A comparison between surgical resection in combination with WBRT or hypofractionated stereotactic irradiation in the treatment of solitary brain metastases.

BACKGROUND: The standard treatment of solitary brain metastases previously has been tumour resection in combination with whole-brain radiation therapy (WBRT). Stereotactic radiotherapy has emerged as a non-invasive treatment option especially for small brain metastases. We now report our results on resection + WBRT or hypofractionated stereotactic irradiation (HCSRT) in the treatment of solitary brain metastases. METHODS: Between 1993 and 2004 patients with metastatic cancer and solitary brain metastases were selected for surgical resection + WBRT or HCSRT alone at the Umeå University Hospital. Fifty-nine patients were treated with surgical resection + WBRT (34 male, 25 female, mean age 63.3 years). Forty-seven patients were treated with HCSRT alone (15 male, 32 female, mean age 64.9 years). FINDINGS: In patients followed radiologically, 28% treated with resection + WBRT showed a local recurrence after a median time of 8.0 months, whereas there was a lack of local control in 16% in the HCSRT group after a median time of 3.0 months. There was a significantly longer survival time for patients treated with resection + WBRT (median 7.9, mean 12.9 months) compared to HCSRT (median 5.0, mean 7.6 months). Even in patients with a tumour volume <10 cc, there was a significantly longer survival in favour of resection + WBRT (median 8.4, mean 17.4 months) compared to HCSRT (median 5.0, mean 7.9 months). CONCLUSION: This retrospective and non-randomised study indicates that surgical resection in combination with WBRT may be an option even for small brain metastases suitable for treatment with HCSRT. Since survival and local control following resection + WBRT was at least as favourable as compared to HCSRT alone, tumour location and expected neurological outcome may be the strongest aspect when selecting treatment modality.

The quality assurance process for the ARTSCAN head and neck study - a practical interactive approach for QA in 3DCRT and IMRT.

AIM: This paper describes the quality assurance (QA) work performed in the Swedish multicenter ARTSCAN (Accelerated RadioTherapy of Squamous cell CArcinomas in the head and Neck) trial to guarantee high quality in a multicenter study which involved modern radiotherapy such as 3DCRT or IMRT. MATERIALS AND METHODS: The study was closed in June 2006 with 750 randomised patients. Radiation therapy-related data for every patient were sent by each participating centre to the QA office where all trial data were reviewed, analysed and stored. In case of any deviation from the protocol, an interactive process was started between the QA office and the local responsible clinician and/or physicist to increase the compliance to the protocol for future randomised patients. Meetings and workshops were held on a regular basis for discussions on various trial-related issues and for the QA office to report on updated results. RESULTS AND DISCUSSION: This review covers the 734 patients out of a total of 750 who had entered the study. Deviations early in the study were corrected so that the overall compliance to the protocol was very high. There were only negligible variations in doses and dose distributions to target volumes for each specific site and stage. The quality of the treatments was high. Furthermore, an extensive database of treatment parameters was accumulated for future dose-volume vs. endpoint evaluations. CONCLUSIONS: This comprehensive QA programme increased the probability to draw firm conclusions from our study and may serve as a concept for QA work in future radiotherapy trials where comparatively small effects are searched for in a heterogeneous tumour population.

Cell cycle disturbances and mitotic catastrophes in HeLa Hep2 cells following 2.5 to 10 Gy of ionizing radiation.

