Chemotherapy induced oral mucositis is a common and debilitating complication in pediatric patients receiving chemotherapy for hematolymphoid malignancies. Oral mucositis can cause painful mouth ulcers, difficulty in eating and drinking, impaired nutrition, increased risk of infection, and significant discomfort. In severe cases, oral mucositis may lead to interruptions, delays, or dose modifications in chemotherapy, which can negatively affect cancer treatment outcomes and quality of life. Current management of chemotherapy induced oral mucositis is mainly supportive and includes maintenance of oral hygiene, bland mouth rinses, topical anesthetics, systemic analgesics, antimicrobial therapy when indicated, and nutritional support. However, these measures do not consistently promote healing of the oral mucosa or reduce the duration and severity of oral mucositis.

Photobiomodulation therapy is a non invasive treatment modality that uses low level red light to stimulate tissue repair, reduce inflammation, and improve pain control. Increasing evidence suggests that photobiomodulation therapy may reduce the severity and duration of chemotherapy induced oral mucositis and improve patient comfort. The treatment is painless, does not involve injections or additional medications, and has shown a favorable safety profile in previous studies. International supportive care guidelines have recommended photobiomodulation therapy in selected oncology settings for the management of oral mucositis.

The purpose of this Phase II single arm open label interventional study is to evaluate the feasibility and safety of photobiomodulation therapy as an adjunct to standard supportive care in pediatric patients with chemotherapy induced oral mucositis. The study will also explore preliminary clinical outcomes related to oral mucositis severity, pain control, nutritional support, and treatment interruptions.

This study will be conducted at Tata Memorial Hospital in Mumbai, India. Pediatric patients aged 3 to 14 years with hematolymphoid malignancies who are receiving chemotherapy and develop World Health Organization grade 2 or higher oral mucositis will be eligible for participation. Written informed consent will be obtained from parents or legal guardians along with age appropriate assent from the child before enrollment.

Participants enrolled in the study will continue to receive standard supportive care for oral mucositis as per institutional protocol. In addition, participants will receive photobiomodulation therapy administered using a handheld low level laser device operating at a wavelength of 660 nanometer. Photobiomodulation therapy will be administered once daily for four consecutive days by trained clinicians. The procedure is expected to take approximately 5 to 10 minutes depending on the extent of oral lesions.

Baseline assessments will include demographic details, diagnosis, chemotherapy information, oral mucositis grading, pain assessment, nutritional status, and routine blood investigation results including absolute neutrophil count where available. Oral mucositis severity will be assessed using World Health Organization oral mucositis grading and National Cancer Institute Common Terminology Criteria for Adverse Events version 6 grading systems. Pain will be assessed using the visual analog scale.

Participants will undergo daily assessments during the intervention period. Researchers will record oral mucositis severity, pain scores, analgesic requirement, nutritional support requirement, chemotherapy delays or interruptions, and adverse events. Absolute neutrophil count values obtained as part of routine oncologic care will also be documented. No additional blood investigations will be performed specifically for study purposes.

The primary outcome of the study is feasibility, defined as the proportion of participants who complete the planned photobiomodulation therapy sessions. Secondary outcomes include improvement in oral mucositis severity by Day 7, change in oral mucositis grade over predefined time points, time to resolution of oral mucositis, change in pain scores, analgesic consumption, nutritional support requirement, chemotherapy delays or interruptions, trends in absolute neutrophil count, and safety and tolerability of photobiomodulation therapy.

Participants will be followed until Day 10 after initiation of therapy for final clinical assessment and documentation of any late adverse events. The study aims to generate preliminary data regarding the feasibility and safety of photobiomodulation therapy in pediatric oncology patients with chemotherapy induced oral mucositis. If found to be feasible and well tolerated, photobiomodulation therapy may become a practical and cost effective adjunctive supportive care option for children receiving chemotherapy.

Inclusion Criteria:

• Pediatric patients aged 3 to 14 years
• Diagnosed with hematolymphoid malignancies
• Currently receiving chemotherapy
• Presence of chemotherapy induced oral mucositis of World Health Organization grade 2 or higher at screening
• Written informed consent obtained from parent or legal guardian along with age appropriate assent from the participant

Exclusion Criteria:

• Pre existing oral mucosal disease unrelated to chemotherapy
• Known photosensitivity or use of photosensitising medications
• Uncontrolled infection or active bleeding
• Any medical or clinical condition interfering with protocol compliance