Linac radiosurgery for locally recurrent nasopharyngeal carcinoma: rationale and technique

Hyperfractionated stereotactic reirradiation for recurrent head and neck cancer

PURPOSE

The goal of this work was to evaluate the efficacy and toxicity of hyperfractionated stereotactic reirradiation (re-RT) as a treatment for inoperable, recurrent, or second primary head and neck squamous cell cancer (HNSCC) that is not suitable for systemic treatment.

PATIENTS AND MATERIALS

Forty patients with recurrent or second primary HNSCC were included in this study. The patients had a median gross tumor volume of 76 ml (range 14-193 ml) and a previous radiotherapy dose greater than 60 Gy. Treatment was designed to cover 95 % of the planning target volume (PTV, defined as gross tumor volume [GTV] + 3 mm to account for microscopic spreading, with no additional set-up margin) with the prescribed dose (48 Gy in 16 fractions b.i.d.). Treatment was administered twice daily with a minimum 6 h gap. Uninvolved lymph nodes were not irradiated.

RESULTS

Treatment was completed as planned for all patients (with median duration of 11 days, range 9-14 days). Acute toxicity was evaluated using the RTOG/EORTC scale. A 37 % incidence of grade 3 mucositis was observed, with recovery time of ≤ 4 weeks for all of these patients. Acute skin toxicity was never observed to be higher than grade 2. Late toxicity was also evaluated according to the RTOG/EORTC scale. Mandible radionecrosis was seen in 4 cases (10 %); however, neither carotid blowout syndrome nor other grade 4 late toxicity occurred. One-year overall survival (OS) and local progression-free survival (L-PFS) were found to be 33 and 44 %, respectively. Performance status and GTV proved to be significant prognostic factors regarding local control and survival.

CONCLUSION

Hyperfractionated stereotactic re-RT is a reasonable treatment option for patients with recurrent/second primary HNSCC who were previously exposed to high-dose irradiation and who are not candidates for systemic treatment or hypofractionation.

Clinical outcomes of single or oligo-fractionated stereotactic radiotherapy for head and neck tumors using micromultileaf collimator-based dynamic conformal arcs

PURPOSE

To assess the clinical outcomes of single or oligo-fractionated stereotactic radiotherapy (SRT) using dynamic conformal arcs (DCA) for head and neck tumors (HNTs).

METHODS

Thirty-four consecutive patients with 35 lesions treated between 2005 and 2009 were retrospectively evaluated, of whom 85.7 % had recurrent or metastatic disease, and 45.7 and 34.3 % had previous radiotherapy and surgery, respectively. The median SRT dose was 22.3 Gy (11.2-32.8) in 2-4 fractions with a median interval of 7 days and 10.4 Gy (9.2-12.4) in one fraction. SRT was combined with upfront conventionally fractionated RT in 48.6 % of patients.

RESULTS

The median follow-up periods were 18.4 months (2-84.1) for the entire cohort and 49.6 months for the survivors. The 1- and 2-year local control (LC) rates were 84.3 and 70.5 %, with the 1- and 2-year overall survival (OS) rates of 78.6 and 51.6 %. LC was significantly better for tumor volumes <25.6 cm(3) (p = 0.001). OS was significantly longer in patients without any disease outside the SRT site (p < 0.001), whereas LC after the SRT did not affect the OS. Late adverse events occurred in 9 patients, including cranial nerve (CN) injury (grade 3/4) in 2, brain radionecrosis in 5 (grade 1), and fatal bleeding in 2 patients harboring uncontrolled lesions abutting the carotid artery.

CONCLUSIONS

DCA-based SRT can confer relatively long-term LC with acceptable toxicity in selected patients with HNTs. The patients with CN involvement or tumor volume ≥25.6 cm(3) were deemed unsuitable for this treatment regimen.

Salvage reirradiaton with stereotactic body radiotherapy for locally recurrent head-and-neck tumors

PURPOSE

In this study, we present our results of reirradiation of locally recurrent head-and-neck cancer with image-guided, fractionated, frameless stereotactic body radiotherapy technique.

METHODS AND MATERIALS

From July 2007 to February 2009, 46 patients were treated using the CyberKnife (Accuray, Sunnyvale, CA) at the Department of Radiation Oncology, Hacettepe University, Ankara, Turkey. All patients had recurrent, unresectable, and previously irradiated head-and-neck cancer. The most prominent site was the nasopharynx (32.6%), and the most common histopathology was epidermoid carcinoma. The planning target volume was defined as the gross tumor volume identified on magnetic resonance imaging and computed tomography. There were 22 female and 24 male patients. Median age was 53 years (range, 19-87 years). The median tumor dose with stereotactic body radiotherapy was 30 Gy (range, 18-35 Gy) in a median of five (range, one to five) fractions.

RESULTS

Of 37 patients whose response to therapy was evaluated, 10 patients (27%) had complete tumor regression, 11 (29.8%) had partial response, and 10 (27%) had stable disease. Ultimate local disease control was achieved in 31 patients (83.8%). The overall survival was 11.93 months in median (ranged, 11.4-17.4 months), and the median progression free survival was 10.5 months. One-year progression-free survival and overall survival were 41% and 46%, respectively. Grade II or greater long-term complications were observed in 6 (13.3%) patients. On follow-up, 8 (17.3%) patients had carotid blow-out syndrome, and 7 (15.2%) patients died of bleeding from carotid arteries. We discovered that this fatal syndrome occurred only in patients with tumor surrounding carotid arteries and carotid arteries receiving all prescribed dose.

