In Endometrial Cancer, Lymphadenectomy Down Since 2007

Fran Lowry

September 08, 2015

In the surgical treatment of endometrioid endometrial cancers, the use of lymphadenectomy has decreased considerably, according to a new study.

This downward trend reflects results from seminal studies that showed no real benefit of removing lymph nodes in women with this early form of uterine cancer, which led to changes in guidelines, said lead researcher Alexander Melamed, MD, from Massachusetts General Hospital in Boston.

Although the rate of lymphadenectomy increased from 1998 to 2007, it is now decreasing annually, Dr Melamed and his colleagues report in their study, published in the October issue of Obstetrics and Gynecology.

"As early as 1988 and throughout the 1990s, more and more gynecologic oncologists started doing lymphadenectomy for endometrioid adenocarcinoma of the endometrium, because there were some small retrospective studies that suggested that taking out the lymph nodes in all women with uterine cancer improved survival," Dr Melamed told Medscape Medical News.

In 2004, the American College of Obstetricians and Gynecologists issued a practice bulletin that advocated the practice, he explained. But since then, studies have cast doubt on the necessity of lymphadenectomy in patients at low risk for lymph node metastasis.

"Two randomized trials showed that removing the lymph nodes in women with early endometrial cancer made no difference in their survival. There was also a seminal study from the Mayo Clinic that found that if you removed the lymph nodes in women with endometrioid endometrial cancer that had certain features, such as a small tumor or a tumor that was only superficially invasive in their uterus, they virtually never had any cancer in their lymph nodes," Dr Melamed said.

The Mayo Clinic team subsequently concluded that these low-risk women do not need to have their lymph nodes removed, he noted.

In 2014, the Society of Gynecologic Oncology issued guidelines stating that lymphadenectomy might not be necessary in patients with endometrial cancer with a tumor smaller than 2 cm, no tumor invasion beyond 50% of the myometrial thickness, and low- to moderate-grade endometrioid histology.

For their study, Dr Melamed and his colleagues conducted a time-trend analysis to determine how often lymphadenectomy was being performed.

They identified 74,365 women from the Surveillance, Epidemiology, and End Results (SEER) cancer registry who underwent surgery from 1998 to 2012.

From 1998 to 2007, the rate of lymphadenectomy increased by 4.2% per year (95% confidence interval [CI], 3.7 - 4.6; P < .001). However, a significant change in the trend began to appear in the second half of 2007, when the rate of lymphadenectomy began to decline by 1.6% per year (95% CI, 0.9 - 2.2; P < .001).

Their analysis showed that from 1998–2000 to 2007–2009, the rate of lymphadenectomy rose from 48.7% to 65.5% — a 16.8% increase.

"In terms of relative risk, women who underwent surgery in 2007 to 2009 were 34% more likely to undergo excision of the lymph nodes compared with women who underwent surgery in the earlier period," Dr Melamed said.

In addition, the proportion of women who were found to have nodal metastasis increased by 1.1% from 1998–2000 to 2007–2009, when the use of lymphadenectomy was at its highest.

However, from 2007–2009 and 2010–2012, when the frequency of lymphadenectomy was on the decline, the proportion of women found to have nodal metastasis remained unchanged (= .17).

And from 1998 to 2009, the frequency of negative lymphadenectomy increased by 15.7%. "Compared with 1998–2000, "for every additional woman found to have nodal metastasis in 2007 to 2009, 15 women underwent a negative lymphadenectomy," Dr Melamed reported.

By 2010–2012, the proportion of women who underwent a negative lymphadenectomy declined by 3.1%.

There was also a difference in disease-specific and overall survival.

For patients diagnosed in 1998–2000, 5-year disease-specific survival was 91.4% (95% CI, 90.7 - 92.0) and overall survival was 84.4%. For patients diagnosed in the most recent period for which 5-year survival was calculable — 2007–2009 — 5-year disease specific survival rate 93.1% (95% CI, 92.7 - 93.5) and overall survival was 87.8%

"Currently, more than half of women diagnosed with endometrioid endometrial cancers are still having their lymph nodes taken out, but, for the first time, we are seeing this decreasing rather than increasing," Dr Melamed said.

"There was a point in time when many gynecologic oncologists would have said that every woman with endometrial cancer should have their lymph nodes out. I don't think all gynecologic oncologists are thinking that way anymore," he explained.

It is important for women diagnosed with uterine cancer to seek care from a practitioner who specializes in the area and who is up to date on the literature, Dr Melamed said.

"There is quite a bit of subtlety in terms of who needs a lymph node assessment and what type of assessment, and the data cannot be applied to every type of uterine cancer, he said. "A woman is best getting this kind of surgery from someone who does this frequently and who really thinks about whether removing the lymph nodes is necessary or not."

"It needs to be somebody who is conversant with these data, who thinks carefully about this, and who is not limited by what they have been trained to do but does what they think is the appropriate procedure for that particular patient," he explained.

This study was funded by the Deborah Kelly Center for Outcomes Research at the Massachusetts General Hospital. Dr Melamed has disclosed no relevant financial relationships.

Obstet Gynecol. 2015;126:815-822. Abstract

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