Therapeutic Ionizing Radiation and the Incidence of Basal Cell Carcinoma and Squamous Cell Carcinoma

STUDY Therapeutic Ionizing Radiation and the Incidence of Basal Cell Carcinoma and Squamous Cell Carcinoma

Michael D. Lichter, MD; Margaret R. Karagas, PhD; Leila A. Mott, MS; Steven K. Spencer, MD; The´re`se A. Stukel, PhD; E. Robert Greenberg, MD; for the New Hampshire Skin Cancer Study Group

Objective: To estimate the relative risk of developing basal tempt was made to review the radiation treatment re- cell carcinoma (BCC) and squamous cell carcinoma (SCC) cords of subjects who reported a history of radio- after receiving therapeutic ionizing radiation. therapy. Overall, an increased risk of both BCC and SCC was found in relation to therapeutic ionizing radiation. Design: Population-based case-control study. Elevated risks were confined to the site of radiation exposure (BCC odds ratio, 3.30; 95% confidence interval, Setting: New Hampshire. 1.60-6.81; SCC odds ratio, 2.94; 95% confidence interval, 1.30-6.67) and were most pronounced for those ir- Patients: A total of 592 cases of BCC and 289 cases of radiated for acne exposure. For SCC, an association with SCC identified through a statewide surveillance system radiotherapy was observed only among those whose skin and 536 age- and sex-matched controls selected from was likely to sunburn with sun exposure. population lists. Conclusions: These results largely agree with those of Main Outcome Measures: Histologically confirmed previous studies on the risk of BCC in relation to ion- BCC and invasive SCC diagnosed between July 1, 1993, izing radiation exposure. In addition, they suggest that through June 30, 1995, among New Hampshire resi- the risk of SCC may be increased by radiotherapy, dents. especially in individuals prone to sunburn with sun exposure. Results: Information regarding radiotherapy and other factors was obtained through personal interviews. An at- Arch Dermatol. 2000;136:1007-1011

REATMENT WITH prolonged to previous therapeutic ionizing radia- administration of low- tion. We examined risks according to age dose ionizing radiation is at first exposure, time since exposure, con- associated with subse- dition for which irradiation was adminis- quent nonmelanoma skin tered, and site of exposure. We further as- From Nashua Dermatology cancer (NMSC), particularly basal cell car- sessed the frequency and number of T 1 Associates, Nashua, NH cinoma (BCC). Implicated treatments in- treatments, and, for those who were irra- (Dr Lichter), and the Section of clude radiotherapy of inflammatory der- diated for cancer, the amount of expo- Biostatistics and Epidemiology, matoses such as eczema, psoriasis, acne sure by dose per week and by dose per Department of Community and vulgaris, and tinea capitis.2,3 Addition- treatment course. Family Medicine, and the Norris Cotton Cancer Center ally, an increased risk of BCC has been re- (Drs Karagas, Stukel, and lated to ionizing radiation treatment of goi- RESULTS 4 5-8 Greenberg, and Ms Mott), ters, ankylosing spondylitis, acute Section of Dermatology lymphocytic leukemia, and astrocy- By design, cases and controls were compa- (Dr Spencer), Department of toma.9 Whether radiotherapy enhances rable for age and sex. The overall mean age Medicine, Dartmouth Medical risk of squamous cell carcinoma (SCC) is of cases with BCC and SCC was 58.5 years School, Lebanon, NH. The less clear. A population-based study among and 64.7 years, respectively, and 60.5 years authors have no commercial, men in Alberta, Canada, reported a 5- to for controls. About 40% of the subjects were proprietary, or financial 6-fold increase in incidence of BCC and women and 98% were white. Seven per- interests in the products or SCC associated with nondiagnostic x-ray cent of the controls and 12% of the cases companies described in this 10 article. A complete list of the exposure. Using data collected as part of reported previous ionizing radiation therapy members of the New Hampshire a large case-control study in New Hamp- for reasons other than skin cancer. Skin Cancer Study Group shire, we also had the opportunity to evalu- For BCC, we found a significantly in- appears on page 1010. ate the risk of BCC and SCC in relation creased risk associated with radiotherapy