CONCLUSIONS

Stereotactic body radiotherapy is an appealing treatment option for patients with recurrent head-and-neck cancer previously treated with radiation to high doses. Good local control with considerable 1-year survival is achieved with a relatively high rate of morbidity and related mortality.

Emerging applications of stereotactic radiotherapy in head and neck cancer

Advances in the management of locally advanced head and neck cancer (HNC) have been focused on treatment intensification, including concomitant chemoradiotherapy, biological agents, and combining surgery with chemoradiotherapy. Despite these improvements, locoregional recurrence still constitutes the main pattern of treatment failure. As improvements in radiotherapy delivery and image-guided therapy have come to fruition, the principles of stereotactic radiosurgery are now being applied to extracranial sites, leading to stereotactic body radiotherapy. This article focuses on the emerging evidence for the use of stereotactic body radiotherapy for treatment of HNC as a boost after conventional external-beam radiotherapy, and also as reirradiation in recurrent or second primary HNC.

Fractionated stereotactic radiotherapy in residual or recurrent nasopharyngeal carcinoma

The aim of this study was to evaluate results of fractionated stereotactic radiotherapy (FSRT) in patients with residual or recurrent nasopharyngeal carcinoma (NPC) in terms of local progression-free (LPFS) and overall survival (OS) rate and complications after treatment. There were 32 residual or recurrent NPC patients treated with FSRT using linac-based radiosurgery system. Time from the previous radiotherapy to FSRT was 1-165 months (median, 15). Two patients were treated for the second and one for the third recurrence. Thirteen patients (40.6%) also received chemotherapy with FSRT. Tumor volume ranged from 6.2-215 cc (median, 44.4). Average FSRT dose was 17-59.4 Gy (median, 34.6) in 4-25 fractions (median,6) in 1-5.5 weeks (median, 3). Median follow-up time was 25.5(3-67) months. LPFS rate at 1 and 3 years after FSRT was 67.8% and 37.9%. OS rate at 1 and 3 years was 89.7% and 71.2%. If all patients who had tumor progression with no further follow-up were assumed dead, the OS rate at 1 and 3 years would be 75.0% and 37.9%. Univariate analysis showed better local tumor control in patients with tumor volume </=100 cc (p=0.04) or in those without chemotherapy (p=0.0005). Only chemotherapy retained significance in multivariate analysis (hazard ratio 5.47, 95%CI 1.86-16.04). Eight patients (25%) had complications after FSRT, all grade 2-3 except 1 grade 4 with complete recovery.

Comparison of single versus fractionated dose of stereotactic radiotherapy for salvaging local failures of nasopharyngeal carcinoma: a matched-cohort analysis

BACKGROUND

Local failure is an important cause of morbidity and mortality in nasopharyngeal carcinoma (NPC). Although surgery or brachytherapy may be feasible in selected cases, most patients with local failure require external beam re-irradiation. Stereotactic radiation using single or multiple fractions have been employed in re-irradiation of NPC, but the optimal fractionation scheme and dose are not clear.

METHODS

Records of 125 NPC patients who received salvage stereotactic radiation were reviewed. A matched-pair design was used to select patients with similar prognostic factors who received stereotactic re-irradiation using single fraction (SRS) or multiple fractions (SRM). Eighty-six patients were selected with equal number in SRS and SRM groups. All patients were individually matched for failure type (persistent or recurrent), rT stage (rT1-2 or rT3-4), and tumor volume (< or = 5 cc, >5-10 cc, or >10 cc). Median dose was 12.5 Gy in single fraction by SRS, and 34 Gy in 2-6 fractions by SRM.

RESULTS

Local control rate was better in SRM group although overall survival rates were similar. One- and 3-year local failure-free rates were 70% and 51% in SRS group compared with 91% and 83% in SRM group (p = 0.003). One- and 3-year overall survival rates were 98% and 66% in SRS group compared with 78% and 61% in SRM group (p = 0.31). The differences in local control were mainly observed in recurrent or rT2-4 disease. Incidence of severe late complications was 33% in SRS group vs. 21% in SRM group, including brain necrosis (16% vs. 12%) and hemorrhage (5% vs. 2%).

CONCLUSION

Our study showed that SRM was superior to SRS in salvaging local failures of NPC, especially in the treatment of recurrent and rT2-4 disease. In patient with local failure of NPC suitable for stereotactic re-irradiation, use of fractionated treatment is preferred.

Validation of a prognostic scoring system for locally recurrent nasopharyngeal carcinoma treated by stereotactic radiosurgery

Background

Selection of patients with local failure of nasopharyngeal carcinoma (NPC) for appropriate type of salvage treatment can be difficult due to the lack of data on comparative efficacy of different salvage treatments. The purpose of the present study was to validate a previously published prognostic scoring system for local failures of NPC treated by radiosurgery based on reported results in the literature.

Methods

A literature search yielded 3 published reports on the use of radiosurgery as salvage treatment of NPC that contained sufficient clinical information for validation of the scoring system. Prognostic scores of 18 patients from these reports were calculated and actuarial survival rates were estimated and compared to the original cohort used to design the prognostic scoring system. The area under the receiver operating characteristic curve was also determined and compared between the current and original patient groups.

