B Lindelöf

A substantial excess risk of lymphomas and nonmelanoma skin cancer has been demonstrated following organ transplantation. Large sample size and long follow-up time may, however, allow more accurate risk estimates and detailed understanding of long-term cancer risk. The objective of the study was to assess the risk of cancer following organ transplantation. A nationwide cohort study comprising 5931 patients who underwent transplantation of kidney, liver or other organs during 1970-1997 in Sweden was conducted. Complete follow-up was accomplished through linkage to nationwide databases. We used comparisons with the entire Swedish population to calculate standardised incidence ratios (SIRs), and Poisson regression for multivariate internal analyses of relative risks (RRs) with 95% confidence intervals (CI). Overall, we observed 692 incident first cancers vs 171 expected (SIR 4.0; 95% CI 3.7-4.4). We confirmed marked excesses of nonmelanoma skin cancer (SIR 56.2; 95% CI 49.8-63.2), lip cancer (SIR 53.3; 95% CI 38.0-72.5) and of non-Hodgkin's lymphoma (NHL) (SIR 6.0; 95% CI 4.4-8.0). Compared with patients who underwent kidney transplantation, those who received other organs were at substantially higher risk of NHL (RR 8.4; 95% CI 4.3-16). Besides, we found, significantly, about 20-fold excess risk of cancer of the vulva and vagina, 10-fold of anal cancer, and five-fold of oral cavity and kidney cancer, as well as two- to four-fold excesses of cancer in the oesophagus, stomach, large bowel, urinary bladder, lung and thyroid gland. In conclusion, organ transplantation entails a persistent, about four-fold increased overall cancer risk. The complex pattern of excess risk at many sites challenges current understanding of oncogenic infections that might become activated by immunologic alterations.

BACKGROUND: Skin cancer following solid organ transplantation is an important cause of morbidity in long-term survivors. This risk is well known but imprecisely quantified. OBJECTIVES: We aimed to determine: (i) the skin cancer risks in transplant patients more precisely; (ii) whether the risk of malignant melanoma is altered; and (iii) whether the risk of epithelial cancers occurring at non-exposed sites is comparable with that seen in sun-exposed sites. METHODS: We linked a population-based cohort of 5356 patients who had received organ transplants in Sweden between 1970 and 1994 with the compulsory Swedish Cancer Registry, to identify all cancer cases except basal cell carcinomas, which are not registered. RESULTS: After a mean follow-up of 5.6 years post-transplantation, 172 of 5356 patients developed 325 non-melanoma skin cancers (excluding basal cell carcinomas) and six malignant melanomas. The relative risk of non-melanoma skin cancer was 108.6 [95% confidence interval (CI) 94.6-123.1] for men and 92.8 (95% CI 73.2-116.0) for women. The highest risks were noted for upper limbs, and the risk increased with time. No significant increase in malignant melanomas was noted: the relative risk was 1.6 (95% CI 0.5-3.7) for men and 0.5 (95% CI 0. 0-2.6) for women. Except for the lip, which is also sun-exposed, other epithelial sites did not show comparable increases in cancer risk. CONCLUSIONS: We conclude that organ transplant recipients are at a highly increased risk for non-melanoma skin cancer and must be closely followed throughout their lives. Cancer risk associated with transplantation is higher for sun-exposed than for non-sun-exposed epithelial tissues, even among populations living in regions with low solar insolation.

The alleged relationship between the cross sectional shape of the hair shaft and the form of the hair, eg, curly or straight hair, has been challenged. By serial sections of human hair follicles from ten patients representing the three biological races, the relation between the follicle form and the hair form was studied. Using three-dimensional computer-aided reconstruction it was demonstrated that the follicle form determines the hair form, eg, the Negroid follicle has a helical form, whereas that of the Oriental follicle is completely straight. The caucasoid follicle represent variation between these extremes. However, even a straight caucasoid follicle may produce a hair shaft that has an oval cross section.

In order to obtain a precise estimate of the relative risk of squamous cell carcinoma (SCC) in venous leg ulcers, we matched 10,913 patients with the diagnosis venous leg ulcer from the Swedish Inpatient Registry with registrations of SCC of the lower limb recorded by the Swedish Cancer Registry, and found 33 cases of non-melanoma skin cancer. After scrutinizing the pathology and case records, 17 cases of SCC were considered as being certainly secondary to venous leg ulcers, whereas in six cases of remitting/relapsing ulcers the connection was probable. The relative risk calculated on 17 cases was 5.80 (95% confidence interval = 3.08-9.29). The median duration of the ulcer before the diagnosis of cancer was 25 years. The mean follow-up time of the cohort was 8.5 years. We conclude that SCC is a complication of chronic venous leg ulcers, although the absolute risk is very small.