This triple-blinded randomized placebo control trial aims to investigate the safety and efficacy of Nutri-PEITC jelly, a functional food, in head and neck cancer patients. The primary outcome measure includes adverse events, health-related quality of life, tumor response and progression-free survival. The secondary outcome includes serum p53 and cytochrome C levels and functional status.

Previously, Nutri-jelly, a novel edible nutritious gel for patients with chewing and swallowing difficulties, was shown to be effective in improving the quality of life of head and neck cancer patients. Recently, Nutri-PEITC jelly is recently developed by addition of Phenethyl Isothiocyanate (PEITC), a phytochemical compound with chemopreventive action in animal bearing oral cancer. It intends to be a functional food for cancer survivor. The dose of PEITC in Nutri-jelly was based on safe and effective dose determined in animal studies. Furthermore, Nutri-PEITC jelly was proven safe in healthy volunteers who daily consumes for a consecutive month with no serious adverse events. The purpose of this study is to determine safety and efficacy of Nutri-jelly with PEITC in head and neck cancer patients.

independent variable: continuous Nutri -jelly with PEITC intake dependent variable (outcome): adverse effects, health-related quality of life score, tumor response, progression-free survival, serum p53 and cytochrome C levels and functional status

Inclusion Criteria:

1. Diagnosis of squamous cell carcinoma in areas of lip, oral cavity, oropharynx and hypopharynx, who receive only palliative care or deny definitive treatment
2. Finished radiotherapy or/and chemotherapy for at least one month
3. Has at least one measurable target lesion
4. Baseline KPS ≥ 40% or ECOG 0-3
5. Blood tests are in acceptable ranges (neutrophils ≥ 1.5 x 109/L, platelets ≥ 100 x 109/L; Hb ≥ 9.0 g/dL), renal function (clearance creatinine using the CKD-EPI formula (Chronic Kidney Disease Epidemiology group) ≥50 mL/min) and hepatic function (SGOT , SGPT, serum bilirubin ≤ 1.5 of upper limits of normal
6. Able to take the intervention (through mouth or NG tube) without aspiration
7. Able to communicate and consent to the study

Exclusion Criteria:

1. Cannot come back for the follow-up visits
2. Receive or had received N-acetylcysteine during the intervention
3. Has systemic diseases that might interfere with the results
4. Chronic kidney disease that requires dialysis
5. Increased risk of aspiration pneumonia
6. Pregnancy or lactation
7. Untreated infectious diseases