Significant changes in tumor growth can be detected through short interval follow-up

May 4 2006

Significant changes in tumor growth can be detected through short interval follow-up CT in patients receiving chemotherapy for non-small cell lung cancer, a recent study found.

These growths may have important clinical implications in the management of patients, enabling early discontinuation of potentially toxic chemotherapy drugs.

The study, lead by Dr. John F. Bruzzi of the department of diagnostic imaging at the MD Anderson Cancer Center in Houston, TX was done to determine whether short term follow-up CT in patients with non-small cell lung cancer can detect significant changes in tumor size due to disease progression or response to therapy.

The study, which was performed within a thirty-one day time period, had 41 patients, both male and female, ranging from 26-85 years of age. Short-term restaging scans in each patient comprised at least two serial CT studies performed during this time period. A significant change in tumor size was observed in seven of the patients, four of whom had poorly differentiated tumors. There was a 33% decrease in tumor size in one patient in response to chemotherapy. In five patients, tumors increased extensively in size by 20-48% over a period of 31 days or less. This prompted either a change or discontinuation of chemotherapy in all five patients.

"We found that 17% of patients with non-small-cell lung cancer being treated with chemotherapy had a significant change in tumor size on restaging CT performed within thirty-one days of their baseline CT scan," said Dr. Bruzzi.

"Twelve percent of these patients had tumor progression, while 3% had tumor shrinkage. This response occurred regardless of initial tumor stage, tumor histology or type of treatment received. This means that an early restaging CT that detects tumor progression can allow the clinician to change or discontinue chemotherapy earlier than might otherwise be done, thereby helping to reduce exposure of the patient to costly and potentially toxic chemotherapy agents that are ineffective; it also gives greater confidence to the clinician in continuing therapy that is producing a good tumor response," said Dr. Bruzzi.

"We believe now that the value of performing early restaging CT should be assessed in a controlled prospective study of a more homogenous population of patients with lung cancer, which could perhaps also incorporate volumetric measurements of tumor size and assess the relative values of restaging CT and CT-PET scanning," stated Dr. Bruzzi.

The full results of this study will be presented on Thursday, May 4, 2006 during the American Roentgen Ray Society Annual Meeting in Vancouver, BC.

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