[Epidemiology of radiation-induced tumors]. / Epidemiologia dei tumori radioinducibili.

The radiation oncogenesis is a theme well defined from the nosological point of view by the "Evidence Based Medicine" (EBM) founded on sound scientific and on sound medical evidences. Radiobiology and radioepidemiology are the scientific and medical branches for this purpose. The very huge number of collected data analysed by numerous international and national scientific organisms (RERF, NIH, BEIR, ICRP, IARC, UNSCEAR) (1-9) can individuate the more susceptible organs and tissues to radiation cancer and the extent of their susceptibility by the evaluation of the relative risk related mainly to dose but also to other exposition parameters. So it is now possible to categorize many organs and tissues bearing in mind their specific susceptibility to cancer induction by ionising radiation. The author on the basis of the literature data propose a scale to categorize the interested organs and tissues in "very high", "high", "medium" and "low" steps of susceptibility to radiation cancer. The aim of this is to give an indicative aid to the occupational physicians actuating the medical surveillance on the radiation exposed workers.

Skin-sparing mastectomy with immediate breast reconstruction: a critical analysis of local recurrence.

PURPOSE: The purpose of this study was to provide follow-up data regarding the incidence of local breast cancer recurrence in patients undergoing skin-sparing mastectomy versus conventional non-skin-sparing mastectomy methods. PATIENTS AND METHODS: A retrospective follow-up study and analysis were performed of patients who underwent mastectomies for invasive breast cancer at The New York Presbyterian Hospital, Cornell University Medical College and Strang-Cornell Breast Center between 1990 and 1998. RESULTS: A total of 198 patients were identified in this study, and the mean follow-up was 49 months. This group included 71 patients who underwent skin-sparing mastectomy and 127 who underwent non-skin-sparing mastectomy procedures. No statistical differences in local recurrence rates were demonstrated between patients treated with skin-sparing mastectomy and those who underwent non-skin-sparing mastectomy. Local recurrence was present in four of 71 (5.6%) patients undergoing skin-sparing mastectomy and in five of 127 (3.9%) of those undergoing non-skin-sparing mastectomy. CONCLUSIONS: The use of skin-sparing mastectomy does not lead to an increase in local recurrence rates when compared with conventional non-sparing mastectomies and provides for improved aesthetic results after immediate reconstruction.

Micronucleus yield and colorimetric test as indicators of damage in patients' lymphocytes after 131I therapy.

UNLABELLED: To estimate the absorbed dose received by patients who underwent 131I therapy, a modified compartmental model of the International Commission on Radiological Protection (ICRP) was used. The activity in plasma and micronucleus (MN) frequency (MN test) were measured before and after therapy. To evaluate whether a correlation exists between lymphocytes and absorbed dose, a colorimetric test, based on the tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT test), was used. METHODS: Twenty patients who underwent 131I therapy were studied. Activity was measured in plasma, and isolated lymphocytes were collected to perform the MN and MTT tests. RESULTS: The mean MN frequency observed in unexposed patient lymphocytes was comparable with that of healthy subjects. 131I therapy induces a small increase in MN, and a good correlation with the bone marrow absorbed dose was obtained (P = 0.040). A consistent decrease in phytostimulation observed after therapy (MTT test) correlated significantly with bone marrow absorbed dose (P = 0.0085). CONCLUSION: The MTT test appears to be more reliable than the MN test for evaluating lymphocyte damage induced by 131I therapy.

Local and distant recurrence rates in skin-sparing mastectomies compared with non-skin-sparing mastectomies.

BACKGROUND: Skin-sparing mastectomies (SSMs) are being used more frequently to treat many cases of breast cancer. This type of surgery maximizes breast skin preservation and facilitates immediate reconstruction, resulting in a superior cosmetic appearance after mastectomy and a more satisfied patient. Although SSMs are becoming more common, there are few data regarding the local and distant recurrence rates. METHODS: A total of 231 patients treated with mastectomies from 1990 to 1998 were studied, including 77 SSM and 154 non-skin-sparing (NSSM) mastectomy patients. RESULTS: The local recurrence rates for SSM and NSSM were 3.90% (3 of 77 patients) and 3.25% (5 of 154 patients), respectively. The local recurrence-free survival at 5 years was 95.3% for SSM patients and 95.2% for NSSM patients (P = .28). The distant recurrence rates of SSM and NSSM were 3.9% (3 of 77 patients) and 3.9% (6 of 154 patients), respectively. The distant recurrence-free actuarial survival at 5 years was 90.2% for SSM patients and 92% for NSSM patients (P = .07). CONCLUSIONS: Mastectomies using the skin-sparing technique do not appear to result in any increase in local or distant recurrence and improve aesthetic results of the immediate reconstruction.

