Cancer Occurrence After a Cerebral Venous Thrombosis: A Nationwide Registry Study

The incidence of cerebral venous thrombosis (CVT) decreases with age in women but increases in men, suggesting that age and sex affect CVT etiology.¹ Cancer is a possible cause of CVT, but the risk of occult malignancy is unknown.² We combined data from 4 nationwide mandatory registries to identify all patients with a CVT in 2005 to 2017 in Finland¹ and to investigate the occurrence of new cancer diagnoses within 2 years of CVT in patients without prior malignancy (Supplemental Methods). This was a retrospective register study, and thus no ethical board review or informed consent was required, and the participants were not contacted. We are not permitted to disclose data to third parties. Requests to access the data set may be sent to Findata (https://findata.fi/en/).

We included 589 CVT patients without cancer (Table S1). Thirteen (2.3%) patients had a new cancer diagnosis during the follow-up. Only 2 patients (both male) were <50 years of age at the time of the CVT (1.8% of all male patients aged <50 years). The risk of a new cancer diagnosis was higher in men compared with women in this age group (P=0.035) and overall (P=0.027), but there was no sex difference in the older patients (P=0.41; Figure). No particular cancer type was predominant (Table S2). Four of the new cancer diagnoses had occurred within a year of the CVT, 3 in men and 1 in women (all in different organs). Four of the 13 patients with cancer died within 2 years, all because of cancer.

Figure.

Probability of a new cancer diagnosis after a cerebral venous thrombosis by age and sex. Cumulative probability of new cancer diagnosis after a cerebral venous thrombosis in (A) patients <50 y of age and (B) patients ≥50 y of age.

Age and sex were associated with the occurrence of a new cancer diagnosis in these CVT patients. In patients under 50 years of age, the risk was absent in women and very low in men, and none of these cancers was diagnosed within a year of the CVT. New cancer diagnoses were more common in patients >50 years of age, and it seems reasonable to maintain clinical vigilance for signs of malignancy when treating patients, especially men, of this age group. Comprehensive screening of all CVT patients for cancers appears unwarranted, although more data are needed to confirm this. The situation could be much the same as after unprovoked venous thromboembolism.³ Given the difference in perspectives, the current results are not directly comparable to previous studies that reported no sex differences in cancer as a predisposing factor for CVT.^4,5 Importantly, it appears there is no specific type of occult cancer to look for after a CVT.

Article Information

Sources of Funding

This study was supported by the Government’s Special Financial Transfer tied to academic research in Health Sciences (Finland).

Disclosures

Dr Sipilä reports shares (Orion Corporation). Dr Ruuskanen reports scientific consultancy fee (Sandoz), speaker fee (Merck) travel/congress sponsorship (Bristol Myers Squibb and Bayer), and shares (Medbase, Ltd). Dr Heervä reports advisory board fees and travel grants (Roche/Genentech, Amgen, AstraZeneca, Bayer, MSD, Merck, Sanofi, and Pierre Fabre). Dr Posti reports academy of Finland grant funding (No. 17379). Dr Kytö reports scientific consultancy fee (AstraZeneca), speaker fee (Bayer), and funding (Finnish Foundation for Cardiovascular Research). The other author reports no conflicts.

Supplemental Material

Supplemental Methods

Tables S1–S2