Clinical Newswire, March 22, 2010 - Colorectal cancer, which claims more than 655,000 lives worldwide annually, is the fourth most common form of cancer in the United States and the third leading cause of cancer-related death in the Western world. As with many cancers, early detection and intervention are crucial. If confined to the wall of the colon (i.e., TNM stages I and II), the cancer may be curable with surgery. Left untreated, the cancer spreads to regional lymph nodes (stage III); this type of cancer is still curable by a combination of surgery and chemotherapy. Colorectal cancer that metastasizes to distant sites (stage IV) is usually not curable, although chemotherapy can extend patient survival. Almost 33% of patients already have metastatic disease at diagnosis, and 50% of the patients diagnosed and resected with early-stage disease subsequently develop metastases.
Several important advances have been made in recent years in the treatment of metastatic colorectal cancer (mCRC). As examples, the introduction of targeted therapies, such as bevacizumab (Avastin) and cetuximab (Erbitux), and the development of rational treatment strategies based on predictive and prognostic biomarkers have had significant impacts on patient survival. However, with tighter healthcare budgets and more patients seeking treatment, the cost of new therapeutic regimens is increasingly a factor in clinical decision-making, and the cost-effectiveness of some of the new treatments has been questioned.
Previous studies using traditional decision modeling approaches for estimating cost-effectiveness based on clinical trials have reported cost-effectiveness ratios of $102,000 for a regimen using irinotecan as first-line therapy and oxaliplatin as second-line therapy versus fluorouracil and leucovorin calcium, and $171 000 for bevacizumab versus irinotecan followed by oxaliplatin.
To address this important issue, Dr. David H. Howard and colleagues at Emory University (Atlanta, GA, USA) assessed the life expectancy and lifetime medical costs in a sample of 4665 patients aged ≧66 years who had been diagnosed with mCRC between January 1, 1995, and December 31, 2005, and who received chemotherapeutic agents within 6 months of diagnosis*. The sample was drawn from the Surveillance, Epidemiology, and End Results (SEER) - Medicare database, which consists of SEER tumor registry records linked with Medicare claims.
In the 10-year period of the study, life expectancy was increased by 6.8 months, while lifetime costs increased by $37,100, with the implied cost per life-year gained calculated as $66,200 (95% CI, $48,100 to $84,200). When adjustments were made for patients' health utility and out-of-pocket expenses, the incremental cost per quality-adjusted life-year gained was $99,100 (95% CI, $72,300 to $125,900).
The authors note that the sample included only elderly patients, and even though these patients can benefit from potent chemotherapeutic agents, the magnitude of benefit may be lower because they have a higher risk of death from competing causes and they are frailer. The Study has the additional limitation that it did not include patients who initially were diagnosed with non-metastatic cancer and later received chemotherapy when they showed evidence of metastasis, which means that the population is not representative of the entire spectrum of patients treated with the newer anti-cancer agents.
Considering that the newer chemotherapeutic agents are associated with increased survival for the patients with mCRC, the authors conclude that the costs do not exceed willingness-to-pay estimates. However, they caution that open-ended coverage policies for new chemotherapeutic agents may be unsustainable in the future as clinical care costs rise.
*Howard DH, et al. Arch Intern Med 2010;170:537-542.
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