Please find a detailed analysis of the treatment and the evidence in this IORT paper.

12 Pages·2014·3.9 MB·English

non-inferior treatment for early breast cancer. BCS has
a higher local recurrence rate than a mastectomy but an
Intra-Operative Radiotherapy equivalent long-term survival. To date, there has been no
subgroup of patients identifi ed in which adjuvant radiotherapy
with Intrabeam: Tailoring of
can be omitted; radiation in BCS reducing the risk of local
recurrence and increasing survival8-16. Adjuvant whole breast
Breast Radiotherapy
radiotherapy is administered to a patient’s breast daily over
3-6 weeks (3 weeks represents a more recent advance with
Dr Erica Whineray Kelly, FRACS accelerated hypofractionation) in 15-30 treatments.
Breast Surgeon Fellow Royal Australasian College Surgeons
This is a burden on the patient and her family, workplace,
fi nances, and the health system. There may be an absence
of a suitable support structure, fi nances, and job security
INTRODUCTION
that remove BCS as an option for particular women. 15-20%
of patients will not complete their treatment and women will
Intraoperative Radiotherapy is radiation therapy delivered
also select an unnecessary mastectomy in order to avoid the
directly into the peritumoural tissue at the time of surgery.
prolonged daily treatment (even within Auckland) or travelling
The Intrabeam device uses low energy 50kV x-rays to treat
to one of the 6 centres in NZ that deliver radiation treatment.
the tumour bed which is the area of the breast which has
Mastectomy rates increase with increasing distance from a
been established as the high risk area for in breast tumour
recurrence in early breast cancer. Potential benefi ts of this radiation centre17, and treatment compliance decreases18.
The failure to complete treatment with an increased risk of
include increased uptake of breast conserving surgery,
recurrence is both costly to the patient and health funder in
improved cosmesis and reduction in painful breast oedema,
the long term.
reduced cost, accurate targeting of tissues to reduce
damage to local structures, and reduced disruption to the
There has been considerable tailoring and conservation
patient and her family & whanau.
of treatment seen in surgical and medical oncology but
apart from hypofractionation, there has been no tailoring of
BACKGROUND
radiotherapy treatment in breast cancer.
Up until the 1970s, women with breast cancer were treated
The tailoring and conservation in breast cancer treatment
with a radical or a modifi ed radical mastectomy as the
represents a paradigm shift away from giving the maximum
standard of care. Following the publication of a number of
tolerable to the minimum effective treatment; an important
randomised controlled trials1-7 and meta-analyses, breast
distinction.
conserving surgery (BCS) with adjuvant whole breast
radiotherapy (WBRT) was established as an alternative and
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The Rationale for Accelerated Partial Breast Irradiation Intraoperative Therapy with Intrabeam
The rationale comes from the observation that breast tumour Intrabeam is a radiation therapy device designed
recurrences are most likely to develop in the tumour bed. specifi cally for use intraoperatively incorporating the Photon
This is in spite of the fact that breast cancer is a multifocal Radiosurgery System (PRS). It was originally developed for
disease with 80% of the additional foci outside of the index the intracranial treatment of brain lesions22,23 and was fi rst
quadrant19. The patterns of failure show the recurrences used in phase one clinical trials in 1992 at Massachusetts
occur around the tumour site with other foci remaining General Hospital24. The original PRS was modifi ed to increase
dormant and subclinical for a patient’s lifetime. its accelerating voltage to 50kV powered via a control unit.
It was fi rst used in breast cancer patients in 1998 at the
University College Hospital, London25.
The Intrabeam device has Class 1 FDA approval for
anywhere in the body, in conjunction with multiple applicator
probes depending on the cancer site being treated. It uses a
miniature electron beam-driven source producing electrons
which pass down the delivery tube, striking a gold target and
producing x-rays in an isotropic distribution from its tip. This
50kV low energy dose attenuates rapidly sparing adjacent
organs and tissues.
