|One of the first questions that comes to mind for newly diagnosed cancer patients is, “am I going to die from this, and if so, when”? Factors affecting survival for GIST include; how early GIST was found, a person’s general health status, type of GIST (mutation type, etc), age, and even gender. It’s very natural to look up statistics on survival and then immediately apply whatever number you find to your situation. The truth is that survival statistics are numbers that apply to groups of people. Any given individual may live longer than the “statistics” from their group imply. A great article on why survival statistics might not apply to a given persons situation is “The median isn’t the message” by Stephen Jay Gould.
In 2012, the LRG published a paper on survival of its members in BMC Cancer, Survival of gastrointestinal stromal tumor patients in the Imatinib era: life raft group observational registry1. The full text of the article (PDF) is available by following the above link to the BMC Cancer website.
Median means in the middle. So a median survival of 10 years would mean that half survived less than 10 years and half survived more than 10 years.
So what are the survival numbers for GIST? This gets a bit complicated for several reasons.
- The introduction of very effective therapies for GIST has made data prior to the year 2000 irrelevant (Gleevec entered trials in 2000). Data prior to 2000 should be considered historical and not applicable today.
- Some patients will have GISTs that have a very low to low risk of recurrence, even without Gleevec. The majority of these patients can be expected to have a normal life expectancy after surgery. In fact, in a recent trial for adjuvant Gleevec, 45% of the patients enrolled had GISTs with a low risk of recurrence.
- Other patients will have GIST that has a higher risk of recurrence. As a group, we might expect that these patients might have a tendency to have a shorter overall survival time than those with low-risk GIST, although we don’t have complete data on that yet. Recent data has shown that treatment with 3 years of Gleevec after surgery for high-risk GIST, significantly improves survival compared to only one year of Gleevec after surgery4. This leads to the question of whether even longer treatment times are needed for GIST patients with a high risk of recurrence after surgery. As these findings are translated into clinical practice, survival times may increase even further.
- As a group, patients with metastatic GIST appear to have a lower overall survival time than those without metastatic disease, however a significant number of metastatic patients have been responding to Gleevec for over 10 years.
- Mutational status affects overall survival.
- Younger patients tend to do better than older patients.
- Females tend to do somewhat better than males.
The following survival data for metastatic GIST comes from a phase II trial and from two large phase III trials. Note that only about 15%- 20% of GIST patients have metastatic GIST at diagnosis.
Data for adjuvant treatment comes from a randomized phase III trial conducted in Europe comparing one year of preventative (adjuvant) Gleevec after surgery to 3 years of adjuvant Gleevec. It’s important to note that this trial was only for GIST patients with a high-risk of recurrence.
|Preventative Treatment after Surgery for High Risk GISTs , 1 year imatinib vs 3 years imatinib|
1 year imatinib
3 years imatinib
|Five year overall survival rate||
|Five year recurrence-free rate||
There have been no clinical trials for patients with pediatric GIST, but different groups have reported very long survival for some patients with pediatric-type GIST and Carney’s Triad (a form of pediatric-type GIST). The LRG registry confirms these reports1.
The Life Raft Group maintains a GIST registry that currently has over 1500 patients. This registry includes all types of GIST patients, young, old, low-risk, high-risk, metastatic and those with no evidence of disease (NED). It includes those taking preventative Gleevec, and those not taking preventative Gleevec. The survival time measured from date of GIST diagnose varies immensely in this group, from less than 1 month to almost 40 years (the longest survivor was diagnosed almost 30 years prior to the Gleevec era). Note that, because the LRG is driven by voluntary internet participation, the membership may not be indicative of all GIST patients, for example, younger patients may be more likely to use the internet than older patients resulting in “selection bias”. Another example is that patients with low-risk or very low-risk GISTs may be less likely to participate; again resulting in selection bias. For example, about 80% of LRG registry members that did not have metastatic disease at the time of diagnosis, and for which we have risk data, were in the high risk category for risk of recurrence. This compares to 23% in a population-based study. The LRG registry also has a higher percentage of patients that were metastatic at the time of diagnosis (about 24% vs. 11-15% in a population-based study. As a result, we can conclude that the LRG registry may be biased towards higher risk patients. As a result, it may underestimate actual survival of all GIST patients.
While we have yet to analyze some of the different subgroups in the LRG registry, we can share some general numbers that apply to the group as a whole and a few different subsets.
As of October, 2010, survival (from the time of diagnosis) for the entire LRG registry, including pediatric-type GIST, adult GIST, and those in all stages (NED, metastatic, etc):
- The median overall survival when all groups were combined was 11.7 years from the time of diagnosis (1195 patients with survival data).
- The 5 year overall survival rate when all groups were combined was 79%.
- Patients diagnosed prior to age 18 did better as a group than those diagnosed over age 35.
- The median overall survival for those diagnosed under age 18 has not been reached.
- The median overall survival for those diagnosed between 18 and 35 was 15.6 years.
- The median overall survival for those diagnosed over age 35 was 11.3 years with females doing slightly better than males.
- About 24% of patients in the LRG registry had metastatic disease at diagnosis. The median overall survival for those diagnosed over the age of 18 with metastatic disease at the time of diagnosis was 6.4 years. A significant number of patients are still responding to Gleevec taken to treat metastatic disease for over 10 years.
In summary, although it’s natural to want to know “how long do I have?”, remember that everyone is different and the “median” is just the number in the middle; half of all patients exceed this number and some of them far exceed it.
1. Survival of gastrointestinal stromal tumor patients in the imatinib era: life raft group observational registry
Call J, Walentas CD, Eickhoff JC, Scherzer N, BMC Cancer 2012, 12:90
2. Long-Term Results From a Randomized Phase II Trial of Standard- Versus Higher-Dose Imatinib Mesylate for Patients With Unresectable or Metastatic Gastrointestinal Stromal Tumors Expressing KIT.
Blanke CD, Demetri GD, von Mehren M, Heinrich MC, Eisenberg B, Fletcher JA, Corless CL, Fletcher CDM, Roberts PJ, Heinz D, Wehre E, Nikolova Z, Joensuu H: J Clin Oncol 2008, 26:620–625.
3. Gastrointestinal Stromal Tumor Meta-Analysis Group (MetaGIST): Comparison of Two Doses of Imatinib for the Treatment of Unresectable or Metastatic Gastrointestinal Stromal Tumors: A Meta-Analysis of 1,640 Patients. J Clin Oncol 2010, 28:1247–1253.
4. One vs Three Years of Adjuvant Imatinib for Operable Gastrointestinal Stromal Tumor (SSGXVIII/AIO) Full text article.
Joensuu H, Eriksson M, Sundby Hall K, Hartmann JT, Pink D, Schütte J, Ramadori G, Hohenberger P, Duyster J, Al-Batran S-E, Schlemmer M, Bauer S, Wardelmann E, Sarlomo-Rikala M, Nilsson B, Sihto H, Monge OR, Bono P, Kallio R, Vehtari A, Leinonen M, Alvegård T, Reichardt P