Proton Therapy in the Treatment of Anal Cancer in Pelvic Kidney Transplant Recipients: A Case Series

Abstract

Purpose: The incidence of anal cancer in patients with kidney transplants has increased. The definitive treatment for anal cancer is chemotherapy and intensity-modulated radiation therapy. In kidney transplant recipients, sparing the pelvic kidney in the process of delivering radiation to the anus can be challenging. Intensity-modulated proton therapy (IMPT) has been proposed as an alternative to intensity-modulated radiation therapy for the treatment of anal cancer in this population, given its increased ability to spare organs-at-risk. Case Series: We present 4 cases of patients with transplanted pelvic kidneys who subsequently developed anal cancer and were treated with IMPT from 2017 to 2019. Conclusion: Use of IMPT appears to be an acceptable option for the treatment of anal cancer in patients with a pelvic kidney.

PTCOG Gastrointestinal Subcommittee Lower Gastrointestinal Tract Malignancies Consensus Statement

“…51 In a series of 4 patients with transplanted pelvic kidneys and AC receiving concurrent definitive PBS-PBT and 5-FU/mitomycin-C, the transplanted kidney mean dose was <1 Gy(RBE) in 3 patients and 3.6 Gy(RBE) in one patient, max V20Gy 5.79%, and max V6Gy 18.26%, well below accepted kidney constraints and what would be achievable with photons. 52 While long-term follow-up data will provide more insight into the impact of radiation dose sparing achievable with PBT, optimal transplanted kidney sparing and integral dose mitigation with PBT should be offered when available.…”

De-Escalation of Therapy for Patients with Early-Stage Squamous Cell Carcinoma of the Anus

“…The dosimetric advantages of proton therapy may also be a useful method to reduce toxicity and spare adjacent organs at risk in the management of SCCA. Use of proton therapy to treat localized SCCA while sparing the pelvic kidney in transplant recipients has been reported in a small case series [ 70 ]. In a multi-institutional single-arm pilot study, patients with localized SCCA were treated with pencil beam scanning proton beam RT with concurrent 5-FU and MMC [ 71 ].…”