Second primary malignancies after high-dose-rate 60Co photon or 252Cf neutron brachytherapy in conjunction with external-beam radiotherapy for endometrial cancer.

PURPOSE: Second primary malignancies (SPMs) may occur in organs after radiotherapy (RT). This study aimed to determine the rate and distribution of SPMs for photon- or neutron-emitting radiotherapy sources for patients treated for primary endometrial cancer. METHODS AND MATERIALS: The cohort comprised 426 patients with 5334 patient-years of observation. Patients were treated by different methods of RT from 1990 to 2000. Patients received postoperative 60Co external-beam radiotherapy (43.4%), external-beam radiotherapy + high-dose-rate (HDR) intracavitary brachytherapy with 60Co or 252Cf (42.3%), or HDR intracavitary brachytherapy alone with 60Co or 252Cf (14.3%). RESULTS: Over a 25-year period, 47 SPMs were observed (21 for HDR 60Co and 26 for HDR 252Cf). SPMs were observed for 13 patients in the high-intermediate risk group for each radiation source. Patients treated with 60Co developed SPMs in the urinary tract (1.2%) and in lymphoid/hematopoietic tissues (1.2%). Only three SPM cases (0.7%) were observed in digestive tract. In comparison, the patient group treated with 252Cf developed SPMs in the digestive tract (1.4%) with the majority in the colon (1.2%), urinary tract (0.9%) primarily the kidneys, and vulva (0.7%). All other SPMs (4.9%) were in the low-risk group. Of these, SPMs in the skin were most prevalent (1.6%) for 60Co, and breast (1.6%) for 252Cf, but believed to be caused by factors other than treatment. SPM incidence in the digestive and urinary tracts were similar (2.1%), regardless of radiation source. CONCLUSIONS: For followup at 25 years, 47 SPMs were observed with no differences in the high-intermediate risk group depending on the RT source.

Californium versus cobalt brachytherapy combined with external-beam radiotherapy for IIB stage cervical cancer: long-term experience of a single institute.

PURPOSE: The purpose of this paper was to observe and compare long-term curative effects and complications of FIGO stage IIB cervical cancer patients (n = 232) treated with high-dose-rate (HDR) californium ((252)Cf) neutron or cobalt ((60)Co) photon intracavitary brachytherapy (ICBT) combined with external-beam radiotherapy (EBRT). MATERIAL AND METHODS: The EBRT dose to the small pelvis was 50 Gy in both groups. The brachytherapy component of (252)Cf or (60)Co was added in the 3(rd) week of EBRT, 5 fractions were performed once per week resulting in a total ICBT dose of 40 Gy/Gyeq (point A). RESULTS: Overall survival (OS) at 5, 10 and 15 years was 63.6%, 50.4% and 38.8% in the (252)Cf group and 62.2%, 50.5%, 39.9%, in the (60)Co group, respectively (p = 0.74). The percentage of tumour recurrence was statistically significantly lower in the (252)Cf group with 7.4% versus 17.1% in the (60)Co group (p = 0.02). Second primary cancers have developed similarly 9.1% and 8.1% cases for (252)Cf and (60)Co groups, respectively. CONCLUSIONS: Our long-term retrospective study comparing (252)Cf and (60)Co isotopes with brachytherapy in combined treatment of FIGO IIB stage cervix carcinoma patients shows, that overall survival in the both groups are similar. However, the recurrence of tumour was significantly lower in the (252)Cf group. The incidence of second primary cancers was similar in both groups.

Second primary malignancies after radiotherapy including HDR (252)Cf brachytherapy for cervical cancer.

PURPOSE: Second primary malignancies (SPMs) are among the most serious late adverse effects after radiotherapy experienced over time by the increasing population of cancer survivors worldwide. The study aim was to determine the rate and distribution of SPMs for neutron- and photon-emitting brachytherapy (BT) sources for patients treated for cervical cancer. METHODS AND MATERIALS: The cohort comprised 662 patients with invasive cervical cancer (Stages IIB and IIIB) and contributed 5,224 patient-years (PY) of observation. These patients were treated by radiotherapy during the 1989-1999 year period with cobalt-60 source ((60)Co) teletherapy. The first group of patients (N = 375; 3,154 PY) received high-dose-rate (HDR) californium-252 source ((252)Cf) BT, whereas the second group (N = 287; 2,070 PY) received HDR (60)Co BT. RESULTS: Over a 25-year period, 35 SPMs were observed, amounting to 5.3% of all observed patients: in 16 (2.4%) heavily, 2 (0.3%) moderately, 14 (2.1%) lightly irradiated body sites, and 3 (0.5%) other sites. Of these, 21 cases (5.6%) were observed in the HDR (252)Cf BT group, whereas 14 cases (4.9%) were observed in the HDR (60)Co BT group. Exposures received during (60)Co teletherapy and HDR BT with either (252)Cf or (60)Co had statistically equivalent (p = 0.68) effects on SPM development. CONCLUSIONS: Cure rates are improving, and therefore, there are more long-term survivors from cervical cancer. This study shows no significant difference in rates or distribution of SPMs in women treated with neutron BT compared with photon BT (p = 0.68). After reviewing related literature and our research results, it is evident that a detailed investigation of SPM frequency, localization, and dose to adjacent organs is a suitable topic for further research.

