Clinical outcome of patients with metastatic melanoma of unknown primary in the era of novel therapy.

Melanoma of unknown primary (MUP) is considered different from melanoma of known primary (MKP), and it is unclear whether these patients benefit equally from novel therapies. In the current study, characteristics and overall survival (OS) of patients with advanced and metastatic MUP and MKP were compared in the era of novel therapy. Patients were selected from the prospective nation-wide Dutch Melanoma Treatment Registry (DMTR). The following criteria were applied: diagnosis of stage IIIc unresectable or IV cutaneous MKP (cMKP) or MUP between July 2012 and July 2017 and treatment with immune checkpoint inhibition and/or targeted therapy. OS was estimated using the Kaplan-Meier method. The stratified multivariable Cox regression model was used for adjusted analysis. A total of 2706 patients were eligible including 2321 (85.8%) patients with cMKP and 385 (14.2%) with MUP. In comparative analysis, MUP patients more often presented with advanced and metastatic disease at primary diagnosis with poorer performance status, higher LDH, and central nervous system metastases. In crude analysis, median OS of cMKP or MUP patients was 12 months (interquartile range [IQR] 5 - 44) and 14 months (IQR 5 - not reached), respectively (P = 0.278). In adjusted analysis, OS in MUP patients was superior (hazard rate 0.70, 95% confidence interval 0.58-0.85; P < 0.001). As compared to patients with advanced and metastatic cMKP, MUP patients have superior survival in adjusted analysis, but usually present with poorer prognostic characteristics. In crude analysis, OS was comparable indicating that patients with MUP benefit at least equally from treatment with novel therapies.

[Pseudoprogression in immune therapy]. / Pseudoprogressie bij immuuntherapie.

Immune therapy is increasingly used as an effective treatment for various types of cancer. The response of tumours to immune therapy is different from conventional chemotherapy. In about 10% of patients, pseudoprogression may occur. This is a phenomenon where disease progression initially appears on imaging due to inflammation, but response is seen with repeated imaging. Pseudoprogression is often accompanied by a good clinical status. We describe a 63-year-old woman with metastasized melanoma, a 53-year-old woman with metastasized lung cancer and a 77-year-old woman with metastasized renal cancer who all developed pseudoprogression upon treatment with immune therapy. Premature discontinuation of treatment should be prevented when suspecting pseudoprogression and care should be taken to avoid burdening patients with bad news. Imaging should be repeated after a minimum interval of four weeks if pseudoprogression is suspected. When in doubt, a biopsy may be performed.