Routine monitoring of carcinoembryonic antigen (CEA) levels is standard in patients with resected colorectal cancer (CRC). The incidence of false-positives and the upper limits of false-positive elevations have not been previously well characterized. A search of medical records at Memorial Sloan-Kettering Cancer Center identified 728 patients who underwent an R0 resection of locoregional CRC between January 2003 and December 2012 and who had an increase in CEA level above the normal range after a normal perioperative CEA level. Of these, 358 had a false-positive elevation of CEA level, 335 had a true-positive elevation indicative of recurrent CRC, and 35 had a true-positive elevation indicative of the development of a new, non-CRC malignancy. Of those with false elevations, 111 had a single isolated CEA level elevation (median highest CEA level of 5.5 ng/mL) with no further abnormal measurements, whereas 247 had elevations on 2 or more readings, with a median highest level of 6.7 ng/mL. Of these 247 patients with confirmed false-positive CEA level elevations, only 5 (2%) had measurements greater than 15 ng/mL, and no confirmed elevation greater than 35 ng/mL was a false-positive. False-positive CEA test results in the range of 5 to 15 ng/mL are common. Confirmation of CEA elevation in this range before initiating imaging studies may be appropriate. False-positive results greater than 15 ng/mL are rare, and all confirmed CEA levels greater than 35 ng/mL were associated with cancer recurrence.
Anya Litvak, Andrea Cercek, Neil Segal, Diane Reidy-Lagunes, Zsofia K. Stadler, Rona D. Yaeger, Nancy E. Kemeny, Martin R. Weiser, Melissa S. Pessin and Leonard Saltz
Andrea Cercek, Karyn A. Goodman, Carla Hajj, Emily Weisberger, Neil H. Segal, Diane L. Reidy-Lagunes, Zsofia K. Stadler, Abraham J. Wu, Martin R. Weiser, Philip B. Paty, Jose G. Guillem, Garrett M. Nash, Larissa K. Temple, Julio Garcia-Aguilar and Leonard B. Saltz
Standard therapy for locally advanced rectal cancer (LARC) is preoperative chemoradiotherapy and postoperative chemotherapy. At Memorial Sloan-Kettering Cancer Center (MSKCC) the authors began offering FOLFOX (5-fluorouracil, leucovorin, and oxaliplatin) as initial treatment for patients with high-risk LARC to target micrometastases while treating the primary tumor. The purpose of this study is to report the safety and efficacy of initial FOLFOX given before chemoradiotherapy on tumor downsizing and pathologic complete response (pathCR) in LARC. The records of patients with stage II/III rectal cancer treated at MSKCC between 2007 and 2012 were reviewed. Of approximately 300 patients with LARC treated at MSKCC, 61 received FOLFOX as initial therapy. Of these 61 patients, 57 received induction FOLFOX (median 7 cycles) followed by chemoradiation, and 4 experienced an excellent response, declined chemoradiation, and underwent total mesorectal excision (TME). Twelve of the 61 patients did not undergo TME: 9 had a complete clinical response (CCR), 1 declined despite persistent tumor, 1 declined because of comorbidities, and 1 developed metastatic disease. Among the 61 patients receiving initial FOLFOX, 22 (36%) had either a pathCR (n=13) or a CCR (n=9). Of the 49 patients who underwent TME, all had R0 resections and 23 (47%) had tumor response greater than 90%, including 13 (27%) who experienced a pathCR. Of the 28 patients who received all 8 cycles of FOLFOX, 8 experienced a pathCR (29%) and 3 a CCR (11%). No serious adverse events occurred that required a delay in treatment during FOLFOX or chemoradiation. FOLFOX and chemoradiation before planned TME results in tumor regression, a high rate of delivery of planned therapy, and a substantial rate of pathCRs, and offers a good platform for nonoperative management in select patients.