番茄社区

CHICAGO -- A diagnosis of in situ or invasive melanoma conferred a similar long-term risk of invasive melanoma recurrence, a 40-year retrospective review showed.

For the first 2 years after initial diagnosis, invasive melanoma had a greater risk of invasive recurrence, as compared with an initial diagnosis of in situ disease. Thereafter, the risk of invasive recurrence remains the same, regardless of the initial diagnosis, Hyemin Pomerantz, MD, of Brown University in Providence, R.I., reported here at the American Academy of Dermatology summer meeting.

"The findings suggest that follow-up after diagnosis of in situ or invasive melanoma should be the same," Pomerantz told 番茄社区. "Because the incidence of melanoma in situ is increasing, surveillance for recurrence in this patient population could help improve outcomes for melanoma."

The incidence of melanoma has since the 1980s. Previous studies have shown that a diagnosis of in situ melanoma increases the risk of subsequent invasive recurrence as compared with the general population. However, the risk of invasive recurrence associated with in situ melanoma had not been compared with the risk of recurrence in patients who have a history of invasive melanoma, Pomerantz said.

To compare recurrence risk associated with the initial diagnosis, investigators reviewed data from the program for 1973 to 2011. They identified all patients with a first diagnosis of melanoma and no history of other types of cancer and determined the classification of the initial diagnosis (in situ, local invasive, or regional/distant invasive).

The primary outcome of interest was invasive recurrence of melanoma at least 2 months after the initial melanoma diagnosis.

The analysis comprised 55,661 patients with an initial diagnosis of melanoma in situ, 97,614 patients with local invasive melanoma, and 14,999 patients with regional/distant disease at initial diagnosis. Follow-up duration averaged 5.7 years for the regional/distant group, 8.3 years for the in situ group, and 10.7 years for the local invasive group.

The in situ group had 1,936 invasive recurrences and an incidence rate of 4.2 cases per 1,000 person-years. That compared with incidence rates of 3.7 per 1,000 person-years for the local invasive group and 4.7 per 1,000 person-years for the regional/distant group.

The patients with melanoma in situ diagnoses served as the reference group for the analysis (hazard ratio 1.0). For all three groups combined, the hazard for invasive recurrence was 1.04 (95% CI 0.99-1.10). The localized group had a hazard of 1.03 (95% C 0.97-1.09) and the regional/distant group had a hazard ratio of 1.08 (95% CI 1.02-1.14).

Pomerantz and colleagues then examined the risk of invasive recurrence by duration from the initial diagnosis. The results showed an initial diagnosis of local invasive or regional/distant disease significantly increased the likelihood of invasive recurrence only during the first 2 years:

• 2 months to 1 year: in situ HR 1.0, localized 1.31 (95% CI 1.11-1.54), regional/distant 1.75 (1.37-2.24)
• 1 to 2 years: 1.0, 1.17 (0.99-1.39), 1.42 (1.07-1.89)
• 2 to 5 years: 1.0, 1.07 (0.96-1.19), 1.21 (0.98-1.51)
• 5 to 10 years: 1.0, 1.02 (0.92-1.14), 1.01 (0.79-1.29)

The results make a case for following patients with in situ melanoma as frequently and for the same duration as patients with invasive melanoma, particularly localized invasive melanoma, Pomerantz said.

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