An uncommon cause of syncope

Syncope as a sign of occult cancers: a population-based cohort study

BACKGROUND

We examined if syncope was a marker of an occult cancer by comparing the risk in patients with a syncope episode with that of the general population.

METHODS

Using Danish population-based medical registries, we identified all patients diagnosed with syncope during 1994-2013 and followed them until a cancer diagnosis, emigration, death or end of follow-up, whichever came first. We computed cumulative risks and standardised incidence ratios (SIR) with 95% confidence intervals (CI).

RESULTS

Among 208,361 patients with syncope, 20,278 subsequent cancers were observed. The 6-month cumulative risk of any cancer was 1.2%, increasing to 17.9 % for 1-20 years of follow-up. The highest cumulative risks after 6 months of follow-up were lung cancer (0.2%), colorectal cancer (0.2%), prostate cancer (0.1%) and brain cancer (0.1%). The 6-month SIR were 2.7 (95% CI: 2.4-3.0) for lung cancer, 2.0 (95% CI: 1.8-2.2) for colorectal cancer, 1.7 (95% CI: 1.5-1.9) for prostate cancer and 10.0 (95% CI: 8.6-11.4) for brain cancer.

CONCLUSIONS

Syncope was a weak marker of an occult cancer. In short-term the highest cumulative risks were observed for lung, colorectal, prostate and brain cancers. An aggressive search for occult cancer in a patient with syncope is probably not warranted.

Small-cell lung cancer with recurrent syncope as the initial symptom: A case report and literature review

Small-cell lung cancer (SCLC) presenting with syncope as the initial symptom is rare in adults. This onset of tumour-induced syncope cannot be screened or differentiated by coronary angiography, magnetic resonance angiography of the neck or 24-hour dynamic electrocardiogram. We herein describe the case of a 61-year-old man who presented with recurrent syncope that resolved after the first course of chemotherapy (carboplatin plus etoposide) for SCLC. A mass measuring 57×53 mm was identified in the left hilum, and a diagnosis of limited-disease SCLC (T4N2M0, IIIB) was made. Considering the rapid and complete remission after the treatment of the primary lesion, we hypothesised that the syncope was neurogenic and associated with cancer. Thus, 8 similar cases retrieved from PubMed were reviewed and, for the first time, the mechanism underlying the syncope was identified, which may involve tumour location, neurobiology and other inducing factors. Thus, for the treatment of such SCLC patients, standard chemotherapy is crucial for preventing syncopal attacks.