Careful studies of disease incidence and the efficacy of early
diagnosis make important contributions to medical care. The current
study, however, has flaws that seriously constrain its utility.
First, while the study is based on adults 65 and older, melanoma is a
disease of younger and middle-aged adults. The median age at diagnosis is
53, and it is the most common cancer among women aged 25-29. Although the
authors note the age limits of their study, they do not mention the
significant epidemiological data on melanoma.
Second, as the authors concede, their database includes biopsies for
basal and squamous cell carcinomas, as well as for cutaneous
manifestations of all forms of systemic disease. Given the prevalence of
these non-melanoma conditions in elderly Americans, the irrelevant
biopsies undoubtedly predominate in the database. Contrary to the
authors' claim, this does not bias their results "to the null." Melanoma
is not a condition that can be detected by sampling skin from any part of
the body; it is site specific. Indeed, melanoma is relatively uncommon on
the face and head--sites where biopsies for other forms of cancer most
frequently are performed.
It would be very useful to know whether biopsies ordered specifically
to rule out melanoma have increased at the same rate as melanoma
diagnoses, but this study does not give us that information. Limitations
in the data may have forced the authors to include such a large number of
irrelevant biopsies in their analysis, but they should be more thoughtful
in exploring those limits. Correlating diagnoses of melanoma with
biopsies ordered for suspected basal cell carcinoma is not much different
from correlating melanoma diagnoses with the prostate biopsies that the
authors mention.
Finally, mortality rates on melanoma are highly suspect. These
rates, like many other disease-specific mortality rates, are drawn from
death certificates prepared by individual physicians. Doctors receive no
formal training in preparing death certificates and are notoriously poor
at recording the cause of death. The attending physician often records
the immediate cause of death (heart or kidney failure, sepsis, pneumonia)
rather than the underlying disease triggering that final event. Since
melanoma kills by metastasizing to other organs, where that cancer becomes
the primary focus of concern, doctors may be even less likely to note
melanoma as the cause of death. This is particularly true in an elderly
population with extensive comorbidity.
The relatively constant rate of melanoma mortality most likely
reveals the low--and relatively constant--rate at which local physicians
record melanoma as an immediate cause of death. It tells us little about
how early diagnoses of melanoma might have affected morbidity and
mortality in affected patients--particularly if the melanoma is caught
before age 65, within the younger group where it is of greatest concern.
In the end, this study tells us two things: that diagnoses of stage
I and II melanomas are rising among older Americans, and that those
diagnoses are rising at the same time that biopsies for all forms of skin
disorders are increasing in the same group. Since the latter category is
so large, and often unrelated to suspicion or demonstration of melanoma,
that correlation does not lend much support to the authors' causal claims.
We could also correlate increased diagnosis of melanoma with increased
office visits, x-rays, CT scans, pap smears, and a host of other medical
procedures. It probably is true that we are diagnosing more melanomas as
access to medical care improves. But that fact alone does not help us
very much in determining how much of the increased diagnosis is related to
increased testing--much less in deciding whether the testing pays off for
patients.
Despite the significant limits in their study, the authors make
sweeping suggestions for health care. The final sentence of their
published report announces that "stable mortality in this population
suggests that the bulk of these additional cases of melanoma may appear
malignant on histology but are nonetheless biologically benign." The lead
author has built upon this statement in the press, noting in today's NY
Times that the efficacy of melanoma screening is the "million dollar
question" and that his study "certainly raises questions about whether
we're doing any good" through such screening programs.
But this study has little to do with biologic activity and nothing at
all to do with screening. The only evidence supporting the authors'
suggestion that most stage I and II melanomas are "biologically benign" is
the relatively flat mortality rate. To base recommendations on that
figure, they at least owed us a thoughtful discussion of limitations in
reporting melanoma as a cause of death.
The study, meanwhile, includes no data at all on screening. The
patients in this study were not screened; they were biopsied, largely for
non-melanoma conditions. The only "screening" recommendation we could
base on this study would be the nonsensical one that dermatologists could
stop biopsying patients with facial lesions highly suspicious for basal
cell carcinoma because primary care physicians rarely report melanoma
(another disease entirely) as a cause of death.
Screening for melanoma is an innocuous component of good medical
care. "Screening" means simply that a patient's primary care physician
examines the skin--the body's largest organ--along with other organs.
Visual screens require no expensive tests and can identify a large number
of possible disorders. It is hard to imagine a doctor performing a good
physical without examining the skin.
Biopsies are more costly, both economically and psychologically. But
patients do not lightly allow their doctors to cut off patches of skin.
Nor are most doctors eager to cut. Most doctors and patients undergo skin
biopsies when there is a strong suspicion of illness--usually a disease
other than melanoma.
The best way to view the appropriate limits of this study, especially
as applied to screening and the possible malignancy of stage I and II
melanomas, is to pose the following questions: (1) Do you want your
primary care physician to stop looking at your skin--or to stop referring
you to a dermatologist if unusual lesions develop? (2) If you had a mole
that fit the ABCD criteria for melanoma, would you refuse to have it
biopsied because biopsies seem to correlate broadly with diagnoses--i.e.,
because the biopsy might reveal a melanoma? Would your decision be
influenced by the fact that attending physicians rarely list melanoma as a
cause of death on formal death certificates? And (3) if the biopsy showed
a stage I or II melanoma, would you accept a recommendation just to wait
and see if it metastasizes, rather than to have the mole excised with a
small margin? I.e., does the fact that doctors rarely report melanoma as
a cause of death in older Americans persuade you that the "bulk" of stage
I and II melanomas are biologically benign?
