Are we winning the war on cancer?

Since the early 1980s, age-adjusted cancer mortality rates have been falling over time. Is this due to better screening, better treatment, or healthier behavioral factors? Is this progress cost-effective? Are we really winning the war on cancer?

A paper by Culter (2008) tries to answer this question. First it is important to note that there are two types of cancer. Localized tumors are located only in the originating tissue and metastatic tumors have spread to other parts of the body. “Localized cancer isn’t fatal; metastatic cancer is both lethal and incurable—even with recent treatment advances.”

Falling Cancer Mortality Rates

Raw cancer mortality statistics mask the significant benefits of cancer treatment and screening.  Since the reduction in the number of deaths from cardiovascular disease has fallen since 1970, the concurrent decline of cancer deaths is even more impressive since individual who will not die of heart disease are more at risk now of dying of cancer.  Of the decline in cancer-related mortality, 78% of this decline is due to decrease mortality in 4 types of cancer: lung cancer, colorectal cancer, breast cancer, and prostate cancer.   The risk factors for each of these disease can be found in Table 1.

Explanations for the reduction in cancer mortality can be found in Table 2.  Of the reduction in cancer mortality 78% comes from improved mortality from lung, colorectal, breast, and prostate cancers.  Of this reduction, 71% is due to healthier behaviors and better screening; only 29% is due to improved treatments.

Cost Effectiveness

One question that remains was whether or not this reduction in mortality was worth the cost.  Many people will say that life is priceless and we can not measure the value of a year of life…but economists believe they can.  “The analysis of screening is complicated, because the cost-effectiveness of screening depends on how frequently it is performed: if screening is either too frequent or too infrequent, it will have high costs relative to benefits.”  Further, decreasing mortality, but ignoring side effects may not be rational.  “Treatment of prostate cancer, for example, may lead to greater survival, but it frequently leads to reduced quality of life—impotence and incontinence are common side effects. For cancers where treatment is not very effective or where cancer would often not be a cause of death, treatment may even reduce quality-adjusted life expectancy.”

Table 3 shows Cutler’s evaluation of the cost effectiveness of various cancer screening tests.  Breast cancer and colorectal cancer screening are highly cost effective.  On the other hand, lung cancer screening is not seen to be cost effective since the knowledge of the existence of lung cancer rarely alters the treatment.  Prostate cancer screening does improve longevity, but the cost effectiveness depends on how one values the potential side effects of impotence and incontinence.

Compared to screening or behavior changes, cancer therapies are much less cost effective (Table 4).  The author notes that “Spending on cancer is generally U-shaped with time from diagnosis. Costs are high immediately after diagnosis, decline as the cancer goes into remission (if it does), and then increase substantially at the end of life.”

More Cost Effectiveness

The cost of treatment is growing over time.  One example of this the price of cancer drugs (see Table 5).  In the U.S., drugs only have to meet a safety and a minimum efficacy requirement.  In the UK, NICE ensures that drugs are cost effective as well.  In fact, NICE does not cover Avastin or Erbitux because they are not deemed to be cost effective.  Another issue related to drug cost-effectiveness is that “Many of the new, expensive drugs are tested first in metastatic settings because that is where clinical trials are easiest to conduct. Only later are tests done in non-metastatic cases. It is possible—even likely—that the effectiveness of new medications will be greater in non-metastatic settings.”

• Cutler, David M (2008) “Are we finally winning the war on cancer?” Journal of Economic Perspectives, v22(4): 3-26.