september, 2019 | The Health
Breathing Easy
C37 M0 Y12 K0
FIGHTING CANCER
/ R161 G255 B224
C100 M50 Y0 K67 / R0 G42 B84
C10 M100 Y50 K0 / R230 G0 B128
C5 M50 Y25 K0
29
/ R242 G128 B191
C0 M0 Y0 K80 / R51 G51 B51
A game changer
in screening
Low dose CT screening for lung cancer
transforms the landscape in cancer diagnosis
W
orldwide lung cancer
remains the leading
cancer and cancer-killer
with approximately 1.5
million new cases being
diagnosed each year and
a similar number of deaths annually. Locally,
lung cancer rivals colon cancer as the com-
monest cancer to affect Malaysian men (15.8
percent) and is the leading cause of cancer
mortality accounting for almost one in four
of all cancer deaths in males. In women, it
is the fifth commonest malignancy (5.6 per
cent) but the second deadliest tumour only
surpassed by breast cancer. Contemporary
National Cancer Registry data shows the
overwhelming majority of lung cancer
patients (90 percent) here are diagnosed too
late with stage III (locally advanced) or stage
IV (metastatic) disease.
Screening is utterly important
It is important to highlight lung cancer
screening to detect early stage disease
as treatment and prognosis (outcome) is
largely stage-dependant. Unfortunately,
diagnosis can be elusive in the early stages
of the cancer as often there are no symptoms
or non specific symptoms. Hence the role of
screening to detect the disease at a pre-clinical
or asymptomatic stage before one develops
symptoms.
Treatment can be done
The treatment intent with early stage lung
cancer is curative and usually involves
surgery in combination with adjuvant (post-
operative) chemotherapy where indicated.
This offers the best chance of a cure and long
term survival.
For advanced stage tumours, the devel-
opment of tumour molecular profiling and
targeted therapies such as tyrosine kinase
inhibitors have improved overall length of
survival. These therapies however remain
non-curative. The potential side effects and
expense also limit the accessibility of targeted
therapy.
Imaging at its best
Improved imaging technology over the past
5-10 years has seen the widespread availabil-
ity of low dose and recently ultra low dose
computed tomography (LDCT) which allows
doctors to accurately identify smaller early
stage lung cancers that are more amenable to
curative therapy.
LDCT has become a game-changer in the
battle against lung cancer. The North Ameri-
can National Lung Screening trial (NLST)
(published in the New England Journal of
Medicine, 2011) reported a survival benefit
(20 per cent mortality risk reduction) with
LDCT screening of high risk individuals
namely long term male smokers and ex-
smokers aged 55-74 years.
More recently, findings of the European
NELSON study reported at the World Lung
Cancer Conference (Toronto, 2018) reiterated
the survival benefit of LDCT screening with
even more impressive results than NLST
especially with women. NELSON reported
a 26 per cent reduction in the risk of death
from lung cancer in men at 10 years and more
favourable results in women (39-61 per cent
death risk reduction).
A painless process
Both trials provide strong evidence on the
life-saving benefit of LDCT screening of high
risk individuals. A screening LDCT scan is
quick, painless and does not require the
person to fast. The dose of ionising radiation
is minimal as the scan uses lower exposure
parameters compared to a normal CT and no
contrast media (dye) is given.
It is highly suggested that screening is truly
life saving and cost effective if done appropri-
ately, targeting those with an elevated risk
of developing lung cancer. The challenge of
whom to offer screening to remains. Based
on published global data and taking into con-
By Dr Anand
Sachithanandan
and
Dr Raja Rizal
Azman
SCANNED FOR
GOOD: An example
of the image taken
from a low dose CT
scan for lung cancer
screening.
sideration local epidemiology of the disease,
it seems reasonable to offer LDCT screening
to Malaysian men and women aged 45 to 75
years who are current or former heavy smok-
ers. The anticipated diagnostic ‘pick up’ rate
is two to three per cent and most will be early
stage tumours amenable to curative therapy.
Others who may benefit include those
with a previous cancer elsewhere or a family
history of lung cancer. Although advances in
imaging technology have mitigated concerns
of false positive results and radiation induced
cancers, no technology is perfect and unneces-
sary biopsies or patient anxiety remain real
albeit uncommon concerns.
It is also important to recognize that
screening is not an isolated test but a process
and some individuals will require a follow up
surveillance scan at an interval of three to six
months based on the findings of the initial
scan.
Additional tests are helpful
Presently blood serum tumour biomarkers
(eg. CEA, proGRP) are not good enough to
be utilised as a screening tool but may help
to risk profile individuals with inconclusive
CT scan findings. Such biomarkers are more
helpful to monitor for early cancer recur-
rence or response to therapy in lung cancer
patients who had raised tumour marker levels
pre-treatment. It is the hope and dream of all
clinicians treating lung cancer that reliable
tumour biomarkers will soon emerge to be
used as a screening tool.
Another challenge that remains is how
to effectively screen for lung cancer in the
non smoker as all the robust scientific trial
evidence to date targets smokers or former
smokers. Tragically, non smokers now account
for up to 20 to 25 per cent of all lung cancer
victims , the majority of whom are women. A
pilot study to screen such individuals may be
necessary. — The Health
Dr Anand Sachithanandan is the President of the
Lung Cancer Network Malaysia (LCNM) and a
Cardiothoracic Surgeon
Associate Prof Dr Raja Rizal Azman Raja
Aman is a council member of the Lung Cancer
Network (LCNM) and a Clinical Radiologist.