PET leads to treatment changes in majority of colorectal cancers

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

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

"Designed with an evidence-based approach, this study confirmed the important role PET plays in the decision-making process for patients with colorectal cancer and the impact of PET on both the management and outcome of disease," said Dr. Andrew M. Scott, director of the Center for PET and the Ludwig Institute for Cancer Research at Austin Hospital in Melbourne, Australia.

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," Scott said. "Just as important, it identified those patients with aggressive disease, enabling them to avoid unnecessary treatment such as surgery."

Imaging results from PET scans in the U.S. have also changed clinicians' decisions in the treatment and care of more than one in three cancer patients, according to data collected by the National Oncologic PET Registry.

The registry, which was formed at the request of the Centers for Medicare and Medicaid Services, has found that PET prompted changes in care decisions in 36.5% of patient cases. The study has to date included over 23,000 patients in more than 1200 PET facilities nationwide.

NOPR study data are collected through a clinical registry and provided to CMS to help determine levels of reimbursement for cancer indications not currently covered. CMS is currently reviewing the data to determine what additional types of cancer may be eligible for coverage.

"These data should encourage molecular imaging practitioners to engage with referring physicians early in the process of cancer treatment," Scott said. "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."

For more information from the Diagnostic Imaging archives:

Report from SNM: PET avoids unnecessary liver resection for metastatic colon cancer

Evidence mounts for PET and PET/CT as standard of care for GI cancers

Agent offers 3D view of colon cancer via dual-modality virtual colonoscopyy