8. Guidelines for Intratumoral Injection of Chlorine Dioxide in Colorectal Cancer

8.1 Indications

• 8.1.1 Early-stage colorectal cancer not suitable for surgery.

• 8.1.2 Mid to late-stage colorectal cancer without complete obstruction of the intestinal lumen or anal canal.

• 8.1.3 Lymph node metastases in the abdomen, pelvis, or groin, or metastases to other organs.

• 8.1.4 Colon cancer causing intestinal obstruction where the tumor cannot be surgically removed, requiring intestinal anastomosis, or rectal cancer requiring colostomy; local chlorine dioxide treatment can be applied to the primary tumor.

• 8.1.5 Recurrence of colorectal cancer post-surgery when a second surgery is not an option.

• 8.1.6 Recurrence of rectal cancer after radiotherapy or chemotherapy.

8.2 Contraindications

• 8.2.1 Advanced colorectal cancer with cachexia.

• 8.2.2 Severe electrolyte imbalance caused by colorectal obstruction.

• 8.2.3 Platelet count < 60×10⁹/L.

• 8.2.4 Severe anemia with Hb < 60g/L.

8.3 Pre-treatment Preparation

• 8.3.1 Conduct necessary examinations:

  • Routine blood, urine, stool tests, including fecal occult blood.

  • Abdominal and pelvic ultrasound or CT.

  • Barium enema.

  • Colonoscopy or rectoscopy.

  • Tumor markers: CEA, AIP.

  • ECG.

• 8.3.2 Discuss treatment with the patient and obtain consent. Explain possible complications, such as fever, local pain, bleeding, intestinal perforation, and peritonitis, to alleviate concerns and build confidence.

• 8.3.3 Perform a cleansing enema the day before and saline enema (500-1000ml) one hour before treatment. Administer intramuscular injections of 0.1g butorphanol, 10mg anisodamine, 1KU antihemorrhagic agent, and 48mg ondansetron 15 minutes before treatment.

8.4 Puncture Needle and Auxiliary Instruments

• 23G×15.0 cm or 25G×9.0 cm puncture needle (for treatments guided by ultrasound or CT), needle via colonoscope, colonoscope, CT or ultrasound machine, and liquid paraffin.

8.5 Treatment Procedure

• 8.5.1 Disinfect the puncture site skin or perianal skin and anus, wear sterile gloves, and cover with a sterile drape.

• 8.5.2 Conduct colonoscopy or rectoscopy via the anus to locate the cancer and puncture site, insert the needle through the scope to the cancer site, connect the syringe, and inject chlorine dioxide solution in multiple spots. Each injection should amount to 30% of the tumor volume (ml), or use CT guidance for percutaneous puncture for tumors ≤4 cm with single-point injection; for >4 cm tumors, use multi-point injections, with each dose based on 30% of the tumor segment volume (cm).

• 8.5.3 Monitor for bleeding at the treatment site. Use 1/1000 adrenaline solution for hemostasis if necessary, and administer hemostatic drugs intravenously post-procedure.

• 8.5.4 After treatment, slowly remove the colonoscope, clean the anal and perianal skin, observe for 5–10 minutes, and then transfer the patient to the ward.

• 8.5.5 If cancer is around the colon or rectum or involves lymph node metastases, use ultrasound or CT to guide the puncture for intratumoral injection.

8.6 Post-treatment Care

• 8.6.1 Administer intravenous antibiotics and hemostatic drugs.

• 8.6.2 Watch for fever, abdominal pain, and blood in stool, and treat symptoms as needed.

• 8.6.3 Maintain hygiene of the anus and perianal area, using a 1000ppm chlorine dioxide solution sitz bath daily, especially after bowel movements.

• 8.6.4 Perform complete blood counts and stool tests twice weekly, and liver and kidney function tests weekly.

8.6.5 The treatment course consists of four sessions, each 7 days apart. After the treatment cycle, assess tumor markers and peripheral blood T lymphocyte subsets (CD4, CD8) to evaluate effectiveness.