Results

The calculated prognostic scores ranged from 0.32 to 1.21, with 15 patients assigned to the poor prognostic group and 3 to the intermediate prognostic group. The actuarial 3-year survival rates in the intermediate and poor prognostic groups were 67% and 0%, respectively. These results were comparable to the observed 3-year survival rates of 74% and 23% in the intermediate and poor prognostic group in the original reports. The area under the receiver operating characteristic curve for the current patient group was 0.846 which was similar to 0.841 in the original group.

Conclusion

The previously published prognostic scoring system demonstrated good prediction of treatment outcome after radiosurgery in a small group of NPC patients with poor prognosis. Prospective study to validate the scoring system is currently being carried out in our institution.

Fractionated stereotactic radiotherapy as reirradiation for locally recurrent head and neck cancer

PURPOSE

We report early preliminary experience with CyberKnife radiosurgery (RS) as salvage treatment for locally recurrent head and neck cancer (HNC).

METHODS AND MATERIALS

Between March 2004 and August 2006, 36 patients (44 sites) were treated with CyberKnife RS as reirradiation for locally recurrent HNC. Treatment sites were as follows: nasopharynx (8), maxillary sinus (8), neck lymph nodes (8), skull base (7), nasal cavity (4), retropharyngeal lymph nodes (3), orbit (2), and others (4). Total doses administered were 18-40 Gy (median, 30 Gy) in 3 to 5 fractions to the 65%-85% isodose line for 3-5 consecutive days. Previous external radiation dose ranged from 39.6 to 134.4 Gy (median, 70.2 Gy). Gross tumor volume ranged from 0.2 to 114.9 cm(3) (median, 22.6 cm(3)). Median follow-up was 17.3 months.

RESULTS

Thirty-five of 44 sites were evaluated for response. Fifteen (42.9%) sites achieved complete response, 13 sites (37.1%) achieved a partial response, 3 (8.6%) sites maintained stable disease, and 4 sites (11.4%) showed tumor progression. Grade III acute complications were noted in 13 patients. Late complications were observed in three patients (1 bone necrosis, 2 soft tissue necrosis) during follow-up.

CONCLUSION

These preliminary results suggest that fractionated stereotactic radiosurgery is an effective treatment modality as a salvage treatment with good short-term local control. The early overall response rate is encouraging. However, more experience and a longer follow-up are necessary to determine the role of fractionated stereotactic radiosurgery as a salvage treatment of locally recurrent HNC and to define long-term complications.

Experience in fractionated stereotactic body radiation therapy boost for newly diagnosed nasopharyngeal carcinoma

PURPOSE

Radiotherapy is the most effective treatment for nasopharyngeal carcinoma (NPC). The aim of this study is to evaluate the efficacy and toxicity of fractionated stereotactic body radiation therapy (SBRT) boost for NPC.

METHODS AND MATERIALS

Sixty-four patients with newly diagnosed, nonmetastatic NPC were treated with conventional radiotherapy 64.8-68.4 Gy followed by fractionated SBRT boost 12-15 Gy between January 2002 and July 2004. Most patients (72%) presented with Stage III-IV disease. Fifty-two patients also received cisplatin-based concurrent (38) or neoadjuvant (14) chemotherapy. The major endpoints were local control, overall survival, and complications.

RESULTS

All patients finished the planned dose of radiotherapy. After a median follow-up of 31 months (range, 22-54), 15 patients developed tumor recurrences--3 in the nasopharynx, 4 in the neck, 5 in distant sites, 1 in both nasopharynx and neck, 2 in the neck and a distant site. The 3-year actuarial rate of local control was 93.1%, regional control 91.4%, freedom from distant metastasis 90.3%, and overall survival 84.9%, respectively. There were no Grade 4 acute or chronic radiation-related complications.

CONCLUSIONS

Fractionated SBRT boost for NPC is technically feasible and provides good local control without any severe complications.

Predictive factors of tumor control and survival after radiosurgery for local failures of nasopharyngeal carcinoma

BACKGROUND

Stereotactic radiosurgery has been employed as a salvage treatment of local failures of nasopharyngeal carcinoma (NPC). To identify patients that would benefit from radiosurgery, we reviewed our data with emphasis on factors that predicted treatment outcome.

PATIENTS AND METHODS

A total of 48 patients with local failures of NPC were treated by stereotactic radiosurgery between March 1996 and February 2005. Radiosurgery was administered using a modified linear accelerator with single or multiple isocenters to deliver a median dose of 12.5 Gy to the target periphery. Median follow-up was 54 months.

RESULTS

Five-year local failure-free probability after radiosurgery was 47.2% and 5-year overall survival rate was 46.9%. Neuroendocrine complications occurred in 27% of patients but there were no treatment-related deaths. Time interval from primary radiotherapy, retreatment T stage, prior local failures and tumor volume were significant predictive factors of local control and/or survival whereas age was of marginal significance in predicting survival. A radiosurgery prognostic scoring system was designed based on these predictive factors. Five-year local failure-free probabilities in patients with good, intermediate and poor prognostic scores were 100%, 42.5%, and 9.6%. The corresponding five-year overall survival rates were 100%, 51.1%, and 0%.

CONCLUSION

Important factors that predicted tumor control and survival after radiosurgery were identified. Patients with good prognostic score should be treated by radiosurgery in view of the excellent results. Patients with intermediate prognostic score may also be treated by radiosurgery but those with poor prognostic score should receive other salvage treatments.

