Radio-guided surgery for persistent differentiated papillary thyroid cancer: case presentations and review of the literature

Radioguided Occult Lesion Localization: Technical Procedures and Clinical Applications

PURPOSE

Regarding radioguided surgery, the concept of "radioguided occult lesion localization" (ROLL) is based on both preoperative interventional imaging and intraoperative radioguided detection of a clinically occult neoplastic lesion.

METHODS

This methodology consists in the direct administration into the lesion of Tc-macroaggregated human albumin formed by relatively large particles retained at the injection site, which direct radioguided excisional biopsy.

RESULTS

This modality has expanded from the classic application of ROLL for nonpalpable breast lesions to other tumors, such as solitary pulmonary nodules or recurrences from differentiated thyroid carcinoma. In 2011, in order to improve the classification of different radioguided surgical procedures, ROLL applications were included in the more complete concept of GOSTT (Guided intraOperative Scintigraphic Tumor Targeting). This concept was introduced to include the entire range of basic and advanced radioguided procedures necessary to supply a "road map" for the surgeon.

CONCLUSIONS

The terms ROLL and GOSTT have further developed by incorporating novel modalities such as hybrid tracers for simultaneous fluorescence and radioactive signal detection and innovative navigation systems based on mixed-reality protocols.

Feasibility of Charcoal Tattooing for Localization of Metastatic Lymph Nodes in Robotic Selective Neck Dissection for Papillary Thyroid Carcinoma

BACKGROUND

This study aimed to evaluate the feasibility and effectiveness of ultrasound-guided charcoal tattooing in locating metastatic lymph nodes in robotic selective neck dissection (SND) for papillary thyroid carcinoma (PTC).

METHODS

The overall study group comprised 21 patients with PTC who underwent robotic SND via a unilateral transaxillary approach for treatment of suspicious lymph node metastasis in the lateral compartment. Charcoal suspension was injected into 10 of the patients (total of 23 lesions) 1 day before robotic SND. The authors evaluated the location of the tattoos, the success rate of localization, the intraoperative detection rate, and the complications associated with the procedure. The perioperative results were compared with those in the control group of 11 patients who did not receive charcoal tattooing.

RESULTS

Charcoal suspension was successfully injected into 22 of the 23 suspicious lymph nodes (95.7 %). The remaining lesion was located posterior to the internal jugular vein. Therefore, the charcoal was injected into the soft tissue around the lymph node. Ultrasound-guided injections were well tolerated in all the patients, and no major complications occurred. All the charcoal-tattooed lesions were identified intraoperatively by the surgeon. The number of harvested and metastatic lymph nodes in the lateral compartment was greater in the patients with charcoal tattoo localization than in the control group. The two groups did not differ in terms of perioperative complications, operation time, or volume of drainage.

CONCLUSION

Ultrasound-guided charcoal tattooing for localization of metastatic lymph nodes is feasible and effective in robotic SND for the treatment of PTC with lateral compartment lymph node metastasis.

The rate of operative success achieved with radioguided occult lesion localization and intraoperative ultrasonography in patients with recurrent papillary thyroid cancer

BACKGROUND

To investigate the rate of operative success in excision of nonpalpable lymph nodes with metastatic disease achieved with radioguided occult lesion localization (ROLL) and intraoperative ultrasonography (IOUS) in patients with papillary thyroid cancer (PTC).

METHODS

Twenty consecutive PTC patients with nonpalpable lymph nodes with metastatic disease localized in previously operated fields were randomized to receive ROLL (n = 11) or IOUS (n = 9). Nodes were excised along with adjacent soft tissue to accomplish a compartment-oriented dissection. The duration of operation, rate of postoperative complications, pre- and postoperative serum thyroglobulin (Tg) levels, and the findings of postoperative neck ultrasonography and postablation scan were recorded in all patients. Measures of operative success included a postoperative Tg level <50% of preoperative Tg level and no abnormal lesions on postoperative imaging.

