Postradiation Reactions Research Articles

Brachytherapy in the Treatment of Non-Melanoma Skin Peri-Auricular Cancers-A Retrospective Analysis of a Single Institution Experience.

This paper presents the results of a retrospective analysis of 33 patients treated with contact or interstitial high-dose-rate (HDR) brachytherapy for skin cancers of the outer ear, involving the auricle and the skin of the adjacent area. Brachytherapy was used both as a definitive treatment (15 patients-43%) and adjuvant treatment after surgery (18 patients-57%). The basic criterion for adjuvant treatment was a positive or narrow (<1 mm) resection margin. Fraction doses from 3 to 7 Gy per fraction were used at intervals from six hours (interstitial brachytherapy) to a maximum of seven days (contact brachytherapy). The treatment time ranged from 1 to 42 days, and the total dose range was 7 to 49 Gy. The follow-up was 29.75 months (range 2-64). In the group of patients treated with adjuvant therapy, in the patients with post-radiation reaction, the mean time from surgery to the start of brachytherapy was 7.72 ± 3.05 weeks, the median was 8 (6-12) weeks, and in the group without post-radiation reaction, the mean time was 11.13 ± 4.41 weeks, the median time was 11 weeks (8-14). The risk of a post-radiation reaction increased significantly more often in patients with more advanced disease. In the case of contact brachytherapy, the post-radiation reaction occurred significantly more often (14/21 patients-43%) than in the case of interstitial brachytherapy (3/11 patients-9.4%). In patients with post-radiation reactions, a significantly larger volume of the skin receiving a dose of 200% was found, and the volume receiving a dose of 150% was close to statistical significance. The mean volume of the skin receiving a 200% dose in the group with post-radiation reactions was 28.05 ± 16.56 cm3, the median was 24.86 (0.5-52.3) cm3, and the mean volume in the group without post-radiation reaction was 17.98 ± 10.96 cm3, median 14.95 (3.9-44.96) cm3. The result was statistically significant (Z = 2.035, p = 0.041). Interstitial HDR (high-dose-rate) brachytherapy for non-melanoma skin cancers around the ear is highly effective, short, and has a relatively low burden on the patient. The toxicity of the treatment was low. In the case of contact brachytherapy, the toxicity profile is slightly higher but acceptable for patients. This method is preferred in patients in whom interstitial brachytherapy is impossible to perform due to anatomical and logistical reasons. The unquestionable advantage of contact brachytherapy is its ability to be performed on an outpatient basis without the need to stay in the hospital. No severe and late CTCAE ≥III and late RTOG ≥III toxicity was observed. In patients after surgery, in order to minimise the risk of radiation reaction, it is optimal to start treatment at least eight weeks after surgery. In the presence of extensive lesions, the use of interstitial brachytherapy seems to be more advantageous, especially when the expected volume of healthy skin in the dose range of 200% and 150% is above 15 cm3 and 50 cm3, respectively.

Hypofractionated radiosurgery treatment of skull base meningiomas

The study objective is to analyze the results of hypofractionated radiosurgery treatment of patients with skull base meningiomas with a complex topographic and anatomical location using the Gamma Knife device. Materials and methods. The study was based on the results of examination and radiosurgery treatment of 36 patients (13 male, 23 female) with skull base meningiomas. Mean age (Me[Q25;Q75]) at the period of the treatment was 65 [42;88]. All patients underwent triple treatment in the dose hypofractionation mode with an interfractional interval of 1-2 days. The follow-up duration was 6-36 months. Results and discussion. All patients underwent control magnetic resonance imaging, which demonstrated tumor growth stabilization or decrease. There were no signs of continued growth and post-radiation reactions of neurotoxicity. The neuropathy of the cranial nerves during the control observation time remained at the preoperative level. The relative decrease in tumor size occurred faster in the group of patients with a tumor volume of more than 10 cm³. Conclusion. Hypofractionated stereotactic radiosurgery is safe and highly effective. High-level tumor control and a low incidence of post-radiation reactions make it possible to use the indicated method in the treatment of skull base meningiomas, involving the anterior parts of the visual analyzer and other radiosensitive structures.