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©2000 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/24/2021 SUBJECTS AND METHODS history of radiotherapy for skin cancer. Patients treated with ionizing radiation for skin cancer are more likely to be in the case group than in the control group. Therefore, the The case-control study group consisted of patients with BCC inclusion of these cases could bias analyses toward an as- and SCC, aged 25 to 74 years at diagnosis, who were iden- sociation with radiotherapy. We adjusted for age (as a con- tified through a population-based incidence survey of skin tinuous variable) and sex in all models. In addition, we ex- cancer conducted in New Hampshire covering diagnoses amined the potentially confounding effects of outdoor from July 1, 1993, through June 30, 1995.11 Age- and sex- exposure (hours per week spent outdoors in the summer— matched controls were selected from state drivers’ license recreationally and occupationally); cigarette smoking his- lists for those younger than 65 years and from Medicare tory (never, former, current); level of education (less than enrollment lists for those 65 years or older. college, college, graduate or professional school); and sun- An in-person interview that took 90 minutes to 2 hours sensitive skin type defined according to skin reaction to to complete was usually conducted in the subject’s home. strong sunlight for the first time in summer for 1 hour (se- Interviewers were masked to the study hypotheses and were vere sunburn with blistering, painful sunburn, mild sun- not told the case-control status of the participant. Inter- burn and some tanning, and tanning with no sunburn). We viewers asked about sun exposure history, outdoor recre- also explored the possibility that the effects of ionizing ra- ation, skin reaction to sunlight, personal use of tobacco and diation exposure may be modified by skin type. alcohol, educational background, and medical history. To We grouped anatomical location of both skin cancer document previous exposure to therapeutic ionizing ra- and radiation field to the head and neck, trunk, or limbs. diation, we asked subjects if they were ever treated with For controls, we randomly assigned a site based on the ana- x-rays along with the condition and anatomical location tomical distribution of the overall case group. Data were treated, age at and duration of treatment, and the fre- too sparse to study specific anatomical sites of involve- quency of treatments. We requested permission to obtain ment. Therefore, we computed separate ORs for skin can- the medical records of those who reported a history of ra- cers in the radiation field and at unirradiated sites. In this diotherapy. Medical records review was done without analysis, we excluded individuals whose tumor or irradia- knowledge of the subject’s case-control status or other data tion occurred at more than 1 anatomical location. collected at the interview. Lastly, we attempted to analyze the dose per week and We estimated the odds ratio (OR) and 95% confi- the dose per treatment course among those who reported dence intervals (CIs) of BCC and SCC associated with ra- treatment for cancer and for whom irradiation records were diotherapy using unconditional logistic regression.12 We available. Treatment for nonmalignant conditions gener- restricted our analysis to the 592 cases of BCC, 289 cases ally had occurred before 1970; thus, the medical records of SCC, and 536 control subjects who did not have a were no longer available.

