Radiation treatment of hemato-oncological patients in times of the COVID-19 pandemic : Expert recommendations from the radiation oncology panels of the German Hodgkin Study Group and the German Lymphoma Alliance.

PURPOSE: The coronavirus pandemic is affecting global health systems, endangering daily patient care. Hemato-oncological patients are particularly vulnerable to infection, requiring decisive recommendations on treatment and triage. The aim of this survey amongst experts on radiation therapy (RT) for lymphoma and leukemia is to delineate typical clinical scenarios and to provide counsel for high-quality care. METHODS: A multi-item questionnaire containing multiple-choice and free-text questions was developed in a peer-reviewed process and sent to members of the radiation oncology panels of the German Hodgkin Study Group and the German Lymphoma Alliance. Answers were assessed online and analyzed centrally. RESULTS: Omission of RT was only considered in a minority of cases if alternative treatment options were available. Hypofractionated regimens and reduced dosages may be used for indolent lymphoma and fractures due to multiple myeloma. Overall, there was a tendency to shorten RT rather than to postpone or omit it. Even in case of critical resource shortage, panelists agreed to start emergency RT for typical indications (intracranial pressure, spinal compression, superior vena cava syndrome) within 24 h. Possible criteria to consider for patient triage are the availability of (systemic) options, the underlying disease dynamic, and the treatment rationale (curative/palliative). CONCLUSION: RT for hemato-oncological patients receives high-priority and should be maintained even in later stages of the pandemic. Hypofractionation and shortened treatment schedules are feasible options for well-defined constellations, but have to be discussed in the clinical context.

Dosimetric properties and commissioning of cone-beam CT image beam line with a carbon target.

BACKGROUND AND PURPOSE: Accurate patient positioning before radiotherapy is often verified using advanced imaging techniques such as cone-beam computed tomography (CBCT). Even for dedicated imaging beam lines, the applied dose is not necessarily negligible with respect to the treatment dose and should be considered in the treatment plan. MATERIALS AND METHODS: This study presents measurements of the beam properties of the Siemens kView (Siemens AG, Munich, Germany) image beam line (IBL) and the commissioning in the Philips Pinnacle(3) treatment planning system (TPS; Philips, Amsterdam, Netherlands). RESULTS: The percent depth dose curve reaches its maximum at a depth of 10 mm, with a surface dose of 44 %. The IBL operates in flattening filter-free mode, showing the characteristic dose falloff from the central axis. Stability over several days to months is within less than 2 % dose deviation or 1 mm distance-to-agreement. Modelling of the IBL beam line was performed using the Pinnacle(3) automatic modelling routine, with absolute dosimetric verification and film measurements of the fluence distribution. CONCLUSION: After commissioning of the IBL beam model, the dose from the imaging IBL CBCT can be calculated. Even if the absolute dose deposited is small, repeated imaging doses may sum up to significant amounts and can shift the position of the dose maximum by several centimetres.

[TNF-alpha mRNA expression in lung cancer cell lines induced by ionizing radiation].

OBJECTIVE: The aim of this study is to investigate the release of TNF-alpha mRNA in two lung cancer cell lines in vitro and the regulation of TNF-alpha mRNA expression by ionizing radiation. METHODS: Two lung cancer cell lines (A549 and NCI-H596) were investigated for their TNF-alpha mRNA expression before and after exposure to different irradiation doses (2, 5, 10, 20, 30 and 40 Gy) and at different time intervals (1, 3, 6, 12, 24, 48 and 72 hours after irradiation). The TNF-alpha mRNA expression was quantified by fluorescence-based real-time quantitative RT-PCR. Colony formation assays were performed after irradiation with a dose of 2, 4, 6, and 8 Gy to determine the clonogenic survival. RESULTS: Dependent on the dose given, irradiation was found to cause increasing induction of TNF-alpha mRNA expression of NCI-H596 cells, reaching maximal level after 40 Gy irradiation, which was 83 times higher than that of normal controls. On the other hand, dependent on the time after irradiation, TNF-alpha mRNA expression of NCI-H596 and A549 cells was increased, reaching maximal level at 6h for NCI-H596 cells, which was 568 times higher than that of normal control cells. TNF-alpha mRNA expression of A549 cells was increased to maximum at 1 h after irradiation and was 136 times higher than that of control cells. Colony formation efficiency (number of colonies divided by the number of inoculated cells) of unirradiated control A549 and NCI-H596 cells was 0.37-0.45 and 0.12-0.24, respectively. The survival fraction (SF) of A549 cells was 47.3% +/- 9.0% at 2 Gy, 18.0% +/- 3.0% at 4 Gy, 6.0% +/- 2.0% at 6 Gy, 1.4% +/- 0.3% at 8 Gy. The SF of NCI-H596 cells was 55.2% +/- 51.0% at 2 Gy, 15.9% +/- 9.2% at 4 Gy, 3.5% +/- 1.7% at 6 Gy; 0.9% +/- 0.6% at 8 Gy. The curves of TNF-alpha expression of the two tumor cell lines were nearly identical, therefore the radiosensitivity of these cell lines was similar. Statistically there was no significant difference for D(0) and D(q) (P > 0.05). CONCLUSION: The two lung cancer cell lines studied express TNF-alpha following irradiation in a time- and irradiation dose-dependent manner. Radiation-induced TNF-alpha production of tumor cells may be of paramount importance not only for tumor behaviour, but also in respect to potential damage to normal tissues and the clinical status of the host.

Medulloblastoma: experience of a single institution.

BACKGROUND: The treatment of medulloblastoma has changed considerably during the last decades. Treatment differences between centers may affect a multicenter analysis. We analyzed data from patients of a single institution gathered over a long period of time. PATIENTS: Between 1968 and 1995, 60 patients with medulloblastoma were treated at the University of Munster. Thirty-six were male, 24-female. The ages ranged between 11 months and 32 years. METHODS: Data were retrospectively analyzed from files. Survival was estimated using the Kaplan Meier method and compared using the logranktest and multivariance analysis. RESULTS: The 5-year survival rate was 37%. This included an early mortality of 20% within the first two months, prior to 1980. Significant single, positive, prognostic factors included: no solid metastases (p = 0.001), age > 10 years (p < 0.002); total resection (p < 0.025); posterior fossa radiation with more than 50 Gy (p = 0.04); and intense chemotherapy (p = 0.02). Male patients did slightly worse (not significant). The three-year event-free survival rate of 16 patients treated after 1991 was 70%. CONCLUSION: The prognosis of medulloblastoma has clearly improved with the reduction of the perioperative mortality, standardized radiotherapy, and the introduction of intense chemotherapy.