[Very late effects of radiotherapy -  limiting factor of current radiotherapy techniques]. / Velmi pozdní následky radioterapie -  limitující faktor soucasných radioterapeutických technik.

BACKGROUND: Very late effects of radiotherapy occur within decades after the initial exposure. Their development is induced by low doses of ionizing radiation (from 4 Gy per radiation series) and their clinical manifestations are difficult to distinguish from other independent diseases diagnosed in individuals not formerly treated with radiation. A long time period from the exposure confounds any causal relationships between radiation and adverse events. Still, these side effects not only reduce the patients quality of life but also lead to an early morbidity and mortality, hence generating significant costs in health care and social systems. PURPOSE: This article summarizes findings about the most common very late consequences of radiotherapy, which include cardiotoxicity, CNS toxicity, pneumotoxicity, renal toxicity and secondary malignancies. This issue is crucial in the group of children cancer patients, malignant lymphomas, testicular tumors and CNS tumors. Generally, the risk of very late effects of radiotherapy (RT) should be considered in all patients irradiated at a relatively early age with a high chance of long term survival. The risk of very late effects of RT is also one of the key limiting factors in the use of RT in the treatment of patients with benign lesions with longterm survival expectation, e. g. in patients with glomus tumors, neurofibromas, desmoid tumors or hemangiomas or other benign lesions (arterio venous malformations). Currently, the only known prevention of these very late adverse effects is to minimize the dose to critical structures to the lowest achievable level.

[Radiobiological pitfalls of new techniques in radiotherapy]. / Radiobiologická úskalí nových technik v radioterapii.

Radiotherapy techniques in the last decade evolved to the stage where the potential dose distribution significantly differs from earlier practices. Rotational IMRT, robotic radiotherapy or proton radiotherapy enables extremely precise dose delivery to target volumes, on the other hand, these techniques can yield a number of problems. As for photon radiotherapy, this concerns primarily the effect of large volume irradiation with doses of 0.10.5 Gy. In this range, the hypersensitivity to low doses and the bystander effect may play an important role. Proton therapy is upredictable in its radiobiological effect at the end of the Bragg curve and there is also uncertainty about the peaks exact location. These effects should be taken into account when choosing among the irradiation techniques or when applying tolerance doses to critical organs in clinical practice, especially in younger patients with long survival expectation.

[Adjuvant treatment for stage I of testicular germ cell tumours]. / Adjuvantní lecba u i. stádia germinálních nádoru varlat.

BACKGROUND: Testicular germ cell tumors (TGCT) are the most frequent malignancy seen in young men. More than 95% of patients diagnosed with early stage TGCT are cured. In management of stage I seminoma there are several treatment options, including adjuvant radiotherapy, adjuvant chemotherapy with one cycle of carboplatin or surveillance. Patients with stage I nonseminoma are treated with adjuvant chemotherapy, with nerve sparing retroperitoneal lymph node dissection or surveillance being considered another treatment alternatives for stage I disease. METHODS AND RESULTS: Fifty five patients with stage I TGCT were diagnosed and treated in Masaryk Memorial Cancer Institute between January 2000 to December 2004. In a retrospective analysis, we reviewed treatment outcome and treatment strategy used in these patients. Patients characteristics also included histological subtype, risk status, age at the time of diagnosis, relapse rate, delayed toxicity, etc. Despite the small number of patients included in the analysis (55), there was observed a clear preference toward adjuvant radiotherapy in seminoma patients (95%) and adjuvant chemotherapy in nonseminoma patients (97%). During median follow up (5,6 years in seminoma group, 5,7 years in nonseminoma group) only two patients experienced relapse of disease in the seminoma group and none in the nonseminoma group. One patient died of metastatic colorectal cancer. Acute toxicity was acceptable, with no treatment related death. The long- term side effects were not significant (no grade 3 or 4 toxicity). CONCLUSION: The achieved cure rates were high, with acceptable toxicity. The role of adjuvant chemotherapy with carboplatin in stage I seminoma remains controversial. Further management of TGCT should be guided by complete and correct assessment of known risk factors to ensure the potential for cure.

[The role of PET in the diagnosis and prediction of the treatment response in patients with cervical carcinoma treated with radiotherapy--results of pilot study]. / Význam PET v diagnostice a predikci lécebné odpovedi karcinomu cervixu u pacientek lécených radioterapií--výsledky pilotní studie.

BACKGROUND: Positron emission tomography (PET) is used to distinguish between benign and malign tumours, to diagnose relapse or post-therapeutic changes and recentlyto predict treatment response. PET is also a complementary method to determine target volumes in radiotherapy. Using the PET in routine oncology practice can change disease management and improve treatment outcomes of cancer patients. We performed a pilot study to validate the role of PET in staging and in radiotherapy treatment planning of cervical carcinoma. PATIENTS AND METHODS: Between March 2005 and May 2007, 51 patients with cervical carcinoma were treated with combination of external beam radiotherapy and HDR brachytherapy, with or without concomitant cisplatin. The lymphatic nodes treatment field size was determined by PET/CT fusion. Treatment results were evaluated by PET 3 and 9 months after completion of radiotherapy. RESULTS: The difference in the results of PET and CT was evaluated in this study. In 32 cases (62.75%) the results of initial PET and CT were identical, in 14 cases (27.45%) the nodal involvement was more extensive according to PET, in 5 cases (9.8%) the nodal involvement was more extensive according to CT. Comparing the results of PET done before and 3 months after the treatment, we found stable disease in 3 cases (5.88%), progression of disease in 4 cases (7.84%), partial regression in 3 cases (5.88 %) and in 35 cases (68.63 %) both PET scans were negative. There should not occur any false positive results caused by inflammatory reaction persisting 3 months after radiotherapy, as was confirmed by repeating PET 9 months after the treatment. CONCLUSION: The results of this study confirmed the important role of PET in diagnosis and treatment of cervical carcinoma and for determination of target volumes in radiotherapy. The predictive value of PET has not yet been validated in our study. PET was integrated into the standard staging of cervical carcinoma in Masaryk Memorial Cancer Institute.

