Researchers validated a method of noninvasive imaging that provides valuable information about interstitial fluid pressure of solid tumours and may aid in the identification of aggressive tumours, according to the results of a study published in Cancer Research, a journal of the American Association for Cancer Research.

Many malignant solid tumours generally develop a higher interstitial fluid pressure (IFP) than normal tissue.

High IFP in tumours may cause a reduced uptake of chemotherapeutic agents and resistance to radiation therapy.

In addition, a high IFP has been found to promote metastatic spread.

“Currently, an imaging method for noninvasive assessment of the IFP of tumours is needed to evaluate the potential of IFP as a biomarker for cancer aggressiveness and, hence, to identify patients with cancer who may benefit from particularly aggressive treatment because of highly elevated tumour IFP,” said Einar K. Rofstad, Ph.D., of the department of radiation biology at the Institute for Cancer Research, Norwegian Radium Hospital, Oslo, Norway.

Rofstad and colleagues tested the use of dynamic contrast-enhanced magnetic resonance imaging (MRI) to evaluate the velocity of fluid flow from tumours in human cell lines of cervical carcinoma and melanoma implanted in mice. Researchers hypothesized that the velocity of fluid flow from tumour tissue into adjacent tissue was determined by the IFP drop at the tumour surface.

Results indicated that the velocity of the fluid flow at the tumour surface strongly correlated with the magnitude of the tumour IFP and that dynamic contrast-enhanced MRI with gadolinium diethylene-triamine penta-acetic acid (Gd-DTPA) as a contrast agent can be used to noninvasively measure the fluid-flow velocity.

In addition, primary tumours of mice with metastases had a significantly higher IFP and fluid-flow velocity at the tumour surface compared with the primary tumours of metastasis-free mice, confirming that the development of lymph node metastases strongly correlated to the IFP of the primary tumour and the velocity of fluid flow as measured by Gd-DTPA-based dynamic contrast-enhanced MRI.

“Our findings establish that Gd-DTPA-based dynamic contrast-enhanced MRI can noninvasively visualise tumour IFP,” Rofstad said. “This reveals the potential for the fluid-flow velocity at the tumour surface determined by this imaging method to serve as a novel general biomarker of tumour aggressiveness.”

Rofstad said that comprehensive prospective clinical investigations in several types of cancer are needed to assess the value of fluid-flow velocity at the tumour surface level assessed by Gd-DTPA-based dynamic contrast-enhanced MRI as a general biomarker for interstitial hypertension-induced cancer aggressiveness.

Source: AACR