PURPOSE: Experimental radioimmunotherapy delivering absorbed doses of 2.5 to 10 Gy has been shown to cause growth retardation of tumors. The purpose of this study was to elucidate the sequential molecular and cellular events occurring in HeLa Hep2 cells exposed to such doses. METHODS: Dose-response curves, activation of cell cycle checkpoints, and mitotic behavior were investigated in HeLa Hep2 cells following 2.5- to 10-Gy irradiation by carrying out 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, Western blots, fluorescence-activated cell sorting analysis, and immunofluorescence stainings. Terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling staining was used to detect apoptosis. RESULTS: A G2-M arrest was shown by fluorescence-activated cell sorting analysis. p53 and p21 were found to be up-regulated but were not immediately related to the arrest. The G2-M arrest was transient and the cells reentered the cell cycle still containing unrepaired cellular damage. This premature entry caused an increase of anaphase bridges, lagging chromosomal material, and multipolar mitotic spindles as visualized by propidium iodide staining and immunofluorescence staining with alpha-tubulin and gamma-tubulin antibodies. Furthermore, a dose-dependent significant increase in centrosome numbers from 12.6+/-6.6% to 67+/-5.3% was identified as well as a dose-dependent increase of polyploid cells from 2.8+/-1.3% to 17.6+/-2.1% with the highest absorbed dose of 10 Gy. These disturbances caused the cells to progress into mitotic catastrophe and a fraction of these dying cells showed apoptotic features as displayed by terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling staining 5 to 7 days after irradiation. CONCLUSION: An absorbed dose of 2.5 to 10 Gy was shown to force HeLa Hep2 cells into mitotic catastrophe and delayed apoptosis. These might be important cell death mechanisms involved in tumor growth retardation following radioimmunotherapy of solid tumors.

Five-year prospective patient evaluation of bladder and bowel symptoms after dose-escalated radiotherapy for prostate cancer with the BeamCath technique.

PURPOSE: Late side effects were prospectively evaluated up to 5 years after dose-escalated external beam radiotherapy (EBRT) and were compared with a previously treated series with conventional conformal technique. METHODS AND MATERIALS: Bladder and bowel symptoms were prospectively evaluated with the Prostate Cancer Symptom Scale (PCSS) questionnaire up to 5 years posttreatment. In all, 257 patients completed the questionnaire 5 years posttreatment. A total of 168 patients were treated with the conformal technique at doses<71 Gy, and 195 were treated with the dose-escalated stereotactic BeamCath technique comprising three dose levels: 74 Gy (n=68), 76 Gy (n=74), and 78 Gy (n=53). RESULTS: For all dose groups analyzed together, 5 years after treatment, urinary starting problems decreased and urinary incontinence increased in comparison to baseline values. No increase in other bladder symptoms or frequency was detected. When comparing dose groups after 5 years, both the 74-Gy and 78-Gy groups reported increased urinary starting problems compared with patients given the conventional dose (<71 Gy). No increased incontinence was seen in the 76-Gy or the 78-Gy groups. Bowel symptoms were slightly increased during the follow-up period in comparison to baseline. Dose escalation with stereotactic EBRT (74-78 Gy) did not increase gastrointestinal late side effects after 5 years in comparison to doses<71 Gy. CONCLUSION: Dose-escalated EBRT with the BeamCath technique with doses up to 78 Gy is tolerable, and the toxicity profile is similar to that observed with conventional doses<71 Gy.

Hypofractionated conformal stereotactic radiotherapy alone or in combination with whole-brain radiotherapy in patients with cerebral metastases.

PURPOSE: The aim was to evaluate treatment of cerebral metastases with hypofractionated conformal stereotactic radiotherapy (HCSRT) or whole-brain radiotherapy (WBRT) in combination with a stereotactic boost. METHODS AND MATERIALS: Forty-seven patients were treated with HCSRT and 14 patients with WBRT in combination with a stereotactic boost. Radiation doses were 40 Gy (5 fractions) in HCSRT or 30 Gy (WBRT) combined with a mean dose of 17 Gy stereotactically (1-3 fractions). RESULTS: The median survival time in the HCSRT as well as the WBRT group was 5.0 months, and 87% died of extracranial disease. Radiologic follow-up (mean, 3.7 months after treatment) showed local control in the HCSRT group in 84% and in the WBRT group in 100%. Patients treated with HCSRT developed new brain metastases distant from the irradiated area in 25%. Two patients treated with HCSRT deteriorated neurologically during treatment, and in 2 patients radionecrosis developed. CONCLUSIONS: Although there may be a higher risk of distant new metastases, HCSRT as a treatment for brain metastases seems to be as effective as WBRT in combination with a stereotactic boost. Complications are in the range of what has been reported previously.

The effect of fraction time in intensity modulated radiotherapy: theoretical and experimental evaluation of an optimisation problem.

