Stereotactic Body Radiotherapy Treatment for Recurrent, Previously Irradiated Head and Neck Cancer

Abstract

Purpose:Locally recurrent, previously irradiated primary head and neck tumors have historically been associated with poor outcomes. Stereotactic body radiation therapy has emerged as a feasible and promising treatment option for tumor recurrence, particularly in nonsurgical candidates. This study aimed to assess the associated outcomes of stereotactic body radiation therapy used in this setting.Methods:Retrospective analysis of a prospectively collected database of 25 patients treated with CyberKnife for unresectable, recurrent head and neck cancer in a previously irradiated field. The primary end points evaluated were rates of survival, tumor control, and treatment-related toxicities.Results:Median survival of the study population was 7.5 months (range, 1.5-47.0 months). Median survival of the 20 (80%) patients who were treated with curative purpose was 8.3 months. One-year overall survival rate for the entire population was 32%. The respective 1-year and 2-year survival rates for the curative subcohort were 40% and 20%, respectively. Local and locoregional failure occurred in 8 (32%) and 7 (28%) patients, respectively. Low severe acute (4%) and late (6%) treatment-related toxicity rates were observed. No grade 4 or 5 toxicities were observed.Conclusion:Stereotactic body radiation therapy is a viable treatment option for patients with unresectable, recurrent head and neck cancer. Significant tumor control rates are achievable with minimal severe toxicity. Although perhaps associated with patient selection and a heterogeneous sample, overall survival of stereotactic body radiation therapy outcomes appears unfavorable.

Estimating PTV Margins in Head and Neck Stereotactic Ablative Radiation Therapy (SABR) Through Target Site Analysis of Positioning and Intrafractional Accuracy

“…SABR is increasingly used to treat recurrent and previously irradiated HNC, with early clinical outcomes suggesting favorable local control rates and manageable acute/ late toxicity. [8][9][10][11] As adoption of SABR is expanded, refinements in the set-up, planning, and treatment processes will be increasingly important to ensure safe and reliable delivery. This study demonstrated a relatively high degree of immobility using our cushion-mask-bite block system but also highlighted the importance of correcting positioning errors with image guidance before treatment, especially in the neck and mucosal groups.…”

“…The importance of limiting dose to nearby structures is reflected in early reports on clinical outcomes for HN-SABR showing 4% to 36% rates of grade 3-4 toxicity and up to 8% to 17% rates of fatal carotid blowout events. 9,11,[21][22][23] Thus, reducing PTV margins may allow better sparing of these critical structures to decrease toxicity. Supporting this concept is a study that compared 3 mm and 5 mm PTV expansions with conventionally fractionated HN-IMRT, finding no difference in control rates or marginal failures but significantly lower rates of feedingtube dependency and esophageal stricture on long-term follow-up.…”

“…24,25 This may play a role in the 11% to 59% local failure rates seen in the HN-SABR outcomes data, although these recurrent tumors are inherently difficult to control and often are not as responsive to radiation as their upfront counterparts. 8,11,21,22 In light of this, using a one-size-fits-all PTV margin may not be optimal for HN-SABR when there appear to be differences between skull base and nonskull base subsites, thereby risking undertreatment of target sites or overtreatment of critical organs. Additionally, analyses on the effect of tumor volume and dose for HN-SABR have shown that large volume tumors required higher doses to achieve the same response rates and that higher doses overall were associated with better locoregional control.…”

“…7 A growing preponderance of data suggest that head and neck SABR (HN-SABR) may lead to better outcomes compared with standard fractionated reirradiation. [8][9][10][11] However, the high doses and tight margins with SABR necessitate an increased level of confidence in the treatment set-up and delivery process. Even minute shifts in patient position, when unaccounted for, can result in insufficient dose to the tumor and/or excessive dose to the adjacent critical structures.…”

Effect of Surgical Mask on Setup Error in Head and Neck Radiotherapy

“…On the other hand, in this group, the majority of patients were brain metastases patients treated with Stereotactic Body Radiation Therapy (SBRT). 18 It is an effective method for the treatment of head and neck tumors. For those patients, the isocenters were placed at tumor location, most likely not in the medial.…”