For most cancers, intensive surveillance after treatment has not been shown to improve survival, and there is growing concern about radiation exposure from routine imaging, according to Crystal Denlinger, MD, Assistant Professor, Fox Chase Cancer Center, Philadelphia, who chairs the NCCN Guidelines Panel for Survivorship. At the NCCN 19th Annual Conference, Dr. Denlinger outlined the recommendations for surveillance for several tumor types.
Based on results from a US cohort of 31,462 patients undergoing diagnostic imaging with CT scans, recurrent imaging appears to convey more than a 1% risk of radiation-induced cancers in a small percentage of patients.1 In the 7% of patients within this cohort whose risk of cancer was increased by 1% or more due to radiation exposure, the majority had a history of malignancy, yet 30% of this group did not have evidence of active disease. “Our zeal for imaging may actually increase cancer risk in some patients exposed to frequent surveillance imaging tests,” Dr. Denlinger said.
The data on the topic are relatively weak, however, because few randomized studies and few recent studies on the most effective modalities have been performed to inform surveillance strategies, according to Dr. Denlinger.
Although many patients and their families view regular surveillance as a mark of good practice and patients yearn to hear the words “cancer free,” testing can also induce anxiety. In addition, false-positive results can trigger additional testing, and this can increase radiation exposure and costs.
As a general rule, less is more, Dr. Denlinger maintained, because most recurrences are detected on clinical examination or by the presence of symptoms, not by imaging tests or blood-based markers. Regardless of how they are picked up, recurrences are rarely cured.
Discussions with patients regarding the risks and benefits of routine imaging tests and laboratory studies are important for defining and adhering to optimal surveillance strategies (see inset), she said.
Dr. Denlinger has disclosed that she has received grants or research support from Astex Pharmaceuticals, Bayer HealthCare, ImClone Systems Incorporated, MedImmune Inc., Merrimack Pharmaceuticals, OncoMed Pharmaceuticals, and Pfizer Inc., and has served as a scientific advisor for Eli Lilly and Company.
Sodickson A, Baeyens PF, Andriole KP. Recurrent CT, cumulative radiation exposure, and associated radiation-induced cancer risks from CT of adults. Radiology 2009;251:175–184.
Primrose JN, Perera R, Gray A. Effect of 3 to 5 years of scheduled CEA and CT follow-up to detect recurrence of colorectal cancer: the FACS randomized clinical trial. JAMA 2014;311:263–270.
Tsikitis VL, Malireddy K, Green EA. Postoperative surveillance recommendations for early stage colon cancer based on results from the clinical outcomes of surgical therapy trial. J CLin Oncol 2009;27:3671–3676.
Renehan AG, Egger M, Saunders MP, O’Dwyer ST. Impact on survival of intensive follow up after curative resection for colorectal cancer: systematic review and meta-analysis of randomized trials. BMJ 2002;324:813.
Sargent DJ, Patiyil S, Yothers G. End points for colon cancer adjuvant trials: observations and recommendations based on individual patient data from 20,898 patients enrolled onto 18 randomized trials from the ACCENT Group. J Clin Oncol 2007;25:4569–4574.
GIVIO Investigators. Impact of follow-up testing on survival and health-related quality of life in breast cancer patients: a multicenter randomized controlled trial. JAMA 1994;271:1587–1592.
Palli D, Russo A, Saieva C. Intensive vs clinical follow-up after treatment of primary breast cancer: 10-year update of a randomized trial. National Research Council Project on Breast Cancer Follow-up. JAMA 1999;281:1586–1586.
Keating NL, Landrum MB, Guadagnoli E. Surveillance testing among survivors of early-stage breast cancer. J Clin Oncol 2007;25:1074–1081.
Rustin GJ, van der Burg ME, Griffin CL. Early versus delayed treatment of relapsed ovarian cancer (MRC OV05/EORTC 55955): a randomized trial. Lancet 2010;376:1155–116.
Lamont JP, Kakuda JT, Smith D. Systematic postoperative radiologic follow-up in patients with non-small cell lung cancer for detecting second primary lung cancer in stage IA. Arch Surg 2002;137:935–939.
Nabhan M, Kim SP, Shah ND. The relationship of the intensity of posttreatment prostate-specific antigen surveillance and prostate cancer outcomes: results from a population-based cohort. Mayo Clin Proc 2012;87:540–547.
Cardoso R, Coburn NG, Seevaratnam R. A systematic review of patient surveillance after curative gastrectomy for gastric cancer: a brief review. Gastric Cancer 2012;15(Suppl):S164–167.
Witkowski ER, Smith JK, Ragulin-Coyne E. Is it worth looking? Abdominal imaging after pancreatic cancer resection: a national study. J Gastrointest Surg 2012;16:121–128.