Treatments > Risks & Benefits - about therapy-related risks

Last update: 02/26/2008

Putting Risks in Perspective | Resources - General | Stem Cell |  Treatment-Related Mortality | Cardiac Toxicity | Immune Suppression | Myelodysplasia & AML- Leukemia | Secondary Cancers ... Melanomas  | Transformation

Here we will post abstracts and resources that describe some of the more serious risks associated with cancer therapies, primarily: secondary cancers, myelodysplastic syndrome, long-term immune suppression, and transformation. 

But we will also try to put the risks into perspective by noting how likely they are to manifest, and in how much time; and by balancing the risks of treatment against the dangers of delaying or avoiding appropriate treatments.  

For example, while it's true that alkylating agents (such as Leukeran and Cyclophosphamide) increase the risk of developing secondary cancers, the increased risks appear to be relatively small and minimal compared to letting the disease progress unchecked. Importantly the risks can often take many years to emerge, often as long as 10 to 20 years. 

See Related PubMed abstracts & Abstracts on Second Malignancies - Medscape free login req.

Alkylating agents, radiotherapy, autologous transplants, and splenectomy increase the risk of developing MDS (Myelodysplastic Syndrome - failure of the bone marrow to produce healthy and sufficient blood cells), but the risks of developing MDS range from small to significant ( 3 - 12%) depending on the therapy type (Auto Transplant seems to have the highest risk), but this approach is generally tried when the patient has aggressive and/or refractory disease.  

Some treatments may be associated with the transformation of indolent lymphomas to a more aggressive disease. However, be aware that associations between specific treatment and transformation do not prove that one caused the other, because transformation is also a part of the natural course of the disease.  

See About Transformation

It appears to be especially prudent to carefully assess treatment-related risks when the treatment path is unclear, as is often the case for indolent lymphomas.

Resources - General

Collecting Stem Cells following treatment

Treatment-related Mortality

Cardiac Toxicity

Immune suppression - Infectious Complications

Almost all treatments for lymphomas suppress or impair immunity. The degree of immune suppression depends on many factors, including dose, dose timing, and the type of agent.  Some agents are associated with more significant immune suppression than others. In general, younger patients are better able to recover bone marrow function following treatment than the elderly.  

"Fludarabine use in previously treated patients with CLL may be associated with infections involving T-cell dysfunction, such as listeriosis, pneumocystosis, mycobacterial infections, and opportunistic fungal and viral infections. These infections may result from T-cell depletion secondary to fludarabine use. Prophylaxis or presumptive therapy should be initiated when appropriate.

Treatment with alemtuzumab, a monoclonal antibody, affects both B cells and T cells and shows a pattern of infections similar to that of purine analogs. Varicella zoster virus, herpes simplex virus, and CMV are all common in patients with CLL." Source: medscape.com (free login req.)

Related Articles:

Myelodysplasia (MDS) & Leukemias

Also See Side Effects > Myelodysplastic Syndrome 

A "rare and potentially fatal blood disorders that occur when the body starts incorrectly manufacturing the three types of blood cells - white, red, and platelets - resulting in malformed, immature cells."  See - Myelodysplasia Syndromes, Basic Explanations - PDF | PDF-help

The following "Published data suggest that the risk of treatment-related-AML/ and treatment-related MDS following standard chemotherapy is 1% to 1.5% per year from 2-10 years after initiation of therapy.^" 

Leukemogenic therapies are agents that increase the risk of developing leukemias. -  "The risk of leukemia was greatest four or five years after chemotherapy began, and the risk was elevated for at least eight years after the cessation of chemotherapy. The drugs cyclophosphamide, chlorambucil, melphalan, thiotepa, and treosulfan were independently associated with significantly increased risks of leukemia, as was the combination of doxorubicin hydrochloride and cisplatin. Chlorambucil and melphalan were the most leukemogenic drugs, followed by thiotepa; cyclophosphamide and treosulfan were the weakest leukemogens, and the effect per gram was substantially lower at high doses than at lower doses. The extent to which the relative risks of leukemia are offset by differences in chemotherapeutic effectiveness is not known." nejm.org  

Secondary Cancers

TOPIC SEARCH: PubMed 

Transformation

See About transformation