From Reuters Health Information
David Douglas
May 7, 2010 — Labor induction, a multiple pregnancy, and cesarean delivery each increases the risk of rare but deadly amniotic fluid emboli, UK researchers report.
Older ethnic-minority women are also at higher risk, according to the article in the May Obstetrics & Gynecology.
"Induction of labor was associated with a population-attributable risk of 35% in our study, suggesting that, assuming causality, if induction of labor were no longer performed, 35% of cases of amniotic fluid embolism could be prevented," said lead author Dr. Marian Knight of the University of Oxford and colleagues.
Of course, they add, labor induction "clearly will continue, and amniotic fluid embolism remains a very rare complication" — but one to keep in mind when considering the risks and benefits of induction.
Using national UK Obstetric Surveillance System data from 2005 to 2009, the researchers found 60 confirmed cases among an estimate of more than 3 million maternities (for estimated incidence of 2.0 cases per 100,000 births).
They note that this rate, based on prospectively collected data, is lower than reported in retrospective studies from Canada and the U.S. (6.1 and 7.7 cases per 100,000 births, respectively).
After adjustment, amniotic-fluid embolism was significantly associated with induction of labor (odds ratio, 3.86) and multiple pregnancy (odds ratio 10.9). This risk was also higher in older, ethnic-minority women (odds ratio 9.85).
Regarding what she called "a possible increased risk of dying from amniotic fluid embolism amongst ethnic minority women," Dr. Knight speculated in email to Reuters Health that "reasons for this...may be related to underlying additional medical problems or access to care."
Cesarean delivery was associated with postnatal amniotic-fluid embolism (odds ratio 8.84).
The emboli occurred at a median gestation of 39 weeks, within a 6-hour range around delivery. All of the women had at least one cardinal sign of an embolism (shortness of breath, hypotension, hemorrhage, coagulopathy, and premonitory symptoms), and more than a quarter of them had at least four signs.
Fetal membranes ruptured at or before presentation in 92% of cases.
Twelve women died, giving a case fatality rate of 20%. These women were significantly more likely to be from ethnic-minority groups (odds ratio, 11.8).
Seven women received exchange transfusion or plasma exchange. All seven of these women survived, although there were too few of them to be able to infer that this treatment is more effective than other approaches. "These therapies should be regarded as an extension of supportive care and not as a substitute," the investigators said.
Outcomes were known for 37 neonates born to mothers with amniotic fluid embolism before or during delivery. Five of these babies died. The perinatal mortality rate was 135 per 1,000 total births.
"Occurrence of amniotic fluid embolism does appear to be associated with induction of labor and caesarean delivery and it is important therefore that both risks and benefits of labor induction and cesarean delivery are considered by clinicians on an individual basis for all women," Dr. Knight said.
"We have no indication from this study that the occurrence has become more frequent in the UK," she said.
Obstet Gynecol. 2010;115:910-917. Abstract
Reuters Health Information 2010. © 2010 Reuters Ltd.
Tuesday, May 11, 2010
Friday, May 7, 2010
Malignancy Risk High With Indeterminate Breast Lesions
From Medscape Medical News
Norra MacReady
May 7, 2010 (San Diego, California) — Indeterminate breast lesions in high-risk women have a relatively high probability of being malignant and should be treated aggressively, investigators reported here at the American Roentgen Ray Society 2010 Annual Meeting.
Of 59 indeterminate lesions identified on magnetic resonance (MR) mammography in 55 women, 13 (22%) proved to be malignant on follow-up MR, mammography, or ultrasound performed 6 months after the initial MR study, said lead author Martin Korzeniowski, MD, from McMaster University in Hamilton, Ontario.
Biopsy or surgical intervention was performed whenever appropriate. The patients all had breast cancer or were deemed to be high risk, either because of personal or family medical history or genetic predisposition.
These findings suggest that "malignant lesions in women with a high risk of breast cancer may present atypically, with an indeterminate morphology or kinetic pattern, and may require more aggressive workup," said Dr. Korzeniowski.
The patients were drawn retrospectively from a database of 727 consecutive magnetic resonance imaging (MRI) scans performed at McMaster University between January 2007 and December 2008. Lesions were classified according to the Breast Imaging Reporting and Data System (BIRADS), developed by the American College of Radiology. Each lesion received a score ranging from 0 (incomplete examination) to 6 (known, biopsy-proven malignancy).
In this study, lesions were considered indeterminate if they could not be definitively classified as suspicious for malignancy but had suspicious abnormalities with a reasonable probability of being malignant (BIRADS 4), or if there was more than a 95% chance that they were malignant (BIRADS 5).