The active component is small & lightweight and fi ts into a
small suitcase. The source is suspended from a mobile stand
and is enclosed in a specially designed drape to ensure
sterility. The six-axis mobility enables accurate positioning of
the selected spherical probe which is sutured into the cavity
after the cancer is removed and 20Gy of radiation is delivered
over approximately 12-40 minutes depending on the probe
The Milan 3 trial included 273 patients treated with whole size.
breast conservation but no radiotherapy. The majority of
recurrences were at the tumour site- the other ipsilateral
and contralateral recurrences were identical in number
ELIGIBILITY CRITERIA
between the two breasts20. Veronesi also observed that the
overall rate of contralateral breast cancer was 0.66 per 100 Patients >45 years
woman-years of observation nearly identical to 0.63 per 100
T1 or small T2 tumours
woman-years of observation in women who received breast
conserving surgery with adjuvant radiotherapy21. (<3cm) Grade 1 or 2
Clear margins
It is therefore appropriate to deliver radiation therapy to the
ER positive
tumour bed alone and spare the remainder of the breast and
organs at risk. Node negative
Invasive ductal carcinoma and subtypes
There is no data to suggest that the target is the whole
breast.
Accelerated Partial Breast Irradiation (APBI) EXCLUSION CRITERIA
APBI is a technique where a larger dose of radiation per
fraction is delivered only to the tumour bed. A number of Invasive lobular carcinoma
APBI techniques have been developed including: Multifocal or multicentric disease
Extensive intraductal component (EIC)
1) Intraoperative Radiation Therapy (IORT)
a. Intrabeam Lymphovascular invasion
b. ELIOT Bilateral breast cancer at the time of diagnosis
2) 3 Dimensional Conformal radiation therapy (3DCRT) Previous ipsilateral breast cancer and or irradiation
3) Interstitial brachytherapy Patients undergoing neoadjuvant medical treatment
4) Intracavity brachytherapy BRCA mutation
Focus Radiotherapy PO Box 31-415, Milford, Auckland 0741 | E [email protected] | www.focusradiotherapy.co.nz
Treatment Benefi ts Extensive modelling has been completed producing a novel
• This represents the fi rst real option for multiple groups of concept of the sphere of equivalence where the increase
women in New Zealand to select BCS. in local control in the high-dose region near the applicator
partly compensates the reduction in local control at greater
• Patient acceptability and convenience.
distances. Within the sphere of equivalence, local recurrence
• Support during treatment- women living out of town only is equal to that after external fractionated therapy29 (see
travel for one treatment. below).
• Targeted accurate treatment.
• Reduction in radiotherapy related side effects and
morbidity including second malignancies and cardiac
morbidity.
• Reduced cost to patients, families, workplace.
• Reduced cost to health provider.
• Reduction in unnecessary mastectomies.
• Increase treatment compliance.
• Increase access to linear accelerator for other cancer
streams.
The radiotherapy effect is increased by the increased
vascularity and oxygenation of a surgical site. IORT also
alters the microenvironment of the surgical cavity changing
it from pro-tumour proliferation to tumour-cidal impairing
Radiobiology of the Intrabeam Device
the proliferation, stimulation and invasion usually induced by
Intrabeam delivers a prescribed dose of 20Gy at the surface
surgical wound fl uid so avoiding a re-population of tumour
of the probe in a single treatment26. The x-rays rapidly
cells after surgery30.
attenuate delivering 5 Gy at 10 mm and 1 Gy at 27 mm. It
produces tissue damage via the photoelectric and Comptom The use of low energy x-rays makes it possible to deliver a
effects causing damage to DNA directly and via oxygen targeted dose of radiation and at the same time protecting
free radicals. The tissue damage arises from the transfer of other organs at risk and simplifying radiation protection.
energy or linear energy transfer (LET) from the (secondary) It can be given as a single dose rather the standard
electrons which have a higher LET at kilovoltage than fractionated radiotherapy where traditionally the size of the
megavoltage. This corresponds to a higher relative biological fraction is limited by the secondary effects of irradiating
effectiveness (RBE) which increases with decreasing photon normal tissues which are spared in traditional fractionating.
energy. The RBE for Intrabeam is approximately 1.5-2.527.
Within the limits of the currently available radiobiological By avoiding fractionating, sub-lethal damage and repair of
models, it is assumed that a dose of 20 Gy at the applicator tumour cells does not occur during the prolonged IORT
surface is equivalent to a fractionated dose of 70 Gy, while a treatment which is seen between standard fractions. It
dose of 5 Gy at 1 cm is equivalent to a fractionated dose of appears that the tissues immediately surrounding the
18 Gy28. tumour bed harbour cells that have a loss of heterozygosity
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in key tumour suppressor genes. These cells may survive The Evidence for Intrabeam IORT in Breast Conserving
conventional fractionated radiotherapy but may not be able to Surgery
survive the high dose IORT31,32. There are several studies validating the use of APBI using
various techniques including interstitial brachytherapy33-36
mammosite37-43 IORT44-47,52,55 and EBRT48-51. The largest
multicentre randomised controlled trial in APBI is the
TARGIT-A trial assessing Intrabeam IORT52,53.
