Concurrent chemoradiotherapy (CT-RT) is often used as definitive treatment for patients with locally advanced head-and-neck squamous cancers (HNSCC). Concurrent cisplatin administered 3- weekly (100 mg/m2 on days 1, 22 and 43 of RT) is the accepted standard-of-care, but causes significant toxicity. This has resulted in altered administration schedules, including weekly (40mg/m2 ) regimen, with conflicting reports on identifying optimal schedule. We compared acute toxicity and response rates between patients on CT-RT receiving weekly and 3-weekly cisplatin in this prospective study. 56 patients received either weekly (40 mg/m2 ; 36 patients) or 3-weekly (100 mg/m2 ; 20 patients) cisplatin concurrently with 3D-conformal radiotherapy (70 Gy/35#/7 weeks) based on physician or patient preference. Patients receiving weekly schedule were older (57.9 vs 50.3 years; p=0.03), but the groups were comparable in other variables including gender, primary site and stage. Acute toxicities (myelosuppression, mucositis, dysphagia, weight loss, etc.) were frequent but similar betweengroups, excepting a significantly lower nausea/vomiting in weekly schedule (grade II in 8.3% vs. 50%; p=0.03). Two patients, both on weekly chemotherapy, expired of aspiration pneumonia during treatment. Complete response rates at 12 weeks were similar between the cohorts (77.7% vs 85% CR, respectively; p= 0.61). At median follow-up of 12 months (range: 4-21.5 months), the estimated disease-free survival (DFS) was comparable between regimens (72% and 78% at 15 months, respectively; p= 0.550). We conclude thatweekly-cisplatin is associated with lower incidence of nausea/vomiting, but has otherwise comparable acute toxicity profile to 3-weekly schedule. Response to treatment and DFS are similar between the two.

Keywords: Sensitizer Chemotherapy; Oral Cancers; Definitive Radiotherapy; Acute Toxicity; Treatment Compliance.