Incidence of in Situ vs Invasive Melanoma: Testing the "Obligate Precursor" Hypothesis

Continuing benefits of the Montreal Protocol and protection of the stratospheric ozone layer for human health and the environment

The protection of Earth's stratospheric ozone (O3) is an ongoing process under the auspices of the universally ratified Montreal Protocol and its Amendments and adjustments. A critical part of this process is the assessment of the environmental issues related to changes in O3. The United Nations Environment Programme's Environmental Effects Assessment Panel provides annual scientific evaluations of some of the key issues arising in the recent collective knowledge base. This current update includes a comprehensive assessment of the incidence rates of skin cancer, cataract and other skin and eye diseases observed worldwide; the effects of UV radiation on tropospheric oxidants, and air and water quality; trends in breakdown products of fluorinated chemicals and recent information of their toxicity; and recent technological innovations of building materials for greater resistance to UV radiation. These issues span a wide range of topics, including both harmful and beneficial effects of exposure to UV radiation, and complex interactions with climate change. While the Montreal Protocol has succeeded in preventing large reductions in stratospheric O3, future changes may occur due to a number of natural and anthropogenic factors. Thus, frequent assessments of potential environmental impacts are essential to ensure that policies remain based on the best available scientific knowledge.

Ecological study estimating melanoma overdiagnosis in the USA using the lifetime risk method

OBJECTIVES

To quantify the proportion of melanoma diagnoses (invasive and in situ) in the USA that might be overdiagnosed.

DESIGN

In this ecological study, incidence and mortality data were collected from the Surveillance, Epidemiology and End Results 9 registries database. DevCan software was used to calculate the cumulative lifetime risk of being diagnosed with melanoma between 1975 and 2018, with adjustments made for changes in longevity and risk factors over the study period.

SETTING

USA.

PARTICIPANTS

White American men and women (1975-2018).

MAIN OUTCOME MEASURES

The primary outcome was excess lifetime risk of melanoma diagnosis between 1976 and 2018 (adjusted for year 2018 competing mortality and changes in risk factors), which was inferred as likely overdiagnosis. The secondary outcome was an excess lifetime risk of melanoma diagnosis in each year between 1976 and 2018 (adjusted and unadjusted).

RESULTS

Between 1975 and 2018 the adjusted lifetime risk of being diagnosed with melanoma (invasive and in situ) increased from 3.2% (1 in 31) to 6.4% (1 in 16) among white men, and from 1.6% (1 in 63) to 4.5% (1 in 22) among white women. Over the same period, the adjusted lifetime risk of being diagnosed with melanoma in situ increased from 0.17% (1 in 588) to 2.7% (1 in 37) in white men and 0.08% (1 in 1250) to 2.0% (1 in 50) in white women. An estimated 49.7% of melanomas diagnosed in white men and 64.6% in white women were overdiagnosed in 2018. Among people diagnosed with melanomas in situ, 89.4% of white men and 85.4% of white women were likely overdiagnosed in 2018.

CONCLUSIONS

Melanoma overdiagnosis among white Americans is significant and increasing over time with an estimated 44 000 overdiagnosed in men and 39 000 in women in 2018. A large proportion of overdiagnosed melanomas are in situ cancers, pointing to a potential focus for intervention.

Epidemiology of Cancer

BACKGROUND

Cancers are a large and heterogeneous group of malignant tumors that collectively accounted for approximately 600 000 US deaths in 2020; only heart disease claimed more lives. A large amount of knowledge has accumulated regarding the epidemiology of most cancer types, including their causes.

CONTENT

The cancer types most frequently diagnosed among adults in most high-income countries are lung, colorectal, female breast, cutaneous melanoma, and prostate. In general cancer incidence and mortality is very low in children and adolescents, rising exponentially with increasing age during adulthood. There is marked international variation in the incidence of most cancers. The most important causes of cancer are tobacco use (primarily cigarette use), excess alcohol consumption, obesity, lack of physical activity, diets low in fruits and vegetables, infectious agents, and sun exposure. Early detection can reduce the chances that a person will die of cancers of the female breast, uterine cervix, colon and rectum, lung, and prostate.

SUMMARY

Although the most common cancers in the United States continue to have a substantial impact on public health, they are caused in whole or part by factors over which people and governments have control through choices they make. Among these are tobacco and alcohol use, obesity, diets low in fruits and vegetables and lack of physical activity, and sun exposure. Thus, a very large proportion of cancer's impact could be ameliorated if more people avoided these exposures.