The TARGIT–A trial commenced in 2000 as a randomised
non-inferiority trial for women with early breast cancer over
the age of 45 years. Patients were enrolled from 33 centres
in 11 countries between 2000-2012; 1,721 to TARGIT and
1,730 to WBRT. This was a pragmatic risk-adapted design so
that women who had received TARGIT could receive WBRT
afterwards if their tumour had poor prognostic features:
15% from the pre-pathology IORT group went onto receive
supplemental WBRT. The non-inferiority margin was set
at 2.5% with acceptable pre-trial 5 year LR rates of 5% for
WBRT and 7.5% IORT rates decided by the international
steering committee.
The TARGIT group was further divided into 2 groups: those
who would receive IORT at the same time as surgery (pre-
pathology) and those who would receive it in the weeks
after as a second procedure (post-pathology). These were
designed as parallel trials so each group can be assessed
The Procedure
independently.
Due to the radiation safety, this procedure can take place
in a standard operating theatre. The unit is mobile and can In November 2013, The Lancet published the 5 year follow up
move between theatres. The Unit undergoes a standard QA data53. 3,451 patients had a median follow up of 2 years and
check before the start of each day and between cases by the 5 months, 2,020 of 4 years and 1,222 of 5 years. In the pre-
Medical Physicist. An accredited Medical Physicist, Radiation pathology TARGIT group, the 5 year risk for local recurrence
Oncologist and Surgeon are present. was 2.1% IORT vs 1.1% for WBRT, in the post-pathology
TARGIT group 5.4% vs 1.7%. The breast cancer mortality
Once the tumour has been removed and the sentinel node
was non-signifi cant p=0.56 but there were signifi cantly less
assessed and found to be negative, the cavity is checked
non-breast cancer deaths in the TARGIT group 1.4% vs 3.5%
for haemostasis. A purse-string suture is placed in the
(p=0.0086) and overall mortality was 3.9% vs 5.3% favouring
subcutaneous fl aps. The tumour cavity is measured and a
TARGIT.
spherical probe is selected and inserted into the cavity under
direct vision and the purse-string suture tied. Saline soaked This was a non-inferiority trial which means that the results
gauze is positioned between the skin and the tissue fl aps to can fall within a pre-specifi ed margin (2.5%) even if there
ensure the probe surface is >5 mm away from the skin and is a statistically signifi cant difference between the arms to
around the neck of the probe. An ultrasound is used to check be demonstrated as non-inferior. There was also a pre-
the distance of the probe from the skin and to confi rm that specifi ed ‘signifi cant p value for difference’ for the log rank
the cavity is sitting against the probe surface. test of <0.01 for local recurrence. The 2% difference in the
pre-pathology group was within the non-inferiority margin,
The anaesthetist remains in theatre behind a lead shield
and with a p value of 0.04 was not-statically signifi cant
where the patient can be monitored. The treatment is
within the pre-defi ned criteria of the trial. The TARGIT A trial
delivered via the consol in the pre-operative bay with the
used the standard method of using binomial proportions to
radiation oncologist and physicist in attendance, lasting
calculate the non-inferiority statistic as single 5- year point
for between 12-40 minutes. The treatment can be paused
estimates do not represent the absolute events and can
if access is needed to the patient. Once the treatment is
lead to erroneous conclusions when the event rate is low.
delivered, the physicist will instruct the team on returning to
This method meant that the whole period of follow up was
theatre. The probe is removed and standard mammoplasty
assessed from randomisation to greater than 12 years as the
and closure is performed. The patient is discharged the
longest follow up. This analysis was repeated for early and
following day.
late cohorts, with all three used to inform the discussion.
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TARGIT was also favoured in Quality of Life Analyses, Public Health System would require two Intrabeam machines
Cosmesis, Toxicity and Patient Preference analyses54-56. with 5-6 arms and consols that are fi xed at their sites. The
small ‘head’ which produces the x-rays is moved between
There is now level one evidence to support the use of IORT centres which has been done very effectively within the
in selected women with breast cancer. German centres that use it. In NZ, if all women eligible moved
to IORT treatment today, 2.5-4 linear acceIerators would
There is debate about the signifi cance of the non-breast
be available for other cancer treatments. This is particularly
cancer mortality in the TARGIT trial, critics claiming that it
important as the NZ public health system is behind on
is ‘unexplained’, ‘too early to tell’, ‘can’t be real as half the
commissioning units to keep up with the modelling of its
tumours were right sided’... This is despite evidence that
linear accelerator requirements which have been predicted to
radiotherapy treatment can cause cardiac morbidity and
increase for other cancer streams in the next 10 years67.
