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Elderly patients represent a growing subgroup of cancer patients for whom the role of radiation therapy is poorly defined. Older patients are still clearly underrepresented in clinical trials, resulting in very limited high-level evidence. Moreover, elderly patients are less likely to receive radiation therapy in similar clinical scenarios compared to younger patients. However, there is no clear evidence for a generally reduced radiation tolerance with increasing age. Modern radiation techniques have clearly reduced acute and late side effects, thus extending the boundaries of the possible regarding treatment intensity in elderly or frail patients. Hypofractionated regimens have further decreased the socioeconomic burden of radiation treatments by reducing the overall treatment time. The current review aims at summarizing the existing data for the use of radiation therapy or chemoradiation in elderly patients focusing on the main cancer types. It provides an overview of treatment tolerability and outcomes with current standard radiation therapy regimens, including possible predictive factors in the elderly population. Strategies for patient selection for standard or tailored radiation therapy approaches based on age, performance score or comorbidity, including the use of prediction tests or geriatric assessments, are discussed. Current and future possibilities for improvements of routine care and creation of high-level evidence in elderly patients receiving radiation therapy are highlighted., Competing Interests: Falk Roeder received travel grants and lecture honoraria from Intraop Medical and PharmaMar. All other authors reported no competing interests., (© 2023 Roeder et al.)

Purpose: As radionuclide therapy is gaining importance in palliative treatment of patients suffering from neuroendocrine tumour (NET) as well as castration resistant prostate cancer (CRPC), the radiation protection of patients, staff, family members and the general public is of increasing interest. Here, we determine patient discharge dates according to European guidelines., Methods: In 40 patients with NET and 25 patients with CRPC organ and tumour doses based on the MIRD concept were calculated from data obtained during the first therapy cycle. Planar whole body images were recorded at 0.5, 4, 20, 68 und 92 h postinjection. Residence times were calculated from the respective time-activity-curves based on the conjugated view method. Residence times for critical organs were fitted into the commercially available OLINDA software to calculate the organ doses. The doses of tumours and salivary glands were calculated via their self-irradiation by approximation with spheres of equivalent volume. Kidney volumes were gained by organ segmentation, volumes of all other organs were estimated by means of OLINDA and hence were lean body mass corrected. Out of the whole body curves reference points for patient discharge were estimated., Results: In patients with NET discharge dates could be properly estimated from dosimetric data, which is not only crucial for radiation protection, but also makes therapy planning easier. For 177 Lu-PSMA-617 ligand therapy it is difficult to seriously estimate a generalized discharge date due to large interpatient variation resulting from different tumor loads and heavy pre-treatment., Conclusion: Patient release is predictable for 177 Lu-DOTATATE therapy but not for 177 Lu-PSMA ligand therapy.

Background: Laser scanning-based patient surface positioning and surveillance may complement image-guided radiotherapy (IGRT) as a nonradiation-based approach. We investigated the performance of an optical system compared to standard kilovoltage cone-beam computed tomography (CBCT) and its potential to reduce the number of daily CBCTs., Patients and Methods: We analyzed the patient positioning of 153 treatment fractions in 21 patients applied to three different treatment regions. Patients were first scanned with CBCT, shifted to the optimal isocenter position, and an optical scan was performed to verify the matching in relation to CBCT., Results: For the head-and-neck region, the lateral/longitudinal/vertical/rotational/roll and pitch shift was 0.9 ± 1.8 mm/-2.7 ± 3.8 mm/-0.8 ± 3.6 mm/0.0 ± 1.1°/-0.5 ± 2.1°/0.2 ± 1.6°. For the thorax, the lateral/longitudinal/vertical/roll and pitch shift was -1.2 ± 3.6 mm/0.8 ± 5.1 mm/0.8 ± 4.3 mm/0.6 ± 1.4°/0.1 ± 0.9°/0.3 ± 1.0°. For the pelvis, the respective values were -2.5 ± 4.1 mm/4.6 ± 7.3 mm/-5.1 ± 7.4 mm/0.3 ± 1.1°/-0.5 ± 1.0°/0.3 ± 2.1°. In total, the recorded disagreement was -1.0 ± 3.6 mm/1.0 ± 6.3 mm/-1.8 ± 5.9 mm/0.3 ± 1.2°/-0.3 ± 1.5°/0.2 ± 1.7°., Conclusion: This analysis showed good agreement between the optical scanner approach and CBCT. The optical system holds potential to ensure precise patient positioning and reduced CBCT frequency in tumor locations with fixed relation to surface structures.

Radiosensitizers represent an enticing concept in tumor therapy. As ionizing radiation affects both neoplastic and normal tissues, its effects are generally non-specific. The aim of applying a radiosensitizing agent is to achieve a maximum effect on tumor tissue, while minimizing the damage to normal tissues. A variety of parameters such as the oxygen supply and the state in the cell cycle, need to be taken into account when evaluating a potential radiosensitizer. Most of the previously known radiosensitizers are neither selective nor tumor specific. In this article, we review the properties and radiosensitizing potential of Photofrin II. Photofrin II is well-known as a photosensitizing agent in photodynamic therapy. In recent years, a radiosensitizing potential of the substance has been demonstrated, specifically increasing the sensitivity of solid tumor tissues, especially of radio-resistant, hypoxic tumor cells, to radiation. This radiosensitizing effect has been demonstrated both by in vitro studies and by animal experiments. Several studies with tissue cultures have demonstrated a radiosensitizing effect of Photofrin II in glioblastoma (U-373MG) and bladder cancer cell lines (RT-4). No effect was noted in colon carcinoma cell lines (HT-29). Unpublished data of additional cell lines will be mentioned in the review. Animal experiments with Lewis sarcoma and with bladder cancer have moreover demonstrated an in vivo effect of Photofrin II as a radiosensitizer. The mechanism of this radiosensitizing effect is not completely understood. In vitro data, however, support the hypothesis that the radiosensitizing action involves OH-radicals in addition to a potential impairment of repair mechanisms after sublethal damage of ionizing radiation. Moreover, early results of a phase I trial are available and document the potential feasibility of the application of Phototofrin II as a radiosensitizing agent in clinical practice.

The biological effects of radiation affect both neoplastic and normal tissues. The nature and extent of such effects, however, depend on selected biological parameters (e.g., oxygen supply, cell cycle) and can be modified by chemical agents such as radiosensitizers, radioprotectors and chemotherapeutic agents. A precise control of the mode of action of the radiation is important in order to achieve the maximum effect on tumor tissue, while minimizing the effect on normal tissues. Most of the known and routinely used radiosensitizers are neither selective nor tumor specific. This article reviews a new selective and specific modality that increases the sensitivity of solid tumor tissue, especially of radio resistant, hypoxic tumor cells, to radiation. This modality is currently under early clinical evaluation and encompasses the application of Photofrin II, which is already used as a photosensitizer in photodynamic therapy (PDT) at predetermined times prior to irradiation.