Successful Treatment of Adenoid Cystic Carcinoma with the Application of a High-Dose Stereotactic Body Radiotherapy Boost

Abstract

Background: Adenoid cystic carcinoma (ACC) should be treated with a surgical procedure. Unfortunately, in some cases, such procedures are impossible to perform. In that event, radiotherapy can be used as a form of radical treatment, although ACC is established as a radio- and chemoresistant tumour. Therefore, unconventional fractionated radiotherapy needs to be considered. Case presentation: Here, we present a case study of a patient with an unresectable tumour of the choanae and nasopharynx treated with a stereotactic radiotherapy boost in combination with conventional radiotherapy. We achieved complete clinical regression after application of a 1 × 18 Gy boost followed by conventional radiotherapy at 50 Gy in 25 fractions. The early and late tolerance of this treatment were positive. During the 2-year follow-up, local and distant recurrence were not detected. Conclusions: This case represents an individualized, modern and safe approach to unresectable ACC. This is one of the first cases to show the use of a combination of stereotactic and conventional radiotherapy in radical, conservative cancer treatment.

High-dose stereotactic radiotherapy boost in the treatment of squamous cell carcinoma of the head and neck region

“…The 5-year follow-up revealed 62% local control and 27% overall survival (secondary malignancy was the cause of death in 5% of cases) with good tolerance—acute mucositis G3 and dysphagia G3 in 10% of patients. In the context of our case report and previously published experience [ 15 ], involving adenoid cystic carcinoma of the choanae and nasopharynx successfully treated with an 18 Gy boost after conventional radiotherapy, we show that stereotactic boost might also be applied in one fraction with effective local control and acceptable tolerance. Unfortunately, the dynamic course of a second malignancy (lung cancer) led to death, similar to two cases in the Czech publication.…”

Stereotactic Radiotherapy Boost in Treatment of Persistent Periocular Sebaceous Carcinoma after Surgery

“…The combined biological effective dose was 98.4 Gy (72 Gy from conventional radiotherapy and 26.4 Gy from the stereotactic radiotherapy boost). Our previous experiences, which considered using a stereotactic radiotherapy boost on patients with adenoid cystic carcinoma and squamous cell carcinoma confirm the usefulness of such an approach in the radioresistant or dynamic course of cancer [ 9 , 10 ]. Early and late toxicities in those cases and in the case of the presented patient were acceptable; however, the application of a stereotactic radiotherapy boost needs very careful qualification and further clinical studies.…”

“…The idea of combining conventional radiotherapy with stereotactic radiosurgery stems from an attempt to increase the biological effective dose (BED) in the target volume and is possible with using unconventional methods of fractionation. One of the clinical trials conducted at the National Research Institute of Oncology in Poland aimed to evaluate the efficacy and safety of a stereotactic boost applied in a range from 10 Gy to 18 Gy [9]. Although the protocol of clinical trial permits using even 18 Gy in tumors <7 cm 3 , the decision to apply a 12 Gy dose of stereotactic boost was made based on the periocular localization and the close distance to organs at risk.…”