Background: In colorectal cancer (CRC) patients, guidelines only recommend measurement of preoperative carcinoembryonic antigen (CEA), although postoperative CEA may be more informative. However, the sensitivity of both preoperative and postoperative CEA in identifying relapse is limited. We studied whether CA19-9, YKL-40, C-reactive protein (CRP) and interleukin (IL)-6 add prognostic information combined with postoperative CEA.
Material and methods: This post-hoc analysis included 147 radically resected stage II (n = 38), III (n = 91) and IV (n = 18) CRC patients treated with adjuvant 5-fluorouracil (5-FU)-based therapy in the phase III LIPSYT study (ISRCTN98405441). We collected postoperative blood samples a median of 48 days after surgery. We analysed relapses, sensitivity, positive predictive value (PPV) and disease-free (DFS) and overall survival (OS) by bootstrap, Kaplan-Meier and adjusted Cox-models in the elevated vs. normal biomarker groups.
Results: Elevated postoperative CEA associated with impaired DFS (HR 7.23; CI95% 3.85-13.58), impaired OS (HR 7.16; CI95% 3.76-13.63), and more relapses (HR 7.9; CI95% 3.4-18.2); but sensitivity for CEA in finding relapses was only 31% (CI95% 21-48%). Normal CEA combined with an elevated YKL-40 or elevated CRP showed more relapses (HR for YKL-40 2.13 [CI95% 1.10-4.13], HR for CRP 3.14 [CI95% 1.21-8.16]), impaired DFS (HR 2.18 [CI95% 1.12-4.24] or 3.23 [CI95% 1.34-7.82]), and impaired OS (2.33 [CI95%1.24-4.40] or 2.68 [CI95%1.12-6.44]). Elevated CEA combined with a concomitantly elevated CA19-9, YKL-40, CRP or IL-6 showed a respective PPV of 100, 90, 100, and 100%.
Conclusion: In radically operated stage II to IV CRC patients who received adjuvant 5-FU-based chemotherapy, a postoperatively elevated CEA alone or in combination with CA19-9, YKL-40, CRP, or IL-6, or a normal CEA combined with an elevated YKL-40 or with an elevated CRP, may indicate patients at high risk of relapse.