1. Hong WK, Lippman SM, Itri LM, Karp DD, Lee JS, Byers RM, et al. Prevention of second primary tumors with isotretinoin in squamous-cell carcinoma of the head and neck. N Engl J Med. 1990;323(12):795–801.
2. Chu PY, Chang SY, Huang JL, Tai SK. Different patterns of second primary malignancy in patients with squamous cell carcinoma of larynx and hypopharynx. Am J Otolaryngol. 2010;31(3):168–74.
3. Lippman SM, Hong WK. Second malignant tumors in head and neck squamous cell carcinoma: the overshadowing threat for patients with early-stage disease. Int J Radiat Oncol Biol Phys. 1989;17(3):691–4.
4. Gluckman JL, Crissman JD, Donegan JO. Multicentric squamous-cell carcinoma of the upper aerodigestive tract. Head Neck Surg. 1980;3(2):90–6.
5. Shapshay SM, Hong WK, Fried MP, Sismanis A, Vaughan CW, Strong MS. Simultaneous carcinomas of the esophagus and upper aerodigestive tract. Otolaryngol Head Neck Surg. 1980;88(4):373–7.