BACKGROUND AND PURPOSE: In intensity modulated radiotherapy (IMRT), the complexity and the number of treatment fields have expanded. This may imply that the delivery time for each fraction becomes prolonged. In a number of IMRT techniques used in the clinic, the delivery time per fraction is usually 10-15 min, sometimes more than 15 min. In studies on human skin, prolonged delivery time is shown to cause significant reduction of radiation effects compared with acute irradiation. In this paper the effect of changes in fraction delivery time was studied by in vitro irradiation of mammalian cells. MATERIAL AND METHODS: Chinese hamster fibroblasts (V79-379-A) were used for simulating clinical situations. Most experiments were performed with 2Gy/fraction with 4-h intervals in 40-60 replicates. Each fraction was divided into different subfractions, simulating the delivery of a complicated treatment. The effect of changing the delivery time for each fraction was studied. Parameters for the cell survival curve and repair kinetics were determined experimentally. The same methods were also used for large fraction sizes (8Gy). The validity of the most widely used models in the literature, all derived from linear-quadratic formalism, were tested against the experimental results. RESULTS: The effect of prolonging the fraction time for 2-Gy fractions was underestimated by the biological models. The experiments showed that 10-min prolonged delivery time gave a ratio between surviving fractions at 2Gy (S-ratio) of 1.054 with a 95% confidence interval (CI) 1.030-1.080, while the models predicted 1.007 and 1.009. Extending the fraction time to 20 min gave an S-ratio of 1.063 with CI of 1.045-1.080, while the models predicted 1.012 and 1.014. For 8-Gy fractions, there was a good agreement between predications and experimental results. The ratio between surviving fractions at 8Gy is 1.370 with CI of 1.300-1.440, while the models predicated 1.37 and 1.35. CONCLUSIONS: The effect of prolonging fraction time at conventional dose/fraction is underestimated by biological models. Prolonging the fraction time will spare tissues with a fast DNA repair. There is a risk for sparing tumours. This should be considered when IMRT technique is implemented in the clinic.

Prospective evaluation of urinary and intestinal side effects after BeamCath stereotactic dose-escalated radiotherapy of prostate cancer.

BACKGROUND: New data suggest that a higher radiation dose will improve outcome in treatment of localized prostate cancer. External beam radiotherapy (EBRT) may on the other hand induce disturbances in the patient's urinary and intestinal function. Since 1997, 195 patients have been treated with a stereotactic boost of 4-8 Gy added to conventional 70 Gy EBRT. Late side effects were prospectively evaluated 3 years after dose-escalated EBRT. METHODS: Urinary and intestinal problems were prospectively evaluated with a validated self-assessment questionnaire, the Prostate Cancer Symptom Scale (PCSS). Two hundred and eighty-seven patients completed the questionnaire at the 1 year follow-up, and 153 at 3 years after treatment. Pre-treatment mean age was 66 years. One hundred and sixty-eight patients were treated with the conformal technique and 195 were treated with the dose-escalated stereotactic BeamCath technique. Mean total dose in the conformal group (< or =70 Gy) was 66 Gy (60.8-70.4 Gy). The dose-escalated group consists of three dose levels, 74 Gy (n = 68), 76 Gy (n = 74), and 78 Gy (n = 53). RESULTS: Analyzing the whole population 3 years after treatment, urgency and starting problems decreased in comparison to pre-treatment. A minor increase in urinary incontinence was reported 3 years after treatment in comparison to pre-treatment. No increases in other urinary symptoms were reported. Intestinal symptoms were slightly increased during the follow-up period in comparison to pre-treatment. Dose escalation with stereotactic EBRT (74-78 Gy) did not increase gastrointestinal or genitourinary late side effects at 1 year or 3 years in comparison to doses < or =70 Gy. CONCLUSIONS: The stereotactic BeamCath EBRT technique facilitates safe dose escalation of patients with prostate cancer.

Hypofractionated conformal stereotactic radiotherapy for arteriovenous malformations.

