Two cases of tumor recurrence within a previously irradiated skin area are reported. Typical lesions evolve from an erythematous base and progress to induration and tumor papules. A review of clinical literature indicates that irradiation does not increase the frequency of metastases. Experimental data suggest that irradiation does increase metastases as a result of both local mechanical factors and increased tumor-cell survival.
Cuncer 53:1864-1868, 1984.
ECURRENT BREAST CANCER confined to a previously R irradiated area is a rarely reported occurrence. A total of 16 cases are partially reported,'-' but only 10 are detailed in the literat~re.',~.~.~.' Experimental data in animals has indicated that irradiation of normal tissues increases the rate of metastases in some irradiated tissue^.^-'^ Current evidence suggests that this is a local effect of irradiation and that the mechanism may be the local changes which enhance survival of tumor cells within the vasculature of the irradiated area.I5-I9
Case Reports
We report two cases of this phenomenon in order to emphasize the clinical course which is quite characteristic. Included is a review of the clinical literature and discussion of experiments examining the phenomenon of radiation enhancement of metastasis.