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I've talked with a woman who had breast
cancer.
After the lumpectomy, she received a 200 rad
exposure to the specific breast each day, for five days in a week, for five
weeks.
This amounts to a total exposure of 200 x 5 x
5 = 5000 rad (local exposure).
Low dose irradiation therapy applies a total body
(or half body) dose of 15 rad, twice a week for 5 weeks. This
amounts to a total exposure of 150 rad. This is useful to deal with
metastases.
Some doctors believe that by the time a malignant
tumour has been detected, in 50% of the cases, the tumour has already begun to
metastasize.
----- Original Message -----
Sent: Thursday, November 08, 2001 1:25
PM
Subject: RE: [cdn-nucl-l] (no
subject)
Actually, this sounds more like just an extra dose of
therapy-level radiation.
Jeremy Whitlock.
> -----Original Message-----
>
From: Adam McLean [mailto:adam.mclean@utoronto.ca]
> Sent: Thursday November 08, 2001 1:16 PM
> Subject: [cdn-nucl-l] (no subject)
>
>
> The
research is finally catching up to theory on low-dose
> radiation treatment,
> Jerry! :)
>
> Adam
>
> ---------------
>
> 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.
>
>
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