Radiation
to Internal Mammary Lymph Nodes Following Autologous Stem
Cell Transplantation Improves Cancer-Free Survival in Breast
Cancer
According to a recent article published in the Journal of
Clinical Oncology, radiation to the internal mammary lymph
nodes following high-dose chemotherapy and autologous stem
cell transplantation may improve cancer-free and overall survival
in patients with stages II-III breast cancer.
Stages II and III breast cancer refers to cancer that has
spread from the breast to nearby axillary (under the arm)
lymph nodes, but not to distant sites in the body. Standard
therapy typically consists of surgery to remove the cancer,
followed by radiation therapy, chemotherapy and/or hormone
therapy if appropriate, to kill any cancer cells remaining
in the body following surgery. The concept of high-dose chemotherapy
is to kill more cancer cells that may exist in the body, compared
to conventional doses. However, the high doses also tend to
kill more healthy cells, causing more side effects from treatment.
Therefore, some physicians remain reluctant to utilize the
approach of high-dose therapy. Although high-dose therapy
is standard treatment for some cancers, it has remained controversial
in the medical arena for the treatment of breast cancer. Researchers
are beginning to sort out different patient or disease characteristics
as well as subtle changes in treatment regimens that improve
survival and tolerability of high-dose therapy.
One main side effect of high-dose therapy is low blood cell
levels. The 3 main types of blood cells are red blood cells
which carry oxygen to tissue in the body, white blood cells
which fight infection and platelets which aid the blood in
clotting. When blood cell levels are reduced to dangerous
levels from high-dose treatments, the result may be life-threatening
for patients. One approach to reduce or mitigate low blood
cells levels from high-dose therapy is to collect immature
blood cells, called stem cells, from the patient prior to
high-dose therapy and re-infuse the cells directly following
therapy. Stem cells can be collected from the bone marrow
(spongy material inside large bones) or from peripheral blood.
This approach is called an autologous stem cell transplant.
Furthermore, research continues to progress, providing additional
convenient supportive care therapy that helps to reduce or
prevent low blood cells levels, including agents such as Neulasta
or Aranesp that stimulate the production and maturation of
white and red blood cells, making high-dose therapy safer.
Patients with stages II-III breast cancer undergoing high-dose
therapy and a stem cell transplant are routinely given radiation
therapy to the site of the breast cancer as well as the axillary
(under the arm) and local lymph nodes to help rid the body
of cancer cells. However, the role of radiation therapy to
internal mammary lymph nodes (behind the breastbone) has remained
controversial and is not routinely performed. Recently, researchers
from Israel conducted a clinical study to determine if the
addition of radiation to internal mammary lymph nodes may
affect outcomes of patients with breast cancer undergoing
high-dose chemotherapy and an autologous stem cell transplant.
In this study, 100 women with stages II or III breast cancer
received high-dose chemotherapy with an autologous stem cell
transplant, radiation to the breast, axilla and lymph nodes
near the neck (supraclavicular) as well as Nolvadex ® (tamoxifen)
if their cancer was hormone-positive. Sixty-seven of these
patients also received radiation to the internal mammary lymph
nodes. At approximately 6 ½ years after diagnosis,
cancer-free and overall survival was superior in the group
of patients treated with radiation to the internal mammary
lymph nodes. Cancer-free survival was 73% in the group of
patients treated with radiation to the internal mammary lymph
nodes, compared to 52% in the group of patients not treated
with the additional radiation. Overall survival was 78% in
the group of patients treated with radiation to the internal
mammary lymph nodes, compared to 64% for those not treated
with radiation to the internal mammary lymph nodes. There
were no treatment-related deaths.
These researchers concluded that the addition of radiation
to internal mammary lymph nodes appears to improve cancer-free
and overall survival in patients with stages II-III breast
cancer undergoing high-dose chemotherapy and an autologous
stem cell transplant. A large ongoing clinical trial in Europe
may help provide a definitive conclusion on the role of radiation
to internal mammary lymph nodes in patients with different
stages of breast cancer. Results from this large trial are
expected in a few years. Patients with stages II-III breast
cancer may wish to speak with their physician about their
individual risks and benefits of radiation therapy to internal
mammary lymph nodes.
Reference: Stemmer S, Rizel S, Hardan I, et al. The Role
of Irradiation of the Internal Mammary Lymph Nodes in High-Risk
Stage II to IIIA Breast Cancer Patients After High-Dose Chemotherapy:
A Prospective Sequential Nonrandomized Study. Journal of Clinical
Oncology. 2003;21:2713-2718.
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