PET shows power in both small and non-small cell lung cancer staging, survival

Jun 5, 2004

NEW ORLEANS - A pair of retrospective analysis studies at the American Society of Clinical Oncology on Saturday showed PET imaging to be useful in predicting survival in patients with non-small cell lung cancer (NSCLC), and helpful in staging patients diagnosed with small-cell lung cancer.

A group of researchers from Groningen University Hospital in Groningen, the Netherlands, evaluated the prognostic value of PET for the survival of patients with NSCLC. The team set out to analyze the modality's relevance in relation with known prognostic factors such as clinical stage and performance score.

For the period of 1996-2001, 268 NSCLC patients (206 males and 62 females) between 29 and 88 (mean age, 63) who had PET scans for staging were reviewed by the group. All the patients had been evaluated by laboratory tests, bronchoscopy, chest x-ray, and chest CT prior to their PET scan. A clinical stage tumor, node, metastasis (c-TNM) was determined on the basis of this information.

A PET-TNM classification was obtained by observers blinded to clinical data, according to Dr. Hendrikus Kramer, who presented the group's research. The two TNM classifications, clinical and PET, were compared and analyzed, as well as weight loss and Lansky and Eastern Cooperative Oncology Group (ECOG) performance scores.

The team found that both clinical and PET-TNM staging were identical in 150 (56%) of the patients. However, 68 patients were upstaged by PET and 48 were downstaged by use of the modality. The group also found that the c-TNM did not accurately overlap with the PET-TNM (p=0.024).

Median survival times in months were calculated for c-TNM and PET-TNM (stage 1 vs. stage 2, 3A, 3B, and 4), ECOG score, and weight loss. The researchers then performed a Cox regression analysis of the data, and said that the PET-TNM was the only significant predictor of poor survival, while c-TNM, performance score, and weight loss were not significant.

In another presentation, Dr. Michael Craig and a team of researchers from the Mary Babb Randolph Cancer Center at the University of West Virginia in Morgantown, WV, conducted a retrospective chart review of all patients from 1998-2003 at their facility who were diagnosed with small cell lung cancer.

Those patients who received a PET scan as part of the initial evaluation were reviewed and comparison was made against CT and MR imaging. Follow-up imaging and clinical outcome were used to evaluate any areas of disagreement between the modalities, according to the researchers.

They reviewed 116 patients with small cell lung cancer, of whom 44 had received a PET scan. The sensitivity of PET imaging was stated as 100%. The group noted that the agreement between PET imaging and CT and MR imaging for limited and extensive-stage disease was 80% (35/44).

Five patients were diagnosed with limited-stage disease instead of extensive disease on the basis of the PET results. Adrenal metastasis was suggested in the CT images of four patients, and opposite lung lesions in another, but the PET scan was not hypermetabolic, according to Craig and his group.

"All but one (who was lost to follow-up) was treated as limited-stage disease with concurrent radiation and chemotherapy. The four who remain have had survival and response suggestive of limited-stage disease (alive at six months, 18 months, 32 months, and three years)," they wrote.

Two patients were increased from limited to extensive stage by PET scan results, one survived nine months, and the other is five months into therapy, they noted.

The researchers observed that, as in NSCLC, changes in the adrenal glands seen on CT images might be difficult to interpret. Their results suggest that PET can clarify incidental findings on CT scans, and can help ensure that small cell lung cancer patients are accurately staged for appropriate treatment.

By Jonathan S. Batchelor
AuntMinnie.com staff writer
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