DOI: 10.12809/hkmj185079
© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
EDITORIAL
Is now the right time to abolish breast cancer
screening in Hong Kong?
Lorraine CY Chow, MB, BS, FRCSEd
Private Practice
Corresponding author: Dr Lorraine CY Chow (drlorrainechow@gmail.com)
![](https://www.hkmj.org/sites/default/files/mjimage/pdficon.png)
In a recent article by the Cancer Expert Working
Group on Cancer Prevention and Screening,1
screening for breast cancer in the general female population was not
recommended based on the lack of evidence for its survival benefit and the
imminent cause of patient anxiety. The criticisms of implementing a
population-based screening programme for breast cancer include
overexposure to radiation and increment in the number of invasive
investigations and treatments for breast lesions that may never become
malignant. Nonetheless it is important to recognise that the primary aim
of screening in breast cancer is to facilitate timely detection of
early-stage disease, and hence improve survival. In contrast to this
notion, several large-scale studies using nationwide data showed that
screening could only prevent one to two cancer deaths in every one to 2000
women screened at the expense of 20% overdiagnosis rates as well as
induction of anxiety in every one to 2000 women.2
3 Nonetheless a more in-depth
analysis would reveal major weaknesses in these studies including their
methodology, inclusion criteria for screening, level of expertise in the
evaluation of screening results, and the standard of equipment used for
screening. For instance, the Canadian National Breast Screening Study was
the only randomised controlled trial that did not show any survival
benefit for screening, but a 35% increment in the overdiagnosis of ductal
carcinoma in situ.4 Nonetheless
randomisations were not blinded and with pitfalls. Women with symptomatic
palpable breast masses were also recruited into the ‘screening’ arm, and
the quality of mammography was suboptimal and evaluation of mammographic
images deficient.
On the contrary, many studies have shown that
treatment for smaller tumours without nodal involvement confers better
oncological outcomes as well as a better chance of undergoing breast
conserving surgery, and fewer postoperative morbidities.5 6 7 This is an important issue that was often not addressed
by these large-scale population studies such as the Swiss Medical Board
study and the Cochrane review.2 3 The primary end-point of these
studies was reduced mortality. They paid no regard to the short-term
physical and psychological impact of cancer treatment. The current trend
in treatment for breast cancer is multifaceted. A smaller tumour size
increases the chances of breast conserving surgery with consequently less
postoperative morbidity compared with standard mastectomy.8 Applying the same principle, the advent of sentinel
lymph node mapping in the management of the axillary area implied a
substantially reduced need for axillary dissection in early tumours, and
hence lower risk of lymphoedema and its associated morbidities.9 10 Moreover,
advances in imaging techniques may further improve the accuracy of
screening. In the Norwegian nationwide study of over 40 000 women with
breast cancer, screening led to a reduction in mortality by 4.8 deaths per
100 000 person-years when compared with the non-screened group.11 Furthermore, screening in the ‘modern’ era further
reduced mortality by 7.2 deaths per 100 000 person-years compared with
screening in the ‘historical’ era implying that changes to breast cancer
awareness, advances in imaging techniques, and improved treatments in
recent years could all contribute to the survival benefit of a screening
programme. Such finding was also in line with the evidence provided by the
National Health Service Screening Programme in which there was a steady
decline in mortality for women with breast cancer aged between 50 and 79
years as the screening programme evolved over a 10-year period from 1990
to 2000.12 In Hong Kong, there has
been a steady increment in the number of new cases of breast cancer over
the last three decades. According to the Hong Kong Cancer Registry, breast
cancer is now the most common female cancer with over 3500 new cases
diagnosed annually.13 Public
awareness of breast cancer has substantially improved in recent years
following promotion by local media and other non-profitable organisations
such as the Hong Kong Breast Cancer Foundation, Well Women Clinic of the
Tung Wah Group of Hospitals, and the Family Planning Association. In fact,
breast screening in our local population has been shown to be feasible and
well accepted.14 Advanced imaging
technology such as three-dimensional mammography has been introduced as an
alternative efficient assessment tool for screening as well as
multidisciplinary management of breast cancer in clinical practice. It may
be premature to conclude that screening for the general female population
in Hong Kong is of little clinical value.
Declaration
The author has no conflicts of interest to
disclose.
References
1. Cancer Expert Working Group on Cancer
Prevention and Screening. Recommendations on prevention and screening for
breast cancer in Hong Kong. Hong Kong Med J 2018;24:298-306. Crossref
2. Gøtzsche PC, Jørgensen KJ. Screening for
breast cancer with mammography. Cochrane Database Syst Rev
2013;(6):CD001877. Crossref
3. Biller-Andorno N, Jüni P. Abolishing
mammography screening programs? A view from the Swiss Medical Board. N
Engl J Med 2014;370:1965-7. Crossref
4. Miller AB, Baines CJ, To T, Wall C.
Canadian National Breast Screening Study: 2. Breast cancer detection and
death rates among women aged 50 to 59 years. CMAJ 1992;147:1477-88.
5. Cossetti RJ, Tyldesley SK, Speers CH,
Zheng Y, Gelmon KA. Comparison of breast cancer recurrence and outcome
patterns between patients treated from 1986 to 1992 and from 2004 to 2008.
J Clin Oncol 2015;33:65-73. Crossref
6. Metzger-Filho O, Sun Z, Viale G, et al.
Patterns of recurrence and outcome according to breast cancer subtypes in
lymph node-negative disease: results from international breast cancer
study group trials VIII and IX. J Clin Oncol 2013;31:3083-90. Crossref
7. Jacobson JA, Danforth DN, Cowan KH, et
al. Ten-year results of a comparison of conservation with mastectomy in
the treatment of stage I and II breast cancer. N Engl J Med
1995;332:907-11. Crossref
8. Eby PR. Evidence to support screening
women annually. Radiol Clin North Am 2017;55:441-56.
9. Veronesi U, Paganelli G, Viale G, et al.
A randomized comparison of sentinel-node biopsy with routine axillary
dissection in breast cancer. N Engl J Med 2003;349:546-53. Crossref
10. Bromham N, Schmidt-Hansen M, Astin M,
Hasler E, Reed MW. Axillary treatment for operable primary breast cancer.
Cochrane Database Syst Rev 2017;(1):CD004561. Crossref
11. Kalager M, Zelen M, Langmark F, Adami
HO. Effect of screening mammography on breast-cancer mortality in Norway.
N Engl J Med 2010;363:1203-10. Crossref
12. Blanks RG, Moss SM, McGahan CE, Quinn
MJ, Babb PJ. Effect of NHS breast screening programme on mortality from
breast cancer in England and Wales, 1990-8: comparison of observed with
predicted mortality. BMJ 2000;321:665-9. Crossref
13. Hong Kong Cancer Registry. Available
from: http://www3.ha.org.hk/cancereg/. Accessed Jun 2018.
14. Kwong A, Cheung PS, Wong AY, et al.
The acceptance and feasibility of breast cancer screening in the East.
Breast 2008;17:42-50. Crossref