Physical aspects of radioisotope brachytherapy: Technical reports series No. 75, International Atomic Energy Agency, Vienna 1967 (London, Her Majesty's Stationery Office) pp. 63 $1.50 (10/8d).

Abstract

Purpose: To evaluate the efficacy of postoperative brachytherapy alone (brachy) for Stage T1-2 squamous cell carcinomas (SCC) of the floor of mouth (FM) and the oral tongue (OT) with close or positive margins.Methods and Materials: Between 1979 and 1993, 36 patients with T1-2 N0 (24 T1, 12 T2) OT (19), and FOM (17) SCC with close or positive margins following surgery underwent postoperative brachy. Mean patient age was 56 years (range 37–81) and sex ratio was 3.5:1 male:female. Mean surgery to brachy interval was 36 days (range 16–68). The technique used was interstitial Iridium-192 (192Ir) brachytherapy with plastic tubes and manual afterloading. Mean total dose was 60 Gy (range 50–67.4) at a mean dose rate of 0.64 Gy/h (range 0.32–0.94). Mean patient follow-up was 80 months.Results: The 5-year actuarial overall and cause-specific survivals of the entire group were 75% and 85%, respectively. The local control was 88.5% at 2 years, with a plateau apparent after 23 months. Of the 4 local relapses, 2 were salvaged with surgery and external beam radiotherapy (EBR). No tumor or treatment factors, including tumor size, margin status, disease site, or radiation dose, were correlated with local control. The 2 head and neck second primaries underwent curative treatment on nonirradiated tissue. One patient developed a grade 3 sequelae (bone and soft tissue necrosis). Grade 2–3 chronic sequelae were seen in 7 of 17 and 3 of 19 FOM and OT tumors, respectively (p = 0.09).Conclusion: Postoperative brachy is a promising approach in T1-2 N0 OT and FOM SCC with close or positive margins. This approach is associated with high rate of locoregional control and low risk of chronic sequelae, obviates major surgery, avoids potential sequelae of EBR (xerostomia, dysgueusia, fibrosis), and avoids treatment of second head and neck primary on nonirradiated tissues.