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| Journal of the New Zealand Medical Association,
24-October-2003, Vol 116 No 1184
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The Auckland Breast Cancer Register: a special project of the
Auckland Breast Cancer Study Group
Lorraine Neave, Vernon Harvey, Chelleraj Benjamin, Paul
Thompson, Ora Pellett, Jeremy Whitlock, Wayne Jones, and Garth Poole
The Auckland Breast Cancer Study Group (ABCSG), established
in 1976, brought together a multidisciplinary group of clinicians with a
particular interest in breast cancer management and research. As such, the
membership includes representatives from both the public and private sectors in
the fields of radiology, surgery, pathology, breast-care nursing, medical and
radiation oncology, and biostatistics.
Between 1976 and 1985 the study group established a
comprehensive database of 2700 cases of breast cancer in the Auckland region.
This computerised database, with continued follow up, has provided important
information on the incidence, pattern and management of breast cancer in a mixed
ethnicity community and it has provided the resource for some 30 publications.
The register was discontinued in 1985 following concerns expressed over privacy
issues.
In 1996 the members of ABCSG agreed unanimously that a new
breast cancer register should be established throughout the Auckland region.
Against a background of important advances in all areas of breast cancer,
including genetics, detection, conservative surgery and chemo/endocrine adjuvant
therapy, there was a need for a new, comprehensive database as a resource for
ongoing audit and research.
In New Zealand there is clearly a need for data on breast
cancer incidence, and analysis of survival by multiple presenting factors
including clinical stage of disease. The Auckland region, particularly, presents
a unique opportunity to accrue the details of clinical presentation and
management in Maori, Pacific Island, and other ethnic groups, which will lead to
a better understanding of why outcomes are worse in some groups than
others.1 Information about current practice
plays a key role in supporting evidence-based
care,2,3 and allows multidisciplinary teams to
provide high-quality care. Each of the specialty groups within the team uses
internationally recognised guidelines and protocols to provide high-quality
care. The ABCSG is not attempting to establish guidelines or recommended
practice documents.
The group has links to the Australia–New Zealand
Breast Cancer Trials Group and the Swiss-based International Breast Cancer Study
Group. It has worked for almost 20 years with both these organisations in the
promotion and data management of a range of ethically approved clinical trials
in both early and advanced breast cancers. The Secretariat for ABCSG is situated
in the Oncology Department at Auckland Hospital but is independently
administered and funded solely by charitable donations.
A subcommittee of the ABCSG met regularly to determine aims
and develop a new breast cancer register. In June 2000 the Auckland Breast
Cancer Register (ABCR) commenced accrual having received approval from the
Auckland Ethics Committee. The Register was also declared a Quality Assurance
Activity under Part VI of the Medical Practitioners Act 1995.
The aims of the Register are to collect in a timely,
accurate and confidential manner a predetermined set of data. These data
will:
MethodsAll patients who are New
Zealand residents residing in the greater Auckland region and have a diagnosis
of breast cancer after 1 June 2000 are eligible to be on the Register. These
patients are identified by pathology reports sent from the National Cancer
Registry. All clinicians involved with the care of patients with breast cancer
were invited to participate. Participating clinicians agreed to approach all
their patients presenting with newly diagnosed breast cancer and provide them
with a patient information sheet and consent form. Detailed information on the
initial diagnosis and treatment is recorded, then follow-up forms are sent
annually to the clinician and information on the diagnosis and treatment of any
loco-regional and or metastatic disease is collected. Confidentiality of the
information collected for the Register is maintained at all times. A summary of
aggregated data is generated annually and the data will be analysed and the
results offered for publication in peer-reviewed journals.
ResultsPatient
accrual Data accrued between June 2000 and June 2002 are summarised in
this article. Of 1497 patients identified as eligible, 1204 (including 10 men,
0.83%), have given consent to be registered. Eighteen (1.2%) patients refused
consent and 18 patients died before consent could be sought. The remaining 257
(17.2%) patients were not approached by their clinicians.
These figures demonstrate that approximately 80% of all the
cases of breast cancer diagnosed in the Auckland region between June 2000 and
June 2002 are represented on the ABCR database. All clinicians, public and
private, who treat breast cancer cases in the Auckland region have patients
registered on the ABCR. However, the main limiting factor for 100%
representation is the requirement from the Health Information Privacy Code 1994
to seek individual informed consent. Those patients easily treated
‘disappear’ from the system very quickly, thus their consent becomes
difficult or impossible to obtain.
