Delayed hypersensitivity in patients treated by curative radiotherapy. Its relation to tumor response and short-term survival.

Delayed hypersensitivity, as determined by skin reactivity to 2-4 dinitrochlorobenzene (DNCB), was tested in 112 patients prior to their undergoing curative radiotherapy. Of the strong DNCB reactors, 84% had an excellent radiation tumor response, while only 48% of the negative reactors had an equivalent response. Almost twice as many strong DNCB reactors were alive and free of disease (NED) at 6 months (70% vs. 38% for nonreactors). Similarly, the positive DNCB reactors had a median survival of 18 months, compared to 10 months for the nonreactors.