Proof-of-concept assessment of metastatic sentinel node involvement by 18F-FDG positron emission tomography/computerized tomography and prediction of disease progression and survival in colorectal cancer patients with peritoneal carcinomatosis

Chi Lai Ho, Sirong Chen, Yim Lung Leung, Kam Chau Cheng, Ka Nin Wong, Shing Kee Cheung, Yuet Hung Wong


Background: We prospectively studied the clinical significance of metastatic portal, celiac and superior mesenteric (PCS) lymph nodes with positron emission tomography/computerized tomography (PET/CT) in relation to metabolic tumor burden, prediction of disease progression and survival in patients with peritoneal carcinomatosis (PC) from colorectal cancer (CRC).
Methods: Seventy-two patients who underwent colonic cancer resection were prospectively recruited into a 3-year longitudinal study with serial 18F-FDG PET/CT (total 310 scans) examining for PC and/or metastatic PCS nodes. PCS-positive patients were subdivided into 3 groups based on the timing of detection of PCS nodal positivity relative to the detection of peritoneal carcinomatosis; group (I) had positive nodes detected before PC; group (II) had PCS and PC detected in tandem while group (III) had nodal positivity detected after detection of PC. PC burden was quantified by a functional index, PCTLG, defined as “summation of total lesion glycolysis (TLG)” of all PC lesions on the first PET study to detect PC. Predictors for 3-year overall survival (OS) were analyzed.
Results: PCS nodes were positive in 26/72 (36%, Groups I + II + III), negative in 46/72 (64%, Group IV) patients. Mean PCTLG was significantly higher in PCS-positive (106±73) compared with PCS-negative (26±21) patients; however, no significant difference was apparent between PCS-positive groups [PCTLGmean =104±72 (I), 138±73 (II), 50±33 (III); one-way ANOVA, P>0.05]. Patients with positive-PCS nodes or PCTLG ≥27 had significantly shorter median survival and lower 3-year OS rate (PCS+: 16 months, 7.7%; PCTLG ≥27:18 months, 14.3%).
Conclusions: PCS nodal positivity appears to predict development of peritoneal carcinomatosis in which setting it appears to correlate with tumor burden and overall survival. PCS nodes may represent a sentinel tier of drainage and spread in colon cancer.