
看看文献如何阐述癌与上皮来源的惰性病变的区别。
WHAT’S
IN A NAME? CANCER – OR INDOLENT LESIONS OF EPITHELIAL ORIGIN
By: DrAttai
In:Advocacy, Cancer Research, Diagnosis and Treatment, Patient
Engagement
Tags: #BCSM Community, Breast Cancer Social
Media, Ductal carcinoma in situ, overdiagnosis of breast cancer,overtreatment
of breast cancer
Aug 3, 2013
What’s in a name? In the case of cancer,
there are myths, fears and misinformation – more than perhaps any other
illness.
Cancer encompasses hundreds of different
diseases and each one is complex. Even
women diagnosed with exactly the same ‘type’ of breast cancer and who undergo
the same treatment can have very different outcomes.
Not all cancers are equal and not all cancers
are lethal.
While early detection and treatment were
once equated with improved survival, we now know that tumor biology
(characteristics governing the behavior of spread and response to treatment)
plays an extremely important role in the prognosis of an individual cancer.
There is an increasing recognition that current screening tests, meant to
diagnose cancer in the earliest stages, will often diagnose lesions that have
minimal potential to become aggressive or lethal. As our screening technology
improves, we are detecting more patients in early stages or with pre-cancerous
conditions (such as atypical ductal hyperplasia), and we are treating those
patients with surgery and other potentially toxic therapies.
In 2012, the National Cancer Institute
convened a working group to “evaluate the problem of ‘overdiagnosis’ which
occurs when tumors are detected that, if left unattended, would not become
clinically apparent or cause death.” Unrecognized overdiagnosis, they stated,
“generally leads to overtreatment” 1.
The recommendations of this panel were
recently published in the Journal of the American Medical Association:
Overdiagnosis and Overtreatment in Cancer, An Opportunity for Improvement. The authors provide five recommendations:
1. Physicians and patients alike need to acknowledge that screening
results in overdiagnosis – especially in breast, lung, prostate and thyroid
tumors.
2. The term ‘cancer’ should be
reserved for describing lesions with a reasonable likelihood of lethal
progression if left untreated.
3. Create observational
registries for low malignant potential lesions in order to better understand
prognosis and best treatment options.
4. Mitigate overdiagnosis with an ultimate goal of preferential
detection of consequential cancer while avoiding detection of inconsequential
disease.
5. Expand the concept of how to approach cancer progression by
controlling the environment in which cancerous conditions arise.
While these are certainly laudable goals,
some important points should be made, especially in regards to breast cancer
and ductal carcinoma in-situ – the most important being that we do not
currently have biomarkers or other indicators that can clearly distinguish a
potentially lethal cancer from a more indolent one. The field of cancer
genomics is rapidly changing, and today more than ever we can obtain very
sophisticated prognostic information regarding an individual patient’s tumor.
Despite that, Dr. Larry Norton, medical director of the Evelyn H. Lauder Breast
Center at Memorial Sloan Kettering Cancer Center, stated “Which cases of DCIS
will turn into an aggressive cancer and which ones won’t? I wish I knew that. We
don’t have very accurate ways of looking at tissue and looking at tumors under
the microscope and knowing with great certainty that it is a slow-growing
cancer” 2.
Regarding
the modern management of DCIS, there are three points to remember:
1. When DCIS lesions diagnosed by needle core biopsy are surgically
removed (which involves removal of substantially more tissue from the abnormal
area), there is an approximately 15% rate of ‘upstaging’ to invasive ductal
cancer 3. Put another way, one cannot always reliably predict the behavior of
an entire lesion based on a core biopsy specimen.
2. During surgery for DCIS, axillary lymph node metastases have been
demonstrated up to 20% of the time, usually indicating missed microinvasion or
invasion 4.
3. Finally, if DCIS recurs, 50% of the time it is invasive 5.
What is important for the #BCSM community
to be aware of is that any woman with breast disease, including DCIS, should be
presented with the information necessary so that she may gain an understanding
of where her diagnosis stands in the biological spectrum and the wide array of
choices she has for treatment. DCIS is far from simple, and it is not to be
taken lightly. Clearly there are cases where ‘watchful waiting’ is safe – but
we cannot always reliably predict who will truly benefit from treatment. Moving
forward, we need to be aware of the facts – what medical technology can provide
the physician and patient now, and we need to ask how we can drive this
conversation in the future.
Jody
Schoger
Michael
S. Cowher, M.D.
Deanna
J. Attai, M.D., F.A.C.S.