[The impact of PET in radiotherapy of the cervical carcinoma--results of pilot study]. / Význam PET v radioterapii karcinomu delozního hrdla--výsledky pilotní studie.

OBJECTIVE: Positron emission tomography (PET) is a complementary method to determine target volumes in radiotherapy. Daily using of PET in the oncology praxis can change treatment strategy and improve its outcome. Results of this pilot study show the role of PET in staging of cervical carcinoma and in the radiotherapeutic planning. METHODS: Between March 2005 and May 2007, 51 patients with cervical carcinoma were treated with combination of external beam radiotherapy and HDR brachytherapy, with or without concomitant cisplatin. The lymphatic nodes treatment field size was determined by PET/CT fusion. RESULTS: The difference in the results of PET and CT was evaluated in this study. In 32 cases (62.75%) the results of PET and CT were identical, in 14 cases (27.45%) the nodal involvement was more extensive according to PET, in 5 cases (9.8%) the nodal involvement was more extensive according to CT. PET results 3 months after treatment were as follows: in 3 cases (5.88%) stable disease, in 35 cases (68.63%) negative, in 4 cases (7.84%), progression of disease, in 3 cases (5.88%) partial regression. CONCLUSION: The results of this study confirmed the important role of PET in diagnosis and treatment of cervical carcinoma and in determination of target volumes in radiotherapy. PET was found to be a standard staging examination of cervical carcinoma in Masaryk Memorial Cancer Institute.

The impact of PET with 18FDG in radiotherapy treatment planning and in the prediction in patients with cervix carcinoma: results of pilot study.

Positron emission tomography (PET) is used to distinguish between benign and malign tumors, to diagnose relapse or post-therapeutic changes. Lately, PET is used to predict the treatment response. and also a complementary method to determine target volumes in radiotherapy. Daily using of PET in the oncology praxis can change treatment strategy and improve its outcome. Results of this pilot study show the role of PET with 8-F-fluorodeoxyglucose ((18)FDG) for staging of cervical carcinoma and in the radiotherapeutic planning. Between March 2005 and May 2007, 51 patients with cervical carcinoma were treated with combination of external beam radiotherapy and HDR brachytherapy, with or without concomitant cisplatin. The lymphatic nodes treatment field size was determined by PET/CT fusion. Treatment results were evaluated by PET 3 and 9 months after treatment. The differences in the results of PET and CT were evaluated in this study. In 32 cases (62.75%) the results of PET and CT were identical, in 14 cases (27.45%) the nodal involvement was more extensive according to PET, in 5 cases (9.8%) the nodal involvement was more extensive according to CT. PET results 3 months after treatment were as follows: in 3 cases (5.88%) stable disease, in 35 cases (68.63 %) negative, in 4 cases (7.84%), progression of disease, in 3 cases (5.88 %) partial regression. There were no false positive results caused by inflammatory reaction persisting 3 months after radiotherapy, as was confirmed by repeating PET 9 months after treatment. The results of this study confirmed the important role of PET in diagnosis and treatment of cervical carcinoma and in determination of target volumes in radiotherapy. PET was found to be a standard staging examination of cervical carcinoma in Masaryk Memorial Cancer Institute. The predictive value of PET has not yet been validated.

Longterm treatment results of childhood medulloblastoma by craniospinal irradiation in supine position.

Medulloblastoma, a primitive neuroectodermal tumor growing in cerebellum, is one of the most sensitive to radiation therapy childhood brain tumors. The radiotherapy is an essential method of treatment for these tumours, but the surgery is the primary treatment of choice in medulloblastoma. I this study between January 1997 and March 2005 were post-operative irradiated a total number of 33 pediatric patients aged under 15 years (median age 8.7 years) with medulloblastoma. All tumors were histologically proved and were localizated infratentorially in the posterior fossa. All of the patients were irradiated with a dose of 24-36 Gy to the whole craniospinal axis and boost with conformal therapy restricted to the tumor bed to the total dose of 50-54 Gy (30-36 Gy "high risk", 24-30 Gy "standard risk" group). Chemotherapy received 26 patients (78%). Patients with craniospinal irradiation were placed in supine position and fixed by a vacuum-form body immobilizer and head mask. Irradiation was performed using standard fractionation (5 fractions per week) with a single dose of 1.5-1.8 Gy for craniospinal axis by photon beam (6 MV) of the linear accelerator. The median overall survival for the whole group was 55.3 months. The median of disease-free survival was 20.6 months, 8 patients (24%) died. In our study the statistical difference in survival rate between standard and high-risk patients with medulloblastoma was not shown. No relationship was found between survival and age, sex or tumor size. Endocrine deficits occurred in 45% (8 patients of the group were hypothyroid, 6 patients needed growth hormone replacement therapy, 1 patient had early puberty). This results (results of overall and disease-free survival) and side-effects of technique of craniospinal axis irradiation in supine position are comparable with results of technique in prone position. Further evaluation of the effectiveness of our therapy is not feasible due to the small number of patients.