The Value of Post Adjuvant Chemotherapy Screening in Colorectal Cancer Patients

Abstract & Commentary

Synopsis: In an analysis of important clinical outcomes after adjuvant chemotherapy for stage II and III colorectal cancer, Chau and colleagues from the United Kingdom reviewed the experiences of 530 patients. Of these, 154 relapsed with metastatic disease, local recurrence, or metachronous tumor. Routine screening (including CEA and CT scans) detected disease recurrence in more than half of those that were to recur, and, for these individuals, survival was superior to those who were discovered to have relapse on the basis of symptoms. The report supports the common practice of scheduled post chemotherapy screening for patients with colorectal cancer.

Source: Chau I, et al. J Clin Oncol. 2004;22:1420-1429.

Nearly 40% of patients with colorectal cancer (crc) experience disease relapse, despite potentially curative surgery.1 For patients with resected stage II or III CRC, the primary objectives of follow-up are to detect either resectable metastases confined to the organs (ie, lungs or liver), resectable local recurrences, or metachronous cancer. However, the value of this follow-up has been highly debated. Chau and colleagues from the Royal Marsden Hospital in the United Kingdom evaluated the role of routine serum carcino-embyonic antigen (CEA) measurement and computed tomography (CT) as follow-up policy, and their impact on survival in adjuvant chemotherapy treated patients who developed disease recurrence or metachronous primary CRC. Following chemotherapy, patients were seen in the outpatient clinic every 3 months for the first year, every 6 months for the second year, and annually from then on. Serum CEA was measured at each clinic visit and CT scans of the thorax, abdomen, and pelvis were performed 12 months and 24 months following the end of chemotherapy.

The median follow-up of the 530 recruited patients was 5.6 years, with disease relapses occurring in 154 patients. Also, 42% (n = 65) of these relapses were detected by symptoms, 29% (n = 45) by CEA, 32% (n = 49) by CT and 6% (n = 9) by other methods, such as colonoscopy. Of the 49 patients in whom relapses were detected by CT, 14 had associated elevated CEA and were included in both the CEA and CT-detected groups. Therefore, 71% (n = 35) of the asymptomatic patients in the CT-detected group had normal CEA and their relapses could not have been identified separately from the CT. In addition, survival after relapse for the CT group was greater than that of the symptomatic group (P = .0046). Thirty three patients (21%) underwent surgery for relapse and had a better survival than those who did not (P = .00001). Only 2 patients from the symptomatic group underwent hepatic or pulmonary metastatic resection vs 13 from the CT group and eight from the CEA group (CT vs symptomatic, P < .001; CEA vs symptomatic, P = .015). Therefore, surveillance CT and CEA are valuable methods of follow-up after adjuvant chemotherapy in stage II and III colorectal cancer.

Comment by William B. Ershler, MD

In this analysis, of the 154 patients who relapsed after adjuvant chemotherapy for CRC, the discovery of recurrence was, as might be expected, earlier for those who had their disease detected by CT or rising CEA. Thirty three of the 154 were discovered early enough to proceed directly to potentially curative resections, but only 2 of these 33 were discovered to have recurrent disease on the basis of symptoms. Although the implications of this analysis support the common practice of routine surveillance of asymptomatic patients after adjuvant chemotherapy, a more skeptical interpretation might be that patients with more aggressive disease will progress to symptomatic disease within the 3- (for CEA) or 12-month (for CT) intervals, and these patients would be expected to have poorer survival. Thus, the screening might be more apt to discover those with more indolent tumor growth patterns. Perhaps a prospective randomized study could be constructed that examined more intensive screening (eg, monthly CEAs and semiannual CT scans) with the more conservative approach taken by Chau et al. Furthermore, the duration of post-adjuvant chemotherapy treated CRC patients remains an issue that needs clarification.

Reference

1. Kievit J. Eur J Cancer. 2002;38:986-999.

William B. Ershler, MD INOVA Fairfax Hospital Cancer Center, Fairfax, VA; Director, Institute for Advanced Studies in Aging, Washington, DC, is Editor for Clinical Oncology Alert.