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Early Use Of Radiation Therapy Associated With Shorter Survival In Multiple Myeloma

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Published: May 6, 2019 1:05 pm

Results of a recent retro­spec­tive­ study show that radiation ther­apy shortly before, or shortly after, the start of drug-based treat­ment in newly diag­nosed multiple myeloma patients is asso­ci­ated with lower over­all survival.

The results are based on in­for­ma­tion for 78,095 multiple myeloma patients from the United States whose data were reported to the National Cancer Data Base be­tween 2004 and 2015.

For their retro­spec­tive­ analysis, the authors of the new study divided the 78,095 patients in their sample into two groups.

One group in­cluded the patients who were found to have undergone “upfront” radiation ther­apy, which the study authors defined as radiation ther­apy carried out after a myeloma diag­nosis and within 90 days before, or up to 14 days after, a patient started drug-based myeloma ther­apy.

The second group in­cluded the patients who did not receive up­front radiation ther­apy.

Because the study in­cludes data for patients diag­nosed up to 15 years ago, survival out­comes are worse than would be ex­pec­ted in data for more recently diag­nosed patients.

Nevertheless, there was a noticeable dif­fer­ence in survival be­tween the two groups of patients. Overall survival for patients who received up­front radiation ther­apy was 3.6 years com­pared to 4.2 years for patients who did not receive up­front radiation ther­apy.

Across all patients in the study, 17 per­cent received up­front radiation ther­apy. Interestingly, patients were almost 25 per­cent more likely to receive up­front ther­apy if they were diag­nosed in a com­munity hospital rather than an academic hospital.

The authors of the new study are not able to conclude from their data why up­front radiation ther­apy is asso­ci­ated with lower over­all survival.

One poten­tial explanation is that radiation ther­apy is more likely to be needed in myeloma that is more aggressive, as it may be more likely to cause bone damage, or in patients whose disease is more ad­vanced due to a comparatively delayed diag­nosis.

Another explanation is that bone-related com­pli­ca­tions that require radiation ther­apy may limit the extent to which a patient’s disease can be treated.

The authors also explore the possibility that radiation ther­apy may be more common in patients who, for socioeconomic reasons, have more limited treat­ment options com­pared to other patients.

Background

Bone disease is a common com­pli­ca­tion of multiple myeloma. Approximately 80 per­cent of multiple myeloma patients show evi­dence of bone lesions at the time of their diag­nosis. Bone-destroying cells are more active in the bones of myeloma patients than bone-forming cells, which ultimately leads to bone destruction and skeletal com­pli­ca­tions such as lesions, fractures, and spinal cord compression.

Radiation ther­apy is one ap­proach to addressing some of the bone-related issues caused by multiple myeloma. It is used primarily to reduce bone pain and to prevent or treat bone fractures that can occur in myeloma patients.

Researchers have long known that the more bone lesions a myeloma patient has at diag­nosis, the poorer their prognosis tends to be. Prior research has not explored, how­ever, whether up­front radiation ther­apy has any association with patient prognosis.

Thus, the authors of the new study sought to examine up­front radiation treat­ment in multiple myeloma patients, in­­clud­ing patterns of its use, factors asso­ci­ated with its use, and its poten­tial impact on survival.

Study Design And Results

The authors analyzed data from 78,095 multiple myeloma patients whose in­for­ma­tion was reported to the National Cancer Data Base be­tween 2004 and 2015. The median patient age in the study sample was 65 years.

Of the 78,095 patient in­cluded in the analysis, slightly less than one fifth (17 per­cent) received up­front radiation ther­apy. Among the up­front ther­apy patients, 70 per­cent received radiation ther­apy before the start of their drug-based myeloma ther­apy, and 30 per­cent started it within 14 days after the start of the drug-based ther­apy.

Radiation ther­apy was predominantly admin­istered to the spine (59 per­cent) and the hip / pelvis area (12 per­cent).

Factors Affecting The Use Of Upfront Radiation Therapy

The odds of receiving up­front radiation ther­apy were sig­nif­i­cantly higher for younger patients, male patients, white non-Hispanic patients, uninsured patients, patients with lower incomes, patients treated at a com­munity hospital rather than an academic hospital, patients who live close to a hospital, and patients who had few or no health issues ("comorbidities") other than their myeloma.

Being treated at a com­munity hospital (rather than an academic hospital) was the strongest factor asso­ci­ated with up­front radiation ther­apy.

The use of up­front radiation ther­apy also appears to have declined over time. Among patients in the sample from 2004 to 2009, 18.6 per­cent underwent up­front radiation ther­apy. In the patients from 2010 to 2015, in comparison, 16.5 per­cent underwent up­front radiation ther­apy.

The study authors speculate that this decline in the use of up­front radiation ther­apy may be a reflection of physicians becoming more confident over time in the ability of drug-based myeloma ther­a­pies to address bone-related issues.

Upfront Radiation Therapy And Survival

Overall survival among the patients in the sample who underwent up­front radiation ther­apy was 3.6 years versus 4.2 years for the other patients. The three-year over­all survival rate was 55.5 per­cent in the up­front radiation ther­apy group versus 59.7 per­cent in the other patients.

The researchers also explored the poten­tial sig­nif­i­cance of the timing of up­front radiation ther­apy. They found that survival was noticeably lower in the up­front patients who received radiation ther­apy within 14 days after the start of their drug-based ther­apy, com­pared to the survival seen in the up­front patients who received their radiation ther­apy prior to the start of their drug-based ther­apy.

The authors also checked whether they still could find an association be­tween up­front radiation ther­apy and survival when they looked only at patients who survived at least a year after diag­nosis, and also when they looked only at patients who underwent a stem cell trans­plant.

In both these smaller samples of patients, the researchers con­tinued to find an association be­tween up­front radiation ther­apy and survival.

To the authors, this speaks in favor of the association be­tween early radiation ther­apy and over­all survival being due to patients with more aggressive myeloma being more likely to need early radiation ther­apy.

For more in­for­ma­tion, please see to the study by Orcutt, X. et al., “Prognostic sig­nif­i­cance of up­front radiation ther­apy in patients with multiple myeloma,” in The American Journal of Hematology, April 21, 2019 (full text).

Photo of a woman receiving radiation therapy.
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One Comment »

  • Susan Mandel said:

    Hmmm, I find this interesting on a few levels. Radiation was what got me into this mess in the first place, so I was happy that radiation was not called for in my case. I received induction therapy of Velcade, thalidomide, and dexamethasone (VTD), had a complete response, and have been on a maintenance therapy of Revlimid 10 mg since October 2008. I had many bone lesions at diagnosis, but am thrilled that I do not fall into the researchers' category of poor prognosis. I am hoping to celebrate 11 years of good numbers this summer. I think it goes to show that this disease is a very individual one.