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One-shot radiotherapy for breast cancer?
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Kounteya Sinha, TNN
NEW DELHI: Radiotherapy for breast cancer patients could soon be a single dose
30-minute affair, instead of the tedious present-day regimen lasting over six
weeks.
In a major breakthrough, a team of British doctors headed by University College
London's Dr Jayant S Vaidya -- an Indian from Goa -- has succesfully created and
tested a new technique that will blast the remnants of a tumour inside the
breast in just one shot, lasting half an hour. The team used radiation on areas
just around the tumour rather than the whole breast, as is done presently.
A 10-year trial of this Targeted Intraoperative Radiotherapy (TIR), conducted in
nine countries involving over 2,200 women, confirmed that radiation targeting a
specific area of the breast was as effective as whole-breast radiation in
reducing breast cancer recurrence in women.
The results of this trial was published in the latest edition of the medical
journal 'The Lancet'.
So, while a patient is still under anaesthesia following the removal of the
tumour, a series of gentle X-rays are administered to destroy any remaining
tumour cells at the cancer site. The technique is highly convenient, requiring
just one session of radiation, making it less time consuming and less costly
than whole-breast treatment.
"TARGIT trial can change two fundamental principles in the treatment of breast
cancer: whole breast radiotherapy can be replaced by a targeted one-time shot
and a much smaller dose of radiation may be adequate," Dr Vaidya told TOI from
UK. Several hospitals in India, including Breach Candy in Mumbai and AIIMS in
Delhi, have expressed interest in his work, he added.
"Breast cancer usually recurs around the area where the tumour was detected the
first time. So it's logical to give concentrated dose of radiation to the
tissues at highest risk of cancer coming back rather than the whole breast," he
added.
Dr Vaidya said that since 2000, the team started delivering TIR to patients. A
special machine called Intrabeam administered radiation from inside the breast
to the exact site of the cancer, instead of the present-day external beam
radiotherapy.
"Our decade-long TARGIT trial has now confirmed that old and new methods are as
good as each other," Dr Vaidya said.
The therapy, however, has a few limitations at present. It can be done on
patients over the age of 45 and the tumour should not be bigger than 3cm. "Our
trials till now tried this technique on women above age of 45. So we don't know
how effective it will be in stopping recurrence of cancer on younger women.
Trials to find this are going to start soon," he said.
Dr Vaidya launched the TARGIT trial on March 24, 2000. In this randomized trial,
women aged 45 years or older with breast cancer undergoing breast-conserving
surgery were enrolled from 28 centres in nine countries. Patients were randomly
assigned in a 1:1 ratio to receive TIR or whole-breast external beam
radiotherapy.
The study said, "At four years, there were six local recurrences in the
intraoperative radiotherapy group and five in the external beam radiotherapy
group. Recurrence in the conserved breast at four years was 1.2% in the targeted
intraoperative radiotherapy and 0.95% in the external beam radiotherapy group.
Radiotherapy toxicity was lower in the TIR group."
Prof Michael Baum, professor emeritus of surgery at University College London
who carried out the first procedure using intraoperative radiotherapy in 1998
said, "Many women specially in the developing world who live hundreds of miles
from a radiotherapy unit will be spared six weeks of treatment going back and
forth to the radiotherapy centre."
* Targeted Intraoperative Radiotherapy (TIR) has a comparable recurrence rate of
around 1% with presently used external beam radiation
* Radiotherapy toxicity were four times lower, with an incidence rate of 0.5%
compared with 2% from EBR
* The new technique involves an intense blast of radiation to the tumour site
extending to a radius of 2 cm lasting 30 minutes
* It takes place after the surgeon has taken out the tumour and before the wound
is closed
* TIR completely avoided irradiation of the heart, lung and oesophagus causing
no damage to these structures
* It is currently only available to women taking part in clinical trials
- Courtesy:
http://timesofindia.indiatimes.com
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