Identified breast cancer cases were distributed between
public (60.6%) and private services (39.4%). These figures are based upon
initial diagnosis and surgical treatment because some treatment options, such as
radiotherapy, are offered only within the public service and therefore many
patients are treated by both public and private sectors.
Age distribution At
the time of diagnosis, 71.9% of the patients were aged 50 and over, with 28.1%
being over 65 years old (Table 1). It is of interest to note that seven of the
ten male patients were over 70.
Table 1. Age distribution of patients accrued on
Auckland Breast Cancer Register, June 2000 to June 2002
Ethnicity Ethnicity
was determined from the National Health Index (NHI). The majority of patients
identified themselves as European (62.0%), with 5.3% identifying as NZ Maori,
5.4% Pacific Island, and 4.2% Asian. For 23.1% of patients ethnicity was
indicated as ‘Other’ or ‘Not stated’.
Family history One
hundred and forty eight (12.3%) patients gave a history of a first-degree
relative (mother, sister or daughter) who had breast cancer; of these, 13 (8.8%)
patients reported a second-degree relative also. Twenty one (1.7%) patients had
more than one first-degree relative with breast cancer.
Clinical
presentation Data for clinical presentation were available for 1181
(98.1%) cases. Six hundred and ninety four women (58.8%) presented with clinical
signs or symptoms, such as a lump, pain, nipple change or skin abnormality,
while 487 (41.2%) patients had a screen-detected cancer. However, 83 (17.0%) of
these screen-detected patients were also found to have a clinically evident
abnormality, and some may have attended screening because of this. It is of
interest to note that 289 (24.5%) women had undergone a previous mammogram.
However, of the 509 women in the age group eligible for inclusion in the Breast
Screen Aotearoa programme, only 169 (33.2%) had undergone a previous mammogram.
Detection rate by age group is seen in Table 2.
Table 2. Age groups of patients presenting with
clinically evident or screen-detected breast cancer (n = 1181)
Radiology
Mammographic findings were analysed for a total of 1135 patients, with 1042
(91.8%) having mammographic features of carcinoma. Breast ultrasound was
performed for 922 patients, with 821 (89.0%) having ultrasound features of
carcinoma.
Of 910 patients on whom both mammography and breast
ultrasound were performed, 877 (96.4%) had malignant lesions detected by either
mammography, ultrasound or both, with only 33 cases (3.6%) not identified by
either of these imaging techniques.
Definitive diagnosis
Data for definitive diagnosis were available for 1185 (98.4%) patients. A
definitive diagnosis was confirmed by core biopsy alone in 632 (53.3%) patients
and fine needle aspiration (FNA) alone in 292 (24.6%). A small number of
patients (181, 15.3%) required both FNA and core
biopsy for confirmation and a further 80
(6.7%) patients had an excision biopsy for definitive diagnosis. The procedure
used for core biopsy was described in 67.3% of cases; of these, 77.9% were
ultrasound-guided biopsies.
Type of cancer
Invasive carcinoma with or without an in situ component was diagnosed in 1014
(84.2%) of the 1204 cases, ductal carcinoma in situ (DCIS) alone was diagnosed
in 154 (12.8%) cases. The other 36 (3.0%) patients had an FNA to determine a
malignant breast carcinoma, but did not proceed with further surgical
intervention because of comorbidity condition or patient refusal to undergo
surgery.
Tumour size (TStage)
Tumour size, as reported from the pathology results, is shown in Table 3. In
48.7% of patients with invasive cancer the tumour was ≤2 cm. Patients with
TX staging had neo-adjuvant therapy, therefore true tumour size could not be
assessed, or declined surgery (Table 3).
Table 3. Tumour size (TStage) in Auckland Breast Cancer
Registry patients, June 2000 to June 2003
Grade of cancer
Tumour grade was reported for 967 (97.4%) of 993 surgical patients with invasive
tumours. Grade 1 tumour was diagnosed in 205 (21.2%) patients, grade 2 in 483
(49.9%) patients, and grade 3 in 279 (28.9%) patients. However, 53% of patients
under 40 presented with grade 3 tumours compared with 26.8% of patients over 40
(Figure 1).