Stereotactic radiosurgery as a salvage treatment for recurrent epipharyngeal carcinoma

Fourteen patients with recurrent epipharyngeal carcinoma (EPC) were treated by gamma knife stereotactic radiosurgery. The tumor volume ranged from 0.3 to 80 ml (median 18.9 ml). Treatment was done with a tumor margin dose of 10-27 Gy (median 15 Gy). The median follow-up period was 15 months (range 2-47 months). Ten patients were alive and 4 were dead at the end of the follow-up period. In 6 patients (43%), the tumor disappeared or decreased in size until the end of the follow-up period. In 2 (14%), the tumor remained unchanged in size. In 6 (43%), the tumor showed regression initially but was enlarged later. A second radiosurgery was performed in 4 of those 6 cases and the tumor decreased in size again in 3 of them. Thus, the overall control rate of local tumor was 79% (11/14). In selected patients with recurrent EPC, stereotactic radiosurgery can be considered as a salvage treatment producing local control.

New Radiation Therapy Techniques for the Treatment of Head and Neck Cancer

This article reviews the most recent technology used in the treatment of head and neck cancer. It discusses brachytherapy, new ways to mix radionuclides for enhanced radiobiologic effects, and different fractionation schemes that have grown in clinical importance. Intensity-modulated radiotherapy has become a mainstay in head and neck cancer treatment, and the authors discuss several popular and emerging approaches. Patient immobilization and imaging are also discussed.

Radiotherapy for nasopharyngeal carcinoma--transition from two-dimensional to three-dimensional methods

This review describes the clinical background that underlies the transition from two-dimensional to three-dimensional (3D) planning techniques in the treatment of nasopharyngeal cancer (NPC). A systematic search of the Medline was performed using 'nasopharyngeal carcinoma', 'radiotherapy', '3-dimensional conformal radiotherapy', 'stereotactic radiosurgery/radiotherapy' and 'intensity-modulated radiotherapy' as keywords. Citing evidence from the published literature and their own institutional experience, the authors critically examined the positive impact of 3D methods--with emphasis on intensity-modulated radiotherapy (IMRT)--on target coverage and geometric accuracy, sparing of normal organs, and dosimetric homogeneity. Potential problems related to the widespread practice of IMRT such as quality assurance, utilization of medical resources and the risk of developing radiation-induced secondary cancers were highlighted. Application of IMRT within the context of altered fractionation, dose escalation and concurrent chemotherapy were discussed. The article concluded with a suggested treatment approach and research direction for different stages of NPC.

Reirradiation for locally recurrent nasopharyngeal carcinoma: Treatment results and prognostic factors

PURPOSE

To analyze the results and evaluate the prognostic factors in the retreatment of locally recurrent nasopharyngeal carcinoma.

METHODS AND MATERIALS

Forty-one patients with locally recurrent nasopharyngeal carcinoma, who were reirradiated between 1979 and 2000, were retrospectively analyzed. There were 32 men and 9 women with median age of 46 years. Histologically, 9 tumors (22%) were World Health Organization (WHO) I, 17 (41.5%) WHO II, and 15 (36.5%) WHO III. According to the 1998 TNM staging system of the American Joint Committee on Cancer, the recurrent disease was Stage I in 5 (12.2%), Stage II in 11 (26.8%), Stage III in 6 (14.6%), and Stage IV in 19 (46.4%) patients. Treatment was delivered with 4-6 MV X-rays or Co-60 gamma rays. The median reirradiation dose was 50 Gy. Treatment was delivered at 1.8-2 Gy/fraction daily, 5 days a week. Chemotherapy was used in 41.5% of the patients.

RESULTS

Median follow-up was 23 months (range, 3-143 months). The 2-year and 5-year local progression-free and overall survival rates were 39%, 23%, 48%, and 28%, respectively. On univariate analysis, age (p = 0.04), total reirradiation dose (p = 0.0008) were significant prognostic factors for local progression-free rate. For overall survival age, total reirradiation dose, stage, T stage were significant. On multivariate analysis only total dose (p = 0.005) remained significant for local progression-free rate and total reirradiation dose (p = 0.02), interval to recurrence (p = 0.03), stage (p = 0.018) were significant for overall survival.

CONCLUSIONS

Early diagnosis of local recurrence and high-dose reirradiation (60 Gy) are crucial for improving the local control and survival.

Effectiveness of brachytherapy and fractionated stereotactic radiotherapy boost for persistent nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC) with local persistence after primary radiotherapy carries a high risk of treatment failure. We compared the effectiveness of brachytherapy and a fractionated stereotactic radiotherapy (SRT) boost in improving tumor control.

METHODS

We retrospectively reviewed the records of 755 patients with NPC treated from 1994 to 2001. Fifty-two patients (7%) had persistent local disease, but seven of them were unsuitable for radiotherapy boost. Overall, 24 patients received brachytherapy boost at a median dose of 20 Gy, and 21 patients received an SRT boost at a median dose of 15 Gy.

RESULTS

Despite the radiotherapy boost, the overall 3-year local failure-free control rate was still significantly lower for patients with persistent disease than for the rest (71% vs 86%, p < .01). Only the SRT subgroup achieved a local failure-free control rate close to that of the complete responders (82% vs 86%, p = .71).

CONCLUSIONS

SRT boost is more effective in reverting the poor prognostic influence of local persistent disease.

Ultrasound-guided extracranial radiosurgery: technique and application

PURPOSE

Stereotactic radiosurgery is an effective treatment modality for many intracranial lesions, but target mobility limits its utility for extracranial applications. We have developed a new technique for extracranial radiosurgery based on optically guided three-dimensional ultrasound (3DUS). The 3DUS system provides the ability to image the target volume and critical structures in real time and determine any misregistration of the target volume with the linear accelerator. In this paper, we describe the system and its initial clinical application in the treatment of localized metastatic disease.

