Survival rates and factors that affect prognosis (outlook) for non-Hodgkin lymphoma

The 5-year survival rate refers to the percentage of patients who live at least 5 years after their cancer is diagnosed. Of course, many people live much longer than 5 years (and many are cured).

Five-year relative survival rates assume that some people will die of other causes and compare the observed survival with that expected for people without the cancer. This is a better way to see the impact of the cancer on survival.
In order to get 5-year survival rates, doctors have to look at people who were treated at least 5 years ago. Improvements in treatment since then may result in a more favorable outlook for people now being diagnosed with non-Hodgkin lymphoma.
Survival rates are often based on previous outcomes of large numbers of people who had the disease, but they cannot predict what will happen in any particular person’s case. Many other factors may affect a person’s outlook, such as their other health problems, the type of lymphoma, the stage (extent) of disease at the time of diagnosis, and the treatment received. Certain other factors, which can be grouped as a prognostic index are also important and are discussed below. Your doctor can tell you how the numbers below may apply to you, as he or she is familiar with your particular situation.
The numbers below come from the National Cancer Institute’s SEER database, and are based on people diagnosed between 2002 and 2008.
The overall 5-year relative survival rate for people with NHL is 69%, and the 10-year relative survival rate is 59%.
The type and stage of the lymphoma provide useful information about a person’s prognosis (outlook), but for some types of lymphomas the stage isn’t too helpful on its own. In these cases, other factors can give doctors a better idea about a person’s prognosis.

International Prognostic Index

The International Prognostic Index (IPI) was first developed to help doctors determine the outlook for people with fast-growing lymphomas. However, it has proven useful for most other lymphomas as well (other than slow-growing follicular lymphomas, which are discussed below). The index depends on 5 factors:

  • The patient’s age
  • The stage of the lymphoma
  • Whether or not the lymphoma is in organs outside the lymph system
  • Performance status (PS) – how well a person can complete normal daily activities
  • The blood (serum) level of lactate dehydrogenase (LDH), which goes up with the amount of lymphoma in the body

Good prognostic factors

Poor prognostic factors

Age 60 or below

Age above 60

Stage I or II

Stage III or IV

No lymphoma outside of lymph nodes, or lymphoma in only 1 area outside of lymph nodes

Lymphoma is in more than 1 organ of the body outside of lymph nodes

PS: Able to function normally

PS: Needs a lot of help with daily activities

Serum LDH is normal

Serum LDH is high

Each poor prognostic factor is assigned 1 point. People with no poor prognostic factors would have a score of 0, while those with all of the poor prognostic factors would have a score of 5. The index divides people with lymphomas into 4 risk groups:

  • Low (0 or 1 poor prognostic factors)
  • Low intermediate (2 poor prognostic factors)
  • High intermediate (3 poor prognostic factors)
  • High (4 or 5 poor prognostic factors)

In the studies used to develop the index, about 75% of people in the lowest risk group lived at least 5 years, whereas only about 30% of people in the highest risk group lived at least 5 years. These numbers show the difference the index scores can make, but the IPI was devised in the early 1990s. Newer treatments have been developed since then, so current survival rates are likely to be higher.

Revised International Prognostic Index

A more recent version of the IPI is based on people with fast-growing lymphomas who have received more modern treatment, including a newer drug called rituximab (Rituxan), which is described in the “Immunotherapy for non-Hodgkin lymphoma” section. The revised IPI uses the same factors but divides patients into only 3 risk groups:

  • Very good (no poor prognostic factors)
  • Good (1 or 2 poor prognostic factors)
  • Poor (3 or more poor prognostic factors)

In the study used to develop this index, about 95% of people in the very good risk group lived at least 4 years, whereas only about 55% of people in the poor risk group lived at least 4 years.
The IPI allows doctors to plan treatment better than they could just based on the type and stage of the lymphoma. This has become more important as new, more effective treatments have been developed that sometimes have more side effects. The index helps doctors figure out whether these treatments are needed.

Follicular Lymphoma International Prognostic Index

The IPI is useful for most lymphomas, but it’s not as helpful for follicular lymphomas, which tend to be slower growing. Doctors have developed the Follicular Lymphoma International Prognostic Index (FLIPI) specifically for this type of lymphoma. It uses slightly different prognostic factors than the IPI.

Good prognostic factors

Poor prognostic factors

Age 60 or below

Age above 60

Stage I or II

Stage III or IV

Blood hemoglobin 12 g/dL or above

Blood hemoglobin level below 12 g/dL

4 or fewer lymph node areas affected

More than 4 lymph node areas affected

Serum LDH is normal

Serum LDH is high

Patients are assigned a point for each poor prognostic factor. People without any poor prognostic factors would have a score of 0, while those with all poor prognostic factors would have a score of 5. The index then divides people with follicular lymphoma into 3 groups:

  • Low risk: no or 1 poor prognostic factor(s)
  • Intermediate risk: 2 poor prognostic factors
  • High risk: 3 or more poor prognostic factors

The study used to develop the FLIPI produced the following survival rates:

Risk group

5-year survival rate

10-year survival rate

Low-risk

91%

71%

Intermediate-risk

78%

51%

High-risk

53%

36%

These rates reflect the number of people who lived for at least 5 or 10 years after being diagnosed – many people lived longer than this. The rates were based on people diagnosed with follicular lymphoma in the 1980s and 1990s. Newer treatments have been developed since then, so current survival rates are likely to be higher.

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