The Impact of Preoperative Radiation Therapy on Locoregional Recurrence in Patients with Stage IV Rectal Cancer Treated with Definitive Surgical Resection and Contemporary Chemotherapy.

PURPOSE: Definitive resection of primary rectal cancers is frequently incorporated, with or without preoperative radiotherapy and perioperative chemotherapy, in the management of selected patients with metastatic rectal adenocarcinoma. This study reviews the impact of preoperative radiotherapy and perioperative chemotherapy on locoregional recurrence and overall survival in these patients. METHODS AND MATERIALS: This retrospective study with an Institutional Review Board (IRB) waiver included 109 patients with metastatic rectal adenocarcinoma who underwent definitive primary resection between 1998 and 2011. In addition to resection, 64 patients were treated with preoperative radiotherapy and perioperative chemotherapy and 45 patients were treated with perioperative chemotherapy alone. Radiotherapy dose was typically 50.4 Gy. Baseline variables were compared using chi-square and unpaired t tests. Overall survival was calculated using Kaplan-Meier method. Univariate and multivariate analyses were performed using Cox proportional hazards regression. RESULTS: There were no significant baseline differences between the two groups. There was no significant difference in locoregional recurrence (10.9 vs. 11.1%; p = 0.90) or overall survival (34.5 vs. 34.8 months; p = 0.89) for patients treated with preoperative radiotherapy compared to those treated with perioperative chemotherapy alone, respectively. Patients who underwent radiotherapy were less likely to have a positive margin (10.9 vs. 20.0%; p = 0.19), lymphovascular invasion (32.8 vs. 53.3%; p = 0.03), and pathologic stage N2 disease (25.0 vs. 42.2%; p = 0.02). Grade 2 postoperative complications were more common in the preoperative radiotherapy group (32.8 vs. 15.6%; p = 0.04). Multivariate analysis demonstrated that patients with poorly differentiated tumors (HR 2.19; p = 0.009) and those that did not undergo liver-directed therapy (HR 2.20; p = 0.005) had inferior survival. CONCLUSIONS: Locoregional recurrence is modest in patients with metastatic rectal adenocarcinoma receiving definitive primary resection, irrespective of the use of radiotherapy. Preoperative radiotherapy may enhance pathologic downstaging at the expense of increased grade 2 postoperative complications. Its use should be reserved for patients at high risk for locoregional recurrence.

Safety and efficacy of tiered limited-dose gamma knife stereotactic radiosurgery for unilateral acoustic neuroma.

Stereotactic radiosurgery has become a more widely employed modality of treatment for acoustic neuromas, but controversy still arises regarding the safety and efficacy of the technique. In general, radiation doses have been reduced over time. Since beginning treatments of acoustic neuromas with the Gamma Knife at the University of Miami/Jackson Memorial Medical Center in 1994, a dose regimen was adopted by the first author employing limited doses selected on the basis of tumor size with the anterior and medial regions of the prescription isodose surface kept just inside the gadolinium-enhanced limit of the tumor, in order to protect the facial nerve and brainstem. The records of patients treated for unilateral tumors were retrospectively reviewed. Fifty-two patients, aged 23-83 years, were treated with peripheral tumor doses of 10-14 Gy at the 45-70% isodoses. No patient developed new facial weakness or sensory loss; 3 patients had minor transient facial twitching within a few months of treatment. Of 34 patients followed more than 1 year (range 14-100 months, mean 43.4 months, median 37 months), 17 tumors reduced in size, 16 remained unchanged, and 1 increased in size. One patient, who had radiosurgery as planned postoperative adjuvant treatment after partial resection of a large tumor, developed an enlarging peritumoral arachnoid cyst that required surgical resection 79 months after radiosurgery. Patients with good pretreatment hearing retained approximately the same subjective level of hearing. Very good control of unilateral acoustic neuroma has been achieved by a limited-dose scheme that produces minimal complications, but due to the frequently indolent course of these tumors, continued long-term monitoring will be necessary.