Neoadjuvant Chemo Combo May Improve Mesothelioma Survival

For treatment of malignant pleural mesothelioma prior to surgery, one chemotherapy combination may be better than another.  That is the central message of a recent Italian study published in Anticancer Research.

Mesothelioma is an aggressive cancer caused by exposure to asbestos. It affects the membranes around organs and is often incurable. According to some studies, patients who have the best odds of survival are those who undergo multimodal therapy, including some combination of chemotherapy, surgery and/or radiotherapy.

The folate antimetabolite pemetrexed (Alimta) was the first chemotherapy drug specifically approved for the treatment of mesothelioma. It can be used prior to surgery (neoadjuvant) as a way to shrink a tumor and make it more operable, or after surgery (adjuvant) as a way to destroy residual cancer cells.  Regardless of how it is used, pemetrexed is usually administered in combination with a platinum-based drug.

In an effort to find the best neoadjuvant drug combination for mesothelioma, researchers in Padua, Italy compared the benefits of two pemetrexed/platinum drug combinations – pemetrexed/cisplatin (AP) and pemetrexed/carboplatin (AC). The study followed 51 patients, each of whom received three cycles of either AC or AP, followed by surgery and radiotherapy. The goal was to determine the effectiveness and tolerability of each combination as a neoadjuvant regimen.

Although the two drug combinations were comparable, overall, the patients on the AP combination fared slightly worse than those on the AC combination. In a summary of their findings, the researchers report, “We observed higher incidence of grade 3 anemia, cumulative grade 2-3 asthenia, and worsening of performance status in the AP group.”

Four percent of the 27 AC mesothelioma patients showed a complete response, versus none of the 24 AP patients. Eighteen percent of the AC group showed a partial response, versus 17 percent of the AP group. Disease progression among the AC group was also slightly slower – 74% versus 79%. Among the AC patients, doctors were able to remove an average of 81 percent of the mesothelioma cells. For AP patients, the resection rate was 79 percent.

The research team concluded that, while both combinations are “active and feasible” neoadjuvant therapies, with similar rates of progression-free survival, response, disease control and resection, AC appeared to be slightly better for this purpose. The team expressed concern that, when used as a neoadjuvant therapy, the slightly lower tolerability of the AP treatment could be enough to “impair the clinical condition” of mesothelioma patients prior to surgery.

It is important to note that in most mesothelioma cases, chemotherapy is a palliative modality and is not considered curative by itself.

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