The 59 lesions that met those criteria were followed up within 6 months of the original MRI examination. Of the 13 malignancies, 9 were infiltrating ductal carcinomas, 2 were ductal carcinomas in situ, and 2 were metastatic lymph nodes. The remaining 46 lesions were benign.
The "substantial" cancer yield in this study suggests that follow-up examinations for indeterminate lesions should be performed sooner than is current practice, Dr. Korzeniowski told meeting attendees.
"The rate of cancer these authors found is much higher than other studies have suggested," Constance Lehman, MD, professor of radiology at the University of Washington and director of imaging at the Seattle Cancer Care Alliance, said in an interview with Medscape Radiology. At the University of Washington and other centers, less than 2% of patients with indeterminate lesions turn out to have malignant disease, she said.
"My guess is that their methods of determining if a lesion is indeterminate are different" than those used at other institutions, said Dr. Lehman, who was not involved in this research. Usually, indeterminate lesions must meet specific criteria involving morphology, margins, and enhancement pattern, and are assigned a BIRADS score of 3. Those lesions are considered "probably benign" because they have more than a 98% chance of being benign, she told Medscape Radiology.
Still, Dr. Lehman said, "this is a very interesting study. It is really important for us to continue to evaluate breast MRIs in high-risk women. This research will stimulate more debate."
Dr. Korzeniowski and Dr. Lehman have disclosed no relevant financial relationships.
American Roentgen Ray Society (ARRS) 2010 Annual Meeting: Abstract 018. Presented May 3, 2010.
Norra MacReady
May 7, 2010 (San Diego, California) — Indeterminate breast lesions in high-risk women have a relatively high probability of being malignant and should be treated aggressively, investigators reported here at the American Roentgen Ray Society 2010 Annual Meeting.
Of 59 indeterminate lesions identified on magnetic resonance (MR) mammography in 55 women, 13 (22%) proved to be malignant on follow-up MR, mammography, or ultrasound performed 6 months after the initial MR study, said lead author Martin Korzeniowski, MD, from McMaster University in Hamilton, Ontario.
Biopsy or surgical intervention was performed whenever appropriate. The patients all had breast cancer or were deemed to be high risk, either because of personal or family medical history or genetic predisposition.
These findings suggest that "malignant lesions in women with a high risk of breast cancer may present atypically, with an indeterminate morphology or kinetic pattern, and may require more aggressive workup," said Dr. Korzeniowski.
The patients were drawn retrospectively from a database of 727 consecutive magnetic resonance imaging (MRI) scans performed at McMaster University between January 2007 and December 2008. Lesions were classified according to the Breast Imaging Reporting and Data System (BIRADS), developed by the American College of Radiology. Each lesion received a score ranging from 0 (incomplete examination) to 6 (known, biopsy-proven malignancy).
In this study, lesions were considered indeterminate if they could not be definitively classified as suspicious for malignancy but had suspicious abnormalities with a reasonable probability of being malignant (BIRADS 4), or if there was more than a 95% chance that they were malignant (BIRADS 5).
The 59 lesions that met those criteria were followed up within 6 months of the original MRI examination. Of the 13 malignancies, 9 were infiltrating ductal carcinomas, 2 were ductal carcinomas in situ, and 2 were metastatic lymph nodes. The remaining 46 lesions were benign.
The "substantial" cancer yield in this study suggests that follow-up examinations for indeterminate lesions should be performed sooner than is current practice, Dr. Korzeniowski told meeting attendees.
"The rate of cancer these authors found is much higher than other studies have suggested," Constance Lehman, MD, professor of radiology at the University of Washington and director of imaging at the Seattle Cancer Care Alliance, said in an interview with Medscape Radiology. At the University of Washington and other centers, less than 2% of patients with indeterminate lesions turn out to have malignant disease, she said.
"My guess is that their methods of determining if a lesion is indeterminate are different" than those used at other institutions, said Dr. Lehman, who was not involved in this research. Usually, indeterminate lesions must meet specific criteria involving morphology, margins, and enhancement pattern, and are assigned a BIRADS score of 3. Those lesions are considered "probably benign" because they have more than a 98% chance of being benign, she told Medscape Radiology.
Still, Dr. Lehman said, "this is a very interesting study. It is really important for us to continue to evaluate breast MRIs in high-risk women. This research will stimulate more debate."
Dr. Korzeniowski and Dr. Lehman have disclosed no relevant financial relationships.
American Roentgen Ray Society (ARRS) 2010 Annual Meeting: Abstract 018. Presented May 3, 2010.
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