Radiotherapy of childhood haemangiomas: from active treatment to radiation risk estimates

Radiation-Related Thyroid Cancer

Radiation is an environmental factor that elevates the risk of developing thyroid cancer. Actual and possible scenarios of exposures to external and internal radiation are multiple and diverse. This article reviews radiation doses to the thyroid and corresponding cancer risks due to planned, existing, and emergency exposure situations, and medical, public, and occupational categories of exposures. Any exposure scenario may deliver a range of doses to the thyroid, and the risk for cancer is addressed along with modifying factors. The consequences of the Chornobyl and Fukushima nuclear power plant accidents are described, summarizing the information on thyroid cancer epidemiology, treatment, and prognosis, clinicopathological characteristics, and genetic alterations. The Chornobyl thyroid cancers have evolved in time: becoming less aggressive and driver shifting from fusions to point mutations. A comparison of thyroid cancers from the 2 areas reveals numerous differences that cumulatively suggest the low probability of the radiogenic nature of thyroid cancers in Fukushima. In view of continuing usage of different sources of radiation in various settings, the possible ways of reducing thyroid cancer risk from exposures are considered. For external exposures, reasonable measures are generally in line with the As Low As Reasonably Achievable principle, while for internal irradiation from radioactive iodine, thyroid blocking with stable iodine may be recommended in addition to other measures in case of anticipated exposures from a nuclear reactor accident. Finally, the perspectives of studies of radiation effects on the thyroid are discussed from the epidemiological, basic science, and clinical points of view.

IADVL SIG pediatric dermatology (academy) recommendations on Hemangioma of Infancy (HOI)

Hemangioma of infancy (HOI) is a benign vascular proliferation. Though resolution is the norm, potential complications make an accurate diagnosis and early management of importance. The Indian association of dermatologists, venereologists and leprologists (IADVL) special interest group (SIG) paediatric dermatology in association with IADVL academy did an extensive analysis of the literature on the clinical features, diagnosis, and management of HOI published between 2010 and 2021. Online meetings were conducted from February 2021 to March 2022 to reach a consensus on these recommendations which are made from an Indian perspective.

Thyroid Cancer after Childhood Exposure to External Radiation: An Updated Pooled Analysis of 12 Studies

Studies have causally linked external thyroid radiation exposure in childhood with thyroid cancer. In 1995, investigators conducted relative risk analyses of pooled data from seven epidemiologic studies. Doses were mostly <10 Gy, although childhood cancer therapies can result in thyroid doses >50 Gy. We pooled data from 12 studies of thyroid cancer patients who were exposed to radiation in childhood (ages <20 years), more than doubling the data, including 1,070 (927 exposed) thyroid cancers and 5.3 million (3.4 million exposed) person-years. Relative risks increased supralinearly through 2-4 Gy, leveled off between 10-30 Gy and declined thereafter, remaining significantly elevated above 50 Gy. There was a significant relative risk trend for doses <0.10 Gy (P < 0.01), with no departure from linearity (P = 0.36). We observed radiogenic effects for both papillary and nonpapillary tumors. Estimates of excess relative risk per Gy (ERR/Gy) were homogeneous by sex (P = 0.35) and number of radiation treatments (P = 0.84) and increased with decreasing age at the time of exposure. The ERR/Gy estimate was significant within ten years of radiation exposure, 2.76 (95% CI, 0.94-4.98), based on 42 exposed cases, and remained elevated 50 years and more after exposure. Finally, exposure to chemotherapy was significantly associated with thyroid cancer, with results supporting a nonsynergistic (additive) association with radiation.

