Venous thromboembolism could be the earliest sign of cancer, as about 10% of patients are diagnosed with cancer in the year following their diagnosis of venous thromboembolism.
However, screening these patients for cancer did not show any real benefit, according to a new study published online in the New England Journal of Medicine.
A screening strategy that included comprehensive CT scanning of the abdomen and pelvis did not lead to fewer missed cancers, as compared with the number of cancers missed in patients who underwent more limited screening.
In addition, more intensive screening did not appear to detect significantly more occult cancers, nor did it shorten the time to cancer diagnosis or reduce cancer-related mortality.
"I think we can now be reassured that the event rate of cancer is small in this population, and if we do routine age- and gender-specific screening, then the rate is very similar to that in the general population," said lead author Marc Carrier, MD, an associate professor of medicine and scientist in the Clinical Epidemiology Program of the Ottawa Hospital Research Institute, in Canada. "There's no need to do extensive screening."
"When we have patients with an unexplained blood clot, instead of extensively looking for cancer, we should just make sure that patients are up to date on their screening," he told Medscape Medical News. "If everything is normal, I would not investigate further. I don't do any further formal screening."
This approach will save a lot of time and resources, Dr Carrier noted. "When we do extensive screening, we often detect incidental findings which may not even be related to cancer, and this inevitably leads to more tests, more biopsies, complications, and more stress for the patient."
Patients already diagnosed with cancer are at high risk of developing venous thromboembolism, and chemotherapy increases it even further. In 2013, the American Society of Clinical Oncology issued clinical practice guidelines on prophylaxis and treatment in patients with cancer, as reported by Medscape Medical News at that time.
"We always thought it was two-way," Dr Carrier said, "that it was bidirectional. Venous thromboembolism can be an early sign of cancer, but cancer patients are at high risk of developing blood clots."
Similar Results for Both Groups
More than 60% of occult cancers are diagnosed shortly after the diagnosis of spontaneous venous thromboembolism, and there has been a great deal of uncertainty about the most optimal screening intervention. The rationale for screening is to allow for early detection and intervention, which hopefully would reduce cancer-related mortality, note the authors. However, there is a wide range of variation in practice, owing to a lack of data.
Dr Carrier and colleagues conducted a randomized, controlled trial in which 854 patients were randomly assigned to either limited occult-cancer screening (basic blood testing, chest radiography, and screening for breast, cervical, and prostate cancer) or limited occult-cancer screening in combination with CT scan.
The primary endpoint was confirmed cancer that was missed by the screening strategy but detected by the end of the 1-year follow-up period.
A total of 33 patients (3.9%) had a new diagnosis of occult cancer between randomization and the 1-year follow-up. Of this group, 14 (3.2%) were in the limited-screening group, and 19 (4.5%) were in the group that included CT scanning (P = .28).
In the primary outcome analysis, four occult cancers (29%) were missed by limited screening, compared with five (26%) that were missed by screening that included CT scanning (P = 1.0). There was no significant difference between the two arms.
The absolute rates of occult-cancer detection were 0.93% (95% confidence interval [CI], 0.36 - 2.36) with the limited screening strategy and 1.18% (95% CI, 0.51 - 2.74) with the addition of CT scans after initial screening was completed.
The cancers most frequently missed by screening included acute leukemia (two cases), gynecologic tumors (two cases), and colorectal tumors (two cases). There were no significant differences between the two strategies.
In the primary per-protocol analysis, 31% (95% CI, 14 - 56) of occult cancers were missed by limited screening compared with 24% (95% CI, 10 - 47) missed with the addition of CT scanning (P = .71).
When they conducted a secondary outcome analysis, the authors did not find a significant difference between the groups in the mean time to cancer diagnosis (4.2 months in the limited-screening group and 4.0 months in the limited-screening-plus-CT group; P = .88), the rate of recurrent venous thromboembolism (3.3% and 3.4%; P = 1.0), overall mortality (1.4% and 1.2%; P = 1.0), or cancer-related mortality (1.4% and 0.9%; P = .75).
"This multicenter, randomized study evaluated how the addition of an abdominal CT scan to an otherwise detailed sex- and age-related screening impacted patients," commented Eric H. Kraut, MD, professor of medicine and director of the benign hematology section, Ohio State University Hemostasis Thrombosis Center, in Columbus. ”The authors demonstrated that a thorough history, physical exam, and standard screening for lung cancer by chest x-ray and, in many cases, CT angiography, prostate evaluation, gynecologic evaluation, and breast evaluation was sufficient."
"This suggests that physicians faced with patients with unprovoked thromboembolic disease may not need to put patients through extensive imaging when they first present but does not change the necessity for careful follow-up over the subsequent 12 to 24 months," he told Medscape Medical News.
Dr Kraut emphasized that it is important for doctors to be aware of the association between unexplained venous thromboembolism and cancer and to maintain close follow-up for the next year or two. "Physicians need to be alert that this is possibly the first sign of cancer," he said.
"And of course, if there is something else going on, such as unexplained weight loss in addition to the blood clot, then you would want to investigate more thoroughly," Dr Kraut added.
The study was supported by the Heart and Stroke Foundation of Canada.
N Engl J Med. Published on June 22, 2015. Full text
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου