Staging lung cancer: total-body PET/CT or whole-body PET/CT?

Total Body PET/CT is increasingly used in clinical practice, but its benefits for lung cancer staging are not fully established. This study aimed to evaluate the impact of Total Body PET/CT on lung cancer staging compared to traditional Whole-Body PET/CT.

Among the 763 patients, 289 (37.9%) had stage IV disease, with 96 (33.2%) showing limb metastases, including those in the lower limbs (legs) or also the upper limbs (arms). Compared to Whole-Body PET/CT, Total Body PET/CT detected additional metastases in 60.4% (58/96) of patients with limb metastases, representing 20.1% (58/289) of all stage IV patients. These included 96 bone and 43 muscle metastases. In patients with isolated limb metastases (n = 31), Total Body PET/CT detected additional metastases in 13 (41.9%) compared to Whole-Body PET/CT, altering tumor staging in only one patient (0.3% of stage IV patients). In those with multiple limb metastases (n = 65), Total Body PET/CT detected additional metastases in 45 (69.2%), but staging remained unchanged. Distal limb metastasis was strongly associated with concurrent bone (OR = 8.288, 95%CI: 3.642-18.861) and muscle metastases outside the limb (OR = 3.911, 95%CI: 1.624-9.417) (both P < 0.001). Additionally, Total Body PET/CT detected acute arthritis in 193 (25.3%) patients and benign lesions (e.g., varicose veins, neurogenic tumors, lipomas, fractures) in 68 (8.9%) compared to Whole-Body PET/CT.

Whole-Body imaging is sufficient to meet the clinical staging requirements for lung cancer. Although Total Body PET/CT detects more distal metastases in approximately 20% of stage IV lung cancer patients, it led to stage shift in only one patient and 0% change in the oncologic treatment.