(age and sex-adjusted OR, 1.88; 95% CI, 1.24-2.87) and The difference between the ORs for the exposed and un- for SCC a borderline significant increased risk (age- and exposed sites was statistically significant for BCC (P=.01) sex-adjusted OR, 1.56; 95% CI, 0.95, 2.55) (Table 1). and borderline significant for SCC (P=.07). When we ex- Adjustment for other potentially confounding factors had amined whether the risks associated with radiotherapy no appreciable effect on the risk estimates. were modified by skin type, we found that for BCC, the The magnitude of the ORs differed according to the ORs for radiation treatment were comparable among those reported reason for treatment. Radiotherapy for acne was who tend to burn and those who tend to tan with first associated with a pronounced and statistically signifi- exposure to sunlight in the summer (among burners, cant increased risk for BCC and SCC (Table 1). A 2-fold OR,1.87; 95% CI, 0.86-4.03 and among tanners, OR, 1.96; increase in BCC risk was found in relation to radio- 95% CI, 1.18-3.26) (P value for interaction, .97). Whereas therapy for cancer, but no increased risk of SCC was found for SCC, risk was increased only among those with a ten- (Table 1). No relation was observed among those who dency to burn (OR, 3.02; 95% CI, 1.37-6.68) and was not had radiotherapy for other benign skin conditions. elevated among those who tend to tan (OR, 0.73; 95% Odds ratios for BCC and SCC according to time since CI, 0.35-1.52) (P value for interaction, .01). the initial exposure and age first treated with radiation Medical records were reviewed for 44 (79%) of the are given in Table 1. Persons whose first radiation treat- 56 subjects who reported receiving therapeutic ionizing ment occurred before they were 20 years old had a greater radiation for cancer. Of the 39 patients receiving radia- risk of BCC and SCC than those treated at older ages. tion beam therapy alone, the type of devices used were An association with BCC and SCC was largely confined cobalt 60 (n=5), linear accelerator with photons (n=27), to radiotherapy 40 years or longer prior to diagnosis. How- linear accelerator with electrons (n=2), and linear ac- ever, risk of BCC was modestly elevated among those who celerator with photons and electrons (n=5). Two pa- were treated in the past 20 years or who were 40 years tients had radiation implants; 3 persons were missing de- or older when first treated. The ORs for BCC and SCC vice information. Restricting to patients with a single seemed to increase with the frequency of treatments and course of beam therapy, the ORs for BCC were elevated the reported number of treatments, but the trends were for exposures less than or equal to 10 Gy/wk (OR, 3.09; not statistically significant. 95% CI, 1.10-8.70), and when the dose per treatment was Risk of BCC and SCC was related specifically to tu- less than or equal to 2 Gy (OR, 3.53; 95% CI, 1.28-9.79). mors arising at the site of prior radiotherapy (Table 2). We were unable to compute ORs for higher doses of treat-

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©2000 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/24/2021 Table 1. Odds Ratio (ORs) and 95% Confidence Intervals (CIs) for Risk of Basal Cell Carcinoma (BCC) or Squamous Cell Carcinoma (SCC)*

Cases of BCC Cases of SCC Controls, Variable No. (%) OR† (95% CI) No. (%) OR† (95% CI) No. (%) Received radiation therapy No 523 (88.3) 1.00 (. . .) 254 (87.9) 1.00 (. . .) 498 (92.9) Yes 69 (11.7) 1.88 (1.24-2.87) 35 (12.1) 1.56 (0.95-2.55) 38 (7.1) Condition treated with radiation‡ No irradiation 523 (88.5) 1.00 (. . .) 254 (87.9) 1.00 (. . .) 498 (93.1) Acne 18 (3.1) 17.35 (2.30-130.8) 5 (1.7) 9.97 (1.15-86.40) 1 (0.2) Benign skin condition§ 12 (2.0) 1.85 (0.72-4.76) 7 (2.4) 1.76 (0.61-5.15) 7 (1.3) Cancer࿣ 28 (4.7) 2.01 (1.05-3.83) 13 (4.5) 1.31 (0.61-2.82) 15 (2.8) Other¶ 10 (1.7) 0.72 (0.32-1.65) 10 (3.5) 1.24 (0.54-2.89) 14 (2.6) No. of years since first radiation treatment No irradiation 523 (88.3) 1.00 (. . .) 254 (87.9) 1.00 (. . .) 498 (92.9) Ͻ20 y 29 (4.9) 2.12 (1.11, 4.02) 12 (4.2) 1.20 (0.55, 2.62) 15 (2.8) 20-39 15 (2.5) 1.09 (0.51, 2.31) 8 (2.8) 1.08 (0.43, 2.68) 13 (2.4) Ͼ39 25 (4.2) 2.64 (1.25, 5.59) 15 (5.2) 2.80 (1.23, 6.37) 10 (1.9) P for trend = 0.61 P for trend = 0.28 Age first treated with radiation, y No irradiation 523 (88.3) 1.00 (. . .) 254 (87.9) 1.00 (. . .) 498 (92.9) Ͻ20 29 (4.9) 3.37 (1.52, 7.46) 10 (3.5) 2.78 (1.07, 7.26) 8 (1.5) 20-39 12 (2.0) 1.05 (0.46, 2.36) 9 (3.1) 1.35 (0.55, 3.28) 12 (2.2) Ͼ39 28 (4.7) 1.74 (0.94, 3.21) 16 (5.5) 1.26 (0.62, 2.53) 18 (3.4) P for trend = 0.37 P for trend = 0.14 Frequency of treatments, No./wk# No irradiation 523 (89.4) 1.00 (. . .) 254 (89.1) 1.00 (. . .) 498 (93.6) Ͻ1 16 (2.7) 1.78 (0.78-4.10) 7 (2.5) 1.45 (0.52-3.99) 9 (1.7) 1 or 2 16 (2.7) 1.21 (0.58-2.52) 11 (3.9) 1.22 (0.54-2.76) 14 (2.6) Ն3 30 (5.1) 2.90 (1.43-5.89) 13 (4.6) 1.88 (0.82-4.30) 11 (2.1) P for trend . . . .19 . . . .56 . . . Total No. of treatments received** 0 523 (88.8) 1.00 (. . .) 254 (88.2) 1.00 (. . .) 498 (93.4) Ͻ5 17 (2.9) 1.24 (0.60-2.56) 10 (3.5) 1.27 (0.55-2.93) 14 (2.6) 5-24 22 (3.7) 2.01 (0.96-4.21) 9 (3.1) 1.35 (0.54-3.33) 11 (2.1) Ն25 27 (4.6) 2.97 (1.41-6.24) 15 (5.2) 2.42 (1.06-5.52) 10 (1.9) P for trend .17 .30