mortality57 and other secondary cancers58-62. This is not a
new fi nding: the Oxford Overview63 and NSABP-068 both Below is the predicted increase in radiotherapy linear
found that the modest breast cancer survival benefi t (3%) accelerator demand in America up until 2018 which will
from post lumpectomy radiation was off-set by the increase mirror the NZ situation demonstrating the increase in demand
risk of death from other causes. Darby et al found that the from other tumour streams in conjunction with increasing
risk is highest in the fi rst 10 years, that the risk of cardiac population growth.
mortality is 16.3% per Gray, and the presence of ischaemic
heart disease is multiplicative with a further increase of
13.4% per Gray. They also found no signifi cant difference
with laterality on cardiac toxicity; ratio1.34 left: right sided
cancers which is consistent with the TARGIT A Trial57.
Perhaps this lethal effect had not been appreciated earlier
in older trials as it was masked by the higher breast cancer
mortality rate. Schultz-Hector et al concluding, “There is
little evidence that the advances in radiotherapy techniques
decreased the excess relative risk of radiation-induced heart
disease signifi cantly.... There is convincing evidence that
radiation doses lower than 10% of the doses usually noted
as tolerance doses for the irradiated heart in radiotherapy
are associated with a signifi cant increase in cardiovascular
morbidity after latencies of >10 years”64.
The DCIS Oxford Overview65 did not detail the cause of
death however they are a similar low risk group as those in
the TARGIT-A study. There were 92 invasive recurrences in
the WBRT arm and 204 in the no WBRT arm. One would
expect that the difference in breast cancer deaths should
be ¼ according to the ‘1/4 local recurrence at 10 years
leads to a death at 15 years”63 so there should have been
28 more deaths in the no WBRT arm. In fact, there were 19
more deaths in the WBRT arm which crudely shows 47 more
deaths in the WBRT than should have been estimated: there The implementation of a new technology is more cost
is a 28% increase in non-breast cancer death with WBRT in effective if it can be used on multiple tumour streams:
the DCIS study. Intrabeam can also be used to treat advanced or locally
recurrent rectal, gynaecological, gastric, pancreatic, bladder,
Cost Benefi t Analysis head & neck/oral cancers and soft tissue sarcomas69. It is
also extremely effective at managing women with metastatic
Intrabeam IORT is a disruptive innovation that provides a
breast cancer with unstable vertebral disease, combining
less costly and more convenient option, ultimately creating a
a IORT sterilisation procedure with a cement kyphoplasty
new market66. It is a new technology which is less costly than
treating the pain and the instability with a short procedure
the current standard but offers similar treatment effi cacy.
without using expensive orthopaedic implants and daily
With the capital investment of NZ$1.3 million (which is low
radiotherapy70. The evidence suggests that intraoperative
compared to the commissioning of a linear accelerator), IORT
radiotherapy as part of multimodal therapy is feasible and
would recover its costs and additionally, due to its mobility
effective at reducing local recurrence with limited toxicity.
allow for inter-DHB cooperation in providing this treatment
In this sense, the use of IORT could represent a substantial
in dedicated centres. It is estimated that the New Zealand
improvement in a strategy of organ and function preservation
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of a variety of tumours considering that the
shortening of treatment time contributes to
improve the quality of life of the patients.
Alvarado and his colleagues71 have modelled
the two treatments for cost-effectiveness:
IORT dominated WBRT in all modelling:
if IORT were the standard treatment today,
WBRT would never be introduced. They
have demonstrated that the 10 year local
recurrence rate would have to be 22% in the
TARGIT group for WBRT to be cost-effective.
With a 5 year LR rate of 2.1%, this 10 year LR will
not be reached. For life expectancy, the
incremental cost-effectiveness ratio (ICER) for
moving from IORT to WBRT was calculated at
USD $29.9 million/life year61.
Below, the table72 compares the fi nancial cost for absolute (cid:129) Sample Size
reduction in mortality of other breast cancer interventions.
The original power calculation required 2,232 patients with
The reduction in non-breast cancer mortality is just less than
the non-inferiority margin of 2.5% and estimated local
that absolute reduction by Herceptin treatment at 5 years.
recurrence rates of 5% WBRT and 7.5% IORT. When the
fi rst analysis took place, the baseline local recurrence
What are the Criticisms? rates were only 1.5 %. With an 80% and 95% CI, the trial
• Lack of Expert Consensus now only required 585 patients65.
