Incidence and survival of glandular vulvar malignancies in the Netherlands.

Aim: There is limited knowledge in the field of glandular vulvar malignancies. The aim of this study is to describe the incidence and survival of women with glandular vulvar malignancies.

Methods: We searched PALGA, a nation-wide database registering all histo- and cytopathology in the Netherlands, for all cases of glandular vulvar malignancies between 2000 and 2015. Additional data were retrieved via the Netherlands Cancer Registry. Incidence rates were calculated per 1,000,000 women per year. Five-year net survival rates were calculated.

Results: We identified 197 patients with a glandular vulvar malignancy. Of these patients 55% had a primary malignancy while 45% had secondary malignancies: expansion of another tumour in 17% and metastases or recurrences of another malignancy in 28%. There is a great variety of different diagnoses of primary vulvar malignancies: 11 different types were identified. We found an overall incidence rate of glandular vulvar malignancies of 0.9-2.5 per 1,000,000 women per year. Five-year net survival for patients with a primary malignancy was 68.5%. Most of the secondary vulvar malignancies originated from (ano-)rectal malignancies.

Conclusion: Glandular vulvar malignancies are extremely rare and primary tumours are slightly more common. Overall survival of patients with primary glandular vulvar malignancies is comparable to patients with a vulvar squamous cell carcinoma, with five-year survival around 70%. The great variety in diagnoses combined with the low incidence should lead to routine pathologic revision and treatment in specialised gynaecologic oncology centres.