PET brings treatment changes in majority of colon ca cases

ABSTRACT: Multicenter data should encourage early engagement between cancer specialists and imaging experts.

MELBOURNE, Australia-The largest multi-institutional study to date examining the effect of PET on the management of recurrent colorectal cancer has shown that PET led to change in the treatment plans for more than half of patients.

“These data should encourage molecular imaging practitioners to engage with referring physicians early in the process of cancer treatment,” said Andrew M. Scott, MD, director of the Center for PET and the Ludwig Institute for Cancer Research at Austin Hospital.

“It is clear that PET had a significant impact for these patients and could be an indispensable part of the standards of care for oncologists,” he added.

The study was conducted at four sites throughout Australia and followed 191 patients divided into two groups.

Group A consisted of symptomatic patients who had residual structural lesions suspicious for recurrent tumor after initial therapy. Group B patients had pulmonary or hepatic metastases that were potentially operable.

Results, which are published in the September issue of the Journal of Nuclear Medicine, were compared with findings from conventional imaging such as CT, and participants were followed for 12 months.

Based on the extent and progression of disease revealed by the scans, treating physicians changed the planned management in more than 65% of patients in group A and nearly 50% in group B.

The researchers also found additional disease sites in 48% of patients in group A and 44% of group B, providing valuable prognostic information about patients that allowed their stratification into curative or palliative groups.

“PET was able to identify those patients who had potential for long-term, progression-free survival and even a potential cure,” Dr. Scott said. “Just as important, it identified those patients with aggressive disease, enabling them to avoid unnecessary treatment such as surgery.”

The center opened in 1992 and performed the first ever PET scan in Australia. The Ludwig Institute also is involved in a trial testing the safety of treating patients with advanced colorectal cancer, with humanized A33 antibody tagged with radioactive iodine (131I-huA33) in combination with capecitabine (Xeloda).

The phase I trial opened in 2003 and closed in February 2008 with 30 patients.