METHODS AND MATERIALS

The extracranial stereotactic system consists of an ultrasound unit that is optically tracked and registered with the linear accelerator coordinate system. After an initial patient positioning based on computed tomographic (CT) simulation, stereotactic ultrasound images are acquired and correlated with the CT-based treatment plan to determine any soft-tissue shifts between the time of the planning CT and the actual treatment. Optical tracking is used to correct any patient offsets that are revealed by the real-time imaging.

RESULTS

Preclinical testing revealed that the ultrasound-based stereotactic navigation system is accurate to within 1.5 mm in comparison with an absolute coordinate phantom. Between March 2001 and March 2002, the system was used to deliver extracranial radiosurgery to 17 metastatic lesions in 16 patients. Treatments were delivered in 1 or 2 fractions, with an average fractional dose of 16 Gy (range 12.5-24 Gy) delivered to the 80% isodose surface. Before each fraction, the target misalignment from isocenter was determined using the 3DUS system and the misalignments averaged over all patients were anteroposterior = 4.8 mm, lateral = 3.6 mm, axial = 2.1 mm, and average total 3D displacement = 7.4 mm (range = 0-21.0 mm). After correcting patient misalignment, each plan was delivered as planned using 6-11 noncoplanar fields. No acute complications were reported.

CONCLUSIONS

A system for high-precision radiosurgical treatment of metastatic tumors has been developed, tested, and applied clinically. Optical tracking of the ultrasound probe provides real-time tracking of the patient anatomy and allows computation of the target displacement before treatment delivery. The patient treatments reported here suggest the feasibility and safety of the technique.

Intensity-modulated radiotherapy for previously irradiated, recurrent head-and-neck cancer

The purpose of this work is to evaluate our initial experience in treating previously irradiated, recurrent head-and-neck cancers using intensity-modulated radiotherapy (IMRT). Between July 1997 and September 1999, 12 patients with previously irradiated, locally recurrent head-and-neck cancers were treated with IMRT. These included cancers of the nasopharynx, oropharynx, hypopharynx, larynx, paranasal sinus, skin of the head-and-neck region, and malignant melanoma. Five of these 12 patients had received radiation as the primary treatment, with doses ranging from 66.0 to 126.0 Gy, and the remaining 7 patients had undergone definitive surgeries followed by an adjuvant course of radiation treatment, with doses ranging between 36.0 and 64.8 Gy. Recurrence after the initial course of radiation occurred in periods ranging from 4 to 35 months, with 11 of 12 cases recurring fully in the fields of previous irradiation. Recurrent tumors were treated with IMRT to total doses between 30 to 70 Gy (> 50 Gy in 10 cases) prescribed at the 75% to 92% isodose lines with daily fractions of 1.8 to 2 Gy. The results revealed that acute toxicities were acceptable except in 1 patient who died of aspiration pneumonia during the course of retreatment. There were 4 complete responders, 2 partial responders, and 2 patients with stable disease in the IMRT-treated volumes. Three patients received IMRT as adjuvant treatment following salvage surgery. At 4 to 16 months of follow-up, 7 patients were still alive, with 5 revealing no evidence of disease. In conclusion, this pilot study demonstrates that IMRT offers a viable mode of re-irradiation for recurrent head-and-neck cancers in previously irradiated sites. Longer follow-up time and a larger number of patients are needed to better define the therapeutic advantage of IMRT in recurrent, previously irradiated head-and-neck cancers.

Stereotactic radiosurgery for locally recurrent nasopharyngeal carcinoma

BACKGROUND

Stereotactic radiosurgery has been used to treat intracranial tumors. Recently, it has also been used for the treatment of head and neck tumors involving the base of skull, including recurrent NPC.

METHODS

From October 1994 to April 1999, 36 patients with recurrent NPC, were retreated by stereotactic radiosurgery. These patients received radiosurgery as a boost treatment after reirradiation for recurrence. The external RT dose ranged from 20 to 60 Gy. The tumor volume ranged from 3.58 to 24.6 cc. The target surface dose ranged from 8 to 20 Gy. The median follow-up was 22.1 months.

RESULTS

The 3-year local control rate was 56%. The 5-year overall survival was 49%. Persistence after radiosurgery had a worse survival than those who had secondary recurrence. Age and gender were marginally significant. No patient had new severe complications after retreatment. Four patients (11%) had nasopharyngeal necrosis after radiosurgery, none had nasal bleeding or headache, but a foul odor was present in one patient.

CONCLUSIONS

Conformal radiotherapy and stereotactic radiotherapy provide good local control and survival without severe complications for patients with recurrent NPC.

