保乳术后局部可植入加速放疗的应用急剧上升.pdf

保乳术后局部可植入加速放疗的应用急剧上升.pdf


Dramatic Increase in the Use of Implantable Accelerated Partial
Breast Irradiation after Breast-Conserving Surgery
A recent study has found that in breast cancer patients, the
use of implantable accelerated partial breast irradiation therapy
(IAPBI) after lumpectomy has increased dramatically
since 2000. The increase was seen in women of all ages, but
was statistically significant in those aged older than 40 years,
and was most notable in those aged older than 80 years.
Andrea Abbott, MD, and colleagues from the surgical
department at the University of Minnesota used the Surveillance,
Epidemiology, and End Results (SEER) database to
evaluate rates and trends of whole-breast radiation therapy
(WBRT) and IAPBI from 2000 to 2007 (Cancer. Published
online ahead of print February 1, 2011. doi: 10.1002/
cncr.25927). The study cohort included women with a diagnosis
of ductal carcinoma in situ (DCIS) or stage I or stage
II breast cancer who had breast-conserving surgery (BCS)
and radiation therapy (RT). The only categories of RT evaluated
were external beam radiation and radioactive implants.
Investigators identified 127,257 patients meeting the
inclusion criteria. Women in the IAPBI group were significantly
more likely to be older, be widowed, and have
stage I disease. Geographical differences were noted, with
0.5% of women treated with RT in Hawaii receiving
IABPI and 7.2% of those in Atlanta receiving IAPBI.
The overall proportion of patients treated with IAPBI
increased from 0.4% to 6.8%, with the proportion of those
receiving WBRT declining from 99.6% to 93.2% over the
study period. The most dramatic increase in the use of
IAPBI was observed in patients aged older than 80 years,
with an increase from 0.85% to 9.6%.
On logistic regression analysis including several patient
and tumor variables, the time trends in IAPBI use
remained significant, with an odds ratio of about 20 for
2007 versus 2000. Older age remained a predictor of use,
with an odds ratio of about 7 for patients aged 80 years
and older versus those aged 18 years to 39 years. Caucasian
women were more likely to be treated with IAPBI
than African American women, with an odds ratio of 1.3.
Patients with DCIS or stage I disease were more likely to
receive IAPBI (odds ratio of 1.9 for DCIS vs. stage II;
odds ratio of 3.1 for stage I vs. stage II).
IAPBI Rates Increasing
The results of this study confirm that IAPBI is being used
more frequently as an adjuvant treatment after BCS. The
authors conclude, however, that this rise is concerning
because randomized controlled trials have not yet shown it
to be equivalent to WBRT. Accelerated partial breast irradiation
(APBI) can be delivered via several methods including
balloon implantable catheters, interstitial brachytherapy, 3-
dimensional conformal RT, and intraoperative RT.
Eleanor Harris, MD, clinical director of radiation oncology
at the H. Lee Moffitt Cancer Center and Research Institute
in Tampa, Florida, says there are no data regarding
which APBI technique is preferable for any given patient.
APBI treats only the tissue around the tumor bed, resulting
in higher doses per fraction because of the decreased
tissue volume in the field. Most local recurrences occur
near the original tumor site, even in patients who have
undergone WBRT, making APBI logical.
There are, however, limited studies with long-term
follow-up to show equivalence to WBRT. Dr. Abbott and
colleagues wrote that to their knowledge, MammoSite is
Depiction of the MammoSite applicator (Proxima Therapeutics Inc,
Alpharetta, Ga) showing the radiation source port pathway, injection port,
and balloon, which can be filled to a maximum of 70 cm3 or 125 cm3,
depending on the model used.