[cdn-nucl-l] (no subject)

[Adam McLean <adam.mclean@utoronto.ca>]

The research is finally catching up to theory on low-dose radiation treatment, 
Jerry! :)  

Adam

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Radiation Boost Wards Off Breast Cancer's Return
By Merritt McKinney

NEW YORK (Reuters Health) - An extra ``boost'' of radiation may nearly halve 
the risk of cancer recurrence in women with early breast cancer who undergo 
surgery that spares most of the breast, according to the results of an 
international study.

So far, investigators have followed the women for 5 years, which they believe 
is not long enough to evaluate the long-term effects of an extra dose of 
radiation. But the approach seems appropriate in women who develop cancer at 
age 50 or younger, who benefited most from extra radiation in the study, the 
researchers note.

During a lumpectomy, a surgeon removes a tumor and some surrounding breast 
tissue. Research has shown that zapping the entire breast after this breast-
conserving treatment lowers the risk that cancer will return. But little is 
known about the effects of an additional dose of radiation that is targeted at 
the site of the tumor.

In the present study, more than 5,000 women with early-stage breast cancer 
underwent a lumpectomy and then received radiation directed at the entire 
breast. In addition to standard radiation therapy, half of the women also 
received additional radiation treatment directed at the part of the breast 
where the tumor had been.

During 5 years of follow-up, women who received the extra dose of radiation 
were less likely to have cancer recur at the site of the tumor, Dr. Harry 
Bartelink, of the Netherlands Cancer Institute in Amsterdam, and colleagues 
report in the November 8th issue of The New England Journal of Medicine (news - 
web sites). The risk of so-called local recurrence was 41% lower in women given 
a boost of radiation.

Although the reduction in risk is ``substantial,'' Bartelink's team points out 
that the benefits of additional radiation depend on each woman's risk of 
recurrence, which varies. For example, the research team found that women who 
were age 40 or younger benefited the most from an extra dose of radiation, 
experiencing a 54% drop in the risk of recurrence.

``In our opinion, the absolute benefit of the additional dose justifies its use 
in patients 50 years old or younger,'' the authors conclude.

Still, Bartelink and his colleagues point out that 5 years is not long enough 
to evaluate the long-term effects of radiation. They plan to continue following 
the women for at least 10 years to see whether extra radiation causes any 
problems, such as an increased risk of second cancers.

The study is a sort of fine-tuning of radiation treatment for women with breast 
cancer, according to Dr. Carla I. Falkson, the director of the breast program 
at the University of Alabama at Birmingham Comprehensive Cancer Center.

In an interview with Reuters Health, however, she noted that there was no 
difference in death rates between the two groups. And as the authors mention in 
the report, Falkson pointed out the need for further follow-up to determine 
whether an additional boost of radiation causes additional long-term side 
effects.

The higher dose of radiation was expected to increase the scar tissue at the 
site, although the researchers found no major increase in scarring due to the 
dose increase. However, the cosmetic results overall were somewhat less 
positive in women who received an additional dose of radiation.

Bartelink and his colleagues conclude that the ``reduction in the incidence of 
local recurrences associated with the additional dose far outweighs the slight 
increase in the poorer cosmetic outcome, especially in patients younger than 50 
years of age.''

SOURCE: The New England Journal of Medicine 2001;345:1378-1387.