There are multiple international groups who have • 15% of Patients still have IORT
produced guidelines for the implementation of APBI
85% of patients still have a single treatment. The IORT
including American Society for Radiation Oncology
dose replaces the 5 day boost treatment at the end of the
(ASTRO), European Society for Radiation and Oncology
WBRT so still reduces their treatment time.
(GEC-ESTRO), American Society of Brachytherapy, and
American Society of Breast Surgeons (see below)73. • Geographical Miss
This is impossible as the cavity is under
direct vision - there are 8 different probes
to select from and an ultrasound probe
is used to confi rm opposition of the tissue
onto the probe surface using the purse-
string suture to control the tumour bed.
• Length of Follow up
Local recurrence rates are well estab-
lished for breast cancer. There is an
established LR peak at 2-3 years after
surgery, even with endocrine treatment
as the ATAC study graph below shows68.
The use of APBI in suitable patients is also included in the
National Comprehensive Cancer Network (NCCN)74. 3 HR local recurrence censoring any recurrence
0.
(cid:129) Comparison to the ELIOT trial39.
8
This is both unscientifi c and obstructive. The ELIOT trial 0.2
used a different surgical technique known to involve
devascularisation of the tissues, a different type of x-ray 6
2
(electrons) and a different patient group. This trial included 0.
many high risk patients which were not included in the
4
TARGIT-A for which the ELIOT trial has been criticised. 0.2
The key to APBI is careful patient selection: when the
consensus guidelines are applied to the ELIOT trial among 22
0.
others, the local recurrence rates are very acceptable.73 0 2 4 6 8
years
Focus Radiotherapy PO Box 31-415, Milford, Auckland 0741 | E [email protected] | www.focusradiotherapy.co.nz
Wickberg et al76 with 20 years of follow up from a sector
resection with or without radiotherapy demonstrated that
radiotherapy protects against recurrences in the fi rst fi ve years
indicating that XRT mainly eradicates undetected cancer
foci present at primary treatment. There were similar rates of
recurrences beyond 5 years in the two arms.
There is no mechanism for a second local recurrence peak.
(cid:129) Tamoxifen is causing the low LR in the IORT group.
65% of the patients received adjuvant endocrine therapy
in all arms. If Tamoxifen was responsible for the low LR
rates then it wouldn’t explain the difference in pre and
post pathology arms which serves as an internal control in
No trial or study has shown a 2nd peak of local recurrence
the study and demonstrates the effectiveness of IORT in
outside the fi rst 5 years. The linear increase of local recurrence
reducing LR.
in the high risk group in the ELIOT trial39 represents residual
The prospective, randomised radiotherapy versus
under-treated disease not true local recurrence.
tamoxifen trials show that tamoxifen is not a universal
substitute for radiotherapy. The Hughes et al77 trial that
showed comparable benefi t within the over 70 year old age
group has not been demonstrated by other groups and has
not led to general recommendations to omit radiotherapy in
older age groups.
What is the Risk of Early Implementation?
Often the results from randomised clinical trials are not
adopted early and particularly if it means giving less treatment.
New approaches such as IORT disrupt the status quo, disrupt
the future planning and resourcing of treatments, are often
not rebated by insurers or public funders, and there may be a
fi nancial disincentive to providing the treatment. Factors other
than evidence and patient benefi t are driving practice changes.
The results of potential harm and opportunity cost from failure
to adopt IORT early are striking and suggest that we should be
doing less for women with low risk tumours78.
Local recurrence curves are not linear - there is diversion
within the fi rst 5 years. In the graph shown the NSABP-068
data shows that the separation at 5 years is almost identical
to the one later.
Focus Radiotherapy PO Box 31-415, Milford, Auckland 0741 | E [email protected] | www.focusradiotherapy.co.nz
What is the risk of early implementation of IORT? This has women opted for IORT even if there was an increased risk
been done with Intrabeam IORT78. Modelling was performed of local recurrence56. This was done when Intrabeam IORT
looking at the impact of early and late adoption, in terms of was still experimental and again after the publication of the
quality of life and resources gained or lost. TARGIT A results, prior to it being found to be non-inferior to
WBRT.
