Radiation Injuries of Oral Cavity and Oropharynx after Interstitial Neutron Brachytherapy and Gamma-Therapy

Abstract

This study covered 418 patients who received interstitial brachytherapy with Cf-252 (382) and Co-60 (36) sources for cancer of the oral mucosa and oropharynx.

Among the patients under observation some radiation complications occurred in 118 (28.2%) patients. The time of diagnosis of radiation injuries varied from 3 months to 9 years. In 95 patients (80.5%) radiation injuries were diagnosed 12 months after completing treatment. In 14 (11.9%) patients they occurred within 1–2 years, in 4 (3.4%) 2–3 years and in 5 (4.2%) patients later then three years.

Radiation lesions developed more often in patients with cancer of tongue and floor of the mouth, 27.1% (58 of 214) and 33.9% (53 of 156), respectively. Radiation injuries of soft tissues of buccal mucosa were found in 11.7% (2 of 17) of patients and those of oropharynx in 16.1% (5 of 31) of patients.

Depending on the extent of the primary tumor, radiation injuries developed with T1 tumors in 7 of 50 (14.0%) cases, T2 -67 of 176 (38%), T3 — 15 of 76 (19.7%) and T4 — 11 of 37 (29.7%). Radiation injuries for the recurrent tumors were observed in 18 of 79 (22.7%) patients. The analysis of these results indicates that the frequency of radiation complications increases with the greater extent of both the primary and relapsing tumors. Radiation injuries were found in 68.4% (13 of 19) of cases after combined therapy using Co-60 and Cf-252 sources, in 31.8% (21 of 66) with neutron brachytherapy alone and 35.2% (6 of 17) following Co-60 only. In different schemes of combined and complex treatments with Cf-252 sources the frequency of radiation injuries varied from 21.3% to 30.4%.

In most patients radiation injuries were managed conservatively. As a result of the conservative therapy and limited surgical interventions 111 (94.0%) patients have achieved a complete healing of ulcers (75) and radionecrosis of the mandible (36) without any functional derangements and cosmetics defects. Only 7 (5.9%) patients needed extended surgical interventions.