Mitoses in melanoma: Is there really a meaning?
Entry posted by Mark A. Hurt MD
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Just this month there are two interesting articles published on the issue of mitosis in melanoma and whether they confer diagnostic or prognostic meaning.
The first is by Gori et al. (1), who make the argument that the presence of greater than 1 mitosis/mm[sup]2[/sup] should not necessarily result in sentinel node biopsy in pregnant women. Their reasoning, based on a single case, was:
[indent=1]"to minimize the risk to the fetus, especially with respect to potential risks to the growing brain and development of the fetus due to general anesthesia, SLNB [sentinel lymph node biopsy] was postponed until after delivery."[/indent]
They state further that:
[indent=1]"On the basis of our limited experience and according to the literature, it is hard to conclude that pregnant women with thin melanomas presenting an MR of 1/mm[sup]2[/sup] would benefit from SLNB in pregnancy or in the postpartum period. SLNB is a procedure with a low but not negligible morbidity and high economic cost; moreover, it results in negative psychological effect on pregnant women."[/indent]
Of course, I can think of another argument against doing a sentinel node biopsy: it has no proven survival benefit. It might offer a benefit for knowing something about [i]prognosis[/i], but not survival. On this basis alone, it would seem that pursuing SLNB during pregnancy is a bad idea.
The second article is by Cooper et al. (2), and it explores their 10-year experience with thin melanomas and SNLB at a single institution. What was interesting to me about this is they found that:
[indent=1]"Our data confirm a statistically significant relationship between SLNB result and likelihood for distant metastasis in thin melanoma. There was a trend for a relationship between mitotic rate and clinical outcome. This relationship reached statistical significance at a mitotic rate of greater than 3 mitoses/mm[sup]2[/sup]."[/indent]
This kind of study brings to bear whether the mitotic index in melanoma is really relevant as a guide to anything except, possibly, the diagnosis. I have always argued that finding mitoses in a melanocytic lesion might aid in establishing the [i]diagnosis[/i] of melanoma in some cases, but I have little confidence that it should be used to target patients for lymph node dissection.
Let me know what you think -- and why.
[center]References[/center]
[url="http://www.ncbi.nlm.nih.gov/pubmed/?term=23852163"]1. Gori A, Salvini C, Fabroni C, Lo Scocco G. Is the mitotic rate of 1/mm2 the correct cutoff point for performing sentinel lymph node biopsy in pregnant patients with thin melanoma? Melanoma Res. 2013; 23:420-421; 2013 Jul 10. [Epub ahead of print] PubMed PMID: 23852163.[/url]
[url="http://www.ncbi.nlm.nih.gov/pubmed/?term=23978604"]2. Cooper C, Wayne JD, Damstetter EM, Martini M, Gordon J, Guitart J, West DP, Nardone B, Rademaker A, Gerami P. A 10-year, single-institution analysis of clinicopathologic features and sentinel lymph node biopsy in thin melanomas. J Am Acad Dermatol. 2013 Aug 23. doi:pii: S0190-9622(13)00768-8. 10.1016/j.jaad.2013.07.016. [Epub ahead of print] PubMed PMID: 23978604.[/url]
The first is by Gori et al. (1), who make the argument that the presence of greater than 1 mitosis/mm[sup]2[/sup] should not necessarily result in sentinel node biopsy in pregnant women. Their reasoning, based on a single case, was:
[indent=1]"to minimize the risk to the fetus, especially with respect to potential risks to the growing brain and development of the fetus due to general anesthesia, SLNB [sentinel lymph node biopsy] was postponed until after delivery."[/indent]
They state further that:
[indent=1]"On the basis of our limited experience and according to the literature, it is hard to conclude that pregnant women with thin melanomas presenting an MR of 1/mm[sup]2[/sup] would benefit from SLNB in pregnancy or in the postpartum period. SLNB is a procedure with a low but not negligible morbidity and high economic cost; moreover, it results in negative psychological effect on pregnant women."[/indent]
Of course, I can think of another argument against doing a sentinel node biopsy: it has no proven survival benefit. It might offer a benefit for knowing something about [i]prognosis[/i], but not survival. On this basis alone, it would seem that pursuing SLNB during pregnancy is a bad idea.
The second article is by Cooper et al. (2), and it explores their 10-year experience with thin melanomas and SNLB at a single institution. What was interesting to me about this is they found that:
[indent=1]"Our data confirm a statistically significant relationship between SLNB result and likelihood for distant metastasis in thin melanoma. There was a trend for a relationship between mitotic rate and clinical outcome. This relationship reached statistical significance at a mitotic rate of greater than 3 mitoses/mm[sup]2[/sup]."[/indent]
This kind of study brings to bear whether the mitotic index in melanoma is really relevant as a guide to anything except, possibly, the diagnosis. I have always argued that finding mitoses in a melanocytic lesion might aid in establishing the [i]diagnosis[/i] of melanoma in some cases, but I have little confidence that it should be used to target patients for lymph node dissection.
Let me know what you think -- and why.
[center]References[/center]
[url="http://www.ncbi.nlm.nih.gov/pubmed/?term=23852163"]1. Gori A, Salvini C, Fabroni C, Lo Scocco G. Is the mitotic rate of 1/mm2 the correct cutoff point for performing sentinel lymph node biopsy in pregnant patients with thin melanoma? Melanoma Res. 2013; 23:420-421; 2013 Jul 10. [Epub ahead of print] PubMed PMID: 23852163.[/url]
[url="http://www.ncbi.nlm.nih.gov/pubmed/?term=23978604"]2. Cooper C, Wayne JD, Damstetter EM, Martini M, Gordon J, Guitart J, West DP, Nardone B, Rademaker A, Gerami P. A 10-year, single-institution analysis of clinicopathologic features and sentinel lymph node biopsy in thin melanomas. J Am Acad Dermatol. 2013 Aug 23. doi:pii: S0190-9622(13)00768-8. 10.1016/j.jaad.2013.07.016. [Epub ahead of print] PubMed PMID: 23978604.[/url]
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