OBJECTIVE: Arteriovenous malformations (AVMs) are congenital vascular lesions that are associated with high morbidity and mortality if left untreated. There are several options for treatment, including radiotherapy. Safe and effective single-fraction radiotherapy for patients with large AVMs has been considered difficult. METHODS: Between December 1986 and June 2001, 36 patients with cerebral AVMs were treated with hypofractionated conformal stereotactic radiotherapy at Umeå University Hospital. Twenty-nine patients have been followed angiographically to date and are reported in this study. RESULTS: Twenty-four (83%) of 29 patients (mean AVM volume, 11.5 cm(3)) underwent complete obliteration of their AVMs. The rates of angiographically verified total obliteration at 2 years after treatment were 56% for AVMs 4 to 10 cm(3) and 50% for AVMs larger than 10 cm(3). The obliteration rate increased considerably with extended follow-up. Five years after treatment, the obliteration rates were 81% for AVMs 4 to 10 cm(3) and 70% for AVMs larger than 10 cm(3). CONCLUSION: Hypofractionated conformal stereotactic radiotherapy may be an important alternative to single-fraction radiotherapy in patients with large AVMs or AVMs located in eloquent areas, because it allows the administration of a higher radiation dose than is possible to deliver in single-fraction radiosurgery. With our technique of hypofractionated conformal stereotactic radiotherapy, the rate of obliterating AVMs was comparable to that of single-dose radiosurgery, although the volumes of the irradiated AVMs in our study were larger than those reported previously.

Apoptotic signalling in HeLa Hep2 cells following 5 Gy of cobalt-60 gamma radiation.

BACKGROUND: The apoptotic signalling pathways involved in the delayed type of apoptosis occurring in HeLa Hep2 cells following radiation were investigated. MATERIALS AND METHODS: HeLa Hep2 cells were exposed to 5 Gy of cobalt-60 radiation. The activation of caspase-2, caspase-8, caspase-9 and effector caspase-3 was investigated by caspase assay plates and Western blots. Cleavage of poly (ADP-ribose) polymerase (PARP) was analysed on Western blots. HeLa Hep2 cells were irradiated with or without preincubation with inhibitors of protein synthesis (cycloheximide, CHX) and caspases, followed by TUNEL staining and caspase assay plate evaluation. RESULTS: Initiator caspases-2, -8, -9, and effector caspase-3, were found to be activated and PARP cleaved following irradiation. CHX completely inhibited the caspase activation and the associated apoptosis. Pretreatment with caspase-2 inhibitor indicated that caspase-2 was involved in the execution of the apoptosis. CONCLUSION: Activation of the apoptotic signalling pathways following irradiation of HeLa Hep2 cells includes components from the intrinsic as well as the extrinsic pathways and seems to require de novo protein synthesis.

Iodine-131 induces mitotic catastrophes and activates apoptotic pathways in HeLa Hep2 cells.

Iodine-131 (131I) has been used both in unconjugated form and conjugated to antibody derivates (i.e., radioimmunotherapy; RIT) to treat malignant diseases. The mechanisms by which 131I-irradiation causes growth retardation are, however, inadequately understood. The aim of this study was to elucidate the sequential molecular and cellular events that initiate cell death in HeLa Hep2 cells exposed to 131I. In this paper, HeLa Hep2 cells were found to display a transient G2-M arrest following irradiation, but then reentered the cell cycle still containing unrepaired cellular damage. An increase of multipolar mitotic spindles, as well as a significant increase in centrosome numbers from 8.8% +/- 1.9% in controls to 54.7% +/- 2.2% in irradiated cells, was observed (p < 0.0001). A subsequent failure of cytokinesis caused the cells to progress into mitotic catastrophe. This was accompanied by the formation of giant cells with multiple nuclei, multilobulated nuclei, and an increased frequency of polyploidy cells. A fraction of the cells also displayed apoptotic features, including the activation of initiator caspases-2, -8, -9, and effector caspase-3, as well as cleavage of poly(ADP-ribose) polymerase, a cell-death substrate for active caspase-3. These findings demonstrate that mitotic catastrophes and the activation of a delayed type of apoptosis might be important mechanisms involved in cell death following the RIT of solid tumors with -emitting radionuclides, such as 131I.

Reproducibility and geometric accuracy of the Fixster system during hypofractionated stereotactic radiotherapy.

