Surviving Cancer

‘Can he survive?’

This is one of the first questions that arise in mind when someone close to us has been diagnosed with cancer.

If the doctor says anything affirmative then the next obvious question will be ‘How difficult or easy will it be?’

It is always difficult to foretell the future of a patient, but based on previous experiences and knowledge an assumption can be made. Here we will try to figure out what kind of knowledge is required to make such assumptions

Cancer survival rate

Cancer survival rate is the percentage of people who live with a specific cancer for a certain period. Cancer survival rates are not calculated on the basis of studies conducted only on a small group of patients. It takes into account thousands of cancer patients with a specific cancer. This reduces the statistical errors that occur due to small sample size. An overall survival rate takes into account people of all ages without considering their health conditions and time of diagnosis (late or early).

Calculation of cancer survival rate

A five year survival rate

The prognosis and treatment of cancer is mostly based on a 5-year survival rate. If the 5 year survival rate of a particular type of cancer is 70 %, then it means that 70 out of 100 people survive the next 5 years after being diagnosed.

Five year survival rates can be of two types:

Absolute survival rate

The percentage of patients who survive the first five years from the time of diagnosis.

Relative survival rate

The percentage of patients who are affected with cancer and  survive 5 years after diagnosis with respect to the general population of same age and sex who survived the 5 years without being affected by cancer. This gives an idea regarding the mortality among cancer patients with respect to the general population.

Overall survival rates do not give any information about the recovery of the patients. Therefore, there is a need of other survival rates to understand the prognosis better. Two other survival rated that gives more specific information regarding survival and recovery are the following:

  • Disease-free survival rate. This survival rate includes only those who are completely cured within the specific time.
  • Progression-free survival rate. This survival rate includes only those who are not completely cured within the specific time.

The stage in which a cancer is diagnosed greatly influences the survival rate. Some cancers are mostly diagnosed at an advanced stage. Survival rates in such cases are generally low. However, if diagnosed early and proper treatment is provided most patients survive.

Although a 5 year survival rate is generally used to study cancers there are chances that the disease recurs after 5 years. This is not taken into account while calculating a 5-year survival rate.

Softwares in use

SEER*Stat software: It is a software designed by the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute (NCI) to analyze their databases and analyze the effect of cancer on a population.

Cancer Survival Analysis Software (Cansurv): It is statistical software to calculate population based survival data. 

Factors on which cancer survival rates depend

The overall cancer survival rate may depend on the following factors in general:

  • The type of cancer
  •  Time of diagnosis
  • Condition of patients at the time of diagnosis
  • Diet and lifestyle of patients
  • Access to proper treatment
  • Proper management of old people 

How to use cancer survival rates?

The cancer survival rates can be beneficial in two ways:

  • Prognosis: Cancer survival rates give an idea of prognosis of a particular type of cancer. This is completely based on research on cancer and experience of a doctor.
  • Treatment plan. Doctors can design the treatment of a particular patient after understanding the person’s chances of survival. Statistics and previous experiences help to understand how most people respond to a particular therapy, what can be the side effects and people of what age should be given chemotherapy for a particular cancer and so on. Therefore. These numbers will be useful in determining the proper combination of drugs and other modes of therapy minimizing as much side effects as possible. 

The negatives

Survival rates can be misleading sometimes. This is because some patients may have other health problems together with the main disease. In such cases, statistics will give false hope. On the other hand, for critical cases, the figures may hardly show any chances of survival. But, mode of treatment has developed recently for many types of cancer. Therefore, in such cases patients are more likely to give up hope, rather than showing urgency.

Conclusion

It’s entirely up to a person to decide whether to show interest on the numbers or not. The best thing to do is to have faith on the doctor and let him decide your chances of survival.

The good news is that the number of cancer survivors in the world has increased several folds in the recent past, but the incidence of cancer is also increasing and more needs to be done to reduce the number of people dying from cancer.

References

  1. Stephen B. Edge, David R. Byrd (2010) AJCC Cancer Staging Manual; Edge, Ajcc Cancer Staging Manual, Published by Spriger
  2. This article was originally published on September 3, 2012 and last revision and update was 9/4/2015.