New NCCN Guidelines for Malignant Pleural Mesothelioma

These new guidelines were presented by Lee M. Krug, MD, Memorial Sloan-Kettering Cancer Center.

A new addition to the NCCN Clinical Practice Guidelines in Oncology, the NCCN Guidelines for Malignant Pleural Mesothelioma (MPM), was announced at the NCCN 15th Annual Conference. These new guidelines were presented by Lee M. Krug, MD, Memorial Sloan-Kettering Cancer Center, who noted that “these guidelines were challenging to prepare as there were areas where there was less data.”

Krug’s presentation started with an overview of MPM, a rare disease that has a male-to-female ratio of 4:1, likely due to the higher incidence of occupational exposure to carcinogens in men, most notably asbestos. The disease can also occur in individuals with a history of radiation exposure, such as to treat Hodgkin’s lymphoma, and may have a latency of 20 years.

Common symptoms include shortness of breath or chest pain, as well as tumor fevers, sweats, weight loss, and pneumonia. “Diagnosing mesothelioma is often difficult, because the symptoms are similar to those of a number of other conditions. In addition, a physician’s initial evaluation of a patient may reveal pleural effusion, but it can often be missed on pleural fluid cytology,” said Krug, noting that a surgical biopsy is often needed to make the diagnosis. While the role of PET scans were downplayed in some NCCN Guideline updates, such as those for breast cancer, the MPM Guidelines indicate that this modality can aid in staging, which is often a challenging endeavor in MPM. Krug noted that PET scans may detect unexpected metastases in 10% of cases. He also noted that when using computed tomography scanning, the abdomen should be included in addition to the chest because of the possibility of peritoneal involvement.

Prognostic factors include the patient’s sex, lymph node status, and histology, but Krug noted that there has been recent interest in serum markers. One such marker is soluble mesothelin-relation protein (SMRP), which may have prognostic significance; however, for now SMRP assays are considered an optional test.

Treatment for mesothelioma may include surgery, chemotherapy, and radiation, depending on the stage and location of the cancer and whether there is metastasis. “Surgery for mesothelioma is a more controversial area,” said Krug, noting that “some patients with early-stage mesothelioma may have slow-growing tumors that can be observed for a time before requiring treatment.” Patients who require surgery may undergo pleurectomy/decortication, a less aggressive surgery, if their disease is caught early, or extrapleural pneumonectomy, a much more aggressive surgery, if they have more advanced disease. Krug cautioned that the decision to recommend extrapleural pneumonectomy requires careful consideration. “As outlined in the Principles for Surgical Resection for Malignant Pleural Mesothelioma in the NCCN Guidelines, physicians need to be highly selective when choosing potential candidates for this procedure,” said Krug.

Because surgery alone can be inadequate due to the presence of micrometastatic disease, the NCCN Guidelines recommend a combined modality therapy approach for select patients, which may include radiation and chemotherapy. “Radiation is recommended as an adjuvant therapy to improve local control after surgery, and it is also an effective palliative treatment for relief of chest pain that is often associated with mesothelioma,” said Krug. While MPM was historically thought to be chemoresistant, recent studies have shown that certain regimens can benefit patients, whether administered before or after surgery. “The NCCN Guidelines recommends pemetrexed with cisplatin or carboplatin as the optimal first-line combination chemotherapy regimen for patients, though others can be considered based on comorbid conditions,” said Krug. Although data on the benefits of second-line regimens were limited, the NCCN Guidelines list a few options that oncologists can try.

To view the full NCCN MPM Guidelines, visit the NCCN Website.