To screen or not to screen for melanoma in people at average risk seems to be an open and shut case: melanoma is a lethal skin cancer. Finding it early must be a good idea!
That’s what a lot of people—including many dermatologists—believe and preach. However, from a science point of view it is difficult to prove.
That is the essence of a research article and two dueling editorials (see 1 and 2) in a recent issue of JAMA Dermatology.
This is not a new question:
- There are lots of believers, including skin cancer organizations, advocates, dermatologists and others who are convinced it does make a difference.
- There are legions of stories out there about how effective various spontaneous screening programs have been.
- These programs often generate publicity sharing how many previously undiagnosed skin cancers and melanomas are found.
- There is strong support for these programs which are conducted in many communities, in Congress and even some meetings of the American Medical Association (when we actually had meetings).
There is an important “but” here:
- The science hasn’t confirmed that these community programs or any other organized effort really change the important outcomes for people at average risk–like premature deaths–because of an earlier diagnosis of melanoma.
- The United States Preventive Services Task Force says there is insufficient evidence to support routine screening for skin cancer and melanoma in people at average risk, namely those without a prior history of skin cancer and/or melanoma, a family history of melanoma or another pre-disposing condition such as organ transplant with the patient on medicines that suppress the immune system.
Who is right in these dueling viewpoints? The reality is that there is evidence to support both sides.
The new research showed that when there was an organized skin cancer screening program started in a university primary care health system the melanomas that were found in the group that underwent screening were more likely to be “in-situ” (which means non-invasive and extremely unlikely to spread) or “thin” (which means very early with a very low likelihood of spreading and leading to death) when compared to the group that did not get screened and just came to the clinic for evaluation when they had a skin lesion of concern.
In addition, in the same research program, those who were screened as part of the organized program and developed a melanoma after screening (called an “interval melanoma”) there was a tendency for those folks to more likely have non-invasive and thin melanomas when compared to the unscreened group.
From a purely observational point of view, this study suggests that screening makes a difference. After all, who wouldn’t agree that finding a potentially deadly melanoma when it is at an earlier stage would be lifesaving?
There is a rub to that assumption: the reality is that finding a melanoma early may not make an eventual difference in how many people will die from that cancer.
Sounds strange, doesn’t it? That issue has faced those who have supported the early detection of melanoma for years. What could possibly be “bad” about finding a cancer early?
Well, first off, if you go looking for melanoma you are more likely to find them so you increase the number of melanomas diagnosed. That sounds good, doesn’t it? However, what if many of those melanomas didn’t need to be found? What if they would never have made a difference?
That’s the hard fact that many consumers, patients, clinicians and others have trouble accepting: you find a lot more melanoma; many of those did not need to be found; the numbers of diagnosed melanomas go way up; the number of deaths remain the same; the percentage of deaths decline a lot.
Looks good and sounds good, but at heart there is not real difference. You just found more of the “easy” ones—and that makes your statistics look better.
After decades of consumer and professional education many of the melanomas we see today are earlier in their trajectory. Many, but not all. We end up diagnosing a lot more melanomas than we did in the past, so the argument goes, because many of those we are diagnosing today would never have caused a problem.
The term for these excess diagnoses is “overdiagnosis,” namely the diagnosis of a cancer—or in this case, melanoma—that would never have caused harm or death. It may sound strange, however the blunt fact is that some cancers will never cause harm and don’t need to be found or treated: they will never cause harm or death. The sad part of this story is that we don’t have the tools today to help us firmly understand at a basic biologic level which cancers are “bad” and which are “not so bad.”
Then there is the fact that we can find a melanoma “early” without interrupting its destined biological path. “Early detection” may not be the same thing as interrupting that cancer’s lethal journey depending on its own internal characteristics. You just find it earlier. You don’t alter the journey and the unfortunate outcome remains the same.
I know that sounds strange but that is what research has shown for other cancers and is suspected by some to be the case in melanoma, even for melanoma diagnosed at the earliest stage.
This reality now sets up the scenario of the dueling editorials: one of which says screening is helpful, particularly if we focused on those at greater risk of serious disease such as older folks (like me), those with prior skin cancer diagnoses (like me), or those with a family history of melanoma.
Not so says the other editorial: routine skin cancer screening has not been proven to save lives, and until we have that proof we shouldn’t be extolling the virtue of all these screening efforts for people at average risk, since that requires a good deal of time on the part of consumers and professionals, not to mention the cost—and in turn will find a lot of folks with melanomas where screening and treatment may never make a difference in outcome.
As noted by the research paper authors and both editorials, doing the studies that would definitively answer the question whether routine skin cancer screening makes a difference or not would require lots of people to be entered into a trial, have them followed over a long time and most of all cost a lot of money—something that is a scarce resource these days. Not to mention that unfortunately such an extensive research program would be close to impossible to organize and complete.
One other item that I can’t fail to mention: and weighs heavily on my own thinking:
For those who advocate routine skin cancer screening by trained clinicians such as dermatologists, let’s remember that there are a lot of people in this country who would require that screening, and too few professionals to do it. I don’t know if you have recently tried to get an appointment with a dermatologist or a primary care clinician, but they are sort of hard to come by. Please let’s not overload an overloaded system with another medical procedure where the evidence is not clear. Please!!!!
It remains a reality when it comes to screening for skin cancer we are going to have dueling arguments for years to come. The USPSTF task force will continue to say the evidence is inadequate; we will continue to have community screening programs (Come on in and get checked! It’s free!!!!) that may or may not save lives but where people believe it saves lives; and we will continue to have dueling camps when it comes to the question whether routine skin cancer screening as opposed to increased consumer awareness is the best approach to reducing the burden of this disease.
Net net: skin cancer screening for those at average risk may or may not make a difference. But what does make a difference is keeping a watch over your own skin and getting things checked when you see a change that is of concern.
That is advice where everyone agrees.