The survival of cancer patients

Key points

• The five-year relative survival ratio is generally used as an indirect measure of recovery from cancer. It shows the proportion of cancer patients that are alive five years after the detection of cancer.
• During the last ten years, the average five-year survival of cancer patients has increased by approximately five percentage points.
• For recently diagnosed Finnish cancer patients, the projected five-year survival ratio is 67% in men and 69% in women.
• Finnish patients’ survival ratios are at Europe’s, and simultaneously the world’s top level.

The relative survival ratio is used as an indirect measure of recovery from cancer. It indicates how many of the cancer patients are alive at a certain period of time (e.g. one year or five years) after the detection of cancer as compared to the proportion of the population of the same age alive in that period. In other words, the relative survival ratio is the probability of being alive if the only possible cause of death of the patient was the cancer they were suffering from.

If the relative survival ratio is less than 100%, cancer causes additional deaths in patients. In general, the statistical limit of cure is considered to be five years, although there are a small number of extra deaths in some cancers even after five years (e.g. breast and prostate cancer), and in some cases, a statistical recovery is achieved even earlier (e.g. testicular cancer and brain meningioma). [1]

The relative five-year survival ratio of Finns diagnosed in 2011-2013 is projected to be 67% in men and 69% in women (Figure 1). The calculation does not take into account the benign basal cell skin cancers or cervical cancer precursors that virtually do not cause any mortality. The higher survival ratio of women with cancer is largely due to the fact that the prognosis of the most common cancer in women, i.e. breast cancer, is considerably better than the prognosis of lung cancer, which is common in men.

For women diagnosed with breast cancer in 2011-2013, the five-year survival ratio is 91%. Similarly, the five-year survival ratio for prostate cancer patients is predicted to be up to 93%, but this figure is somewhat misleading as PSA testing also finds many local, low-risk prostate cancers. A large proportion of cancers found by PSA testing are such that they do not impact life expectancy, and these men die from other diseases. Cancers with good prognosis include testicular cancer (94%) and thyroid cancer (90%).

_{Figure 1.Projected relative five-year survival ratios (%) for cancer patients diagnosed in 2011–2013. In male breast cancer, the estimate is based on longer period 2008–2013 because of small number of patients.}

The ten and fifteen-year survival ratios for prostate and breast cancer are also interesting, because the patients’ mortality rate is elevated for a long time after the detection of cancer. In these cancers, the relative survival ratio is 80%, when 15 years has passed since the cancer diagnosis (Figure 2). Instead, with cancers of testis and corpus uteri, the patients’ mortality rate is the same as that in the Finnish population of the same age as early as five years after the detection of cancer. Therefore, the survival ratio at 10 and 15 years is approximately at the same level as that at 5 years. Excess mortality caused by colorectal cancer continues at least ten years from the detection of cancer.

The average five-year survival ratio of all cancer patients has increased by about five percentage points over the past ten years. The most common cancer diseases from the past decades, i.e. stomach and lung cancer, still have poor prognosis (Figure 3). When their relative share decreases and the prognosis of other cancers improve, cancer’s reputation as a deadly disease will slowly change.

_{Figure 2. Projected relative survival ratios (%) after the first 15 years from diagnosis for patients diagnosed with testicular, prostate and colorectal cancer and cancer of corpus uteri in 2011–2013.}

However, some cancers are still very difficult to cure. Such cancers include lung, liver, gallbladder and pancreatic cancers. Only five percent of patients with pancreatic cancer are alive five years after the detection of the cancer. With modern treatments the cancer that has spread can be kept under control for some time and the survival ratio improves although the patient eventually dies of cancer. The one-year survival ratios of liver, gallbladder and pancreatic cancer have improved considerably, but lung cancer prognosis has improved only slightly over the last two decades (Figure 4).

