Screening for melanoma promotes overdiagnosis, more biopsies

DT: I’m John Jessitas. Dermatology Times.. Joining me today is Professor David Whiteman. Would you please introduce yourself to your name and title, and where you work?

Dr. Whiteman: Of course. good morning. My name is David Whiteman. I am the Head of the Cancer Control Group at the QIMR Berghofer Medical Research Institute in Brisbane, Australia.

DT: What are the key discoveries in your research?

Dr. Whiteman: We have been investigating this problem of overdetection or overdiagnosis in cutaneous melanoma. It has long been known that the incidence of melanoma is rising rapidly in Queensland and other parts of the world, including the United States. And much of the increase in incidence there Melanoma, pre-invasive melanoma.

We followed up a large cohort of more than 43,000 residents in Queensland who completed a baseline questionnaire with a detailed risk factor study. And an important question, or a series of questions we asked them, was to have a doctor examine their skin for the purpose of detecting skin cancer during the three years prior to hiring. We then followed these people for seven years and linked their records to the cancer registry. Over the seven years, we found that 29% excess melanoma was detected in the screened arm compared to the unscreened arm. And that was after adjusting for all the known risk factors for melanoma. This suggests that this unique detection rate is higher in screened individuals than in unscreened individuals. And this is a flag that indicates that over-detection of painless lesions is occurring.

DT: And what do these results mean for dermatologists in clinical practice? Should they do less screening and why or why not?

Dr. Whiteman: I quickly point out that this is not a randomized trial, but these are from observational data. There is no clear evidence that screening is harmful. There is also a very strong clinical opinion that early detection certainly saves lives. At this time, we are not advocating any actual changes. But what we are doing is assessing the scale and quantifying the magnitude of this potential problem of overdiagnosis. It is a flag for future research. What we really need to do now is not only to identify harmful melanocyte neoplasms and make sure they are properly resected and treated, but also to have a very good prognosis, not melanoma or harmful. Is related to. Addressing this issue of detecting and distinguishing harmful melanoma from non-harmful melanoma is really important for researchers.

DT: And in your number one measurement of results on the screening side, what does that mean in a separate analysis of invasive pairs? there Melanoma, a higher risk associated with skin tests (diagnosed as melanoma), there Isn’t it invasive?

Dr. Whiteman: This discovery was not unexpected. In Australia, there is a great incentive to see a doctor, especially if you notice a pigmented lesion on the skin. This leads to an increase in the biopsy rate of the population.And that leads to an increase in both diagnostic rates there Melanoma and very thin invasive melanoma.

In our study, we saw a newly detected excess of melanoma among those who underwent skin examinations and whose skin was screened by a doctor. there Melanoma; that is, pre-infiltration melanoma. This suggests that we are harvesting a pool of lesions in the population that are not yet completely invasive cancers and may not actually become completely invasive cancers. .. They may never be destined to break through the basement membrane and become truly invasive melanoma. Therefore, it is considered that we have discovered lesions that do not harm the patient in the long term. However, at this point, we don’t know what it will do in the future, so we need to remove it.

DT: And what are the biggest weaknesses or limitations of research design?

Dr. Whiteman: As I said, this study is an observational study. The best way to test and look for overdiagnosis in screening is to perform randomized controlled trials. In this trial, people are randomized to receive a skin test or routine care, and then follow up with them for a long period of time. We are not doing that research. Frankly, no group in the world is unlikely to have the resources and budget to conduct a melanoma screening trial. So that’s a weakness. There is no randomized data.

Another weakness was that the primary exposure measurements were self-reported. That is, baseline people filled out a risk factor questionnaire and self-reported their past history of skin tests. Our secondary exposure measurement was to have a skin biopsy in the first year of follow-up. It was an objective measure taken from the medical administration database. Therefore, there is almost no measurement error in the systematic sense of the item. We also found that the same phenomenon occurs with any exposure measurement. Therefore, it is unlikely that it is a significant weakness in the study.

DT: And what were the main strengths of research design?

Dr. Whiteman: The main strength of the research program is the large sample size. We hired more than 40,000 people. We gathered comprehensive risk factor information at baseline and fully followed up study participants through a record link with the Australian Cancer Registry. In Australia, reporting of cancer and melanoma is mandatory. Therefore, long-term follow-up with a large sample size and high quality result information were the main strengths. Also, the analysis we performed was a trend-weighted analysis. It emulates a clinical trial, but not a clinical trial.

Disclosure:

Whiteman has not reported any relevant financial benefits.

reference:

Whiteman DC, Olsen CM, McGregor S, etc. Effects of screening on the incidence and biopsy rate of melanoma [published online ahead of print, 2022 May 9].. Br J Dermatol.. 2022; 10.1111 / bjd.21649. doi: 10.1111 / bjd.21649