Age factor relevant to the development of radiation pneumonitis in radiotherapy of lung cancer.

The significance of age factor for the development of radiation pneumonitis is evaluated in 62 patients with lung cancer between 1977 and 1985. The younger group consists of those less than 70 years old and the elderly group of those 70 years old or more. Radiation doses ranged from 1.5 to 2 Gy, 3 to 5 times per week, therefore the delivered doses were converted to nominal single doses (rets dose). Severe radiation pneumonitis was more often observed in the elderly than in the younger regardless of radiation field size and chemotherapy (n.s.). The onset of radiation pneumonitis occurred earlier in a field size of 90 sq cm or more than in that of less than 90 sq cm in both age groups; there was no significant difference between the two age groups in each field size. The pneumonitis was more frequently noted with increasing rets dose in both age groups (n.s.) regardless of field size and chemotherapy. It is concluded that there is no significant difference in the development of radiation pneumonitis between the younger group and the elderly group, but the pneumonitis is inclined to be more severe in the latter.