The purpose of this ongoing study is to determine whether thoracic
radiotherapy for
lung cancer produces an early increase in serum
copper (Cu) concentration, an increase which might predict clinical outcome.
Copper and
iron concentrations were measured in serum obtained from
nonsmall cell lung cancer patients at 0, 1, 2, 4, and 6 weeks after the start of
radiotherapy. Control groups included patients irradiated for
breast cancer (low dose of radiation to the lung), for endometrial, cervical or
prostatic cancer (no dose to lung), and patients with
congestive heart failure,
pulmonary hypertension,
chronic obstructive pulmonary disease (
COPD), and cutaneous
burns with or without
smoke inhalation (no irradiation). Serum Cu concentration increased at least 10 micrograms/dl from the pretreatment level in approximately 75% of the
adenocarcinoma and squamous cell
lung cancer patients, but in only 1 of 4 undifferentiated
lung cancer cases. In virtually all of these responders, serum Cu increased to a maximum at 2 weeks after the start of
therapy, then plateaued or decreased slightly despite continuing irradiation. Within the subset of squamous cell
lung cancers, there was a direct correlation between the degree of histologic differentiation and both baseline serum Cu concentration and the probability of an early increase therein. In contrast, only 33% of
breast cancer patients and 15% of endometrial, cervical and
prostate cancer patients exhibited an increase in serum Cu concentration at 2 weeks after the start of
radiotherapy. Serum Cu concentration was within normal limits in virtually all patients with
congestive heart failure,
pulmonary hypertension, and
COPD.
Burn patients exhibited a significant reduction in serum Cu, although concomitant
smoke inhalation increased serum Cu back to low-normal levels. Serum
iron concentration did not change significantly in any category of patients. These data suggest that thoracic
radiotherapy for well differentiated
non-small cell lung cancer is accompanied by an early increase in serum Cu concentration. This increase is partly but not wholly related to lung dose in particular rather than tissue dose in general, and specifically reflects radiation-induced
lung injury rather than pneumopathy in general. In
lung cancer patients, the change in serum Cu concentration during the first 2 weeks of
radiotherapy exhibits a sufficiently broad range (+60 to -13 micrograms/dl) to permit testing this parameter as a predictor of
tumor response and pulmonary complications.