Recurrence after colorectal cancer surgery
Advances in surgery and adjuvant therapy have reduced local recurrence of rectal cancer, but it still occurs in some patients. Such recurrences are often difficult to resect or require major surgery. Most colorectal cancers are adenocarcinomas, and recurrent tumors contain many hypoxic cells and are often radioresistant; if the pelvis has already received X-ray therapy, repeat X-ray therapy is difficult. Carbon ion therapy is included in Japan’s colorectal cancer treatment guidelines.
Insurance coverage in Japan
Since April 2022, “localized colorectal cancer difficult to cure surgically (limited to postoperative recurrence)” has been covered by insurance, mainly pelvic recurrence. Abdominal lymph node recurrence outside the pelvis is provided as Advanced Medical Care. The primary colorectal tumor itself is not treated. Treatment may be possible even after preoperative pelvic radiotherapy or when a recurrent lesion grows again after radiotherapy.
Exclusions
Metastases difficult to cure in organs other than the pelvic recurrence or abdominal lymph nodes; recurrent tumor widely in contact with or invading the digestive tract, bladder, etc.; active or intractable infection in the irradiated area; serious complications; or the physician judging treatment difficult.
Schedule for pelvic recurrence
After eligibility confirmation, written consent, and approval by the hospital’s multidisciplinary cancer board, an immobilization device is made and a treatment-planning CT is taken. Preparation takes about 10 days, and irradiation is 16 fractions over 4 weeks. Chemotherapy is not combined during treatment. The plan considers the dose to surrounding normal tissues such as the bladder and digestive tract and includes nearby lymph node regions where possible.
Schedule for abdominal lymph node recurrence
The process is the same as for pelvic recurrence, with 12 fractions over 3 weeks.
Side effects
Skin redness and itching, fatigue, diarrhea, abdominal discomfort, and nerve problems may occur. Rarely, serious side effects such as digestive tract ulcers, bleeding, and pelvic infection occur.