Localization of radiation damages in X-rays irradiated cis-syn-cis-dicyclohexano-18-crown-6 and its inclusion complex with BaCl2

For the first time, structures of radical intermediates generated upon low temperature (77K) X-rays radiolysis of “free” dicyclohexano-18-crown-6 (cis-syn-cis-isomer, DCH18C6) and its inclusion complex with barium chloride (DCH18C6·BaCl2) were identified using EPR spectroscopy. A set of radicals originated from polyether and cyclohexyl rings was detected in DCH18C6·BaCl2 complex and “free” crown ether DCH18C6 irradiated at 77K. Cyclohexyl, macrocyclic OCHCH2 and acyclic CHC(H)O radicals were suggested to be formed at early stages of radiolysis in both investigated compounds, and the fraction of macrocyclic OCHCH2 radicals was predominant immediately after irradiation at 77K. Additionally, an effect of barium cation on post-radiation reactions of the radicals in irradiated DCH18C6·BaCl2 complex upon its subsequent thermal annealing at temperature above 333K was found. In particular, the analysis of EPR spectrum of the irradiated complex annealed at 333–413K implied a presence of signal from acyclic cyclohexanonyl radicals, which may presumably resulted from rearrangement of cyclic α-alkoxycyclohexyl radical precursors. This post-radiation reaction may contribute to accumulation of acyclic radiolytic products in the irradiated complex when comparing with radiolysis of free DCH18C6. The results obtained are essential for understanding the peculiarities of radiation resistance of extraction and sorption systems based on the crown ether under real conditions of radioactive waste reprocessing.

Radiotherapy versus radiochemotherapy with cisplatin in treatment of cervical cancer

To compare effects of concomitant radiochemotherapy (RCTh) and radiotherapy (RTh) alone in patients with cervical carcinoma and with 36-months follow-up analysis. 106 stage IIA-IVA cervical carcinoma women were divided in two groups. RCTh group was treated with teleradiotherapy (50.4 Gy/T), intracavitary brachytherapy (46 Gy), and iv cisplatin (40 mg/m(2)). RTh group was treated with pelvic teletherapy (52-54 Gy/T) and intracavitary brachytherapy (50-55 Gy). In RCTh group absorbed radiation dose was significantly lower (50.4 vs. 52.7 Gy) and the duration of treatment was significantly shorter (45.1 days vs. 47.8 days). There were no statistical differences in both groups in survival (59% in RCTh group vs. 56% in RTh group), response to treatment (86% vs. 90%), local recurrence (42% vs. 49%) metastasis occurrence (21% vs. 17%), anemia (40% vs. 26%), early postradiation reactions in intestines (77% vs. 65%) and bladder (71% vs. 61%) as well as in incidence of rectovaginal (10% vs. 4%) and vesicovaginal formation of fistulas (6% vs. 4%), respectively. There were significant differences between two groups in: nausea (77% vs. 6%), vomiting (65% vs. 3.7%), leucopenia (69% vs. 26%) and thrombocytopenia (35% vs. 9%), and late postradiation bladder effects (94% vs. 74%). RCTh patients with anemia had lower 36-months survival rates (42% vs. 71%), more frequent local recurrences (77% vs. 31%) and metastasis-free survival rates (61% vs. 90%) than RCTh patients without anemia. RCTh gives better treatment results in patients without than in patients with anemia and higher overall survival rates than RTh in patients without anemia. The only clinical prognostic factor for advance cervical carcinoma is the clinical stage of the disease.

An analysis of long term complications in breast cancer patients after conservative therapy

