Imaging studies and the prognostic value of serum calcitonin in staging small-cell lung cancer.

The controversial prognostic significance of serum calcitonin in small-cell lung cancer (SCC) prompted this retrospective study relating serum levels to (1) stage of disease [limited disease (LD) vs. extensive disease (ED)], (2) imaging studies of metastases to bone, liver, and brain, and (3) survival. Of the 127 previously untreated patients with SCC presenting from 1979 to 1984, calcitonin levels could be compared to the stage of the disease in 69 patients (25 LD and 44 ED) and to various staging procedures including 99mTc methylene diphosphonate bone scans (63 patients), 99mTc sulfur colloid liver-spleen scans (64 patients), computed tomography of the head (63 patients) and serum calcium (61 patients). 71% (49/69) of patients had elevated calcitonin of whom 65% (32/49) had ED. 29% (20/69) had normal levels of whom 60% (12/20) had ED. 40% (18/45) of patients with raised calcitonin had liver metastases. 100% (19/19) with normal calcitonin had no liver involvement. Two patients with hypercalcemia and increased calcitonin had extensive bony metastases. The survival experiences of patients with normal and elevated serum calcitonin levels were analyzed. No significant differences were found within each stage or in the group overall. The positive correlation of serum calcitonin to liver metastases was statistically significant. No such relationship could be demonstrated with stage of disease, bone metastases, brain metastases, or survival.