BACKGROUND: Hypofractionated radiotherapy has been used for the treatment of AVMs and brain metastases. Hypofractionation necessitates the use of a relocatable stereotactic frame that has to be applied on several occasions. The stereotactic frame needs to have a high degree of reproducibility, and patient positioning is crucial to achieve a high accuracy of the treatment. METHODS: In this study we have, by radiological means, evaluated the reproducibility of the isocenter in consecutive treatment sessions using the Fixster frame. Deviations in the X, Y and Z-axis were measured in 10 patients treated with hypofractionated radiotherapy. RESULTS: The mean deviation in the X-axis was 0.4 mm (range -2.1 - 2.1, median 0.7 mm) and in the Y-axis -0.3 mm (range -1.4 - 0.7, median -0.2 mm). The mean deviation in the Z-axis was -0.6 (range -1.4 - 1.4, median 0.0 mm). CONCLUSION: There is a high degree of reproducibility of the isocenter during successive treatment sessions with HCSRT using the Fixster frame for stereotactic targeting. The high reducibility enables a safe treatment using hypofractionated stereotactic radiotherapy.

Daily-diary evaluated side effects of dose-escalation radiotherapy of prostate cancer using the stereotactic BeamCath technique.

The aim of this study was to evaluate self-assessed late side effects in patients with prostate cancer treated with frameless stereotactic dose-escalation radiotherapy using BeamCath, a new technique that has been developed for accurate positioning of the prostate at treatment set-up, and in which a specially designed urethral catheter containing high-density fiducial markers is used. The method was tested in the first 104 patients in a Scandinavian dose-escalation study with doses up to 76 Gy. Side effects were reported in a daily diary and evaluated at the start of treatment (baseline) and at 1-year follow-up. The patients were compared with those treated with conventional (n = 53) and conformal techniques (n = 175). Dose-escalation radiotherapy (76 Gy) decreased urinary frequency, urgency and starting problems at 1-year in comparison with baseline. The dose-escalation therapy did not induce any increase in gastrointestinal side effects in comparison with the effect of conformal therapy < or = 70 Gy at the 1-year follow-up, apart from a slight increase in rectal mucus in the 76 Gy group. All groups, except patients receiving the 74 Gy with smaller fields, reported a slight increase in gastrointestinal toxicity at 1-year compared with baseline. Dose-escalation radiotherapy of prostate cancer using the BeamCath technique did not induce any significant increase in late side effects in comparison with conformal technique.

Combined low dose radio- and radioimmunotherapy of experimental HeLa Hep 2 tumours.

Radiation therapy of malignant tumours can be delivered by external beam radiation (RT) or radioimmunotherapy (RIT), using nuclides attached to monoclonal antibodies (mAbs). These treatment modalities have now been combined in order to investigate putative therapeutic advantages and elucidate the biological responses involved. Nude mice were transplanted subcutaneously on the back with human HeLa Hep2 tumour cells. RT (3x5 Gy) and/or 100 microg (131)I-labelled mAb H7, against placental alkaline phosphatase, or (131)I-labelled mAb TS1, against cytokeratin, was administered separately or in combination (specific activity of 120-200 MBq/mg antibody). Significant tumour growth retardation was observed both with RT alone and with RIT alone. Combining these regimens enhanced the therapeutic effects further, and a significant reduction in tumour volume could be demonstrated. The tumours were subjected to extensive histochemical and immunohistochemical investigations in order to elucidate changes in biology and histology within them. The following stainings were used: haematoxylin-eosin (morphology), Ki67 (proliferation), M30 (apoptosis), TUNEL (apoptosis) and endoglin (vascularisation). Tumours in the control group grew fast, with an average tumour doubling time of 9 days. These tumours contained large viable tumour cell masses displaying vast proliferation zones of Ki67-positive tumour cells, as well as necrotic regions and small amounts of connective tissue. Apoptotic cells could be identified both with M30 and TUNEL staining. When RT was applied, the growth rate was significantly reduced (doubling time 19 days) and typical alterations in morphology were seen, with a relative increase in connective tissue and a decrease in necrotic regions. Apoptotic cells were identified and a decrease in cell density was also observed. When RIT alone was applied, the growth parameters indicated a longer lasting growth reduction, especially when TS1 was used separately or in combination with H7. The histological appearances of these tumours were somewhat different from the RT-treated tumours, with a larger portion of intratumoural cysts. These tumours also presented a reduced tumour cell density. Dramatic effects were observed when RT was combined with RIT, with a pronounced growth reduction seen in all combination treatment groups. Pronounced tumour volume reduction was also evident in both the RT + RIT ((131)I-TS1) group and RT + RIT ((131)I-TS1/(131)I-H7) group, and in some animals no tumour remained at all. The morphology of the tumour remnants at day 22 was chaotic with a drastically changed histology, with presence of abundant cysts, low fractions of Ki67-positive cells, reduction in cell density, increased amounts of connective tissue and a decrease in necrotic regions. Again, apoptotic cells could be identified, scattered throughout the viable regions. Combining RT and RIT seems to generate an efficient treatment with convincing and long-lasting tumour growth inhibition, which is reflected in a highly aberrant histology within the tumour. Results obtained in this study indicate that both necrosis and apoptosis may be involved in the process leading to this efficient therapy of epithelially derived tumours.

