Chemotherapy of skeletal metastases

Abstract

INTRODUCTION Metastatic cancer to bone is the most common bone cancer,23 unlike primary bone tumors, occurs at multiple sites 90% of the time.13 The axial skeleton is most often affected; the extremities rarely. Neoplasms of the breast, lung, prostate, kidney and thyroid account for nearly 80% of bone metastases. Skeletal metastases from the colon, pancreas and stomach are uncommon, occurring in less than 10% of patients with these tumors.‘.‘333 Radiographic appearance of the bone metastases aids in the identification of the primary source. Osteoblastic lesions in males most frequently will be of prostatic origin, rarely from pancreas, colon, lung, carcinoid tumor, Hodgkin’s disease, or myeloma. _41though the majority of skeletal breast lesions are lytic, the most common source of blastic bony metastases in women is breast cancer. Lytic bone lesions generally are without characteristic identifying features which would help in the identification of the primary cancer, with the exception of kidney, which often presents as a solitary radiolucent expansile bone lesion. Radiotherapy is the treatment of choice for skeletal metastases which are painful and few in number or located in strategic areas of skeletal support. However, many bone lesions, can be expected to respond favorably to chemotherapy. The effectiveness of chemotherapy on various skeletal metastases is reviewed. THYROID Thyroid carcinomas characteristically have many long term survivors following surgical therapy, 80-90% live 10 years or greater. The small number that succumb to ‘their disease often have bone or pulmonary metastases or both.1%1834 Papillary carcinoma occurs in approximately 66% of patients and tends to metastasize to local lymph nodes. Follicular carcinoma occurs in 20% of patients with a predilection for vessel invasion and subsequent bone and lung metastases. Treatment other than surgery has resided consistently with oral 13’1 administration. The dose is generally lOO-300mCi given repeatedly over 2 years for a total dose of 500 mCi.” I31 I has been documented to accumulate in bone metastases and to have a favorable effect on survival. In one study, all of 10 patients lived 5 years, with 3 patients living 6, 15 and 25 years after ‘9 therapy.” There is even documentation of roentgenograms returning to normal in 5 of 30 patients, with total regression of pain in all patients.” Other chemotherapeutic agents used in metastatic thyroid cancer without success are 5-fluorouracil, methotrexate, actinomycin D, cyclophosphamide, phenylaline mustard, and others.” The use of bleomycin has had conflicting reports.‘6 Adriamycin (75 mglm’ q3 week) achieved 4 partial remissions in 12 patients with bone involvement, it was documented as 50% radiographic regression for 1 month. One patient had relief of pain.‘O 13’1 appears to be the agent of choice when metastases are small and capable of concentrating 1311. Thus far, adriamycin is the only chemotherapeutic agent shown to be effective in advanced bone metastases.