Prospective evaluation of Intensity Modulated Radiation Therapy with Simultaneous Integrated Boost (IMRT-SIB) in head and neck squamous cell carcinoma in patients not suitable for chemo-radiotherapy.

•Locally advanced cancers of pharynx and larynx are treated with chemo-radiotherapy.•Management of these patients not fit for chemo-radiotherapy is challenging.•Conformal radiotherapy yields better response with reduced toxicity.•Intensity modulated radiotherapy with simultaneous boost (IMRT-SIB) is a new way.•IMRT-SIB helps in dose escalation as well as better normal tissue sparing.•IMRT-SIB is a safe and acceptable option for patients unfit for chemo-radiotherapy.