This report is the ninth annual report from the Norwegian melanoma registry. The results are presented for each hospital or area of residence. The melanoma registry has complete data back to 2008, but this report mainly focuses on results from 2020 and 2021. In Norway, 2874 cases of melanoma were diagnosed in 2021, compared to 2770 cases in 2020. Although the registry has data on all melanomas- skin, eye and mucosal – this report primarily focuses on melanomas of the skin (C43), which make up 95 % of all reported melanoma cases. In 2021, 2634 cases of cutaneous melanoma were diagnosed. 66 patients had more than one case of cutaneous melanoma that same year. Cutaneous melanoma is the second most common type of cancer for people aged 25-49 years. Please refer chapter 3.3 for details. The report also include some results concerning eye- and mucosal melanomas. These are treated in separate chapters. In 2021, 82 cases of melanoma in the eye and 28 cases of mucosal melanoma were diagnosed.
Incomplete reporting to the melanoma registry has been a major issue. The Cancer Registry of Norway, together with the Norwegian Melanoma Group (NMG), have initiated several measures to increase the reporting. In 2021, the reporting rate has decreased to 77.1 %, from 80.6 % in 2020. Various measures to improve the reporting rate have resulted in an improvement, especially that of establishing local contacts at the hospitals. It takes time to establish good reporting routines, and this will be a major focus for the melanoma registry in the years to come. Refer to chapter 5.4.1.
Tumor thickness, ulceration and mitotic rate are key parameters in classification of melanomas. We observe some variations between different pathology departments in whether or not tumor thickness and
ulceration have been documented in the pathology report. However, all hospitals are within the highest targeted standard for this quality indicator, that is above 90 % (fig. 3.5).
The proportion of patients in Norway, with a histologically verified free margin after primary excisions is 71.7 % (fig. 3.11) among the primary healthcare physicians, which is below the 90 % target level for this quality indica- tor. This shows that more resources should be spent on training primary healthcare physicians and on increasing the dermatologists’ skills, both to detect melanomas earlier and to perform correct primary excisions. Among the hospitals, the proportion of patients with a histologically verified free margin after primary excisions is 86.1 % (fig. 3.12). An important quality indicator to prevent local recurrences is, according to the guidelines, to remove the melanoma with sufficient distance to healthy tissue. In Norway, this measure is just below the recommended level of 90 % or more (fig. 3.13). There may be several reasons why melanomas are removed without sufficient tissue mar- gin. For instance, the melanoma may be situated in an area where removal of skin and tissue will reduce function and aesthetics, such as in the head and neck region.
For melanomas in stage T1, the thickness of the melanoma is 1 mm or less. An early diagnosis improves prognosis and at least 60 % of patients should be diagnosed at stage T1. In 2021, 55 % of patients were diagnosed with a T1 melanoma (fig. 3.21). This indicates that we still have a way to go when it comes to early diagnosis, compared to countries such as Australia and the USA.
The survival rate is very good for patients diagnosed with early stage melanoma. The survival rates for stages pT3 and pT4, for both men and women are high (figs. 3.31 and 3.32), at 75.7 % and 80.8 %, respectively. In a national comparison, the survival rates show only minor variations for patients with thick melanoma, which indicates equal treatment and follow-up nationwide.
The three-year relapse-free survival rate among patients in stages I and II is also very good, at 88.9 %. Patients diagnosed in stage III have a three-year relapse-free survival rate of approximately 70 %.
We see a positive development with a significantly increased survival in the group with distant metastases. This is the result of new treatments, which seems to have a positive long-term effect on this patient group (fig. 3.33).
This year’s report presents results on Patient Reported Outcome Measures (PROMs) and Patient Reported Expe- rience Measures (PREMs) for the first time. There is a low reporting rate, so the results must be interpreted with caution as these may indicate random differences. Nevertheless, the results consistently show good results, both in terms of self-assessed health and quality of life, information about treatment options and how satisfied the patients were with the treatment they received (figs. 3.43-3.47).