*Ellipses indicates not applicable or reference category. †Adjusted for age (continuous) and sex. ‡Two persons who were irradiated for more than 1 condition are excluded (1 with BCC, and 1 control). §Benign skin conditions include the following: tinea or ringworm or skin fungus, birthmark, rash, warts, eczema or dry skin, noncancerous skin lesion, and keloid. ࿣Cancers include the following: prostate, breast, uterine, respiratory tract, colon, bladder, ovarian, pancreatic, and testicular, lymphoma, leukemia, melanoma, bone, and female reproductive system not otherwise specified. ¶Other conditions include the following: enlarged tonsils, enlarged thyroid gland, enlarged thymus, infection or allergy, noncancerous growth or tumor, bursitis, incision, or difficulty conceiving. #Nine persons with more than 1 course of treatment are excluded (4 with BCC, 3 with SCC, and 2 controls). Six persons were excluded who had missing data for frequency of treatments (3 with BCC, 1 with SCC, and 2 controls). **Seven persons with missing information for the total number of treatments are excluded (3 with BCC, 1 with SCC, and 3 controls).

ment because only a few individuals had them. There were Although risk of BCC has been consistently related too few cases of SCC for which we obtained radio- to radiation exposure in prior studies, results regarding therapy records to examine risk by dose of treatment for SCC are less clear. Studies of atomic bomb survivors in this cell type. Japan have found a relation for BCC, but not SCC.13,14 Prior cohort studies of individuals previously treated with COMMENT ionizing radiation for tinea capitis found 5- and 6-fold increases in the relative risk for head and neck BCC, but Our data indicate that previous therapeutic ionizing ra- no increase in SCC.13 The lack of increased risk for SCC diation leads to an increased risk of BCC and SCC. For possibly could be because of the younger age of those stud- both histological types, risks were confined to the re- ied especially in the follow-up studies of childhood ex- gion of the body to which radiotherapy was delivered. posures. A Canadian case-control study of men identi- Risk also was highest among those who had radio- fied through the Alberta Cancer Registry reported ORs therapy for treatment of acne. For SCC, risk was princi- of 5.7 and 4.8 for BCC and SCC, respectively, following pally elevated among those with a sun-sensitive pheno- nondiagnostic radiation exposure.10 In a recent cohort type. study of patients with NMSC, a relative risk of 1.7 was

