Can a 35mm tonsil tumor be removed by surgery or it must be treated by radiotherapy? what will be the best therapy for stage 1 carcinoma of tonsil?

Yes, but..: A 35 mm tumor is actually a stage 2 lesion of the tonsil, based on the t2 stage. T2 tumors are curable by tonsillectomy, provided there is no spread to the lymph nodes. Primary radiation of the tonsil also provides a high rate of cure. The risk of occult spread to the neck is very high, more than 20%. For this reason, radiation of the entire zone of tonsil and regional lymph nodes is reasonable.

Both: Tonsillar cancer has commonly been treated with radiation therapy with concurrent chemotherapy with great efficacy. More recently a robotic surgical resection of the tonsil has been done; however, many of these cases still require radiation therapy after surgery due to high risk pathologic features.