Figure 1. Percentage of patients in each age group with
a grade 1, 2 or 3 tumour (data labels = number of patients)
 Nottingham Prognostic Index
(NPI) The NPI,4 a model of prognosis
developed from tumour size, grade and nodal involvement (tumour size (cm) x 0.2
+ grade + nodes (0 = 1, 1–3 = 2, ≥4 = 3)) could be calculated for
905 (89.3%) of 1014 patients diagnosed with invasive breast cancer. Patients for
whom NPI could not be calculated had no surgical intervention, did not have an
axillary dissection, or had neo-adjuvant treatment (chemotherapy/hormone therapy
and/or radiotherapy prior to surgical intervention) (Table 4).
Table 4. Range of Nottingham Prognostic Index (NPI)
scores for patients with invasive breast cancer
Hormone receptor
status The pathologist reported receptor status for 962 (79.9%) patients.
Oestrogen-positive tumours were found in 722 (75.1%) patients and
progesterone-positive tumours in 640 (66.5%) patients. Both receptors were
positive for 606 (63.0%) patients. One hundred and sixty five patients were also
tested for Her2 status, and 52 patients were status 2+ or 3+ using
immunostaining techniques.
Figure 2. Type of definitive surgery by type of cancer
(n = 1204)
 Type of definitive surgery
by type of cancer Five hundred and fifty four patients (55.8%) with
invasive cancer had mastectomy and 439 (44.2%) had a partial mastectomy. In
patients diagnosed with in situ cancer alone, 49 (32.7%) had mastectomy, 101
(67.3%) a partial mastectomy, but 28 (27.7%) of these patients had only a
diagnostic lumpectomy and no further surgery. Sixty one patients did not have
primary surgery (Figure 2).
Breast
reconstruction One hundred and eleven women (18.4%) treated by mastectomy
also chose to have breast reconstruction. Sixteen had an implant, 19 latissimus
dorsi reconstruction, and 76 underwent a TRAM (transverse rectus abdominus
myocutaneous) flap reconstruction. However, these data do not account for the
number of women who may be on the waiting list for reconstruction.
Axillary surgery
Axillary node dissection was performed for 934 (94.1%) of the 993 patients who
underwent surgery for invasive cancer. Axillary nodes were involved in 367
(39.3%) patients and 567 (60.7%) patients had negative nodes. Of the 150
patients with in situ disease only, 28 (18.7%) had axillary surgery and none of
these patients had nodal involvement.
Oncology referral Of
the 1204 patients registered with the ABCR between June 2000 and June 2002, 949
(78.8%) were referred to a medical and/or radiation oncologist for consideration
of local and/or systemic treatment. Of these, 846 (89.1%) patients had adjuvant
treatment (Table 5), 36 (3.8%) had neo-adjuvant treatment alone, and 38 (4.0%)
had both neo-adjuvant and adjuvant treatments. Adjuvant radiotherapy treatment
was given to 81.3% of patients who had a partial mastectomy, and 35.0% who had
mastectomy.
Table 5. Adjuvant oncology treatment given to patients
referred to medical and/or radiation oncologists (n = 846)
Recurrence and
deaths At this early stage of data collection, 102 (8.5%) patients have
been diagnosed with a recurrence: 66 with metastatic disease, 18 with
loco-regional recurrence, and 18 with both. Six patients had another primary
breast cancer diagnosed in the contralateral breast.
A total of 65 patients have died, 40 from breast cancer and
25 from other causes (Table 6).
Table 6. Patient outcome within a maximum of two years
from initial presentation
DiscussionGiven that the data presented in
this paper are from the first two years of data collection, detailed analyses
would be premature. Of the 1497 patients identified as eligible for inclusion in
the Register, only 18 (1.2%) patients have refused consent (8 of these refusing
all treatment). We would hope that with continued development and acceptance of
the Register this figure would fall, as would the number of patients who have
not been asked to participate by their clinicians. We recognise that the data
collection generates extra work, but believe that the need to document current
practice justifies this.
Most women present with clinical symptoms, such as a lump.
