Colony Stimulating Factors in Solid Tumor Cancer and Acute Leukemia

US Oncology Review, 2005;1(1):46-8


Almost daily, and from many media sources in the US, one is confronted with the disquieting demographic fact of the early 21st century that the baby ‘boomers’ are getting older. This fact introduces many of the grants reviewed at the National Institutes of Health (NIH), which emphasize the growing population at risk for cancer development. Of course, this fact seems to inform almost every disease analysis that could possibly be age-dependent, as well as some lesser known facts such as that as people age, they are less likely to relocate, which is illustrated by the statistic that the moving rate drops from 70% in those who are 20–29 years old, to 9% in 45–65 year-olds. Perhaps as the boomers grow older, they will have their cancer treated in more nonurban settings, further stressing the supportive care networks. Unfortunately, not all cancer treatments may be applied uniformly throughout the US, making this relocation statistic even more interesting. To quote an important finding from the Surveillance, Epidemiology, and End Results (SEER) data provided in 2004:

Citation US Oncology Review, 2005;1(1):46-8

“The continued measurable declines for overall cancer death rates and for many of the top 15 cancers, along with improved survival rates, reflect progress in the prevention, early detection, and treatment of cancer. However, racial and ethnic disparities in survival and the risk of death from cancer, and geographic variation in stage distributions suggest that not all segments of the US population have benefited equally from such advances.”1

The diversity of the 76 million baby boomers born between 1946 and 1964, and their projected longer life span, create challenges for all those examining these facts. These demographic issues also inform the discussion of the use of myeloid colony stimulating factors (CSFs) in cancer. Their use is projected to increase and is not uniformly applied across the US, and the new molecular advances in translational cancer medicine may yet alter their use as well.

There are four general ways that CSFs are used in general cancer treatment in a non-transplant setting.The first is as a primary prophylactic measure to prevent severe neutropenia with its attendant morbidity and mortality risks and cost consequences. The ASCO guidelines point out that cost analyses have shown that CSFs save money when the risk of febrile neutropenia (FN) is greater than 40%.2 These guidelines also point out that most moderate-dose-intensity solid tumor cancer regimens have FN rates of approximately 15%, and that primary prophylaxis is not a regular approach for these chemotherapies. The exception to this rule is the older patient where the 15% assumption is not correct. In nine clinical trials of older patients with large cell non-Hodgkin’s lymphoma, the risk of FN was between 21% and 47%, and many authors indicate that primary prophylaxis is appropriate for patients receiving moderate intensity chemotherapy who are aged 70 years or older.3 Furthermore, advances in treatment have made the combination of monoclonal antibody therapy, using Rituxan™, with chemotherapy the standard of care, or at least the benchmark of care, in the lymphoid malignancies, lymphoma, and chronic lymphocytic leukaemia (CLL). This has resulted unexpectedly in increased myelosuppression in some of these combination regimens. Thus, the on-coming aging boomers will require increased use of CSFs in these clinical situations. Clinical practice for primary prophylaxis is also quite varied in the US, as suggested by the aforementioned SEER results statistics, indicating disparity of outcomes. Several studies have indicated that compliance with ASCO guidelines for primary prophylaxis with CSFs is not much better than 50%,4