(cid:129) If IORT was adopted now and the local recurrence
rates were to be 10% at 10 years (which is higher than Informed patients may choose not to follow a guideline that
expected) then the life expectancy lost is less than does not incorporate their preferences and especially if there
1 day. is inconvenience associated79. Clinicians do need guidance
(cid:129) In this analysis, the mortality was assumed to be equal and clear guidance supports effi cient and effective practices.
between IORT and WBRT. The mortality data actually Yet guideline panels should become much more comfortable
favours (statistically signifi cant) IORT so over time IORT with ambiguity, both in the tradeoffs involved and in the
is favoured on the basis of mortality benefi t as well recommendations given, and explicitly report how patient
quality of life and resources gained or lost78. preferences and context were considered in formulating the
panel’s recommendations79. The risk here is that women
eschew adjuvant radiotherapy after breast conserving
Patient Preference, Philosophy and Iatrogenics
surgery all together.
Research evidence is necessary but insuffi cient for making
patient care decisions. Whilst guidelines and pathways The lack of long term data is a limitation which will be
are useful they do not replace patient preference, clinical overcome by time and follow up. Wickberg et al76 found no
expertise and wrongfully assert that there is ‘only one additional protective effect of radiotherapy against breast
right way’. cancer events after 5 years of follow-up. Similar results
were presented in the National Surgical Adjuvant Breast and
Women are informed and educated in breast cancer options Bowel Project B-068 trial in which, in the group treated with
now more than ever. In the same way women refused to lumpectomy alone, 73.2% of the local recurrences occurred
have mastectomies in the 1970’s, women are informed within the fi rst 5 years after surgery. However, a well-informed
and choosing single dose intraoperative radiotherapy. patient now is able to balance the risks and benefi ts of
They will even accept higher local recurrence rates for the this treatment, and as oncologists, we offer women similar
convenience of IORT. Using trade off techniques in women choices everyday with much bigger % of gain and loss than
being treated at the UCSF Breast Cancer Centre, 64% of is seen with this treatment.
Focus Radiotherapy PO Box 31-415, Milford, Auckland 0741 | E [email protected] | www.focusradiotherapy.co.nz
There is also the principle of Primum non nocere and the
principle of iatrogenics... There is evidence that in low risk
patients more harm is being done with WBRT than benefi t in
comparison to IORT. Iatrogenics is not linear: we should not
take risks with near healthy people but we should take big
risks with people who are deemed in danger80.
Finally...
The paradigm shift of the 20th century in breast cancer
treatment was the surgical conservation of the breast.
Veronesi and Fisher independently published their
Milan and NSABP-04/-06 demonstrating the safety of
conserving the breast. The Milan trial published 7 years
after commencement and the NSABP-06 after 5 and 8
years. These trials were practice changing, a new era of the
informed patient and ‘medical feminism’ meant that women
were demanding the less mutilating surgery and the trial
results ended the era of the radical mastectomy. Doctors and
patients did not wait for 20 year follow up to do so.
At 20 years, what they would have found is that, “the survival
rate was the same in both groups, even though the rate of
local recurrence was higher in the group that received breast
conserving surgery, supports the original basis of our trial-
namely, that the prognosis of breast cancer is linked to the
presence or absence of occult distant foci of metastatic cells
and not to the extern of local surgery”81.The BCS group had
4 times the number of local recurrences at 20 years, with
the same breast cancer survival. It is striking that there is
concern about the difference between 2.1% and 1.1% 5 year
local recurrence rates in the TARGIT A Trial, given that BCS is
accepted treatment.
Well-informed patients make trade-offs with adjuvant
treatment everyday deciding to have or not to have hormone
manipulation, chemotherapy and Herceptin with % gain
as much at 15%. That is patient choice. In the same way,
patients should be able to choose to have cheaper, more
acceptable and as effective treatment as Intrabeam IORT.
It is irresponsible to ignore the knowledge that has been
gained in the last 30 years and the data from good quality
trials such as the TARGIT A trial while there is a clear survival
advantage and patient preference for its implementation.
The optimal practice of evidence based care is the tailoring
of treatments for women according to the biology of their
tumours based on randomised trial evidence. It is known
that 16-30 sessions of WBRT is overtreatment for the 60-
70% of women whose cancers are not going to recur. The
evidence demonstrates that there is at least a group that
can safely receive less treatment with single dose Intrabeam
Intraoperative Radiotherapy. The challenge lies not with
the proponents of Intrabeam IORT but with the proponents
of WBRT to justify its continuing use without tailoring the
treatment to the patient and her cancer.
Focus Radiotherapy PO Box 31-415, Milford, Auckland 0741 | E [email protected] | www.focusradiotherapy.co.nz
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