Repetitive transcranial magnetic stimulation for depression after colorectal cancer treatment with chemotherapy‐induced peripheral neuropathy: A case report

Background Treatment of depression in patients with cancer requires individualized decision‐making considering physical symptoms, drug interactions, adverse effects, treatment burden, and acceptability. We report a patient with persistent depression after colorectal cancer treatment, in whom pharmacotherapy was constrained by insufficient efficacy and tolerability, improvement with modified electroconvulsive therapy (mECT) was temporary, and reintroduction of mECT was difficult. She subsequently received repetitive transcranial magnetic stimulation (rTMS). Case Presentation A woman in her 60s developed depression after emergency surgery for lower gastrointestinal perforation caused by descending colon cancer and later developed chemotherapy‐induced peripheral neuropathy (CIPN) after postoperative chemotherapy. Pharmacotherapy produced insufficient improvement. Although 10 mECT sessions led to improvement, symptoms recurred after discharge. Reintroduction of mECT was not possible because of strong fear of the treatment and general anesthesia. She was referred to our hospital and received 27 rTMS sessions without changes in psychotropic medication. Her 17‐item Hamilton Depression Rating Scale and Clinical Global Impressions–Severity (CGI‐S) scores improved from 19 to 8 and from 4 to 1, respectively, whereas the pain Numerical Rating Scale score remained 8. Behavior and daily functioning also improved. Six months after treatment, limb discomfort persisted, but she could still perform household chores and go out. The referring physician rated the CGI‐S score as 1. Conclusion When pharmacotherapy for depression after cancer treatment is constrained by insufficient efficacy or tolerability, and the benefit of mECT is transient or its reintroduction is difficult, rTMS may be considered as a treatment option.