Competing interests:
None declared
Competing interests:
No competing interests
10 August 2005
Deborah J. Merritt
John Deaver Drinko Chair in Law
Moritz College of Law, The Ohio State University, 55 West 12th Avenue, Columbus, OH 43210 USA
Rapid Response:
Making Molehills of Melanomas
Careful studies of disease incidence and the efficacy of early
diagnosis make important contributions to medical care. The current
study, however, has flaws that seriously constrain its utility.
First, while the study is based on adults 65 and older, melanoma is a
disease of younger and middle-aged adults. The median age at diagnosis is
53, and it is the most common cancer among women aged 25-29. Although the
authors note the age limits of their study, they do not mention the
significant epidemiological data on melanoma.
Second, as the authors concede, their database includes biopsies for
basal and squamous cell carcinomas, as well as for cutaneous
manifestations of all forms of systemic disease. Given the prevalence of
these non-melanoma conditions in elderly Americans, the irrelevant
biopsies undoubtedly predominate in the database. Contrary to the
authors' claim, this does not bias their results "to the null." Melanoma
is not a condition that can be detected by sampling skin from any part of
the body; it is site specific. Indeed, melanoma is relatively uncommon on
the face and head--sites where biopsies for other forms of cancer most
frequently are performed.
It would be very useful to know whether biopsies ordered specifically
to rule out melanoma have increased at the same rate as melanoma
diagnoses, but this study does not give us that information. Limitations
in the data may have forced the authors to include such a large number of
irrelevant biopsies in their analysis, but they should be more thoughtful
in exploring those limits. Correlating diagnoses of melanoma with
biopsies ordered for suspected basal cell carcinoma is not much different
from correlating melanoma diagnoses with the prostate biopsies that the
authors mention.
Finally, mortality rates on melanoma are highly suspect. These
rates, like many other disease-specific mortality rates, are drawn from
death certificates prepared by individual physicians. Doctors receive no
formal training in preparing death certificates and are notoriously poor
at recording the cause of death. The attending physician often records
the immediate cause of death (heart or kidney failure, sepsis, pneumonia)
rather than the underlying disease triggering that final event. Since
melanoma kills by metastasizing to other organs, where that cancer becomes
the primary focus of concern, doctors may be even less likely to note
melanoma as the cause of death. This is particularly true in an elderly
population with extensive comorbidity.
The relatively constant rate of melanoma mortality most likely
reveals the low--and relatively constant--rate at which local physicians
record melanoma as an immediate cause of death. It tells us little about
how early diagnoses of melanoma might have affected morbidity and
mortality in affected patients--particularly if the melanoma is caught
before age 65, within the younger group where it is of greatest concern.
In the end, this study tells us two things: that diagnoses of stage
I and II melanomas are rising among older Americans, and that those
diagnoses are rising at the same time that biopsies for all forms of skin
disorders are increasing in the same group. Since the latter category is
so large, and often unrelated to suspicion or demonstration of melanoma,
that correlation does not lend much support to the authors' causal claims.
We could also correlate increased diagnosis of melanoma with increased
office visits, x-rays, CT scans, pap smears, and a host of other medical
procedures. It probably is true that we are diagnosing more melanomas as
access to medical care improves. But that fact alone does not help us
very much in determining how much of the increased diagnosis is related to
increased testing--much less in deciding whether the testing pays off for
patients.
Despite the significant limits in their study, the authors make
sweeping suggestions for health care. The final sentence of their
published report announces that "stable mortality in this population
suggests that the bulk of these additional cases of melanoma may appear
malignant on histology but are nonetheless biologically benign." The lead
author has built upon this statement in the press, noting in today's NY
Times that the efficacy of melanoma screening is the "million dollar
question" and that his study "certainly raises questions about whether
we're doing any good" through such screening programs.
But this study has little to do with biologic activity and nothing at
all to do with screening. The only evidence supporting the authors'
suggestion that most stage I and II melanomas are "biologically benign" is
the relatively flat mortality rate. To base recommendations on that
figure, they at least owed us a thoughtful discussion of limitations in
reporting melanoma as a cause of death.
The study, meanwhile, includes no data at all on screening. The
patients in this study were not screened; they were biopsied, largely for
non-melanoma conditions. The only "screening" recommendation we could
base on this study would be the nonsensical one that dermatologists could
stop biopsying patients with facial lesions highly suspicious for basal
cell carcinoma because primary care physicians rarely report melanoma
(another disease entirely) as a cause of death.
Screening for melanoma is an innocuous component of good medical
care. "Screening" means simply that a patient's primary care physician
examines the skin--the body's largest organ--along with other organs.
Visual screens require no expensive tests and can identify a large number
of possible disorders. It is hard to imagine a doctor performing a good
physical without examining the skin.
Biopsies are more costly, both economically and psychologically. But
patients do not lightly allow their doctors to cut off patches of skin.
Nor are most doctors eager to cut. Most doctors and patients undergo skin
biopsies when there is a strong suspicion of illness--usually a disease
other than melanoma.
The best way to view the appropriate limits of this study, especially
as applied to screening and the possible malignancy of stage I and II
melanomas, is to pose the following questions: (1) Do you want your
primary care physician to stop looking at your skin--or to stop referring
you to a dermatologist if unusual lesions develop? (2) If you had a mole
that fit the ABCD criteria for melanoma, would you refuse to have it
biopsied because biopsies seem to correlate broadly with diagnoses--i.e.,
because the biopsy might reveal a melanoma? Would your decision be
influenced by the fact that attending physicians rarely list melanoma as a
cause of death on formal death certificates? And (3) if the biopsy showed
a stage I or II melanoma, would you accept a recommendation just to wait
and see if it metastasizes, rather than to have the mole excised with a
small margin? I.e., does the fact that doctors rarely report melanoma as
a cause of death in older Americans persuade you that the "bulk" of stage
I and II melanomas are biologically benign?
Competing interests:
None declared
Competing interests: No competing interests