In the 50- to 64-year age group, when women are eligible for free screening
through the Breast Screen Aotearoa programme, 62% of tumours were diagnosed at
screening; however, 15.9 % of these were also clinically evident. It appears
that women and doctors may be using the screening programme for diagnostic
mammography of clinical abnormalities. This will distort the screening figures.
It is worrying that overall more than 50% of women are still presenting with
clinical disease. There is clearly a need to increase recruitment to screening
within the target group, particularly Maori and Polynesian
women.1 Of the 509 women who would have been
eligible for a breast screen since screening became free in 1999 only 169
(33.2%) had undergone a previous mammogram. However, these figures may be merely
reflecting the relative newness of free breast screening. With greater public
awareness and acceptance of the breast screen programme, it is hoped and
expected that these figures will improve.
Mammography remains the primary screening technique in the
diagnosis of breast cancer, with a mammographic detection rate of 92% in this
patient group. This is comparable to detection rates reported in the
literature.5,6 However, breast ultrasound, in
conjunction with mammography, has become an integral part of the diagnostic work
up for patients with clinical symptoms or mammographically detected
abnormalities. Ultrasound was also the method of choice in 77.9% of patients who
underwent image-guided needle biopsy.
Core biopsy, which allows differentiation between DCIS and
invasive cancer, is clearly preferred over FNA for definitive diagnosis, as
demonstrated in this patient group.7
Pleasingly, only a small number of patients required excision biopsy to confirm
the diagnosis.
The pathological characteristics of the tumours at this
early stage of the Register are in line with those reported in the
literature.8,9 Morrow et al report that 92% of
tumours were infiltrating ductal, or lobular, 50.4% T1, and 75% N0 (T1 and T2
tumours only were included in this study).9 In
the present study, 18.5% of patients who underwent breast-conserving surgery for
invasive cancer had nodal involvement, which is consistent with Morrow et al;
however, 44.3% of patients requiring mastectomy had nodal involvement, which is
high compared with other studies.8–10
There was also a trend for younger patients to present with more aggressive
disease, with 53% of patients under 40 years old having a grade 3 tumour
compared with 26.8% over 40 years.
The incidence of a family history of breast cancer was
higher than that reported in the
literature.11–13 However, these data are
self-reported and may not reflect a true familial rate. It would be interesting
to further investigate these reports, but privacy regulations makes this event
unlikely in the near future (consent would have to be sought from every relative
for their records to be reviewed).
According to the guidelines the rate of breast-conserving
surgery (44.8%) might be considered low.2,14,15
However, these same guidelines would exclude 6.6% of the present population
because of T3 and T4 tumours. In addition, some patients with T2 tumours may
have been advised to have a mastectomy by their surgeons because the size of the
tumour relative to the breast size may not have allowed clear margins to be
obtained with an acceptable cosmetic result.14
Furthermore, the present study includes 11% of New Zealand Maori and Polynesian
patients, who as a group seem to present with a more advanced stage of breast
cancer than other ethnic groups.1
Many women also choose to have a mastectomy even though
breast-conserving surgery is feasible. Barriers to adjuvant treatment include
transport difficulties, distance from radiotherapy unit, obligations at home,
and fear of radiotherapy. Some women are also anxious about the possibility of
recurrence even though it is now well accepted that the two forms of local
treatment are equivalent for outcome.9,16 In
addition, some women may opt for mastectomy and immediate reconstruction,
instead of breast-conserving surgery.
Morrow et al report rates of breast-conserving surgery
ranging from 54% in the Northeast and Pacific regions, to 32% in Southern and
Midwest regions of the USA, with an overall rate of 42.6% which is lower than
the present report.9 However, cases with T1 and
T2 tumours only were included. There is growing evidence to suggest that the
rate of mastectomy is dropping, albeit more slowly than guidelines
recommend.9,10 A further decrease might be
encouraged by targeting improved participation in screening programmes and
improvement in information and education of both patients and
physicians.16,17
Referral to medical or radiation oncology for additional
therapy is common and possibly reflects the widespread involvement of
multidisciplinary groups in the identification of patients who may benefit from
oncology treatment. Additionally, it may also reflect the high number of
clinical research trials coordinated through the Oncology Department. We have
not analysed oncology treatment practices or outcome measures, as numbers for
individual therapies remain small and follow up short.