[Treatment of nasopharyngeal cancer: literature review]

The conventional radiotherapy and the associated treatments improved the prognostic of nasopharyngeal cancer. A better selection of the patients who must have a more aggressive treatment also probably contributed to this improvement. Even if a relation could be found between the locoregional relapse rate and the distant relapse rate, these two events remain often independent. It results from it that the improvement of local control rate necessarily does not result in a better control of the disease. The patients with a locally advanced tumor, with or not an invasion of the base of the skull and/or neurological symptoms, must have an aggressive locally treatment. This probably includes the increase in dose delivered to the tumor via a more conformational radiotherapy, a brachytherapy, radiotherapy in stereotaxic conditions or other techniques. Dose within the tumor must be at least 70 Gy and the prophylactic nodal dose, at least 50 Gy. CT scan and MRI are essential for delineating the volumes of interest. The protocols of hyperfractionated radiotherapy did not give convincing results. Association with chemotherapy allowed, on the other hand, an improvement of the prognostic locally advanced cancers. Neoadjuvant or adjuvant chemotherapy was largely used to attempt to limit the risks of systemic dissemination, but an improvement of results was not clearly demonstrated. An improvement of the rates of survival and control of the disease, on the other hand, was observed in a certain number of studies with the chemoradiotherapy. In the event of locoregional relapse, an aggressive attitude can allow the control of the disease in the absence of systemic dissemination. Salvage treatments are, however, disappointing for when distant relapse occurs which suggests a difference in chemosensitivity between primary tumor and metastasis.

Ultrasonographic guidance for spinal extracranial radiosurgery: technique and application for metastatic spinal lesions

Object

The relatively stationary anatomy of the intracranial compartment has allowed the development of stereotactic radiosurgery as an effective treatment option for many intracranial lesions. Difficulty in accurately tracking extracranial targets has limited its development in the treatment of these lesions. The ability to track extracranial structures in real time with ultrasound images allows a system to upgrade and interface pretreatment volumetric images for extracranial applications. In this report the authors describe this technique as applied to the treatment of localized metastatic spinal disease.

Methods

The extracranial stereotactic system consists of an optically tracked ultrasonography unit that can be registered to a linear accelerator coordinate system. Stereotactic ultrasound images are acquired following patient positioning, based on a pretreatment computerized tomography (CT) simulation. The soft-tissue shifts between the virtual CT-based treatment plan and the actual treatment are determined. The degree of patient offset is tracked and used to correct the treatment plan.

The ultrasonography-based stereotactic navigation system is accurate to within an approximate means of 1.5 mm based on testing with an absolute coordinate phantom. A radiosurgical treatment was delivered using the system for localization of a metastatic spinal lesion. Compared with the virtual CT simulation, the actual treatment plan isocenter was shifted 12.2 mm based on the stereotactic ultrasound image. The patient was treated using noncoplanar beams to a dose of 15.0 Gy to the 80% isodose shell in a single fraction.

Conclusions

A system for high-precision radiosurgical treatment of metastatic spinal tumors has been developed, tested, and applied clinically. Optical tracking of the ultrasonography probe provides real-time tracking of the patient anatomy and allows computation of the target displacement prior to treatment delivery. The results reported here suggest the feasibility and safety of the technique.

Fractionated stereotactic radiosurgery for 50 patients with recurrent or residual nasopharyngeal carcinoma

PURPOSE

This study was conducted to evaluate the clinical value of fractionated stereotactic radiosurgery (FSRS) as a boost treatment in 44 patients with residual or recurrent nasopharyngeal carcinoma after conventional radiotherapy (70-80 Gy) or a second course of radiotherapy (50 Gy) or as salvage treatment in 6 patients with recurrent nasopharyngeal carcinoma after a first or second course of radiotherapy at the primary site.

METHODS AND MATERIALS

From September 20, 1995 to December 30, 1998, 50 patients were treated with FSRS with 6 MV of photons. The total FSRS dose was 14-35 Gy (median dose 24) prescribed at 1-4 centers on the 60-90% isodose curves normalized to the isocenter by multiple fractions of 6-8, 12, or 15 Gy, with interfraction intervals of 4-6 days.

RESULTS

Thirty-eight patients (76%) had a complete tumor response, 9 (18%) had a partial response, and 3 (6%) were not assessable. The overall rate of survival was 83.6% at 1 year, 65.0% at 2 years, and 59.6% at 3 years. The overall disease-free survival rate among patients with residual tumor was 89.94% at 1 year, 73.97% at 2 years, and 73.97% at 3 years. Patients who were treated for recurrent lesions or who received FSRS as salvage therapy had a 46.53% rate of disease-free survival at both 1 and 2 years after therapy.

CONCLUSION

FSRS is strongly indicated for recurrent or residual nasopharyngeal carcinoma at the primary site.

Linear accelerator based radiosurgery as a salvage treatment for skull base and intracranial invasion of recurrent nasopharyngeal carcinomas

Nasopharyngeal carcinoma is a common disease entity in Taiwan. It can spread in the prestyloid, retrostyloid compartments, parapharyngeal space, and skull base, and induce paralysis of cranial nerves. We have treated more than 1,500 cases in the past 14 years. Since 1994, we have treated 11 cases of nasopharyngeal carcinomas with skull base invasion by linear accelerator-based stereotactic radiosurgery. There were six male and five female patients. The mean age was 48.4 years. Seven patients had symptoms of low cranial nerves. For these patients, conformal radiotherapy plus brachytherapy was used for the masses beyond the skull base. Stereotactic radiosurgery with a dose of 10 Gy to 19 Gy for one treatment was used for the masses invading the skull base. Eight patients died in follow-up periods from 5 months to 2 years 7 months. Approximately half of patients revealed good response of tumor to radiosurgery. Two patients demonstrated no response of tumors to radiosurgery. Stereotactic radiosurgery may be an adjuvant treatment for recurrent nasopharyngeal carcinomas with skull base and intracranial invasion.

Salvage radiation therapy for locally recurrent nasopharyngeal carcinoma

PURPOSE

To study the treatment outcome in patients with locally recurrent nasopharyngeal carcinoma (NPC) and to explore whether a combination of high-dose-rate (HDR) intracavitary brachytherapy and external beam radiation therapy (ERT) could improve the therapeutic ratio.