Peripheral blood lymphocyte decrease and micronucleus yields during radiotherapy.

PURPOSE: To investigate the relationship between lymphocyte decrease and cytogenetic response in individual patients undergoing radiotherapy. MATERIALS AND METHODS: Peripheral blood lymphocytes obtained from 35 patients with pelvic and from 14 with head and neck tumours before and during radiotherapy were PHA-stimulated in vitro and the cultures prepared for the cytokinesis-block micronucleus test. For some patients only, the micronucleus test was carried out after 2 Gy in vitro X-irradiation, and 3-aminobenzamide (2 mM) was used to calculate the 3AB-index. RESULTS: The initially observed individual variation in the decrease of lymphocytes disappeared with increasing number of radiation exposures, reaching a stable level at about 500/microl lymphocytes in the blood. The slope of the relationship between the reciprocal of the lymphocyte decrease ratio and equivalent dose indicates the radiosensitivity of the lymphocyte pool in individual patients. The micronucleus test performed on lymphocytes obtained from patients during radiotherapy (in vivo) provided a lower cytogenetic response than the in vitro micronucleus yield for the same dose, so it was possible to calculate the cytogenetic recovery factor k. A correlation was found between the 3AB-index calculated before radiotherapy, and the recovery factor k. CONCLUSIONS: The 3AB-index, the micronucleus frequency after 2 Gy in vitro X-irradiation, and the cytogenetic recovery factor are proposed as predictive of individual response to radiotherapy.

Functional reconstruction for severe postburn microstomia.

A man with severe burn microstomia refractory to traditional management (Z release, skin grafting, splinting, bilateral commissuroplasty, and extensive physical therapy) is presented. Successful functional microstomia reconstruction was achieved with a three-stage approach consisting of the following: (1) lip, commissure, and cheek reconstruction with bilateral temporalis muscle transfers; (2) free flap neck and lower lip contracture release; and (3) vestibuloplasty with a stented full-thickness skin graft.

Facial skeletal growth after timed soft-tissue undermining.

This study was designed to answer the following questions: (1) Does aggressive bilateral soft-tissue undermining of the nasomaxillary complex in an immature animal without an iatrogenically produced cleft lip significantly inhibit growth? (2) If so, is the early timing of this undermining crucial? Fifty New Zealand White rabbits were used in this study, and bilateral buccal sulcus incisions with extensive nasomaxillary supraperiosteal undermining were performed in the experimental groups. There were five groups: (1) control, (2) undermining at 3 to 4 days, (3) undermining at 7 to 10 days, (4) undermining at 18 to 21 days, and (5) undermining at 50 to 56 days. The animals were sacrificed at 6 months of age, and direct osteometric measurements were made. Results demonstrated that a significantly retruded, constricted, and vertically shortened maxilla was produced as a direct result of bilateral nasomaxillary soft-tissue undermining alone regardless of the timing.

The Le Fort III advancement osteotomy in the child under 7 years of age.

This is a longitudinal study of 12 patients with craniofacial synostosis syndromes (Crouzon's, Apert's, Pfeiffer's) who underwent Le Fort III advancement under the age of 7 years (average age 5.1 years, range 4.0 to 6.7 years). The average follow-up was 5.0 years and included clinical, dental, and cephalometric examinations according to a prescribed protocol. The study demonstrated that the procedure could be safely performed in the younger child with an acceptable level of morbidity. There was a remarkable degree of postoperative stability of the maxillary segment. However, although vertical (inferior) growth or movement of the midfacial segment was demonstrated, there was minimal, if any, anterior or horizontal growth. Any occlusal disharmony developing during the period of follow-up could be attributed to anticipated mandibular development and could be corrected by orthognathic surgery. The roles of surgical overcorrection and anterior-pull headgear therapy after release of intermaxillary fixation are also discussed. The Le Fort III osteotomy is justifiably indicated during early childhood for psychological and physiologic reasons.

Hypertelorism correction in the young child.

