Naming and Staging Lung Cancers
JNCI J Natl Cancer Inst (
news Naming and Staging Lung Cancers
By Cathryn Delude
-
In any clinical trial or study of cancer,
edition, with its eighth TNM edition2
pathology classification from relying on
researchers must compare how tumors
slated for publication in 2017.
grow
and respond to therapy, which
requires everyone calling the same thing
by the same name. That truism applies
to both the pathological subtype of the
tumor, small-cell or non–small-cell lung
cancer, for example, and the clinical
stage, from early to metastatic disease.
Both the pathologic classification and
clinical staging influence treatment
decisions, albeit in different ways. Pathologic
classification tells
what subtype the
cancer is, which often indicates which
therapy is
most appropriate. Staging
tells where the cancer is in the body and
whether it has spread beyond the pri
mary tumor to lymph nodes or
metastases, which helps determine whether
to treat a patient with local therapy
(surgery and/or radiation), systemic therapy,
or both.
The fast pace of clinical research
“If different clinicians
classify the same cancer
subtype differently, or
two different subtypes as
the same type, then any
data about how these
tumors behave or respond
to therapies will not be
reliable.”
Progress in Pathological
Classification
Frank Detterbeck, M.D.
in lung cancer has complicated both
“WHO took the lead many decades ago in
efforts, particularly for the most
comclassifying lung cancer pathologies,” said
Illei said. “A promising area that is not
mon category, non–small-cell
carcinoPeter Illei, M.D., a lung cancer patholo
addressed is immunotherapy because
mas. For this large, heterogeneous group
gist at the Johns Hopkins Kimmel Cancer
the data are still coming in.”
of adenocarcinomas, identifying genetic
Center in Baltimore. It published the first
One major change is the
reclassificaabnormalities in specific subtypes has
issue pathologic classification in 1967,
tion of tumors previously classified as
led to targeted therapies that improved
with updates every decade or so. The
large-cell carcinoma, “a term that was
survival of patients with even advanced
previous 2004 edition began including
historically a wastebasket for poorly
difdisease.
some genetic and
immunohistochemferentiated tumors,” Travis said. With the
The two most widely used systems are
istry findings, but the next decade of
availability of easily applied antibodies
the World Health Organization’s (WHO)
research revealed many more clinically
for immunohistochemical markers of
pathologic classification of lung tumors
significant molecular distinctions among
adenocarcinomas (such as TTF-1) and
and the International Association for the
lung cancer subtypes. In 2011, IASLC, the
squamous cell carcinomas (such as p40
Study of Lung Cancer’s (IASLC) tumor–
premier organization for treating and
or P63), most of these tumors now have
node–metastasis (TNM) staging system.
diagnosing lung cancer, and other
collabmore definitive designations, so
cliniThose systems are trying to keep abreast
orators revised the system for pathologic
cians have a better idea how to treat the
of recent research findings. In September
classification of lung adenocarcinomas
patient.
2015, WHO published its first update1
after reviewing evidence-based
medi
Another change addresses the issue
since 2004, and IASLC announced
reccine and genetic studies. “That 2011 revi
that most lung cancer patients are elderly
ommendations for revisions to its 2011
sion fundamentally changed the role of
and first present with advanced disease
histology to also analyzing
molecular
biology
and
immunohistochemistry,”
said William Travis, MD, a pathologist
at the Memorial Sloan–Kettering Cancer
Center in New York and editor of the
1999, 2004, and 2015 editions of the WHO
classification.
The 2015 WHO classification now includes more genetic testing for driver mutations, such
as
EGFR
ALK, that
and
are
targeted by U.S.
Food and Drug
Administration–
approved
therapies. “WHO also
did a good job by
including
additional
genetic
targets that have
targeted therapy
in clinical trials,”
1 of 8
that cannot be surgically removed. Those
said Patrick Forde, M.D., an oncologist at
Detterbeck said. “If different clinicians
cancers are diagnosed in small biopsies
Johns Hopkins Kimmel Cancer Center.
classify the same cancer subtype differ
or cytology specimens that may not
rep“Some have a very small primary tumor
ently, or two different subtypes as the
resent the entire tumor. In recognition of
but lots of nodes; others have larger pri
same type, then any data about how
this problem, the classification includes
mary tumors but no nodes. Some have
these tumors behave or respond to ther
a separate terminology for these small
better prognosis than others.”
apies will not be reliable.”
tissue samples and offers guidelines
Recent TNM revisions reflect attempts
A
similar issue
affects
whether
for using special stains and for
triagto better group sta (...truncated)