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©2000 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/24/2021 Table 2. Basal Cell Carcinoma (BCC) and Squamous Call Carcinoma (SCC) Risk According to Site of Radiation Treatment*

Cases of BCC Cases of SCC Controls, Radiation Site No. (%) OR† (95% CI) No. (%) OR† (95% CI) No. (%) Received no irradiation 499 (88.8) 1.00 (. . .) 251 (87.8) 1.00 (. . .) 498 (92.9) Received no irradiation to site of tumor‡ 31 (5.5) 1.23 (0.72-2.10) 19 (6.6) 1.13 (0.61-2.07) 28 (5.2) Received irradiation to site of tumor‡ 32 (5.7) 3.30 (1.60-6.81) 16 (5.6) 2.94 (1.30-6.67) 10 (1.9)

*Restricted to patients with 1 site of tumor and 1 site of radiation. OR indicates odds ratio; CI, confidence interval; ellipses, reference category. †Adjusted for age and sex. ‡Tumor site for control subjects is a randomly assigned site based on the anatomical distribution of the combined cases of BCC and SCC.

2,14,16 The New Hampshire Skin Cancer Study Group presumed to be at least 20 years. However, it is dif- ficult to separate the effects of latency from those of age at treatment and type of therapy received. In our data, risks Duane R. Anderson, MD; Robert W. Averill, MD; An- of BCC and SCC were highest among those treated 40 years thony J. Aversa, MD; Bruce A. Bairstow, MD; Richard D. or longer before diagnosis. Basal cell carcinoma risk also Baughman, MD; Lawrence G. Blasik, MD; Carolyn Car- roll, MD; William E. Clendenning, MD; Daniel W. Col- was increased within 20 years of treatment; this finding lison, MD; George L. Crespo, MD; Stephen M. Del Guid- may be explained in part by the association we observed ice, MD; Robert L. Dimond, MD; Wilmot S. Draper, MD; between radiotherapy for cancer, a more recent expo- Jeremy P. Finkle, MD; William E. Frank, MD; John L. sure. To fully tease out the effects of latency from other Fromer, MD; Norman C. Goldberg, MD; David Gold- effects would require an even larger study than ours. minz, MD; Robert Gordon, MD; David S. Greenstein, MD; In epidemiological studies, cancer risks associated Thomas P. Habif, MD; Charles Hammer, MD; Tom Ho- with radiotherapy are specific to the sites or organs in kanson, PA; Steve A. Joselow, MD; Michael D. Lichter, the radiation field. Indeed, most skin cancer studies MD; Maritza O. Liranzo, MD; Michael A. Mittleman, MD; were restricted to the site of exposure (eg, head and Jose Peraza, MD; Robert B. Posnick, MD; Warren M. Prin- neck skin cancers for tinea capitis treatment). Thus, our gle, MD; Mark Quitadamo, MD; Pauline B. Reohr, MD; N. Chester Reynolds, MD; Peter Sands, MD; Mitchell E. data confirm that the risk of BCC and SCC is confined Schwartz, MD; Steven K. Spencer, MD; James C. Starke, to the region of the body to which the therapeutic ion- MD; Susan Sullivan, MD; N. Hakan Thyresson, MD; izing radiation was delivered. Andrew P. Truhan, MD; Mauray J. Tye, MD; K. William Potential limitations of our study are that our re- Waterson, MD; Kathryn Zug, MD. sults are based mainly on self-report of prior therapy and that New Hampshire state driver’s licenses were used to obtain age- and sex-matched controls. Regarding the first limitation, we did not find evidence of differential mis- found for new BCC occurrences, and a relative risk of classification based on our medical record review. In the only 1.0 for new SCC occurrences15; a limitation of this subset of subjects for whom we obtained medical rec- study is that all subjects had at least 1 prior NMSC. ords, the agreement with self-report was virtually 100% In our current case-control study, an association be- for previous history of radiotherapy (data not shown). tween radiotherapy and risk of SCC was found specifi- For the second limitation, all except 5 study partici- cally among those with a sun-sensitive phenotype. To our pants younger than 65 years had valid driver’s licenses. knowledge, this finding has not been observed previ- Therefore, exclusion of these individuals did not affect ously, and in part, may explain the absence of an asso- our results (data not shown). ciation with SCC among atomic bomb survivors in Ja- We were able to obtain total radiation doses from the pan. In a cohort study of children irradiated for tinea medical records of a high percentage of study partici- capitis,14 the relation with NMSC was lower among Is- pants who received linear accelerator photon radio- raelis of Asian or African descent than other Israelis. Fur- therapy for cancer. All but 2 of these patients had total ra- ther studies may help to clarify the possibility of indi- diation doses higher than 30 Gy, which is consistent with vidual susceptibility to radiation-induced NMSC. previous estimates for the total radiation dose necessary Younger age at first ionizing radiation exposure has to induce NMSC. In these patients, the risks of BCC and been associated with greater risk of subsequent NMSC. Japa- SCC were increased specifically among those treated with nese atomic bomb survivors from Hiroshima or Nagasaki 10 Gy/wk or less and less than or equal to 2 Gy per treat- who were aged 40 years or older at detonation had no ap- ment. Study participants previously irradiated for acne had parent increased risk of NMSC.15 Among children irradi- especially high ORs for BCC and SCC, and these individu- ated for tinea capitis, there was an inverse relation with age als probably received highly fractionated doses over longer at treatment, although the oldest treated age group was 10 periods.17 More highly fractionated doses of ionizing ra- to 14 years old.13 In our data, earlier age at first treatment diation, involving moderate doses for each individual frac- also was more strongly related to BCC and SCC risk. tion, is also more carcinogenic in animal models.1 The latency period between first exposure to thera- Data from this population-based case-control study peutic ionizing radiation and the appearance of NMSC is indicate that persons previously exposed to therapeutic ion-

