NAPLES, FLA. The use of anticoagulants during and after skin cancer surgery involves a low risk of bleeding complications for most patients, especially aspirin users, but the risk may be greater in the elderly, warfarin users, and those on multiple agents, according to the results of two studies presented at the annual meeting of the American College of Mohs Surgery.
"It's been said by many that … bleeding from skin surgery is never life threatening. Well, that was certainly what we noticed," said Dr. Anthony J. Dixon, a dermatologic surgeon who practices in Belmont, Australia.
He and his colleagues conducted a prospective study of bleeding complications in skin cancer surgery on 5,990 lesions. During the 44-month enrollment period, 40 bleeding events (26 hemorrhages and 14 hematomas) occurred.
Analysis showed that, at the time of surgery, age 67 years or older and warfarin use were significant and independent risk factors for bleeding complications.
A large age difference in the rate of bleeding complications was "perhaps the most surprising feature we found," said Dr. Dixon, who also is director of research for Skin Alert Skin Cancer Clinics, a network of 13 clinics in Australia.
In surgery for 2,947 lesions in patients younger than 67 years, there were only 5 bleeding complications, compared with 35 complications in 2,939 lesions in patients 67 years or older.
Bleeding events developed in 8 (2.5%) of 320 lesions in patients who were taking warfarin. Patients who were using warfarin prior to surgery were included in the study unless their international normalized ratio (INR) was greater than 3 in the days immediately before surgery. Two patients on warfarin were the only ones to have late bleeding events in the study. Their INRs were less than 3 at the time of surgery but then increased after surgery.
It is important to measure INR not only in the days before surgery, but also in the days afterward, Dr. Dixon suggested. In all, warfarin should only be stopped in "very limited circumstances" and definitely not if the patient had a deep vein thrombosis or a pulmonary embolism within 1 month of the surgery.
Aspirin users developed bleeding complications in 9 (1%) of 890 total cases. All patients who were taking aspirin at the time of surgery were included. "Aspirin is not a risk factor. It's just that older people take aspirin, and older people are more likely to be on a combination of warfarin and aspirin," he said.
Among patients who took both anticoagulants, bleeding complications occurred in 2 (6%) of 35 lesions.
In a separate presentation at the meeting, Ikue Shimizu reported that the use of multiple anticoagulants may increase the risk of bleeding complications. She and her colleagues at Brown University in Providence, R.I., found that only four bleeding complications developed in 760 patients who were undergoing Mohs surgery, but that three of these occurred in patients who were taking two or more oral anticoagulants.
Patients who took two or more anticoagulants were significantly more likely to have bleeding complications than were those who took no agent or only one, she said.
The investigators reviewed the charts of patients who underwent the procedure and received postoperative care at one center during a 1-year span. Patients who received outside postoperative care or had incomplete data were excluded from the trial.
Most of the patients (62%) were not taking any anticoagulants at the time of surgery; the others took one (30%) or two or more agents (8%).
Other studies that have examined the risk of developing bleeding complications after dermatologic surgery have analyzed the effect of using only one anticoagulant agent and not two or more, said Ms. Shimizu, a medical student at the university.
For patients who are on multiple anticoagulants, surgeons at the Brown University Mohs surgery unit try to use extra caution in obtaining hemostasis, and they decrease the use of epinephrine during repair and follow up with patients the next day.
"We feel that there is a need for more prospective studies with increased numbers to properly assess the risks of different complications," Ms. Shimizu said.