Assessment of annual average effective dose status in the cohort of medical staff in Lithuania during 1991-2013.

The use of radiation sources for various medical purposes is closely related to irradiation of the medical staff, which causes harmful effects to health and an increased risk of cancer. In total, 1463 medical staff who have been occupationally exposed to sources of ionising radiation (IR) had been monitored. Records with annual dose measurements (N = 19 157) were collected and regularly analysed for a 23-y period: from 01 January 1991 to 31 December 2013. The collected annual average effective dose (AAED) data have been analysed according to different socio-demographic parameters and will be used in future investigation in order to assess cancer risk among medical staff occupationally exposed to sources of IR. A thorough analysis of data extracted from medical staff's dose records allows one to conclude that the average annual effective dose of Lithuanian medical staff occupationally exposed to sources of IR was consistently decreased from 1991 (1.75 mSv) to 2013 (0.27 mSv) (p < 0.0001).

Radiation exposure received by the medical radiation workers in Lithuania at the Institute of Oncology, Vilnius University, 2004-2011.

The occupational radiation exposure of medical radiation workers at the Institute of Oncology, Vilnius University (IOVU) was analysed. Quartile dose measurements were collected and routinely analysed for a period of 8 y from 1 January 2004 to 31 December 2011. A total of 193 medical radiation workers were monitored, comprising 34 % physicians (radiologists and radiotherapists), 8 % physicists, 42 % radiological technologists and 16 % ancillary staff. A statistically significant decrease by 18 % has been detected when comparing the annual average effective doses (AAEDs) received by medical radiation workers at the IOVU during periods 2004-2007 and 2008-2011 (p < 0.0001). The main occupation categories responsible for this reduction were of Nuclear Medicine (p < 0.028) and Radiology (p < 0.0001) departments. The values of AAED in Radiology, Radiotherapy and Nuclear Medicine departments are quite low and well below the annual limit of 20 mSv, averaged over a period of 5 consecutive years.

The risk of cancer among Lithuanian medical radiation workers in 1978-2004.

OBJECTIVES: To describe the cohort of Lithuanian medical radiation workers and to estimate the risk of cancer during 1978-2004. METHODS: Analysis of cancer risk evaluation was done using the retrospective cohort method, an indirect standardization. The observed numbers of cancer cases were obtained from the National Cancer Registry. The expected numbers were based on the age- and gender-specific incidence rates for the general Lithuanian population in 5-year periods. The standardized incidence ratios and 95% confidence intervals (assuming that the incidence of cancer follows the Poisson distribution) were calculated. RESULTS: During the follow-up of 1978-2004, 159 cases of cancer were observed. There was no increased overall cancer risk in men (SIR=0.92, 95% CI=0.62-1.33, based on 29 cases) and women (SIR=0.97, 95% CI=0.81-1.15, based on 130 cases). The risk of leukemia among men and women was insignificantly increased. CONCLUSIONS: During the follow-up period, the overall cancer risk among medical radiation workers was the same as in the general population of Lithuania.

Occupational exposure of medical radiation workers in Lithuania, 1950-2003.

This study presents the summary of historical exposures, measurement practice and evolution of the recording of the individual doses of medical radiation workers during 1950-2003 in Lithuania. The aim of this study is to present occupational exposure of medical radiation workers in Lithuania since the earliest appearance period. Data from publications have been used for the earliest two periods prior to 1969; data from the archives of the largest hospitals, for the period 1970-1990 and data from Lithuanian Subdivision of Individual Dosimetry of Radiation Protection Center, for the period 1991-2003. The analysis of the data obtained from personal records allows to conclude that the average annual effective dose of Lithuanian medical radiation workers was greatly reduced in radiology, radiotherapy and nuclear medicine in all occupational categories from 1950 to 2003. During the last period 1991-2003 extremity doses clearly decreased and after 1994 were no longer present in Lithuania.