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©2000 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/24/2021 izing radiation have an increased risk for BCC and SCC. 4. Hildreth N, Shore R, Hempelmann L, Rosenstein M. Risk of extrathyroid tumors Our data also suggest that SCC risk following irradiation following radiation treatment in infancy for thymic enlargement. Radiat Res. 1985; 102:378-391. may be highest in persons with a sun-sensitive phenotype. 5. Wollenburg A, Peter R, Pryzybilla B. Multiple superficial basal cell carcinomas (basalomatosis) following cobalt irradiation. Br J Dermatol. 1995;133:644- Accepted for publication March 2, 2000. 646. This study was supported in part by grants CA58290, 6. Good AE, Diaz LA, Bowerman RA. Basal cell carcinomas following roentgen therapy CA57494, and CA23108 from the National Cancer Insti- of ankylosing spondylitis. Arthritis Rheum. 1980;23:1065-1066. tute, National Institutes of Health, Bethesda, Md, and grant 7. Rampling RP, Lambert HE. Multiple basal cell carcinomas in two cases of ankylosing spondylitis treated with x-ray therapy. Br J Radiol. 1985;58:178-181. ACS SIG-17 from the American Cancer Society, Atlanta, Ga. 8. Sarkany I, Fountain R, Evans C, et al. Multiple basal cell epitheliomata following We are grateful to the pathology laboratories and phy- radiotherapy of the spine. Br J Dermatol. 1968;80:90-96. sicians who took part in the study. We also thank Mark 9. Dinehart SM, Anthony JL, Pollack SV. Basal cell carcinoma in young patients after Brauning, MD, for his assistance reviewing the medical rec- irradiation for childhood malignancy. Med Pediatr Oncol. 1991;19:508-510. 10. Gallagher RP, Bajdik CD, Fincham S, et al. Chemical exposures, medical history, ords, Virginia Stannard, MEd, for coordination of the study, and risk of squamous and basal cell carcinoma of the skin. Cancer Epidemiol and Jennifer Miglionico, MS, for assistance in obtaining the Biomarkers Prev. 1996;5:419-424. medical records. 11. Karagas MR, Greenberg ER, Spencer SK, Stukel TA, Mott LA. Increase in inci- Corresponding author: Margaret R. Karagas, PhD, dence rates of basal cell and squamous cell skin cancer in New Hampshire, USA. Dartmouth Medical School, Section of Biostatistics and Int J Cancer. 1999;81:555-559. 12. Breslow N, Day N. The Analysis of Case-Control Studies. Lyon, France: Interna- Epidemiology, 7927 Rubin 462M-3, One Medical Center tional Agency for Research on Cancer; 1980. Statistical Methods in Cancer Re- Drive, Lebanon, NH 03756-0001 (e-mail: margaret.karagas search; vol 1. @dartmouth.edu). 13. Thompson DE, Mabuchi K, Ron E, et al. Cancer incidence in atomic bomb survivors, part II: solid tumors, 1958-1987 [published erratum appears in Radiat Res. 1994;139:129]. Radiat Res. 1994;137(suppl 2):S17-S67. REFERENCES 14. Ron E, Preston DL, Kishikawa M, et al. Skin tumor risk among atomic-bomb survivors in Japan. Cancer Causes Control. 1998;9:393-401. 15. 1. Goldschmidt H, Breneman JC, Breneman DL. Ionizing radiation therapy in der- Karagas MR, McDonald JA, Greenberg ER, et al, for the Skin Cancer Prevention matology. J Am Acad Dermatol. 1994;30:157-182; 183-186. Study Group. Risk of basal cell and squamous cell skin cancers after ionizing 2. Albert R, Shore R. Carcinogenic effects of radiation on the human skin. In: Up- radiation therapy. J Natl Cancer Inst. 1996;88:1848-1853. ton A, Albert R, Burns F, Shore R, eds. Radiation Carcinogenesis. New York, NY: 16. Shore R, Albert R, Reed M. Skin cancer incidence among children irradiated for Elsevier Science Inc; 1986:335-345. ringworm of the scalp. Radiat Res. 1984;100:192-204. 3. Ron E, Modan B, Preston D, Alfandary E, Stovall M, Boice JD Jr. Radiation- 17. Goldschmidt H. x-Ray therapy. In: Arnold H, Odom R, James W, eds. Diseases induced skin carcinomas of the head and neck. Radiat Res. 1991;125:318-325. of the Skin. 8th ed. Philadelphia, Pa: WB Saunders Co; 1990:1016-1027.

