 8) | |||
| LAMN (Involved margins, Intact mucocele) (6 cases) | |||
| With acellular mucin (2 cases) | Acellular mucin, no neoplastic epithelium (2 cases) | Close follow up (2 cases) | One lost to follow up within 1 year; second followed for 2 years, no recurrence |
| With neoplastic epithelium (4 cases) | Mucin, neoplastic epithelium (4 cases) | Excision of appendicular stump (developed tumor at stump appendix) (1 case) | Alive, followed for < 1 year with no recurrence, then lost to follow up |
| Right hemicolectomy (3 cases) | Followed between 1 and 7 years, all no recurrence | ||
| Appendiceal adenoma (2 cases) | Involved margins + intact mucocele (1 case) | Partial cecectomy (dysplasia at resection margin) (1 case) | Followed for < 1 year with no recurrence, then lost to follow up |
| NET (carcinoid) + mucinous cystadenoma (1 case) | Right hemicolectomy (1 case) | Followed for 4 years, no recurrence | |
| High recurrence risk (n = 18) | |||
| LAMN (8 cases) | Local perforation or spillage±involved margin | CRS + HIPEC (done) (3 cases) | Patients developed PMP, underwent CRS + HIPEC, followed for 3–6 years after HIPEC, all no recurrence |
| CRS + HIPEC (not donea) (3 cases) | 2 patients followed for 2 years, both had recurrence. 1 patient followed or 4 years, no recurrence. | ||
| Right hemicolectomyb (1 case) | Followed for 1 year, no recurrence | ||
| Close follow upc (1 case) | Followed for 1 year, no recurrence | ||
| LAMN + pseudomyxoma peritonei (5 cases) | PMP or peritoneal seeding during surgery or follow up | CRS + HIPEC (done) (2 cases) | Followed for 3–5 years, no recurrence post CRS + HIPEC |
| CRS + HIPEC (not done) d (3 cases) | Followed for 0.5–2 years, then lost to follow up | ||
| Mucinous adenocarcinoma (5 cases) | PMP or peritoneal seeding during surgery or follow up | CRS + HIPEC (done) (4 cases) | Followed for 2–6 years post CRS + HIPEC, 2 patients had no recurrence, other 2 developed recurrence |
| CRS + HIPEC (not done) e (1 case) | Followed for 1 year then lost follow up | ||
d,e MDT decision was to undertake CRS + HIPEC for those cases but the procedures were not undertaken because the procedure is not performed in our institution and hence patients were referred abroad with regular follow up.
*Curative, low risk, high risk according to AJCC 8th edition [16], and the PSOGI 2016 classification consensus of mucinous neoplasia of the appendix [4]; LAMN: low appendicular mucinous neoplasm; CRS: cytoreductive surgery; HIPEC: hyperthermic intraperitoneal chemotherapy; PMP: pseudomyxoma peritonei; NET: neuroendocrine tumor.
MDT decision was to undertake CRS + HIPEC for these 3 cases but the procedures were not undertaken because the procedure is not performed in our institution and hence patients were referred abroad.
Right hemicolectomy was undertaken as the previous consensus was to perform completion surgery for positive margin.
Close follow up was undertaken due to recent changes in the guidelines suggesting watchful waiting management as possibility in acellular mucin spillage.