Comparative study of two cohorts of older adults with advanced cancer treated before and after implementation of a geriatric oncology service.

Abstract

12036 Background: A comprehensive geriatric assessment (CGA) has been recommended by guidelines for older adults with cancer for whom chemotherapy is considered. As a quality assessment effort, we examined the effect of CGA conducted by a geriatric oncology service (GOS) in routine practice on clinical outcomes. Methods: This was a comparative study of two cohorts of consecutive patients aged ≥ 70 years with unresectable, locally advanced or metastatic cancer who were referred to medical oncology for first-line chemotherapy before (September 2015-August 2018) and after (September 2018-March 2021) the establishment of a GOS at a single institution in Japan. When the treating physician requested a consultation, the GOS conducted a CGA and provided recommendations for the oncologic treatment plan and geriatric interventions. We compared time to treatment failure (TTF) rates at 30, 60 and 90 days as well as 6-month overall survival (OS) rates between the two cohorts adjusting for potential confounders. TTF was defined as the time from start of first-line chemotherapy to discontinuation of first-line chemotherapy for any reason. Results: The study population consisted of 342 patients. Median age was 75 years (range: 70-95 years) and 85% had gastrointestinal tract cancer including gastroesophageal (43%) and colorectal (41%). Baseline characteristics of the patients treated before (n = 151) and after (n = 191) GOS implementation were similar with regard to age, sex, cancer type, and performance status. In the after GOS cohort, 82 patients (43%) received CGA before the treatment decision and oncologic treatment plans were changed after consultation in 49 patients (60%). For the majority of these patients, the treatment plan was adjusted to a less intensive option. Two hundred and eighty-two patients received chemotherapy (n = 128 before, n = 154 after GOS cohort) and 60 patients were treated with best supportive care only (n = 23 before, n = 37 after GOS cohort). More patients in the after GOS cohort were treated with reduced-intensity chemotherapy compared with those in the before GOS cohort (55% vs. 39%, P = 0.007). TTF event rates at 30 days (5.7% after vs. 14% before, P = 0.02), 60 days (13% after vs. 29% before, P = 0.001) and 90 days (26% after vs. 36% before, P = 0.06) were lower in the after GOS cohort compared to the before GOS cohort. Among patients receiving chemotherapy, significantly more patients were alive at 6 months in the after GOS cohort compared to the before GOS cohort (84% vs. 72%, P = 0.01). In all patients receiving CGA (n = 94), 219 interventions to address health problems were recommended and 97 interventions were conducted with an overall implementation rate of 44%. Conclusions: In this before-and-after quality assessment study, implementation of the GOS was associated with improved TTF and OS in older adults with advanced cancer receiving first-line chemotherapy.