This series reports on 20 patients who underwent orbital hypertelorism correction under 5.3 years of age (average age 3.9 years). The patients were followed an average of 5 years, and six patients were followed in excess of 7 years with clinical and cephalometric parameters. The study demonstrated that the procedure could be safely performed at this age and was aesthetically desirable. There was minimal clinical or cephalometric evidence of skeletal orbital relapse except in three patients, for whom individual explanations are given. During the period of postoperative study, nasomaxillary growth and development proceeded as expected, except in those patients with associated clefting. All patients demonstrated increased cranial width measurements preoperatively and postoperatively, but bigonial and bimastoid measurements were generally within normal range. Excessive resection of nasoglabellar skin at the time of hypertelorism correction appeared to adversely affect nasal development.

[Possibilities and limitations of the predictive risk estimates and epidemiological studies following the Chernobyl incident]. / Possibilità e limiti di stime predittive di rischio e indagini epidemiologiche a seguito dell'incidente di Chernobyl.

The disastrous accident at the nuclear power station at the Chernobyl on 1986 (April 26) has brought attention to the estimation of radiation health effects and many "experts" were attending to the evaluation on oncogenic mortality increase among the Italian population in the next future. On the contrary at that time too few peoples were worried about the possibility of detecting such an increase. Discussion of this topic is notoriously fraught with difficulties arising from differences of opinion how to estimate low-dose risk in humans without data from direct observation. One opinion is to extrapolate from the data points obtained at relatively high doses toward zero dose (zero extrapolation theory). This permit estimates of risk to be made but, in the final analysis, no data from humans exist that show that low-level radiation exposures produce measurable biologic effects. For that this theory is more useful in radio-protection and medico-legal subjects. It is easy on a statistical basis to prove the impossibility to establish an increase in human cancer after low doses of ionizing radiation such as those received environmentally after the Chernobyl's accident. In this condition to observe the numbers of radiation-induced cancer deaths that far exceed the "natural" incidence would require a follow-up a sample more and more greater than the italian population herself. Indeed the statistical power of a hypothetical follow-up study at a suitable confidence level would require a sample size higher than a milliard of persons for the detection of an increase of a generic cancer mortality and higher then seven hundred of millions for the detection of an increase of the specific thyroid cancer mortality. In more detail the following figures for the parameters needed to curring out the evaluation have been used: medium dose equivalent to the thyroid, 2.03 mSv; medium effective dose equivalent up to december '87, 0.6 mSv; thyroid cancer mortality in the italian population, 0.94 10(-5) y-1; total cancer mortality in the italian population, 22.2 10(-2) y-1; risk factor per unit dose equivalent in thyroid, 0.5 10(-6) mSv-1; risk factor per unit effective dose equivalent, 2.0 10(-5) mSv-1. Applying the foregoing values in statistical inference methods it could be achieved that 7.5 18(8) and 1.25 10(9) persons must be followed-up in the next 30 years to detect a significant increase over the "natural" cancer mortality for thyroid and "total body" radioinduced cancers respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Health safety planning for possible accidental exposures of workers and population in Italy

Unforeseeen radiation exposures may be caused by technical or human faults in the utilization of radioactive devices, namely radionuclide sources, as well as from the peaceful uses of nuclear energy; the first instance is in general the more common one. The paper discusses the principal basis for health ntervention planning in the case of possible accidental exposures of workers and/or the population to ionizing radiation, also with reference to hypothetical accidents at nuclear power stations. For this last purpose and important aspect is the definition of the 'source term' problem. The main differences existing between 'conventional' and radiation emergencies in the pre-planning of technical and health safety operations are discussed. Even if the general organizatioonal planning is based on similar operating structures, radiation emergencies require a somewhat different approach. Besides the specialized aspects of prophylaxis and therapy which are needed in theses cases, radiation emergencies call for a comparison of the social cost, the possible health detriment induced by health-realted countermeasures and the specific radiation risk in a single case. In many instances, furthermore, a key role may also be played by psychological factors. Following this philosophy, a flexible organization plan has been drawn up, whih consists of three-steps as follows: (1) local and/or regional level; (2) national level; (3)j European or international level. For the first two levels, besides the possibility of utilizing health services, there is provision to arrange them into structures of increasing complexity, using modular, integrated and dfixed operative units to adapt the intervention to specific aspects of each accident or emergency. The thrid level is represented by the WHO International Centre of Radiopathology (ICR) in Paris. An official agreement was recently signed by the ENEA and the Centre. (AU)