Multi-Institutional Fact-Finding Study: Association between Geriatric Assessment and Reduction in Intensity of Radiotherapy for Elderly Cancer Patients without Metastasis

Abstract

Vulnerable patients receive a low-intensity, palliative treatment rather than the standard treatment. Defining vulnerability in terms of standard or reduced radiation intensity can result in appropriate radiotherapy for elderly cancer patients without excessive adverse events and poor outcomes. However, it is difficult to define vulnerability, because radiation oncologists hesitate to include vulnerable patients in clinical trials involving radical radiotherapy. We hypothesized that for elderly cancer patients without metastasis, vulnerability scores, obtained by geriatric assessment (GA), could help in predicting the reduction in radiation intensity determined by radiation oncologists based on their experience. In this multicenter prospective study, we enrolled cancer patients (70 years or older) without metastasis. The reduction in radiation intensity was categorized into 3 groups as follows: i) standard schedule of radiotherapy, but conversion of irradiation fields, ii) standard irradiation fields, but converted schedule of radiotherapy, and iii) conversion of radiotherapy schedule and irradiation fields. Standard radiotherapy was defined as recommended doses and radiation fields according to the guidelines for the primary tumors analyzed. GA was performed by calculating geriatric 8 (G8) and vulnerable elders survey (VES-13) scores before radiotherapy and 3-5 and 8-16 weeks after completion of radiotherapy. The primary endpoint was to evaluate the correlation between vulnerability assessed by G8 and change in radiation intensity. Between November 2020 and February 2022, 317 patients were included in this study at 13 centers in Japan. The median age was 77 (range, 70-90) years. The primary cancer sites were head and neck, esophagus, lungs, breasts, pancreas, bladder, uterus, and prostate in 63, 22, 62, 48, 6, 5, 26, and 85 patients, respectively. High-precision radiotherapy was performed for 199 patients (63%). Of the 31 patients (10%) whose radiation intensity was reduced, 14, 9, and 8 patients were provided i, ii, and iii category, respectively. Planned radiotherapy was completed for 312 patients (98%). G8 and VES-13 vulnerability scores were obtained for 201 and 61 patients, respectively, before radiotherapy. The mean G8 and VES-13 scores were 13.3 ± 2.4 and 1.8 ± 1.8, 12.9 ± 2.6 and 2.0 ± 2.0, and 13.4 ± 2.4 and 2.0 ± 1.9 before radiotherapy and 3-5 and 8-16 weeks after completion of radiotherapy, respectively. Multivariate analysis revealed that reduction in radiation intensity was significantly associated with vulnerability assessed using VES-13 (p < 0.001) but not G8 (p = 0.06). An excellent completion rate was obtained for planned radiotherapy, and vulnerability assessed using VES-13, not G8, was associated with the reduction in intensity of radiotherapy.