Memorial Sloan Kettering surgeons have pioneered a way to eliminate the need for extensive pelvic lymph node removal in most patients undergoing surgery to treat some early-stage gynecologic cancers. The approach, which employs a technique called sentinel lymph node mapping (SLNM), could greatly improve patients’ quality of life without placing them at risk for undetected cancer.
“Women with early-stage forms of cervical and endometrial cancer are cured more than 90 percent of the time, and many of them are still young — in their 30s or 40s,” says gynecologic oncologist Nadeem R. Abu-Rustum, who led the team that developed the new approach. “Sparing them unnecessary node removal and the side effects they might endure for decades would be a huge benefit.”
In addition to removing the malignancy in the uterus, surgeons treating women with early-stage gynecologic cancer often take out numerous lymph nodes in the pelvis so they can be examined for cancer cells that may have spread from the primary tumor. This practice, called pelvic lymphadenectomy, may reduce the threat of cancer recurrence but often causes lymphedema, a condition characterized by swelling and skin changes — in this case in the legs.
Now Dr. Abu-Rustum and his colleagues have developed a way to use SLNM to potentially eliminate the need for pelvic lymphadenectomy in these patients.
Tracking Cancer’s Spread
Abu-Rustum’s SLNM technique involves the injection of a blue dye in several locations near the tumor. Lymph fluid carries the dye to the sentinel nodes, the first lymph nodes to which cancer cells are likely to spread.
During the operation to remove the tumor, the sentinel nodes are identified, removed, and examined for cancer cells by a pathologist. If they are free of cancer, usually no additional lymph nodes need be taken out. If any of the nodes do contain cancer cells, the surgeon may remove more nodes for further inspection, and the patient may need chemotherapy or radiation.
One key to SLNM’s effectiveness is that removal of fewer nodes means they can be subjected to more intensive examination by pathologists — a sensitive technique called ultrastaging.
“This is a much more precise, fine-tuned approach because we’re removing only the nodes that are truly important,” Dr. Abu-Rustum says. “It provides pathologists with a better specimen, and they actually find more cancer cells. This enables clinicians to be more accurate in the way they stage and define the disease. For patients, a less extensive operation reduces time spent in surgery, speeds recovery, and decreases the chance they will develop lymphedema.”Back to top
An Effective Model
Dr. Abu-Rustum and other Memorial Sloan Kettering experts have now generated a great deal of evidence to validate the use of SLNM for cervical and endometrial cancers and recently reported their success in a series of publications in the journal Gynecologic Oncology.
To ensure that cancer spread does not go undetected, Dr. Abu-Rustum’s group developed an algorithm — a specific set of steps to follow — for SLNM use with stage I cervical or endometrial cancers. An essential part of the algorithm calls for the removal of additional lymph nodes when SLNM provides inconclusive results.
Ultimately, Dr. Abu-Rustum estimates SLNM should make it possible to avoid complete pelvic lymphadenectomy in 75 percent of patients with stage I cervical and endometrial cancers while reliably detecting metastasis. He also is confident the algorithm could be broadly adopted at other institutions, where SLNM use is still rare.
“Memorial Sloan Kettering is leading the way with this effort, but I think it will start to be used more widely,” he says. “The bottom line is that this is a much more accurate approach that dramatically improves patients’ quality of life.”Back to top