On the estimation of radiation-induced cancer risks from very low doses of radiation and how to communicate these risks

The article is intended to give a short overview of epidemiological data on cancer risks associated with very low absorbed doses of ionising radiation. The linear no-threshold (LNT) approach to estimate cancer risks involves the use of epidemiological data at higher doses (>100 mSv), but is supported by data from lower exposure of more sensitive population groups like fetuses and children and the presence of rare types of cancer. The International Commission on Radiological Protection (ICRP) concludes that the LNT model, combined with a dose and dose-rate effectiveness (reduction) factor (DDREF) of 2 for extrapolation from high doses, should be used. The numerical value of the DDREF is challenged by the findings from some recent epidemiological studies demonstrating risks per unit dose compatible with the risks observed in the higher dose studies. In general there is very limited knowledge about the cancer risk after low absorbed doses (10-100 mSv), as most of epidemiological studies have limitations in detecting small excess risks arising from low doses of radiation against fluctuations in the influence of background risk factors. Even if there may be significant deviations from linearity in the relevant dose range 0-100 mSv, one does not know the magnitude or even the direction of any such deviations. The risks could be lower than those predicted by a linear extrapolation, but they could also be higher. Until more results concerning the effects of low-dose exposure are available, a reasonable radiation protection approach is to consider the risk proportional to the dose.

A huge infiltrating squamous cell carcinoma of the neck 46 years after radiotherapy of a haemangioma

BACKGROUND

There is a higher risk for malignant tumours in patients who underwent any kind of radiotherapy.

MAIN OBSERVATIONS

An 87-year-old patient with an extended squamous cell carcinoma of the neck was referred to our hospital. The large ulcerated tumour showed a deep infiltration of the para-vertebral muscles and the spinal processes C6-C7. The tumour was known since about six years and appeared about 46 years after low-dose radiotherapy of a cervical haemangioma of the neck in 1961. The large dimension of the tumour leaded to a radical surgical removal and a sufficient fast reconstruction strategy. The extended defect was covered by a pedicled lower musculocutaneous trapezius flap. No postoperative complications like partial necrosis, infection or movement disorders of the shoulder or a shoulder drop syndrome were seen. Ten weeks after the operation the patient showed a good functional and aesthetic result with no limitation of arm mobility. Two and a half years after radical intended surgery the patient was still alive and showed no recurrence of the tumour.

CONCLUSIONS

In conclusion there is a need for a life-time lasting dermatological supervision in patients with a history of radiotherapy in the past, because the handling of patients with such an enlarged tumour is complicated.

Infiltrating basal cell carcinoma of the neck 34 years after irradiation of an haemangioma in early childhood. A case-report

A case of a 34-year-old Caucasian male is presented with a basal cell carcinoma deeply infiltrating the structures of the neck, including skeletal muscles and reaching the parotid gland. Radical surgical removal under meticulous histological control was performed. 18 months postoperatively, the patient is still free of recurrence. Thirty years ago the patient had undergone radiotherapy for an infantile haemangioma of the skin of the neck. The effects of this treatment when given in childhood in the aetiology of a basal cell carcinoma are discussed.

The impact of reproductive factors on breast cancer risk - The feasibility of using Swedish population-based registers to account for the effect of confounding in cohort studies

OBJECTIVE

The aim of this study was to analyze the impact of reproductive factors on breast cancer risk among Swedish women by using nationwide population registers.

METHODS

A cohort including all Swedish women born between 1920 and 1959 was followed up to 1997 by record linkage to different population-based registers. More than 4 million children were linked to the women in the cohort and 60,328 women were diagnosed with breast cancer. Poisson regression was used to model the breast cancer incidence by risk groups. In a sub-cohort of 18,164 women irradiated for skin hemangioma in infancy, the breast cancer risk was analyzed in relation to radiation dose and accounting for reproductive factors.

RESULTS

The relative breast cancer risk (RR) for the reproductive factors was 0.35 [ 95% confidence interval (CI) 0.30--0.42] for women with 6 or more children and the first child before the age of 20 years, and RR was 1.11 (95% CI 1.06--1.18) for uniparous women with the first child at age 35 years or older, compared to nulliparous women. The discrepancies of reproductive factors in the hemangioma cohort compared to Swedish women had a minor effect on RR, with a reduction from 1.13 (95%CI 1.00--1.26) to 1.11 (95% CI 0.99--1.25).

CONCLUSIONS

This study shows the feasibility of using population-based registers to retrieve reliable information on reproductive factors to eliminate its confounding effect when analyzing other risk factors.