Calculator of Colorectal Cancer Survival Probability
This calculator was developed by Eric A. Engels, M.D., M.P.H., Branch Director, Infections and Immunoepidemiology Branch, and colleagues in the Biostatistics Branch, for use by health professionals to estimate the probability that a patient with colorectal cancer will not die from their cancer in the next five years. This probability may be useful for clinical decision-making.
About the Calculator
What is five-year cancer-specific survival?
The calculator provides estimates of five-year cancer-specific survival probability, i.e., the probability that a patient with colorectal cancer will not die from their cancer in the next five years. The probability ranges from 0 (i.e., 0% chance that the patient will die from colorectal cancer in the next five years) to 1 (i.e., 100% chance that the patient will die from colorectal cancer in the next five years).
These cancer-specific survival estimates reflect only the risk that the cancer will lead to death, and they do not consider other potential causes of death. Five-year cancer-specific survival probabilities can be estimated at any time after cancer diagnosis, and they typically increase with longer time since cancer diagnosis, as the subset of patients who die from their cancer are removed from the population and those who remain alive have a better prognosis.
Why are cancer-specific survival estimates useful?
The estimated five-year cancer-specific survival probability offers prognostic information that may be helpful for counseling or clinical decision-making in a variety of scenarios.
One possible application is for deciding when it is safe to offer solid organ transplantation. Solid organ transplantation can enable long-term survival for patients with end-stage organ disease. However, the decision regarding whether a patient can be safely placed on the organ transplant waitlist accounts for comorbid medical conditions that would make transplantation high-risk or of limited benefit to the patient. For patients with a history of cancer, such considerations indicate a need to systematically select those individuals for transplantation who have an acceptably low risk of dying from their cancer.
The five-year cancer-specific survival probability estimated by this calculator can be compared with a threshold to determine which individuals with end-stage organ disease and a history of colorectal cancer may be referred for transplantation. In the setting of consideration for organ transplantation, an estimated five-year cancer-specific survival of at least 0.80 has been recommended, but a higher threshold probability of 0.90 may offer further reassurance.1,2
How is the five-year cancer-specific survival probability estimated?
The survival probability estimates provided by this calculator are based on statistical modeling of data from 230,465 patients with colorectal cancer diagnosed during 2004-2015 in the Surveillance, Epidemiology, and End Results (SEER) cancer registries. The information used in the calculations includes the patient’s sex, age at diagnosis, cancer subsite (proximal colon, distal colon, rectum), cancer stage at diagnosis, and initial cancer treatment (surgery, radiation, chemotherapy).
The calculator uses a type of statistical model called a “cure model.” For a population of cancer patients, the cure probability is the proportion of people who will not die from their cancer. For ease of clinical interpretation, the cure probabilities from the model have been translated into estimates of five-year cancer-specific survival probability.
How should the survival estimates be interpreted?
The calculator’s estimates utilize cancer registry data on patients with similar clinical presentations and treatment histories, but they are average population-level probabilities that cannot exactly predict outcomes for an individual patient. Clinicians should rely on their clinical knowledge, additional available clinical data, and judgement when interpreting the cure probability estimates for a particular patient.
The estimated survival probabilities do not account for several important factors, including: molecular tumor characteristics, which can have prognostic importance; treatment details; or updated clinical information of cancer status, such as follow-up imaging, after a patient’s initial diagnosis and staging. Thus, the calculator’s survival probabilities should be viewed as a starting point for a provider’s own estimate of the patient’s prognosis. Specifically, the individualized survival probability estimates would need to be lowered if there are additional adverse patient characteristics or evidence for cancer recurrence. Alternatively, the estimates could be increased if there is no evidence for residual or current cancer after a thorough assessment.
Finally, a patient's other medical conditions could affect their cancer-specific survival. For example, there are very limited data on the impact of immunosuppression on patient outcomes when organ transplantation is performed soon after cancer diagnosis. If immunosuppression increases the recurrence risk, then the five-year cancer-specific survival probability at the time of cancer diagnosis may under-estimate recurrence risk if an organ transplantation is performed immediately after the cancer diagnosis.
Access Calculator
Access the Calculator of Colorectal Cancer Survival Probability.
References
- Al-Adra DP et al. Pre-transplant solid organ malignancy and organ transplant candidacy: A consensus expert opinion statement. Am J Transplant. 2021.
- Engels EA at al. Predicted cure and survival among transplant recipients with a previous cancer diagnosis. J Clin Oncol. 2021
- Engels EA et al. Cure models, survival probabilities, and solid organ transplantation for patients with colorectal cancer. Am J Transplant. 2024.
For more information, please contact Dr. Engels.