RESULTS

Histopathologic examination confirmed the excision of all preoperatively identified metastatic nodes. Additional nodes also were excised (2.3 ± 3.3 per specimen in the ROLL group and 1.6 ± 1.8 per specimen in the IOUS group), 23% of which were metastatic. No postoperative complications occurred in either group. The duration of operation was similar in the 2 groups (P = .4). Postoperative imaging confirmed the clearance of suspicious nodes in all patients. The rate of operative success in ROLL and IOUS group were 100% and 89%, respectively.

CONCLUSION

In patients with recurrent PTC, a high rate of operative success in excision of nonpalpable metastatic lymph nodes was achieved by both ROLL and IOUS. We recommend compartment-oriented dissection; this approach may maximize the removal of metastatic nodes not identified by preoperative imaging.

Detection and management of cervical lymph nodes in papillary thyroid cancer

Lymph node metastases in papillary thyroid cancer are a common occurrence; however, the management of clinically negative cervical lymph nodes remains controversial. Preoperative neck ultrasound mapping is crucial, and complete dissection of a nodal compartment is recommended for any metastatic lymph nodes. The role of prophylactic central neck dissection remains controversial. The BRAF V600E mutation is a common mutation in papillary thyroid cancer, and has been associated with more aggressive tumor behavior. Evaluating the BRAF status of tumors may have implications for treatment and surveillance. New areas of research continue to focus on risk stratification and identifying which patients benefit from a more aggressive treatment, such as prophylactic central lymphadenectomy and radioiodine ablation and more intense surveillance strategies.

Preoperative US-guided hookwire localization for nonpalpable cervical masses

PURPOSE

We investigated whether the preoperative ultrasound (US)-guided hookwire localization for nonpalpable cervical masses allows surgeons to find these masses more easily and more confidently.

METHODS

Eight patients underwent preoperative US-guided hookwire insertion for nonpalpable cervical masses at our institution between January 2008 and January 2011. Cervical masses were detected by US or CT, and seven of the eight patients underwent US-guided fine-needle aspiration. Before surgery, a radiologist inserted a hookwire into the cervical mass, under US guidance.

RESULTS

US-guided hookwire insertion took about 5-10 minutes and was successful in all cases without complications. Final pathologic results were metastatic papillary thyroid cancer (n = 4), no metastasis (n = 1), parathyroid adenoma (n = 1), tuberculosis (n = 1), and Kikuchi's disease (n = 1).

CONCLUSIONS

Preoperative US-guided hookwire insertion in nonpalpable cervical lesions provides surgeons with an effective means of lesion location.

Excision efficiency of radioguided occult lesion localization in reoperative thyroid and parathyroid surgery

BACKGROUND

The purpose of this study was to investigate the efficiency of a radioguided occult lesion localization technique in reoperative thyroid and parathyroid procedures in patients who had undergone previous neck exploration for thyroid or parathyroid disease.

METHODS

Twenty-one consecutive patients who were scheduled for reoperative thyroid or parathyroid surgery were studied. The indication for reoperation was recurrent papillary thyroid cancer (PTC) in eight patients, completion thyroidectomy for PTC in eight patients who had previously undergone a bilateral subtotal thyroidectomy, recurrent goiter in two patients, primary hyperparathyroidism in two patients, and recurrent parathyroid cancer in one patient. Ninety minutes before surgery, 0.1 mL of Technetium-99m (0.2 mCi)-labeled macroaggregated albumin was injected directly into the lesion under ultrasonographic guidance. During surgery, a handheld gamma probe was used to localize and excise the lesions. The background and postexcisional site radioactivities were compared to confirm the completeness of each procedure. The radiation dose in the operating room environment, duration of surgery, and postoperative complication rates were evaluated in all patients. In patients with PTC, the change in serum thyroglobulin (Tg) following surgery was noted.