Summary Background Breast conserving surgery followed by irradiation and subsequent systematic application of therapy has been recognized as an efficient method for the treatment of early breast cancer for many years. The results of conservative treatment show a relatively low percentage of local relapses and good cosmetic results Aim The aim of the paper was to analyse the frequency and intensity of late complications after conservative treatment in breast carcinoma patients. Materials/Methods A group of 67 patients with stage I and II breast carcinoma, according to the TNM classification, and who underwent conservative treatment in the Lower-Silesian Centre for Oncology between 1995 and 2001 were included in the study. All patients underwent irradiation of the breast after conservative treatment. In 93% the total dose was 50 Gy and in the remaining 7% the dose amounted to 46–48 Gy. The dose was around 10 Gy higher at the tumour site. Irradiation of the lymph nodes was applied in 25% of cases and chemotherapy was used in 40%. The occurrence and intensity of late complications were assessed at 3–6 monthly intervals. Complications included: lymphatic swelling of the ipsilateral upper limb, necrosis of the soft tissues, post-radiation pneumonia, lung fibrosis, post-radiation rib fractures, plexopathy, late skin reaction and telangiectasia. Intensity was assessed using our own 4 level scale. Results Level 2 complications were observed in 22% of the patients and Level 3 complications were seen in 6%. No Level 4 complications were observed. Lymphatic swelling of the ipsilateral upper limb was the most frequent complication and occurred in 22% of the patients. Level 2 and Level 3 swelling was observed in 14.5%. Level 2 and 3 late post-radiation reactions were observed in 9% of the patients. Telangiectasia within the boost area was observed in 4.5% of the patients and outside the boost area in 9%. No local recurrence of carcinoma was observed. Conclusions The results of conservative treatment of breast carcinoma patients show low intensification of complications.

Stereotactic radiosurgery VIII. The classification of postradiation reactions

Postradiation reactions in the CNS are well described and catalogued in the conventional radiotherapy literature; acute, subacute and late CNS reactions are recognized. Tumours predispose to these normal tissue reactions by the oedema and pressure epiphenomena that occur in their environs, and probably by other mechanisms associated with tissue breakdown. That late normal tissue reactions (particularly permanent late sequelae- universally referred to as 'necrosis') occur in the normal nervous system is in the complication list of every radiosurgery centre. This article, for the first time, places postradiosurgery observations within or without the existing classification of reactions, and draws attention to the fact that previous 'radiosurgery risk factor' papers in the literature may be wrong to pool different 'reactions' in the formulation of risk formulae for normal brain damage following single shot radiotherapy. Acute reactions occur in the same manner as described for conventional radiotherapy, being a transient swelling phenomenon that occurs 12-48 h after therapy; they are fully reversible and do not usually augur late problems; routine administration of short duration steroids around the time of radiosurgery may prevent or delay the clinical signs. Subacute reactions occur 3-10 months later (a later time than the subacute reactions following conventionally fractionated radiotherapy), and may prove fully or partially reversible, or progress to permanent sequelae; the difference between these and late sequelae (which tend to be permanent themselves) then becomes blurred. That tumour swelling occurs in the subacute phase and is associated with oedema in the surrounding normal brain is an interesting observation (occurring in extra- and intra axial slow-growing tumours); it denotes tumour damage and has not been encountered in the conventionally-fractionated radiotherapy literature. Tumour shrinkage occurs later, with subsidence of the surrounding oedema, and this phenomenon may therefore be regarded (paradoxically) as a good prognostic sign, a point about which the referring clinician should be made aware. Similarly, contrast enhancement in the tumour perimeter at this time reflects a host reactive response and not tumour activity. Persistent clinical neurological signs and MRI changes (best seen on the T2 weighted sequences) beyond 2 years, indicate late damage or reaction. Usually, this represents scarring or coagulative necrosis without mass effect, but if there is a low signal area with mass effect and considerable surrounding oedema, liquefactive necrosis has occurred and (as in the brachytherapy literature) surgical decompression is very occasionally needed.

Radiation color center formation in silica glasses: a review of photo- and thermo-chemical aspects of the problem

The results of the investigation of post-irradiation thermo- and photo-stimulated phenomena concerning radiation-induced color centers (RCC) in quartz and silica glasses are presented and discussed in detail. The new concept was suggested and developed to explain the formation processes of RCC in silica glasses. Because of impurities (hydrogen, chlorine, etc.) in so-called ‘high-purity’ silica glasses and because of free-radical-type defects (E′ centers and non-bridging oxygen hole centers) in their networks, the proccesses of RCC formation can be considered not only from the solid state physics point of view, but also as complex thermo- and photo-chemical post-radiation reactions.