Clinical outcomes of single or oligo-fractionated stereotactic radiotherapy for head and neck tumors using micromultileaf collimator-based dynamic conformal arcs

Retreatment of Recurrent or Second Primary Head and Neck Cancer After Prior Radiation: Executive Summary of the American Radium Society® (ARS) Appropriate Use Criteria (AUC): Expert Panel on Radiation Oncology - Head and Neck Cancer

BACKGROUND

Re-treatment of recurrent or second primary head and neck cancers occurring in a previously irradiated field is complex. Few guidelines exist to support practice.

METHODS

We performed an updated literature search of peer-reviewed journals in a systematic fashion. Search terms, key questions, and associated clinical case variants were formed by panel consensus. The literature search informed the committee during a blinded vote on the appropriateness of treatment options via the modified Delphi method.

RESULTS

The final number of citations retained for review was 274. These informed five key questions, which focused on patient selection, adjuvant re-irradiation, definitive re-irradiation, stereotactic body radiation (SBRT), and re-irradiation to treat non-squamous cancer. Results of the consensus voting are presented along with discussion of the most current evidence.

CONCLUSIONS

This provides updated evidence-based recommendations and guidelines for the re-treatment of recurrent or second primary cancer of the head and neck.

Long-Term Tumor Control despite Late Pseudoprogression on(18)F-FDG-PET following Extremely Hypofractionated Stereotactic Radiotherapy for Retropharyngeal Lymph Node Metastasis from Esthesioneuroblastoma

(18)F-FDG-PET is a valuable adjunct to conventional imaging for evaluating treatment response following stereotactic body radiotherapy (SBRT) for head and neck malignancies (HNM). The effect of treatment-related inflammation is generally deemed negligible after 12 weeks following conventionally fractionated radiotherapy. Herein, we describe an unusual case showing pseudoprogression on (18)F-FDG-PET 2 years after SBRT for retropharyngeal lymph node metastasis (RPLNm) from esthesioneuroblastoma. A 36-year-old man presented with right RPLNm 32 months after the diagnosis of esthesioneuroblastoma associated with ectopic adrenocorticotropic hormone production. The RPLNm was treated with SBRT in 2 fractions over 8 days using dynamic conformal arcs with concomitant chemotherapy with cisplatin and etoposide. Although follow-up MRI showed sustained lesion regression, the early/delayed maximum standardized uptake (SUVmax) values on dual-time-point (18)F-FDG-PET obtained 1 and 2 years after SBRT were 7.7/8.3 and 8.5/10.1, respectively, suggesting local progression. Despite no subsequent focal or systemic treatment, the SUVmax values gradually decreased thereafter over a period of 4 years (3.3/3.4 at 76 months). MRI obtained 7 years after SBRT revealed sustained tumor regression. No obvious relevant toxicities have occurred. Thus, caution should be exercised in the interpretation of the SUVmax change following ablative irradiation for HNM.

Target volume geometric change and/or deviation from the cranium during fractionated stereotactic radiotherapy for brain metastases: potential pitfalls in image guidance based on bony anatomy alignment

INTRODUCTION

This study sought to evaluate the potential geometrical change and/or displacement of the target relative to the cranium during fractionated stereotactic radiotherapy (FSRT) for treating newly developed brain metastases.

METHODS

For 16 patients with 21 lesions treated with image-guided frameless FSRT in 5 or 10 fractions using a 6-degree-of-freedom image guidance system-integrated platform, the unenhanced computed tomography or T2-weighted magnetic resonance images acquired until the completion of FSRT were fused to the planning image datasets for comparison. Significant change was defined as ≥3-mm change in the tumour diameter or displacement of the tumour centroid.

RESULTS

FSRT was started 1 day after planning image acquisition. Tumour shrinkage, deviation and both were observed in 2, 1 and 1 of the 21 lesions, respectively, over a period of 7-13 days. Tumour shrinkage or deviation resulted in an increase or decrease in the marginal dose to the tumour, respectively, and a substantial increase in the irradiated volume for the surrounding tissue irrespective of the pattern of alteration. No obvious differences in the clinical and treatment characteristics were noted among the populations with or without significant changes in tumour volume or position.

CONCLUSION

Target deformity and/or deviation can unexpectedly occur even during relatively short-course FSRT, inevitably leading to a gradual discrepancy between the planned and actually delivered doses to the tumour and surrounding tissue. To appropriately weigh the treatment outcome against the planned dose distribution, target deformity and/or deviation should also be considered in addition to the immobilisation accuracy, as image guidance with bony anatomy alignment does not necessarily guarantee accurate target localisation until completion of FSRT.

Cerebral cyst formation following stereotactic ablative irradiation for non-nasopharyngeal head and neck malignancies: imaging findings and relevant dosimetric parameters

OBJECTIVE

To describe the clinical characteristics, imaging findings and relevant dosimetric parameters of cases presenting with cerebral cyst formation (CCF) after single or oligo-fractionated stereotactic radiotherapy (SRT) for non-nasopharyngeal head and neck malignancies (HNMs).

METHODS

We identified four cases with the follow-up duration of 5.7-9.1 years from SRT. The irradiated sites included the middle ear in one case and the ethmoid sinus in three cases, two of the latter possessed brain invasion. The chronological changes in MR images and the dose-volume histogram of the adjacent brain tissue were evaluated.

RESULTS

CCF with or without multiple septi presented with a latency of 29-86 months (median, 45.5 months), which was preceded by either non-specific parenchymal enhancement or typical radiation necrosis. In three cases, CCF adjacent to the frontal base resultantly caused mass effect, and two of these three cases required surgical intervention at 38 and 54 months, respectively, after SRT for alleviation of symptoms. The relation of the irradiated brain volumes to the biological equivalent dose based on the linear-quadratic (LQ) and LQ-cubic models was represented as a threshold.

CONCLUSION

When contemplating SRT for HNM cases, caution should be exercised to the dose-volume relation-ship of the adjacent brain tissue, especially the frontal base, as well as other critical structures, and long-term vigilant follow-up is also mandatory.

ADVANCES IN KNOWLEDGE

CCF can occur as an unusual consequence of late brain injury with variable but mostly long latency following SRT for non-nasopharyngeal HNMs adjacent to the brain, even superficial parts that were previously irradiated via conventional radiotherapy.

Stereotactic ablative radiotherapy delivered by image-guided helical tomotherapy for extracranial oligometastases

PURPOSE

To investigate the outcomes and risk factors of patients treated with stereotactic ablative radiotherapy (SABR) delivered by image-guided helical tomotherapy (HT) for extracranial oligometastases.

METHODS

From August 2006 through July 2011, 42 consecutive patients (median age 69 years [range 16-87]) with oligometastases (≤3) received HT to all known cancer sites (lung, n = 28; liver, n = 12; adrenal, n = 2). Prognostic factors were assessed by Cox's proportional hazards regression analysis.

RESULTS

A total of 60 lesions were treated with hypofractionated HT (median dose 39 Gy [range 36-72.5]; median dose per fraction 12 Gy [range 5-20]). Complete or partial response was observed in 40 (54 %) patients. With a median follow-up period of 15 months, 1- and 2-year overall survival (OS) was 84 and 63 %, respectively; and 1- and 2-year local control (LC) was 92 and 86 %, respectively. Four patients had pneumonitis Grade ≥2 and two patients had lower gastrointestinal toxicity Grade ≥2. Only the lack of complete/partial response was associated with higher risk of mortality on univariate (HR = 3.8, P = 0.04) and multivariate (HR = 6.6, P = 0.01) analyses.

CONCLUSIONS

SABR delivered by image-guided HT is well tolerated and offers adequate LC with low acute morbidity in patients with extracranial oligometastatic disease. We found that the response to HT was the only predictor for OS.