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More treatment is not always better. Cancer patients and their doctors often face difficult decisions about how much chemotherapy and/or radiotherapy is the best course for the individual. For colon cancer diagnosed at stage I, II, or III, surgery is the first line treatment. Adjuvant, meaning additional, treatment with chemotherapy is believed to be beneficial for stage III cancer, but not for stage I. For stage II, the use of chemotherapy is still a topic of debate.
Each individual is different, and the optimum treatment depends on many factors. Two research groups have developed computer models to predict the results of chemotherapy. Both are available online. The Numeracy calculator is provided by the Mayo Clinic, based on data from 3,302 patients from seven randomized trials. It has four inputs:
1. Lymph nodes (none, 1 – 4, or 5+)
2. Tumor stage (T1/T2, T3, or T4)
3. Grade (low or high)
4. Age (49 or younger, 50 – 59, 60 – 69, or 70+)
Thus, there are 72 different combinations. The Adjuvant! calculator is based on data from the U.S. Surveillance Epidemiology and End Results (SEER) tumor registry, and provides additional inputs:
1. Gender (male or female)
2. Comorbidity (perfect health, minor problems, average for age, or major problems)
3. Number of examined lymph nodes (0, 1 – 3, 4 – 10, >10)
The chemotherapy regimens are 5-FU (5-fluorouracil plus leucovorin) and FOLFOX ( 5-fluorouracil plus leucovorin plus oxaliplatin).
Researchers at Johns Hopkins University, the Mayo Clinic, Creighton University in Nebraska, and the University of British Columbia performed a comparison of these two calculators. They chose 192 hypothetical patient scenarios, using characteristics of individuals who could be chemotherapy candidates. The results indicated small but statistically significant differences between the two calculators.
Thus, when you see small differences between survival rates with different treatment options, it is important to understand that these could be numerical artifacts.