A recent study shows heating malignant tumors could improve treatments for mesothelioma and other cancers.
Researchers in France successfully softened malignant tumors by heating them, a process known as nanohyperthermia.
The application of heat altered the collagen fibers and reduced the rigidity and volume of the tumors, making them more susceptible to chemotherapy and other therapeutic treatments.
Malignant tumors, such as those found in mesothelioma patients, demonstrate a mechanical resistance to standard treatments, hindering efforts to defeat cancers. Stiffening is a characteristic of cancer cells, and one that may help the cells proliferate and metastasize.
Researchers at the Centre national de la recherche scientifique (CNRS), the French National Institute of Health and Medical Research (INSERM), Paris Descartes University and Paris Diderot University published the study Jan. 1 in the journal Theranostics.
“Nanohyperthermia was demonstrated to improve drug transport and tumor accumulation due to an increase of blood flow and interstitial extravasation,” lead researcher Iris Marangon wrote in the study.
Tumor Stiffness Plays Key Role in Success of Treatments
Tumor stiffening is considered a predictive marker for tumor malignancy, often assessed noninvasively through an ultrasound.
When tumors become stiff, they restrict the delivery of diagnostic and therapeutic agents to the tumor.
Tumors stiffen because of the abnormal organization of collagen fibers and extracellular matrix (ECM) that hold cells from the same tissue together.
Current treatments to disrupt the structure or microenvironment of tumors pose problems because the ECM is also common to healthy organs, so attempts to soften tumors could cause more harm than good.
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By using nanohyperthermia, the researchers in France were able to target malignant tumors in mice directly, leaving healthy nearby tissue intact.
The process involves inserting carbon nanotubes directly into the tumors, then activating those nanotubes with laser irradiation.
Researchers heated the tumors to 125.6 F for three minutes. After initially becoming more rigid, the treated tumors softened over the 10 days following the procedure while the control tumors increased nearly 12 times in volume.
“Through a local denaturation of adjacent tissue and particularly on collagen fibers, nanomaterial-generated heat stress induce a remodeling and softening of the tumor microenvironment concomitant to tumor regression,” Marangon wrote in the study.
Potential Impact on Future Mesothelioma Treatments
While still in the experimental stages, using nanohyperthermia on malignant tumors could prove to be beneficial for the treatment of challenging cancers such as pleural and peritoneal mesothelioma.
Treating mesothelioma is difficult because the cancer is rare and has a long latency period. By the time doctors diagnose most mesothelioma cases, the tumors are well-established.
The aggressive cancer is often diagnosed in the later stages after tumors have metastasized and potentially curative surgeries are no longer an option.
Oncologists and researchers are constantly searching for better ways to make cancer cells more vulnerable to treatments. Marangon believes nanohyperthermia is a step in the right direction.