An extensive screening strategy for occult cancers did not provide clinical benefit over a more limited screening in patients with first unprovoked venous thromboembolism (VTE). Marc Carrier, MD, MSc, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada, presented data from the SOME trial [Carrier M et al. N Engl J Med. 2015].

Currently, there is little consensus regarding cancer screening strategies in patients with unprovoked VTE [Carrier M et al. Ann Intern Med. 2008]. Some strategies are extensive, including abdominal and pelvic computed tomography (CT) imaging, whereas others are more limited and include a physical examination, routine blood testing, and a chest radiograph. The purpose of the SOME trial was to determine the efficacy of occult cancer screening with a comprehensive abdominal/pelvic CT scan in patients with unprovoked VTE.

The multicenter, open-label SOME trial randomly assigned 862 patients who presented with first unprovoked VTE to undergo limited screening or limited screening plus comprehensive CT for occult cancer, with a follow-up period of 12 months. Limited occult cancer screening was defined as basic blood work, a chest radiograph, and breast/cervical/prostate cancer screening. The comprehensive CT scan included a virtual colonoscopy and gastroscopy, a biphasic enhanced CT scan of the liver, a parenchymal pancreatogram, and a uniphasic enhanced CT scan of the distended bladder.

The primary end point was confirmed cancer detected within 1 year that was missed by screening. The secondary end points included total number of occult cancers diagnosed, total number of early cancer diagnoses, 1-year cancer-related mortality, 1-year overall mortality, time to cancer diagnosis, and recurrent VTE. The intention-to-treat analysis included 854 patients. At baseline, the mean age was 53.5 years, 67.5% were men, and the mean weight was 90.1 kg. In addition, 5.9% of patients had a prior cancer, 5.5% had a prior provoked VTE, 15.5% were current smokers, and 33.3% were former smokers. Deep vein thrombosis occurred in 67.5% of patients, pulmonary embolism in 32.5%, and both in 12.3%.

There was no significant difference in new cancer diagnoses among patients in either arm of the study, with 3.2% of patients in the limited-screening arm (95% CI, 1.9% to 5.4%) and 4.5% of patients in the limited screening with comprehensive CT arm (95% CI, 2.9% to 6.9%; P = .28). In addition, the time to cancer diagnosis was similar among both arms, with 4.2 months in the limited screening group and 4.0 months in the limited plus CT screening group (P = 0.88). Furthermore, there was no significant difference in the detection rate of early cancers, overall mortality, cancer-related mortality, time to cancer diagnosis, and rate of recurrent VTE.

Dr Carrier stated that it is possible that an even more extensive screening strategy may have missed fewer occult cancers. He highlighted that there was an overall low rate of occult cancers in patients with unprovoked VTE, and the results of this study indicate that a comprehensive CT scan of the abdomen and pelvis does not provide a clinical benefit.