International Journal of Technology Assessment in Health Care

General Essays

Can calcium chemoprevention of adenoma recurrence substitute or serve as an adjunct for colonoscopic surveillance?

Aasma Shaukata1, Murtaza Parekha2, Joseph Lipscomba3 and Uri Ladabauma4

a1 University of Minnesota

a2 University of California, San Francisco

a3 Emory University

a4 University of California, San Francisco

Abstract

Objectives: The aim of this study was to examine the potential cost-effectiveness of calcium chemoprevention post-polypectomy as a substitute or adjunct for surveillance.

Methods: We constructed a Markov model of post-polypectomy adenoma recurrence and colorectal cancer (CRC) development, calibrated to data from prospective chemoprevention trials of fiber, calcium, antioxidants, and aspirin. We modeled four scenarios for 50-year-old patients immediately after polypectomy: (i) natural history with no further intervention; (ii) elemental calcium 1,200 mg/day from age 50–80; (iii) surveillance colonoscopy from age 50–80 every 5 years, or 3 years for large adenoma; (iv) calcium + surveillance. Patients were followed up until age 100 or death.

Results: Calcium was cost-effective compared to natural history ($49,900/life-year gained). However, surveillance was significantly more effective than calcium (18.729 versus 18.654 life-years/patient; 76 percent versus 14 percent reduction in CRC incidence) at an incremental cost of $15,900/life-year gained. Calcium + surveillance yielded a very small benefit (0.0003 incremental life-years/patient) compared with surveillance alone, at a substantial incremental cost of $3,090,000/life-year gained.

Conclusion: Post-polypectomy calcium chemoprevention is unlikely to be a reasonable substitute for surveillance. It may be cost-effective in patients unwilling or unable to undergo surveillance.

Footnotes

Supported in part by NIH R01 CA101849–01A1 (UL) and Minneapolis Center for Epidemiological and Clinical Research (CECR), a VA Clinical Research Center of Excellence award #04S-CRCOE-001 (AS). The authors have no disclosures.