Second Re-irradiation: Clinical Examples of Worthwhile Treatment

Abstract

Introduction: Improved treatment approaches have resulted in longer survival of patients with certain types of incurable cancer, without eliminating the need for symptom palliation and supportive measures. In this context, re-irradiation is an increasingly important option. Little data exists about a second or repeat re-irradiation.Methods: From a single institution database, patients who received a second re-irradiation with cumulative equivalent doses (equivalent dose in 2-Gy fractions (EQD2) for late effects, alpha/beta-value 3 Gy) of more than 90 Gy and survived for more than six months were identified. Illustrative clinical examples were provided.Results: The examples describe the treatment of sacral bone metastases, recurrent rectal cancer, and pelvic lymph node metastases. The maximum cumulative EQD2 was 142 Gy. Symptomatic responses were obtained without clinically relevant side effects.Conclusion: These three cases illustrate that a second re-irradiation has the potential to provide worthwhile palliative effects without causing overt late toxicity during the remaining life time. In patients who tolerated previous radiotherapy well, further re-irradiation may contribute to the ever-increasing armamentarium of options that increase the survival of patients with incurable cancer and try to prolong the time period where independent living is possible.

Second re-irradiation: A delicate balance between safety and efficacy

“…This hypothesis is accessible for testing in experimental and clinical settings. So far, the clinical toxicity data [7,8,24,25,26] is fully compatible with the proposed 50% increase for time intervals ≥12 months. It is not recommended to assume 100% recovery at any longer interval.…”

“…The vast majority of these carefully selected patients receive treatment for metastatic bone lesions. However, we have recently also provided other examples of worthwhile re-re-irradiation to pelvic target volumes [8]. No serious toxicity was observed.…”

“…Even if second re-irradiation is a challenging topic that receives less attention than other recent developments, the available evidence and the experience at the author's department suggest that this strategy, which is inexpensive compared to other oncological treatments [32], may be effective in terms of symptom palliation, e.g. pain from bone metastases or soft tissue/lymph node tumors [8][9][10][24][25][26]. However, the therapeutic window is narrow and several studies have reported clinically relevant, sometimes fatal side effects such as soft tissue necrosis and fistula [33,34].…”

Second Re-irradiation of Brain Metastases: A Review of Studies Involving Stereotactic Radiosurgery

“…Both local and distant brain relapse can occur after variable time intervals, resulting in the demand for additional radiotherapy, if death from neurologic causes is to be prevented. Prescribing more than two courses of radiotherapy to the same target volume or, in this case, a brain lesion is a controversial approach [11-13]. Opponents have questioned the radiosensitivity of recurrent tumors and pointed toward a lack of consensus regarding the dose constraints for organs at risk (safety concerns).…”