Radiation myelopathy after radioactive iodine therapy for spine metastasis

Risk factors for surgical site infection after posterior fixation surgery and intraoperative radiotherapy for spinal metastases

PURPOSE

Posterior surgery with intraoperative radiotherapy for spinal metastases offers effective therapy, as we have reported previously. However, the procedure involves transfer from the operating room to the radiotherapy room, and as these patients are somewhat immunocompromised, the risk of postoperative surgical site infection (SSI) may be increased. The aim of our study was to identify risk factors and patient characteristics associated with postoperative SSI following posterior fixation surgery and intraoperative radiotherapy for spinal metastases.

METHODS

Participants comprised 279 patients who underwent IORT for the treatment of spinal metastases between August 2004 and June 2013. Patients who suffered SSI within 1 month after surgery were categorized as infected, and all others were categorized as non-infected. We compared factors of age, sex, use of pre-operative corticosteroid, medical history of diabetes, prognosis scores (Tomita, Tokuhashi, and Katagiri), pre- and postoperative Frankel scale scores, site of tumor origin, administration of pre-operative radiotherapy, operation time, intraoperative blood loss, intraoperative irradiation dose, and pre- and postoperative performance status between groups.

RESULTS

SSI occurred in 41 patients (14.7%). Katagiri's and Tokuhashi's prognostic scores (P < 0.05 each), postoperative Frankel scale score (P < 0.01), administration of pre-operative radiotherapy (P < 0.05), and postoperative performance status (P < 0.05) all correlated significantly with occurrence of SSI. Multivariate analysis using those factors revealed administration of pre-operative radiotherapy as a factor independently associated with SSI (P < 0.05).

CONCLUSIONS

Patient prognosis, postoperative ambulatory function, and pre-operative radiotherapy were risk factors for SSI in patients with spinal metastases. Duration of surgery and intraoperative blood loss were not associated with occurrence of SSI.

Spinal metastases due to thyroid carcinoma: an analysis of 202 patients

BACKGROUND

Spinal metastases (SMs) due to thyroid cancer (TC) are associated with significantly reduced quality of life. The goal of this study is to analyze the clinical manifestations, presentation, and treatments of TC SMs, and to describe specific features of SMs associated with different TC types.

PATIENTS AND METHODS

A retrospective analysis of 202 TC SM patients treated at Medstar Washington Hospital Center (37) and collected from the literature (165) was performed.

RESULTS

The mean age of patients with SMs was 56.9±14.7 years, and the female-to-male ratio was 2.1:1. Of all patients, 29% (28% of follicular thyroid cancer [FTC] and 37% of papillary thyroid cancer [PTC]) had SMs only. Twenty-nine percent of all patients and 54% of patients with single-site SMs had neither bone non-SMs nor solid organ metastases at the time of presentation. Thirty-five percent of patients had SMs as an initial presentation of TC. TC patients presenting with SMs had a lower rate of other bone and visceral involvement compared with patients whose SMs were diagnosed at the time of thyroid surgery or during follow-up (p<0.05). SMs were more often the initial manifestation of FTC (41% vs. 24%), while PTC SMs were more commonly diagnosed after TC diagnosis (76% vs. 59%; p<0.05). PTC SMs were more frequently diagnosed as synchronous (63% vs. 36% in FTC) versus FTC SMs that developed as metachronous metastases (64% vs. 37% in PTC; p<0.01). All FTC SMs developed within 82 (0-372) months and all PTC SMs within 35 (0-144) months (p<0.01). In FTC SMs as TC manifestation, solid organ metastases involvement was less common than in FTC SMs that were found after TC diagnosis (34% vs. 67%; p<0.01); multisite FTC SMs compared to solitary FTC SMs were associated with the development of other bone nonspinal metastases (82% vs. 30%; p<0.01) and solitary organ metastases (65% vs. 41%; p<0.01). These correlations were not observed in PTC SMs. FTC patients often had neural structure compression (myelopathy/radiculopathy; 72% vs. 36% in PTC), while PTC patients frequently were asymptomatic (38% vs. 5% in FTC; p<0.01). FTC SMs more commonly were (131)I-avid (p<0.01). FTC patients required surgery more frequently (72% vs. 55% in PTC; p<0.05).

CONCLUSIONS

Our study reveals that a significant part of TC SMs patients have solitary spinal involvement at the time of presentation and may be considered for aggressive treatment with the intention to improve quality of life and survival. FTC SMs and PTC SMs appear to have distinct presentations, behavior, and treatment modalities, and should be categorized separately for treatment and follow-up planning.

The benefits and risks of I-131 therapy in patients with well-differentiated thyroid cancer

BACKGROUND

I-131 has been used in the therapy of well-differentiated thyroid cancer for over 50 years. Although the benefits and risks of I-131 remain issues of controversy and research, our understanding of them continues to improve. This review presents an overview of the benefits of I-131 therapy for ablation, adjuvant treatment, and treatment of locoregional and/or metastasis of well-differentiated thyroid cancer and considers the risks of complications of I-131 therapy.

SUMMARY

The benefits of I-131 remnant ablation include: [1] facilitating the interpretation of subsequent serum thyroglobulin levels, [2] increasing the sensitivity of detection of locoregional and/or metastatic disease on subsequent follow-up radioactive iodine whole-body scans, [3] maximizing the therapeutic effect of subsequent treatments, and [4] allowing a postablation scan to help identify additional sites of disease that were not identified on the preablation scan or when a preablation scan was not performed. The potential benefits of I-131 adjuvant treatment include decreasing recurrence and disease-specific mortality for unknown microscopic, locoregional, and/or distant metastatic disease. The potential benefits of I-131 treatment of known locoregional and/or distant metastases are [1] decreasing recurrence, and [2] decreasing disease-specific mortality and/or palliation. The more significant risks and side effects involve organ systems including eye/nasolacrimal, salivary, pulmonary, gastrointestinal, hematopoietic, and gonads as well as secondary primary malignancies.

CONCLUSIONS

Although there are never-ending controversies regarding I-131 therapy in well-differentiated thyroid cancer, the benefits and risks are becoming better understood. This in turn helps the treating physician and patient in making decisions regarding therapy.