The risk of radiation-induced toxicity in patients treated for head and neck (HN) cancer with radiation therapy (RT) is traditionally estimated by condensing the 3D dose distribution into a monodimensional cumulative dose-volume histogram which disregards information on dose localization. We hypothesized that a voxel-based approach would identify correlations between radiation-induced morbidity and local dose release, thus providing a new insight into spatial signature of radiation sensitivity in composite regions like the HN district. This methodology was applied to a cohort of HN cancer patients treated with RT at risk of radiation-induced acute dysphagia (RIAD). We implemented an inter-patient elastic image registration framework that proved robust enough to match even the most elusive HN structures and to provide accurate dose warping. A voxel-based statistical analysis was then performed to test regional dosimetric differences between patients with and without RIAD. We identified a significantly higher dose delivered to RIAD patients in two voxel clusters in correspondence of the cricopharyngeus muscle and cervical esophagus. Our study goes beyond the well-established organ-based philosophy exploring the relationship between radiation-induced morbidity and local dose differences in the HN region. This approach is generally applicable to different HN toxicity endpoints and is not specific to RIAD.

To retrospectively evaluate external beam reirradiation (re-EBRT) delivered to the prostate/prostatic bed for local recurrence, after radical or adjuvant/salvage radiotherapy (RT). 32 patients received re-EBRT between February 2008 and October 2013. All patients had clinical/radiological local relapse in the prostate or prostatic bed and no distant metastasis. re-EBRT was delivered with selective RT technologies [stereotactic RT including CyberKnife(TM) (Accuray, Sunnyvale, CA); image-guidance and intensity-modulated RT etc.]. Toxicity was evaluated using the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria. Biochemical control was assessed according to the Phoenix definition (NADIR + 2 ng ml(-1)). Acute urinary toxicity: G0, 24 patients; G1, 6 patients; G2, 2 patients. Acute rectal toxicity: G0, 28 patients; G1, 2 patients; and G2, 1 patient. Late urinary toxicity (evaluated in 30 cases): G0, 23 patients; G1, 6 patients; G2, 1 patient. Late renal toxicity: G0, 25 patients; G1, 5 patients. A mean follow-up of 21.3 months after re-EBRT showed that 13 patients were free of cancer, 3 were alive with biochemical relapse and 12 patients were alive with clinically evident disease. Four patients had died: two of disease progression and two of other causes. re-EBRT using modern technology is a feasible approach for local prostate cancer recurrence offering 2-year tumour control in about half of the patients. Toxicity of re-EBRT is low. Future studies are needed to identify the patients who would benefit most from this treatment. Our series, based on experience in one hospital alone, shows that re-EBRT for local relapse of prostate cancer is feasible and offers a 2-year cure in about half of the patients.

Background: This study investigated the risk of reconstruction failure after mastectomy, immediate breast reconstruction, and radiotherapy to either a temporary tissue expander or permanent implant. Methods: Records of women treated at a single institution between June of 1997 and December of 2011 were reviewed. Two patient groups were identified based on type of immediate breast reconstruction: tissue expander followed by exchange with a permanent implant and permanent implant. The study endpoint was rate of reconstruction failure, defined as a replacement, loss of the implant, or conversion to flap. Results: The tissue expander/permanent implant and the permanent implant groups consisted of 63 and 75 patients, respectively. The groups were well balanced for clinical and treatment characteristics. With a median follow-up of 116 months, eight implant losses, 50 implant replacements, and four flap conversions were recorded. Reconstruction failure occurred in 22 of 63 patients in the expander/implant group and in 40 of 75 patients in the permanent implant group. A traditional proportional hazards model showed a higher risk of reconstruction failure for the expander/implant group (hazard ratio, 2.01) and a significantly shorter time to reconstruction failure compared with the permanent implant group (109.2 months versus 157.7 months; p = 0.03); however, according to a competing risk model, the between-groups cumulative incidences were not significantly different (hazard ratio, 1.09). Conclusions: Radiotherapy to either a tissue expander or a permanent implant presented a fairly large risk of reconstruction failure over time. The expander/implant group was not more likely to develop reconstruction failure compared to permanent implant group, but the timing of onset was shorter. More complex techniques should be investigated to lower the risk of reconstruction failure. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.