RESULTS

Thirty lesions were marked and excised. The postexcisional bed gamma counts (610 ± 141) were markedly decreased compared with the pre-excisional site counts (21,415.8 ± 4993.4; p = 0.0001). The ratio of the postexcisional and background counts (4.6 ± 4.3) was significantly lower than the ratio of the pre-excisional and background counts (173.7 ± 156.4; p = 0.0001). The mean operation duration was 53.3 ± 7.5 minutes. The dose absorbed by the hands of the surgeon was estimated as 0.07 ± 0.02 and 0.15 ± 0.05 millisievert/h when one or three lesions were marked, respectively. One patient developed postoperative transient hypoparathyroidism. After surgery, serum Tg levels dropped to <2 ng/mL in 86% (6/7) of the patients with PTC whose preoperative serum Tg was elevated.

CONCLUSIONS

The radioguided occult lesion localization technique was efficient in the perioperative identification of thyroid and parathyroid tumors in patients who were undergoing reoperation for PTC and hyperparathyroidism.

A comprehensive overview of radioguided surgery using gamma detection probe technology

The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology.

Radiation dose to surgical staff from positron-emitter-based localization and radiosurgery of tumors

Surgical tissue characterization based on radiotracer uptake has become much more common in recent years, particularly due to the advent of the sentinel lymph node biopsy technique. Radiolabeled pharmaceuticals are used with hand-held gamma-sensitive probes, which are capable of localizing small tumors and lymph nodes that are first identified via scintigraphy. The radiation safety of such radioguided procedures, which typically employ 99mTc, has been well established. Now, with the emergence of 18F-fluorodeoxyglucose (18FDG) as a widely used tracer for PET imaging of cancer patients, there is increasing interest in the possibility of utilizing 18FDG for intraoperative tumor detection. First, though, the exposure to operating room personnel must be shown to be at a safe level. Due to the short half-life of 18F, the exposure rate will vary significantly with the start time post-injection as well as the duration of the procedure. The aim of this investigation is to determine empirically an exposure rate equation that can be integrated to estimate the exposure to a surgeon and assistants, from patients injected with 18FDG, over an arbitrarily chosen time interval. The study was conducted by measuring the radiation exposure rate from hospital in-patients receiving 18FDG-PET scans at various times from one to seven hours post injection; the empirical equation was determined from the plot of exposure rate vs. time for all patients. The resulting effective dose equivalent for the surgeon for typical values of injected activity, delay time and procedure duration was approximately 60 microSv.

I-123-guided excision of metastatic papillary thyroid cancer

The use of a gamma probe for intraoperative localization of a cervical lymph node, which contained recurrent metastatic papillary thyroid cancer, facilitated a radio-guided minimally invasive outpatient surgical procedure and resulted in complete excision of clinically occult disease. The technique raises the issue of whether nonpalpable regional node recurrences should be locally excised, removed in a formal modified neck dissection, or treated with therapeutic doses of I-131.

Radio-guided nonpalpable metastatic lymph node localization in patients with recurrent thyroid cancer

The detection of nonpalpable recurrent thyroid carcinoma has increased due to the use of imaging techniques in time. This report is to investigate whether preoperative injection of a radiotracer under ultrasound guidance is useful in nonpalpable recurrent thyroid carcinoma. The neck of two patients with recurrent thyroid carcinoma was scanned with the probe to localize the area of maximal radioactivity allowing appropriate location of the incision over the lesion. After the lymph nodes were removed, radioactivity was measured in the lesion bed to confirm the success of the dissection. In conclusion, the radio-guided nonpalpable lesion localization technique can be performed safely for the detection and excision of metastatic foci.

Wiederholungseingriffe beim Schilddr�senkarzinom

Reoperation for thyroid cancer needs to consider patient-, tumor- and therapy-related aspects as well as present diagnostic results. Reoperation because of thyroid remnants, persistence of the primary tumor and lymph node metastasis (completion surgery) has to be distinguished from reoperation due to locoregional recurrence (primary tumor, lymph nodes). The primary surgical strategy should avoid the need for reoperation. The extent of reoperation is related to the extent of primary surgery, stage, and distant metastasis. The timing and indication of reoperation for differentiated thyroid carcinoma in an interdisciplinary multimodal treatment setting depends on diagnostic radioiodine scans and radioiodine therapy. Long-term, recurrence-free survival is achieved by sufficiently radical surgery with acceptable morbidity, including all additive or adjuvant treatment options.