Can hyperbaric oxygen therapy be used as an adjunct in oncology for radiation‑induced tissue injury, and what are the recommended protocol, contraindications, and alternatives?

Hyperbaric Oxygen Therapy in Oncology for Radiation-Induced Tissue Injury

Hyperbaric oxygen therapy (HBOT) should be offered as an adjunctive treatment for established late radiation tissue injury (LRTI) affecting the head, neck, pelvis, anus, and rectum, particularly when standard care has failed, using protocols of 2.2–2.8 ATA for 60–120 minutes per session. 1

Indications and Evidence Base

Established Radiation Injuries with Strong Evidence

HBOT demonstrates moderate-quality evidence for treating specific radiation-induced complications:

• Osteoradionecrosis (ORN): HBOT significantly improves mucosal coverage (RR 1.3; 95% CI 1.1–1.6, NNTB 5) and reduces wound breakdown following operative treatment (RR 4.2; 95% CI 1.1–16.8, NNTB 4) 1
• Radiation proctitis: Significant improvement or cure rates (RR 1.72; 95% CI 1.0–2.9, NNTB 5) with demonstrated benefit in chronic bleeding 1, 2
• Radiation cystitis: Symptomatic benefit documented in refractory cases 3
• Post-extraction healing: Improved healing of irradiated tooth sockets following dental extraction (RR 1.4; 95% CI 1.1–1.7, NNTB 4) 1

Clinical Outcomes in Head and Neck Cancer

For head and neck cancer patients specifically, HBOT shows reliable safety and positive outcomes in 14 of 17 reviewed studies, with particular benefit for ORN and oral health complications. 4 The therapy promotes angiogenesis, fibroblast activation, and tissue remodeling in hypoxic environments 5

Recommended Treatment Protocols

Standard HBOT Protocol

The evidence-based protocol consists of:

• Pressure: 2.2–2.8 atmospheres absolute (ATA) 6
• Duration: 60–120 minutes per session 6
• Frequency: Daily sessions 7
• Total sessions: Typically 20–40 sessions, though clinical experience suggests little benefit until at least 30 sessions are completed 2

Timing Considerations

HBOT should ideally be initiated as early as possible after radiation injury is identified, though benefit can still be achieved months to years post-radiation. 1 For prevention of ORN following dental extraction in irradiated fields, the protocol typically involves 20 sessions preoperatively and 10 sessions postoperatively 8

Patient Selection Criteria

Appropriate Candidates

Consider HBOT for patients with:

• Established LRTI affecting head, neck, pelvis, anus, or rectum where standard care has failed 1
• Radiation proctitis causing bleeding that affects quality of life, causes anemia, or requires transfusion 2
• ORN requiring surgical intervention or refractory to conservative management 1, 4
• Soft tissue necrosis in irradiated fields 3
• Planned dental extraction in previously irradiated mandible (>50 Gy) 8

Exclusion Criteria and Contraindications

Patients with general frailty and significant comorbid conditions may need to be excluded due to increased risk of adverse events. 9 While the reviewed trials did not report specific adverse events, standard HBOT contraindications apply in clinical practice 1

Alternatives and Adjunctive Therapies

When HBOT is Unavailable or Unsuitable

Alternative management strategies include:

• Sucralfate enemas: Recommended for chronic radiation-induced proctitis with rectal bleeding 10, 2
• Pentoxifylline plus tocopherol (vitamin E): Weak recommendation for perioperative use around dental procedures in irradiated fields, though primarily based on observational data showing lower ORN rates with full compliance 8
• Argon plasma coagulation/heater probe: For ablating telangiectasia causing bleeding, though carries risk in non-healing tissues 2
• Formalin therapy: Simple to perform for radiation proctitis but carries risk of severe colitis, stricturing, and perforation 2
• Purastat (hemostatic peptide): Licensed for bleeding radiation proctopathy, showing reduced bleeding in 75% of patients at 1 year in a 21-patient study 2

Combination Approaches

For radiation proctitis management, optimize bowel function and stool consistency first, reduce anticoagulants if possible, and consider sucralfate enemas for severe bleeding until definitive therapy can be arranged. 2

Safety Profile in Cancer Patients

Tumor Progression Concerns

A 2025 retrospective analysis of 45 patients with solid tumors receiving a median of 27 HBOT sessions found no evidence that HBOT contributes to tumor progression, recurrence, or metastasis, with no significant correlations between number of sessions and metastasis (p=0.213) or mortality (p=0.881). 11 No HBOT-related complications were observed during treatment 11

HBOT appears safe in patients with active or previously treated solid tumors, though this evidence comes from observational data rather than randomized trials. 11

Practical Implementation Considerations

Resource and Access Limitations

HBOT requires established hyperbaric units, significant costs, and weeks of intensive treatment. 9 The intervention is only feasible for individuals who:

• Live in close proximity to established hyperbaric facilities 9
• Can commit to daily sessions over several weeks 9
• Have access to facilities with existing infrastructure (cost-effectiveness improves where units already exist for other medical conditions) 9

This conditional recommendation acknowledges reduced equity, as HBOT is limited to geographically and logistically suitable patients. 9

Quality of Evidence Limitations

The certainty of evidence for HBOT in radiation injury is low to moderate, with most studies at high risk of bias, though the studies with lowest risk of bias suggest benefit for selected tissues. 9, 1 The 2016 Cochrane review concluded that application to selected participants and tissues may be justified, but further research is needed to establish optimal patient selection and timing 1

Clinical Decision Algorithm

For radiation-induced tissue injury:

1. Confirm diagnosis of LRTI through clinical evaluation and endoscopy (avoid biopsy in irradiated mucosa due to fistula/necrosis risk) 2
2. Optimize standard care including wound management, infection control, and symptom management 9
3. If standard care fails and patient has head/neck/pelvic LRTI, assess for HBOT candidacy:
   • Proximity to hyperbaric facility
   • Ability to commit to 30+ daily sessions
   • Absence of severe frailty or prohibitive comorbidities
4. If HBOT unavailable or unsuitable, implement tissue-specific alternatives (sucralfate enemas for proctitis, pentoxifylline/tocopherol for dental procedures, argon plasma coagulation for bleeding telangiectasia) 10, 2, 8
5. For prevention of ORN before dental extraction in irradiated mandible, consider 20 preoperative + 10 postoperative HBOT sessions 8