DENVER—When cancer patients with brain metastases have to undergo palliative radiation therapy, the one constant is that the treatment almost always results in complete loss of their hair.
“For many patients, the prospect of complete hair loss is a devastating consequence,” said Todd Scarbrough, MD, a radiation oncologist at Melbourne Internal Medicine Associates in Florida. “Not only do these patients have a limited lifetime, but hair loss—for both female and male patients—may adversely affect their social life, making their remaining days less fulfilling.”
In a report here at the American Society for Therapeutic Radiology and Oncology Annual Meeting, though, Dr. Scarbrough, who is on the adjunct medical staff of the University of Miami School of Public Health and at the University of Texas Health Science Center at San Antonio, said that since early 2005 he has been treating people with intensity-modulated radiation therapy (IMRT) instead of the standard two-beam whole-brain radiation procedure.
Three Instead of Two Beams
Instead of two beams, each covering half of the brain, IMRT uses three beams to more precisely focus radiation. It proved to be a classic case of more producing less—in this case, hair loss.
Of his 14 patients, six suffered no hair loss, Dr. Scarbrough said at his poster presentation. The other eight had only mild hair loss. All the patients treated in the program are still alive, Dr. Scarbrough reported, although one patient has experienced central nervous system disease progression.
“With standard two-beam whole-brain radiation, almost every patient loses all his or her hair,” he said. “We thought that by using a multi-beam approach we could do a better job of focusing the radiation on the tumors and less on the patients' scalps.”
The mean scalp dose of IMRT totaled 18.5 Gy and is significantly less than the two-field plans of 27 Gy. The difference in radiation between the two procedures reached significance at the p=0.00001 level, he said.
He explained that in the IMRT procedure the lenses of the eyes were contoured in the treatment planning as was the “scalp”—defined as the skin with 3 mm of underlying tissue, contoured as a “cap” from the level of the canthi to the vertex.
For the three-field beam arrangement, roughly opposed laterals were positioned to achieve perfect “lens superimposition” for maximal lens sparing on beam's eye views, along with a “hemivertex” field in which the couch rotated at 90º with the gantry aligned to provide a beam's eye view angle, usually a gantry angle of 35º to 55º.
No Scale of Alopecia
He said that subjective mild hair loss is truly in the eye of the beholder because there is no scale to describe stages of alopecia: “In some cases, mild hair loss could be thinning of the hair; in other cases it might refer to areas of the scalp that are devoid of hair, but no one has yet devised a scale for alopecia.”
No significant skin toxicity occurred either on the scalp or skin behind the ears. All patients had some remaining hair at the end of treatment and in the first follow-up four weeks later.
Dr. Scarbrough said he could find no correlation between the radiation dose the patients' received and hair loss.
All the patients in the study had Stage 4 disease with metastases to the brain. “Our treatments are palliative, and as such sometimes they are not reimbursed,” Dr. Scarbrough said, “However, if third parties do pay for the palliation, they will often pay for the intensity-modulated radiation therapy, which is more expensive than two-beam irradiation.”
More Expensive & Still Unproven
Still, the expense is a big factor, noted ASTRO's Chairman of the Board, Theodore Lawrence, MD, Professor and Chair of Radiation Oncology at the University of Michigan. “It may be difficult to sell to patients the idea that they might be able to protect their hair with a procedure that is both more expensive than the standard and unproven.”
He said that the physics behind the concept is sound and there should be less of a dose of radiation to the scalp. Nevertheless, Dr. Lawrence said the treatment needs to be compared in a randomized trial to determine its true effectiveness.
Figure. Todd Scarbro...Image Tools
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