News and Notes

oard Examination Review, September 6-9, 2000. The Harvard Medical School Dermatopathology Residency Training Program will present a 31⁄2-day postgraduate B course in dermatopathology with a 1-day symposium on cutaneous infections under the direction of Lyn M. Dun- can, MD, to be held at the Fairmont Copley Plaza Hotel, Boston, Mass. Faculty will include Christopher D. M. Fletcher, MD, Thomas J. Flotte, MD, Marshall Kadin, MD, Eugene L. Mark, MD, Phillip H. McKee, MD, Martin C. Mihm Jr, MD, and Samuel L. Moschella, MD. Participants will review practical dermatopathology with attention to board certification and will learn to assess prob- lems that arise in dermatopathology practice. The course is aimed at practicing pathologists and dermatologists as well as residents and fellows preparing for board certification examinations. On Friday a symposium on cutaneous infections will be presented. On Saturday morning there will be a board examination review session. A detailed syllabus consisting of lecture outline material and references will be provided. The course has Category 1 accreditation for 26 hours of CME credit by the American Medical Association. The fee for the course is $650.00 (residents and fellows $350.00). For further information contact the Department of Continuing Edu- cation, Harvard Medical School, 25 Shattuck St, Boston, MA 02115 (Telephone: 617-432-1525; Fax: 617-432-1562).

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