Colorectal cancer patients 65 and older without other serious medical problems benefitted when Avastin® (bevacizumab) was added to chemotherapy.
Combining results of four randomized clinical trials of Avastin and chemotherapy in patients with advanced colorectal cancer, researchers found that adding Avastin increased both the time older patients lived and the time before their cancer got worse.
Patients who were 70 and older had similar improvements.
There were more serious problems caused by blood clots (thromboembolic events) in patients who got Avastin, mostly related to arterial events. However, other serious side effects were no more common in older patients than in those who were younger than 65.
Although two-thirds of patients with advanced colorectal cancer are 65 or older and four out of ten are older than 74, older patients are not well represented in clinical trials. Even when there are no age limits on trials, they may not be enrolled because of other medical problems or a conservative approach to treatment of the elderly.
Therefore, to get a clearer idea of how adding Avastin to chemotherapy affects patients 65 and older, the research team combined information from three first-line and one second-line trial of Avastin and chemotherapy together including 1,100 patients who were 65 or older.
They found that both progression-free survival and overall survival improved when Avastin was added to chemo, and that age made little difference in benefits.
Progression-free survival time with and without Avastin was:
- For those under 65: 6.7 months vs 9.5 months
- Those 65 and older: 6.9 months vs 9.3 months
- Those 70 and older: 6.4 months vs 9.2 months
Overall survival time with and without Avastin was:
- For under 65: 16.5 months vs 19.9 months
- 65 and older: 15.0 months vs 17.9 months
- 70 and older: 14.1 months vs 17.4 months
As patients got older arterial thromoembolytic events (ATE) such as heart attack, stroke, TIA’s, and angina increased with the addition of Avastin.
- Under 65: no difference in ATEs was found — 2 percent in both Avastin and non-Avastin groups
- 65 and older: 5.7 percent ATE for Avastin compared to 2.5 in non-Avastin group
- 70 and older: 6.7 percent ATE for Avastin, 3.2 with no Avastin
Age made no difference in other serious side effects including bleeding, hypertension, and gastrointestinal perforations.
The study authors point out that patients in clinical trials are carefully chosen and may not reflect the health of a patients in the general population. They warn that overall health should be carefully assessed before beginning treatment.
James Cassidy and his colleagues wrote,
In conclusion, this pooled analysis of data from phase II and III metastatic colorectal cancer studies demonstrates that bevacizumab in combination with chemotherapy had a similar impact on PFS and OS in protocol-eligible older versus younger patients. Careful patient selection, however, remains important and should include an objective assessment of the patient’s physical and mental status.
SOURCE: Cassidy et al., Journal of Cancer Research and Clinical Oncology, Online First November 10, 2009.
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