 

_{Figure 3. Trends in relative five-year survival ratio for cancer patients in 1954–2013.}

Factors affecting survival

Cancer patient survival ratios vary considerably depending on whether the cancer has spread upon its detection. The prognosis is better for patients with local diagnosed cancer, as it is often possible to remove the entire tumor with surgery.

The differences can be remarkable. For example, notorious skin melanoma is nowadays diagnosed mainly in the form of thin and local tumor, for which surgery is almost always curative. For patients diagnosed with localized skin melanoma, the relative survival ratio after five years is 96%. If the cancer is diagnosed after spreading, the survival ratio is only 46%. On average, even with stomach cancer, a cancer with relatively poor prognosis, the five-year survival ratio is 64% when diagnosed at the local stage.

Breast cancer is an example of a disease that patients can survive for considerable time periods due to effective treatments even when the cancer has spread. The five-year survival ratio for breast cancer diagnosed at the local stage is as high as 99%. If the disease has spread when diagnosed, the five-year survival ratio is 83%.

The five-year survival ratio for patients diagnosed with localized  prostate cancer is 102 percent. In other words, the patients’ mortality rate is lower than mortality in the Finnish male population of the same age. This low mortality rate is due to the fact that many of the locally diagnosed cancers have been found in PSA testing and the men tested have, on average, healthier lifestyles.

Young patients recover from almost all cancers better than the elderly. In the early 1970s leukemia patients were an exception to this rule, as relative survival ratios of those under 15 years of age was less than 10% and 20% for those over the age of 45. This exception is explained by the fact that children more often had acute leukemia with poorer prognosis than adults.

The survival ratios of patients with the same cancer type do not usually differ considerably by gender (Figure 1). The biggest differences are in the brain and central nervous system tumors and lung cancer, in which women have a better prognosis than men. In the tumors of brain and central nervous system, the difference is due to the fact that meningiomas are more common among women than men and the survival of patients diagnosed with meningioma is high compared to the other tumors.

Social status also affects, to some extent, the prognosis of the cancer patient: the wealthy and those with higher education survive almost all cancers slightly better than those of lower socioeconomic status and with lesser education [2, 3].

The survival ratios vary considerably among patients treated in different ways, but direct conclusions cannot be made between the superiority of different treatments. Best treatment results are obtained with the most extensive treatments that are suitable specifically for those patients who are most likely to be cured. With these patients, their condition must also be good enough to withstand the strain of the treatment. At best–for example, for localized cervical cancers treated with extensive surgery–the relative survival was 100% already in the late 1960s [4].

Significant differences in the survival ratios between treatment institutions and between countries are often due to the fact that patients are different. In international comparisons, the survival ratios of Finnish patients are at the top level both in European and worldwide [5].

_{Figure 4. Trends in relative five-year survival ratio in cancers with the lowest survival in 1954–2013.}

Literature

_{[1] Dickman PW, Hakulinen T, Luostarinen T et al. Survival of cancer patients in Finland 1955–1994. Acta Oncol 1999; 38 (Suppl 12): 1–103.}

_{[2] Auvinen A, Karjalainen S, Pukkala E. Social class and cancer patient survival in Finland. Am J Epidemiol 1995; 142: 1089–102.}

_{[3] Pokhrel A, Martikainen P, Pukkala E, Rautalahti M, Seppä K, Hakulinen T. Education, survival and avoidable deaths in cancer patients in Finland. Brit J Cancer 2010; 103: 1109–14.}

_{[4] Hakulinen T, Pukkala E, Hakama M, Lehtonen M, Saxén E, Teppo L. Survival of cancer patients in Finland in 19}53–1974_{. Ann Clin Res 1981; 13 (Suppl 31): 1–101.}

_{[5] Allemani C, Weir HK, Carreira H et al. Global surveillance of cancer survival 1995-2009: analysis of individual data for 25,676,887 patients from 279 population-based registries in 67 countries (CONCORD-2). Lancet 2015; 385: 977–1010.}