METHODS AND MATERIALS

Ninety-one patients with nonmetastatic locally recurrent NPC who were treated with curative intent during the years 1990-1999 were retrospectively analyzed. Eighty-two patients had histologically proven carcinoma. The remaining 9 had clinical and imaging features suggestive of local recurrence. The Ho's T-stage distribution at recurrence (rT) was as follows: rT1-37, rT2-14, rT3-40. Total equivalent dose (TED) was calculated by the linear-quadratic formula without a time factor correction. For those treated by combined-modality treatment (CMT), the TED was taken as the summation of the equivalent dose by ERT and the absolute dose delivered to floor of the sphenoid by brachytherapy. Eight patients were treated solely with brachytherapy, all receiving 24-45 Gy in 3-10 sessions. Forty-one patients were treated with ERT alone receiving a median TED of 57.3 Gy (range, 49.8-62.5 Gy). Forty-two patients were treated by CMT with a median equivalent dose of 50 Gy (range, 40-60 Gy) given by ERT and 14.8 Gy by brachytherapy (range, 3-29.6 Gy). Multivariate analyses were performed using the Cox regression proportional hazards model.

RESULTS

The 5-year actuarial overall survival rate, disease specific survival rate and local failure-free survival (LFFS) rate for the whole group were 30%, 33. 3% and 37.8%, respectively. The 3-year LFFS rates of rT1, rT2, and rT3 diseases were 64%, 61.5%, and 18.4%, respectively (p = 0.001). Of the 8 patients treated with brachytherapy alone, 4 failed locally. Further analyses were concentrated on the ERT (41 patients) and CMT (42 patients) groups. The 3-year LFFS rates of rT1, rT2, and rT3 diseases were 66.7%, 66.7%, and 18.4%, respectively (p = 0.0008). Better local control for patients who received a TED of 60 Gy or greater was shown. The corresponding 3-year LFFS rates were 29% and 60% (p = 0.0004). Subgroup analysis on the ERT and CMT groups showed a 3-year LFFS rate of 33.5% and 57% (p = 0.003). ERT group had an excess of patients with rT3 disease. Further analysis was performed on the rT1-2 patients showing a trend toward improvement in local control in favor of the CMT group (3-year LFFS rates: CMT, 71.7%; ERT, 54%; p = 0.13). Multivariate analyses showed that rT stage (p = 0.002) and TED (p = 0.01; HR, 0.93; 95% confidence interval, 0.88-0. 98) remained significant. The 5-year major and central nervous system (CNS) complication-free rates were 26.7% and 47.8%. The following factors were found to be significant on univariate analyses for both complications in the ERT and CMT groups: (1) Modality of treatment: more complications with ERT group; and (2) rT stage. Multivariate analyses showed that the rT stage was significant for predicting the occurrence of major (p = 0.004) and CNS complications (p = 0.04).

CONCLUSION

For rT1-2 local recurrences, CMT with at least 60 Gy TED is recommended. The high incidence of major late complications is of serious concern. Ways of improving the local control of Ho's rT3 disease and reducing the risk of late complications should be explored.

Fractionated stereotactic radiation therapy for extracranial head and neck tumors

BACKGROUND

This study is to report the clinical experiences of fractionated stereotactic radiation therapy (FSRT) for extracranial head and neck tumors.

METHODS AND MATERIALS

Between the period of July 1995 and November 1998, 48 patients with extracranial head and neck tumors were given FSRT as a boost and sole modality. Individualized treatment planning was performed using XKnife-3 system with relocatable Gill-Thomas-Cosman frame. In 24 patients, FSRT was applied as a boost technique following the 2-dimensional conventional external radiation therapy (ERT); in 24 patients FSRT was the sole radiotherapy modality. The primary diseases in the boost group consisted of nasopharynx cancer (19), lacrimal gland adenoid cystic carcinoma (3), orbital lymphoma (1), and skull-base recurrence of maxillary sinus adenoid cystic carcinoma (1). The primary diseases in the sole modality group consisted of recurrent nasopharynx cancer (12), orbital pseudotumor (4), skull-base recurrence of maxillary sinus, submandibular gland, and hypopharynx cancers (3), orbital rhabdomyosarcoma (2), orbital lymphoma (1), orbital metastasis of neuroblastoma (1), and nasal cavity melanoma (1). The fractionation schedule was to give 5 treatments per one week and the fractional doses were 2.0-3 Gy depending on the treatment aim and the FSRT volume. The FSRT doses varied depending on the nature of the primary diseases.

RESULTS

The local tumor response in nasopharynx cancer patients was excellent compared to retrospective data without occurrence of unexpectedly severe complication. FSRT to other regions was well tolerated by the patients and resulted in good to excellent local tumor responses with no unacceptable side effects as expected by the authors.

CONCLUSION

Based on the current observations, FSRT is a very effective and safe modality in the treatment of extracranial head and neck tumors.

Clinical experience with retreatment for palliation

Every radiation oncologist is faced occasionally with the need to consider reirradiation for palliation. Because reirradiation has the potential to exceed normal tissue tolerances, there is a need to have information on the efficacy and toxicity of retreatment. This article reviews the reirradiation literature and provides guidance to clinicians with regard to the risks, benefits, and side effects of retreatment.