Despite the brevity of the annual follow ups, 102 (8.5%)
patients had further disease diagnosed within two years of initial presentation.
Sixteen of these patients had metastatic disease diagnosed at presentation and
nine patients had a loco-regional recurrence diagnosed within six months of
initial diagnosis. The latter may in part represent progression of undiagnosed
primary disease rather than recurrence.
The database is providing detailed information on breast
cancer in Auckland for the first time since the previous database had to be
discontinued in 1985. The rapid acceptance of the Register has already led to an
expanding workload. After only two years staffing requirements for documentation
have increased from 0.5 FTE to 2.0 FTE and are anticipated to grow further.
While this has significant funding implications we remain convinced that the
value of the Register will justify the costs. Once established, wider coverage
might be considered.
All members of the ABCSG are directly involved in the
diagnosis and treatment of breast cancer patients, and the ABCR was established
so that the best possible outcomes could be achieved for individual patients.
The value of cancer registries and high-quality audit or surveillance in cancer
control is well documented.18 To fully achieve
the aims of the ABCR, 100% accrual is necessary, but, as stated earlier, the
primary limiting factor is the requirement for individual informed consent. Even
though all the participating clinicians have the highest regard for patient
privacy and confidentiality, it is recognised that there are situations in which
patients can not be approached for their individual informed consent and indeed
in many audit tools such consent is not required.
The ABCSG is currently trying to address this issue and has
made an application to the Auckland Ethics Committee to review the national and
international guidelines for a waiver of individual informed consent for this
audit of information already in the medical record. At the time of writing no
decision had been reached. However, this issue is one that also needs to be
addressed by the New Zealand public; as Jocelyn Chamberlain stated, in a review
of breast cancer screening in New Zealand, ‘If the popular feeling remains
“Privacy at all costs” then it must be recognised that one of those
costs is ineffective and inefficient public health
systems.’19
There is an extensive literature supporting the association
between process of care and outcomes in breast cancer. Aspects of detection,
diagnostic evaluation and therapy are known to have an important effect on
quality of life and mortality. There is a broad consensus on screening,
diagnosis and treatment strategies for breast cancer, and many studies on the
patterns of care in oncology focus on breast
cancer.3 As such, we would propose that breast
cancer is an ideal condition (common, protocol driven, managed by
multidisciplinary teams) to act as an audit tool for cancer therapy per
se.
Author information:
Lorraine Neave, Breast Care Nurse, North Shore Hospital, Auckland; Vernon
Harvey, Clinical Director Oncology Department; Chelleraj S Benjamin, Clinical
Director Radiation Oncology; Paul Thompson, Consultant Medical Oncologist; Ora
Pellett, Project Coordinator ABCR, Oncology Department; Jeremy Whitlock,
Radiologist, Radiology Department; Wayne Jones, Clinical Director General
Surgery, Department of Surgery, Auckland City Hospital, Auckland; Garth Poole,
Breast, Laparoscopic and General Surgeon, Department of Surgery, Middlemore
Hospital, Auckland
Acknowledgements: It
is through the commitment of all the members of the Auckland Breast Cancer Study
Group and the breast care nurses in the Department of Oncology at Auckland
Hospital that this information can be provided for the Auckland region. We thank
the patients and clinicians involved and the following funding organisations for
their support: The New Zealand Breast Cancer Foundation, The Maurice and Phyllis
Paykel Trust, Avon Cosmetics, Scottwood Group, Mary Kay Cosmetics, Webber Trust
and AstraZeneca.
The Auckland Breast Cancer Study Group are: C Benjamin, J
Blue, J Blackburn, S Cacala, I Campbell, M Christie, J Collins, J Craik, A
Doyle, W Hadden, R Harman, V Harvey, I Holdaway, F Jones, W Jones, R Kay, A
McCann, M McCrystal, L Neave, A Ng, R Oldfield, O Pellett, G Poole, R Ram, R
Ramsaroop, B Scott, T Smith, A Stewart, P Thompson, S Urry and J
Whitlock.
Correspondence: Dr C
S Benjamin (Chairman ABCSG), Clinical Director Radiation Oncology, Oncology
Department, Auckland Hospital, Private Bag 92019, Auckland. Fax: (09) 623 4161;
email CSBenjamin@adhb.govt.nz
References:
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