Cancer survival statistics are very general estimates and must be interpreted very carefully. Because survival statistics are based on the experience of groups of people in the general population, they cannot be used to predict a particular person’s chances of survival.
There are many different ways to measure and report cancer survival statistics.
Observed survival is the proportion of people with the same cancer who are alive at a given period of time after their diagnosis. Relative survival is a ratio that compares the observed survival of a group of people with cancer to survival of people in the general population who do not have cancer, but who share the same characteristics (such as age, sex, place of residence) as the people with cancer.
Survival statistics for non-Hodgkin lymphoma (NHL) are generally reported as 5-year relative survival. However, other types of survival statistics may be used.
The 5-year relative survival for NHL is 66%. This means that, on average, people diagnosed with NHL are 66% as likely to live 5 years (or more) after diagnosis as people in the general population who do not have cancer.
However, survival varies with each stage and particular type of NHL. There are over 30 different subtypes of NHL and each behaves and responds to treatment differently. Each subtype needs to be considered separately in terms of its behaviour, prognostic factors and expected response to treatment before the outcome can be predicted.
Prognostic indexes have been developed to predict the general outcome for indolent and aggressive lymphomas. Survival rates are included in these indexes.
Follicular Lymphoma International Prognostic Index (FLIPI) is a prognostic index that has been developed for follicular lymphoma, which is the most common slow-growing or indolent lymphoma. This index uses 5 prognostic factors to determine the level of risk of relapse for people with follicular lymphoma. One point is given for each poor prognostic factor. The points are added to give a score between 0 and 5, and then categorized into levels of risk. People with lower FLIPI scores have better survival rates.
|Number of poor prognostic factors||Level of risk||5-year survival rates||10-year survival rates|
People with lower-grade or indolent follicular lymphomas can live for several years and have a median survivalmedian survivalThe period of time (usually months or years) after diagnosis or treatment at which half the people with a given disease will live longer and the other half will live less. of about 8–10 years.
Aggressive lymphomas tend to grow quickly and behave aggressively.
International Prognostic Index (IPI) is used to help estimate the outcome for many types of lymphomas. This index uses the 5 prognostic factors to determine the level of risk of relapse. One point is given for each poor prognostic factor. The points are added to give a score between 0 and 5, and then categorized into levels of risk. People with lower IPI scores have better survival rates.
|Number of poor prognostic factors||Level of risk||5-year relapse-free* survival rates|
*Relapse-free survival is the length of time following treatment when there are no clinically detectable signs of a relapse, or the amount of time a person is free of relapsed disease or a recurrence. For example, 70% of people with NHL who had 0–1 poor prognostic factors were relapse-free 5 years after their cancer treatment. Therefore 7 out of every 10 people did not have any signs of relapsed disease for 5 years after treatment.
People with cancer should talk to their doctor about their prognosis. Prognosis depends on many factors. Only a doctor familiar with a person’s medical history, type of cancer, stage, characteristics of the cancer, treatments chosen and response to treatment can put all of this information together with survival statistics to arrive at a prognosis.