fo i) Table 13 Residual! Beta Burns Subject No. & sex 2M Subject No. & sex Roughening and pigment variation on front of neck. Several pigmented macules ACF.* Periana! depigmentation. 39 F 3M Mottled pigmentation both axillae. Pigmented area behindleft ear. 49 F 11M “Pigment changesleftACF, dorsum first right toe; pigmented nevi axilla. 34M 17F Scarring and pigmentation left ACF. 39 F 20 M Pigmented patch back of neck. 23M Pigmented macules left axilla, front of neck and chest. Depigmented spots shaft penis. 24F Slight pigmentvariation on front of neck; several pigmented macules dorsum left foot. 25 M Scarring dorsum left foot. Biopsy at 2 years hyalinization of connective tissue and thickening of blood vessel walis of cutis. Died 1956. Slight roughening and pigmentation back of neck; pigment variations andslight hyperpigmentation dorsum right foot. Numerous pigmented maculesboth sides of neck and a few on arms and ACF. =Mottled pigmentation and depigmentation on front of neck. Died 1972. Mottled pigmentation and depigmentation on back of neck. Died 1968. 63 F Slight rugosity and pigmented ridges on back of neck. 64 F Moie back of neck; slight pigment variation and afew macules front of neck. Mole back of neck. 65 F Pigment variation and roughening front of neck. Not apparent now. 67 F Depigmented scars dorsum left foot. 26M Scarring and depigmentation of dorsum right foot. Died 1962. 75 F Slight pigmented area dorsum right first toe. 34 F Slight roughening and pigmentation backof neck. Moles on front of neck. 78 F Numerous pedunculated moles on sides and front of neck. 79M Pigmented and depigmented scar posterior surfaceleft ear. *ACF = antecubital fossa. mentation, but the scars have faded and repigmentation has tended to occur in most cases. No evidence has beenseen for the developmentof chronic radiation dermatitis or premalignant or malignant changesin any case, and most people now show little residual evidence of lesions. Hair of normal color and texture regrew by 6 to 12 monthsin all cases except for one man whostill has spotty epilation on the back of his head. Follow-up skin biopsies of residual lesions, studied at 6 months? and at 3 and 10 years®1! post ex- maybe as long as 48 years and may, on the average, be longer than for some othertypes of radia- tion-induced malignancy. Manyof the youngerexposed Marshallese still have a long life expectancy. There are several reasons, however, why skin cancer may not occur in the Marshallese. The low posure, histologically showed excellent healing, average energy of the beta rays resulted in much less damage to the dermis than to the epidermis. This would make the prognosis favorable if, as many investigators believe, the developmentof skin cancer requires sufficient damage to the dermis to impair nutrition of the epidermal cells. In the Marshallese the superficial nature of the skin burns, rapid healing, and absenceof chronic radiation dermatitis are factors against the developmentofskin cancer®°; nevertheless, persisting cellular changes are seen in their residual skin thus far been noted in the Marshallese, the de- sults from directirradiation of the epidermis with- but in most cases residual evidence of exposure wasnoted, such as epidermal atrophyandthickening of the corium with collagen bands,although little evidenceof significant vascular changes was seen in the corium (see Figure 19). Though no malignant changes in the skin have velopmentof skin cancer due to radiation exposure is still a distinct possibility, since its latent period lesions. If, as Teloh et al.3! believe, skin cancerre- out necessarily severe dermalinjury, its occurrence would be morelikely. The appearance of nevi in