bone marrow cancer
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Bone marrow cancer is very difficult to treat. A recent study tested if prolonged treatment with the drug lenalidomide can help treat the disease.

Multiple myeloma is a serious type of bone marrow cancer. It occurs when large numbers of a specialized type of blood cell, called plasma cells, start to grow inside the bone marrow. These extra plasma cells can crowd out normal blood cells. Symptoms of the disease include bone pain, bone weakness leading to fractures, and frequent infections.

A typical treatment procedure for multiple myeloma starts with aggressive chemotherapy. This decreases the number of plasma cells in the bone marrow. Younger, healthier patients may have a bone marrow transplant, followed by additional chemotherapy. This usually drives cancer into remission. During remission, the patient is outwardly healthy, with no signs of cancer. Unfortunately, multiple myeloma can never be truly “cured”, and cancer often returns. Because of this, some doctors continue to treat patients with low doses of chemotherapy drugs. This “maintenance” therapy is believed to keep cancer in remission for longer.

A large study of maintenance therapy for bone marrow cancer

A recent study in the UK tested the anti-cancer drug lenalidomide as maintenance therapy for multiple myeloma. This study followed almost 2,000 cancer patients. More than a 1,000 of them were randomly chosen to receive lenalidomide maintenance therapy. The rest did not receive lenalidomide but were still regularly monitored. The researchers kept track of both groups of patients for up to six years. The results of the study were published in The Lancet Oncology, a scientific journal.

Lenalidomide extended lifespan for some bone marrow cancer patients

Lenalidomide maintenance therapy extended the average lifespan of patients who were under 65 years of age, or who had had a bone marrow transplant. For example, 80% of patients who received a transplant were still alive three later. Lenalidomide increased these survival odds to 88%.

Unfortunately, lenalidomide maintenance therapy did not extend the average lifespan of patients who were not able to have a bone marrow transplant. Only 68% of these patients were still alive three years after they started the study. Lenalidomide did not increase their survival odds. The treatment also had no effect on patients older than 65 years of age.

Lenalidomide decreases of the risk of a relapse

Quality of life is important to cancer patients. One important consideration for quality of life is how long the remission period lasts. In this study, the average patient experienced an initial 20-month-long remission period. Lenalidomide maintenance therapy almost doubled this, up to 39 months.

It is an unfortunate reality of multiple myeloma that multiple relapses are common. These relapses are treated by additional rounds of full-strength chemotherapy. This may relieve the symptoms, starting another remission period. Without lenalidomide maintenance treatment, 39% of patients in this study had a second relapse or died. Lenalidomide successfully decreased the chances of a second relapse or death to 25%.

Potential risks of lenalidomide maintenance treatment

A risk of chemotherapy drugs such as lenalidomide is that they can actually cause additional cancers in patients. In this study, patients on lenalidomide maintenance therapy were more likely to develop new cancers compared to patients who were not being treated. However, this only affected a small number: 5% of treated patients developed new cancers over the first three years of lenalidomide treatment, compared to 3% in the non-treated group.

Chemotherapy can cause other side effects. In this study, 15% of patients had to stop the lenalidomide maintenance therapy because of various treatment-related problems.

New treatment options for bone marrow cancer

This study had some limitations. It was not a double-blinded study, meaning that patients and their doctors were aware if they were receiving lenalidomide. This means that there could have been a “placebo effect”, where a patient’s belief in treatment increases its effectiveness. It is also possible that doctors may have paid more attention to patients receiving lenalidomide. This means that they may have received better care than non-treated study participants. Furthermore, the researchers did not directly measure how the treatment affected the quality of life, which is an important issue for cancer treatment.

Despite these issues, the researchers are very optimistic about these results. Long-term lenalidomide treatment prolonged the remission period for the average multiple myeloma patient. It also increased the lifespan of patients who were under 65 years, or who had received a bone marrow transplant. This study adds a new entry to the list of treatment options for this very serious disease.


Written by Bryan Hughes, PhD

References:

  1. Jackson, G. H., F. E. Davies, C. Pawlyn, D. A. Cairns, A. Striha, C. Collett, A. Hockaday, J. R. Jones, B. Kishore, M. Garg, C. D. Williams, K. Karunanithi, J. Lindsay, M. W. Jenner, G. Cook, N. H. Russell, M. F. Kaiser, M. T. Drayson, R. G. Owen, W. M. Gregory and G. J. Morgan (2018). “Lenalidomide maintenance versus observation for patients with newly diagnosed multiple myeloma (Myeloma XI): a multicentre, open-label, randomised, phase 3 trial.” The Lancet Oncology. https://doi.org/10.1016/S1470-2045(18)30687-9
  2. “Treatment shown to improve the odds against bone marrow cancer” (2018). Newcastle University. https://www.eurekalert.org/pub_releases/2018-12/nu-tst121418.php
  3. “Multiple myeloma” (2018). Canadian Cancer Society. http://www.cancer.ca/en/cancer-information/cancer-type/multiple-myeloma/multiple-myeloma/
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