A new study by thoracic surgeons and pathologists at Memorial Sloan Kettering shows that an abnormal cell pattern found in the tumor tissue of some lung cancer patients may help to predict which tumors are more likely to recur after surgery. This pathology feature eventually could become an important factor doctors use to guide treatment decisions for people with lung cancer.
“Our research offers the first scientific evidence that may help surgeons identify not only which patients are more likely to benefit from less radical lung-sparing surgery, but also which patients will benefit from more-extensive surgery, potentially reducing the risk of lung cancer recurrence by up to 75 percent,” says thoracic surgeon Prasad Adusumilli, senior author of the study, which was published online earlier this week by the Journal of the National Cancer Institute.
Choosing the Best Surgical Approach
The goal of surgery for lung cancer is to completely remove the tumor while sparing as much of the surrounding tissue as possible, which enables people to have the best possible quality of life after the procedure. How extensive surgery is depends partly on how large the tumor is and to what extent it has spread within the chest.
Some patients with early-stage lung cancer may undergo what is called lung-sparing surgery, or limited resection, in which the tumor and only a small amount of surrounding tissue are removed, usually using minimally invasive techniques. Other patients may undergo a more extensive procedure known as lobectomy, which is more common and involves the removal of up to a third of the lung along with the tumor.
Until now, there have been no evidence-based criteria for choosing the most effective surgery for individual patients. However, surgeons tend to offer limited resection for lung cancers less than two centimeters in size.
In the current study, researchers retrospectively evaluated the clinical characteristics and pathology information of 734 patients treated at Memorial Sloan Kettering for early-stage adenocarcinoma — the most common subtype of non-small cell lung cancer — and observed them for evidence of recurrence. They found that in 40 percent of the patients, tumor cells exhibited a characteristic pattern under the microscope known as micropapillary (MIP) morphology.
Further analysis showed that patients with the MIP pattern who underwent lung-sparing surgery had a 34 percent incidence of the cancer returning within five years of surgery, with two-thirds of the recurrences occurring within the spared lobe of the lung. In contrast, patients with the MIP pattern who underwent the more extensive lobectomy procedure had only a 12 percent incidence of recurrence over a five-year period.
Improving the Precision and Timing of Tumor Pathology
The study’s observations may offer an important tool in deciding whether to perform lung-sparing surgery or lobectomy for patients with small lung adenocarcinomas. However, challenges remain before this tool can become a standard part of treatment decision making. Only a handful of cancer centers in the country currently have the pathology expertise needed to identify the MIP pattern during surgery. This means that patients whose tumors were found to have the MIP pattern after undergoing lung-sparing surgery would require an additional surgical procedure to reduce their risk of recurrence.
“If we can precisely identify during surgery which tumors do not have the micropapillary pattern, lung-sparing surgery can be performed on these patients with confidence, resulting in fewer patients requiring additional treatment,” says thoracic surgeon Nabil Rizk, a coauthor of the study.
“We are now working to develop new technology that can be used to identify which tumors have the micropapillary pattern using noninvasive imaging, ideally before or during surgery, and hopefully what we do here can be extended to other medical centers,” says Dr. Adusumilli.
“We draw from the vast experience and expertise we have at Memorial Sloan Kettering,” Dr. Rizk adds, citing the nearly 400 lobectomies and 600 limited resections performed by thoracic surgeons each year, half of which are done by minimally invasive means such as video-assisted thoracic surgery.