Apoptosis induced by low-dose and low-dose-rate radiation.

BACKGROUND: It has been claimed that external radiation, as a treatment modality for malignant diseases, partly induces apoptosis. It is not known, however, whether therapeutic low-dose and low-dose-rate radiation are able to induce apoptosis. METHODS: The effect of low-dose radiation on apoptosis induction in HeLa Hep2 cells was studied, and quantitation of the apoptotic cells was performed by immunocytochemistry using TdT-mediated dUtp-x Nick End Labeling (TUNEL) technology and the M30 CytoDEATH antibody method. RESULTS: When TUNEL staining was used to quantify apoptosis in untreated HeLa Hep2 cells kept in culture, approximately 5 plus minus 3% of the cells showed positive staining without any treatment. In the first experiment, the HeLa Hep2 cells were exposed to gamma radiation (i.e., 0.5, 1, 2, 5, 10, and 15 grays [Gy]) from a cobalt-60 radiation source delivering a dose rate of 0.80 Gy/min. The radiated cells were cultivated for 5, 10, 24, 48, 72 and 168 hours after irradiation. Radiation doses below 2 Gy did not cause any significant apoptosis, but between 5 and 15 Gy significant apoptosis was observed, with peak values at 5 Gy (P < 0.001). Up to 60% of the investigated cells were shown to display apoptosis. Time to this peak value was 168 hours after irradiation. The HeLa Hep2 cells were exposed to doses of 2, 5, and 10 Gy at a 10-fold lower dose rate (0.072 Gy/min). The cells that achieved a dose below 2 Gy did not present increased apoptosis. At doses above 2 Gy, however, the cells again demonstrated significant apoptosis. Up to 24 hours following irradiation, no apoptosis could be documented, whereas beyond 24 and up to 168 hours a highly significant apoptosis induction was observed. Significant cytotoxicity was confirmed by chromium-51 release from the cells at 5 Gy. CONCLUSIONS: Low-dose and low-dose-rate radiation are able to induce significant apoptosis, and apoptosis may be one of the mechanisms by which low-dose radiation causes growth inhibition.

The combination of external beam radiotherapy and experimental radioimmunotargeting with a monoclonal anticytokeratin antibody.

BACKGROUND: Doses to tumors of up to 80 grays (Gy) have been postulated to eradicate solid experimental tumors with radiommunotargeting, but this value has proved difficult to reach. Combining two treatment modalities, external beam radiotherapy and radioimmunotargeting, could potentially give rise to a number of advantages. METHODS: The purpose of this study was to detect potential benefits with different treatment timing strategies when combining external beam radiotherapy and radioimmunotargeting, with the anticytokeratin monoclonal antibody (MAb) TS1 injected into a nude mouse model carrying subcutaneous human HeLa Hep 2-cell tumors. Cytokeratins are present in necrotic regions within tumors, thereby providing a potential increase in binding sites for TS1 if combined with external beam radiotherapy. External beam radiotherapy was given before, after, and simultaneously with injection of radiolabeled MAb. RESULTS: The highest yields in terms of total accumulated dose (Gy), percentage of injected activity per gram of tumor tissue, and accumulated dose per injected activity (Gy/MBq) were seen in the group receiving external beam radiotherapy prior to MAb-injection. CONCLUSIONS: Enhanced effects may be achievable by combining external beam radiotherapy with experimental radioimmunotargeting using the monoclonal anticytokeratin antibody TS1, if the radiotherapy is given prior to MAb injection.