Topical and Intralesional Immunotherapy for Melanoma In Situ: A Review

The incidence of in situ melanoma (MIS) has increased over the last decades. The mainstay of treatment for MIS, including lentigo maligna (LM), is complete surgical excision with clear margins (0.5 to 1.0 cm). Nevertheless, MIS lesions often affect elderly patients with comorbidities and involve large lesions in cosmetically sensitive areas, which means surgery is not always appropriate. Non-surgical treatments have a role in these cases, and include radiotherapy, cryosurgery, immunotherapy, laser therapy, and other topical medications. This study aims to review the applications of immunotherapy in MIS, either in monotherapy or in combination with other therapeutic alternatives. The main forms of immunotherapy used are imiquimod and, to a lesser extent, intralesional interferon-α (IL-INF-α) and ingenol mebutate (IM). IL-INF-α and IM have not been studied as extensively as imiquimod, whose results in real-life practice are encouraging. The clearance and recurrence rates reported in MIS treated with imiquimod as monotherapy, or as an adjuvant after surgery with affected or narrow margins, make imiquimod a reliable therapeutic alternative in selected cases. Also, its use as a neoadjuvant therapy before surgery was shown to reduce the final surgical defect size required to confirm negative histologic margins. In conclusion, local immunotherapy is frequently used in clinical practice and experience confirms it to be an excellent option for certain patients.

Risk of Mortality After a Diagnosis of Melanoma In Situ

Importance

The incidence of melanoma in situ (MIS) is increasing more rapidly than any invasive or in situ cancer in the US. Although more than half of melanomas diagnosed are MIS, information about long-term prognosis following a diagnosis of MIS remains unknown.

Objective

To evaluate mortality and factors associated with mortality after a diagnosis of MIS.

Design, Setting, and Participants

This population-based cohort study of adults with a diagnosis of first primary MIS from 2000 to 2018 included data from the US Surveillance, Epidemiology, and End Results Program, which were analyzed from July to September 2022.

Main Outcomes and Measures

Mortality after a diagnosis of MIS was evaluated using 15-year melanoma-specific survival, 15-year relative survival (ie, compared with similar individuals without MIS), and standardized mortality ratios (SMRs). Cox regression was used to estimate hazard ratios (HRs) for death by demographic and clinical characteristics.

Results

Among 137 872 patients with a first-and-only MIS, the mean (SD) age at diagnosis was 61.9 (16.5) years (64 027 women [46.4%]; 239 [0.2%] American Indian or Alaska Native, 606 [0.4%] Asian, 344 [0.2%] Black, 3348 [2.4%] Hispanic, and 133 335 [96.7%] White individuals). Mean (range) follow-up was 6.6 (0-18.9) years. The 15-year melanoma-specific survival was 98.4% (95% CI, 98.3%-98.5%), whereas the 15-year relative survival was 112.4% (95% CI, 112.0%-112.8%). The melanoma-specific SMR was 1.89 (95% CI, 1.77-2.02); however, the all-cause SMR was 0.68 (95% CI, 0.67-0.7). Risk of melanoma-specific mortality was higher for older patients (7.4% for those 80 years or older vs 1.4% for those aged 60-69 years; adjusted HR, 8.2; 95% CI, 6.7-10.0) and patients with acral lentiginous histology results (3.3% for acral lentiginous vs 0.9% for superficial spreading; HR, 5.3; 95% CI, 2.3-12.3). Of patients with primary MIS, 6751 (4.3%) experienced a second primary invasive melanoma and 11 628 (7.4%) experienced a second primary MIS. Compared with patients without a subsequent melanoma, the risk of melanoma-specific mortality was increased for those with a second primary invasive melanoma (adjusted HR, 4.1; 95% CI, 3.6-4.6) and was decreased for those with a second primary MIS (adjusted HR, 0.7; 95% CI, 0.6-0.9).

Conclusions and relevance

The results of this cohort study suggest that patients with a diagnosis of MIS have an increased but low risk of melanoma-specific mortality and live longer than people in the general population, suggesting that there is significant detection of low-risk disease among health-seeking individuals. Factors associated with death following MIS include older age (≥80 years) and subsequent primary invasive melanoma.