The Downstream “Halo Effect” of Opening a Single-Vault Proton Therapy Facility at a Cancer Center

Abstract

There have been limited reports evaluating the effect of a proton center (PC) on a radiation oncology department at a medical center (MC). We hypothesized that the opening of our PC would both directly and indirectly increase the number of patients treated at the MC.The impact of a new single-vault PC on patient volume at the MC was evaluated from fiscal year 2016 (FY16) through FY19, representing the year prior to induction of the PC through the first 2.5 years of operation. Patient starts and fractions were obtained through hospital patient tracking and billing systems for our primary site (MC1), which shares a campus with our PC, and two additional sites (MC2 and MC3) on separate campuses. Resident Accreditation Council for Graduate Medical Education case logs were also analyzed. To determine the effect of the PC on MC1, MC2, and MC3, we reviewed the electronic medical record for all patients seen in in consultation for PC, where consults were initiated in July 2017.Photon-based treatment starts at MC1 increased by a total of 4% (P = 0.49) from FY16-FY19. Combined photon and proton starts at MC1/PC increased by a total of 27% (P < 0.0001). The total combined number of photon starts at MC1, MC2, and MC3 increased by 11% (P = 0.002). Proton starts were 38 in FY17, 174 in FY18, and 191 in FY19. A total of 523 patients were seen in consultation at the PC (185 for prostate cancer), of whom 187 ultimately underwent proton therapy (36%), 36 prostate HDR (7%), 7 Gamma Knife radiosurgery (1%), 45 photon-based treatment (9%), and 248 no treatment within our department (47%). An additional 216 patients received proton therapy following consultations for photon-based treatment at MC1, MC2, or MC3. There was a cumulative 104% increase in HDR prostate implants from FY16-FY19 at MC1 (P = 0.0005), with PC consultations directly resulting in 69 HDR prostate implants in 36 patients. There was a 96% increase (from 25 in FY16 to 49 in FY19) in pediatric yearly case volume at MC1 from FY16-FY19 (P = 0.007).The opening of our single-vault PC, which has been at full capacity since April 2018, has had no deleterious effect on photon-based treatment volume. However, there has been an approximate doubling in HDR prostate implants and pediatric treatment starts. Clinicians and administrators should be cognizant of this "halo" effect when balancing the costs and benefits of opening a particle-based therapy center.