Skeletal Metastases in Carcinoma

The skeleton is one of the two most important sites for the antemortem demonstration of cancer metastases. In cases of latent primary carcinoma manifested only by secondary deposits in the bones, the site of the primary lesion will be more readily ascertained if the diagnostic work-up is based on a sound appraisal of the incidence of skeletal metastases. The patient who is sent to the radiologist because of back pain, and who is discovered to have a destructive lesion in his vertebrae, presumably metastatic, presents to the clinician the problem of tracking down a hidden source. The latter will be directed in his search by his conception, or misconception, of the primary sites from which carcinomas commonly metastasize to bone. In particular, he is likely to exclude from consideration such sites as the stomach, colon, rectum, pancreas, uterus, bladder, and ovary, or at least to relegate them too far into the background of his thinking. There is a voluminous literature on the incidence of metastases in carcinoma. In the present study, an attempt has been made to relate incidence of skeletal metastases found at autopsy to the estimated prevalence in the population of carcinoma arising from different primary sites. Method and Results The metastases in 1,000 consecutive cases of malignant neoplasms of epithelial origin autopsied at the Montefiore Hospital between 1943 and 1947 were analyzed (1). In every instance, gross and microscopic studies of bone for metastases were undertaken. Sections of thoracic and lumbar vertebral bodies were obtained routinely, and where clinical information warranted it, further studies were made. The skeletal metastases were tabulated and the incidence for each primary site was determined. The results are presented in Table I. Primary sites are listed in descending order of frequency (percentage) of metastases. Of 1,000 carcinomas, 272 were found to have metastasized to bone. There were 10 primary sites with bone metastases in more than 10 per cent of the cases. Frequency Of Skeletal Metastasis at Autopsy: Comparison with the Literature In Table II, the incidence of skeletal metastases at autopsy in cases collected from the literature has been summarized. In general, our figures were higher than those in other series. This was particularly true in carcinoma arising from the gastro-intestinal tract. It has been assumed that gastro-intestinal carcinoma metastasizes to bone only in rare instances. Coley classifies gastric and colonic carcinoma as “ossophobe” (7), and Ewing does not even mention figures on the incidence of skeletal metastases from this source (14). Among 373 gastrointestinal carcinomas in our series, however, 41 (11 per cent) had metastasized to the skeleton. Although most figures are appreciably lower than ours in this respect, some reports have shown a comparable incidence of metastases (2, 4, 45).