Salvage brachytherapy for patients with locally persistent nasopharyngeal carcinoma

PURPOSE

Locally persistent nasopharyngeal carcinoma (NPC) carries an increased risk of local failure if additional treatment is not given. This study was conducted to evaluate the outcomes of patients with locally persistent NPC as treated by high-dose-rate (HDR) intracavitary brachytherapy, and to explore whether routine brachytherapy boost could improve the local control.

METHODS AND MATERIALS

Eighty-seven patients with locally persistent NPC treated during 1990-1998 with HDR intracavitary brachytherapy were retrospectively analyzed. Fibreoptic nasopharyngoscopy was performed 3-6 weeks after completion of the primary external radiation therapy (ERT). Biopsies were only taken from suspicious areas. Those with complete regression of local disease were put on observation. Eighty-seven patients were shown to have persistent viable disease at a median time of 6 weeks post-RT. The distribution according to Ho's staging system at initial diagnosis was as follows: Stage I-8, II-33, III-41, IV-5; T1-19, T2-48, T3-20; N0-32, N1-22, N2-28, N3-5. CT scan for restaging was not performed after the documentation of persistent disease. Our policy was to treat all patients with persistent disease with brachytherapy irrespective of the extent of disease just prior to brachytherapy. They were treated with HDR intracavitary brachytherapy, with either cobalt sources or an iridium source, giving 22.5-24 Gy in 3 weekly sessions in all but 4 patients. This dose was prescribed at a distance of 1.5 cm from the center of the surface as defined by the sources in the first six patients and subsequently reduced to 1 cm for the others. Twelve patients were treated with neoadjuvant chemotherapy. To compare the efficacy of brachytherapy, another 383 consecutive nonmetastatic patients, treated with curative intent by ERT, during the years 1990-1993, were evaluated. Multivariate analysis was performed using the Cox regression proportional hazards model.

RESULTS

The 5-year actuarial local failure-free survival (LFFS) rates and disease-specific survival rates for the brachytherapy group and ERT group were 85% and 76.6% (p = 0.15), and 72% and 67.8% (p = 0.2), respectively. The corresponding 5-year actuarial LFFS rates for T1, T2, and T3 disease were 94.7%, 88.2%, 67.4%, and 84.1%, 79.8%, 62.6%. In assessing the local control, only the T staging was significant on multivariate analysis (p = 0.0004). Other parameters such as age, sex, and persistence of disease (giving brachytherapy) were all nonsignificant. Complications were comparable between the two groups. In the persistent group, the local failure rates of the patients treated with and without neoadjuvant chemotherapy were 17% (2/12) and 13% (10/75) respectively. When analyzed according to different brachytherapy sources, the 5-year LFFS rates of the T1, T2, and T3 patients treated with iridium and cobalt sources were 100% vs. 85.7 (p = 0.19), 93.6% vs. 70% (p = 0.04), and 67.7% vs. 60% (p = 0.72). The difference was statistically significant for the T2 groups. When early T-stage (T1 and T2) patients were grouped together for analysis, the iridium group again showed a statistically significant improvement in 5-year LFFS rate when it was compared with the cobalt group (95.3% vs. 76.5%, p = 0.03) and the ERT alone group (95.3% vs. 81.5%, p = 0.03). The improvement of local control is attributed to a higher nasopharyngeal mucosal dose that is achieved by using small-size flexible applicators with an iridium source. It is interesting to note that the 5-year LFFS rates for the ERT alone group (T1: 84.1%, T2: 79.8%, T3: 62.6%) are comparable to the corresponding rates of the cobalt group. This information supports our speculation that an adequate booster treatment could compensate for inadequate primary treatment. The prognosis of patients with locally recurrent NPC is grave. Maximizing the local control is therefore crucial for the survival of the patients. (ABSTRACT TRUNCATED)

Locally recurrent nasopharyngeal carcinoma

PURPOSE

To assess the outcome of and determine prognostic factors for locally recurrent nasopharyngeal carcinoma (NPC) in patients treated with a second course of radiotherapy (RT).

MATERIALS AND METHODS

From 1982 to 1995, 186 NPC patients, who had initially been treated in the Department of Radiation Oncology, Chang Gung Memorial Hospital-Linkou, developed local recurrence in the nasopharynx and were re-treated with RT (>/=20 Gy). The time from the initial RT to re-treatment ranged from 8 to 136 months (median: 23 months). All patients were treated with external RT and conformal radiotherapy was used in 35 patients after 1993. Fifteen received radiosurgery as a boost treatment. The RT dose at the nasopharyngeal tumor area ranged from 20 to 67.2 Gy (median 50 Gy). Eighty-two patients received one to eight courses of cisplatin-based chemotherapy in addition to RT.

RESULTS

The 1-, 3- and 5-year survival was 54.9, 22. 1 and 12.4%, respectively. Patients whose tumor relapsed later than 2 years after the first treatment had a better survival than those with earlier relapse (3-year survival: 30.1 vs. 10.8%; P=0.015), but the difference became insignificant in patients who received >/=50 Gy. Patients without evidence of intracranial invasion or cranial nerve palsy had better survival than those with such lesions (3-year survival: 30.9 vs. 3.7%; P=0.006). A re-treatment dose >/=50 Gy yielded better survival (3-year survival: 22.8 vs. 18.5%; P=0.003). Addition use of radiosurgery may improve survival. The use of chemotherapy did not improve survival. Conformal radiotherapy resulted in significantly fewer severe complications than conventional RT.

CONCLUSIONS

A repeat course of RT for locally recurrent NPC successfully prolongs survival in a significant number of patients. Intracranial invasion and/or cranial nerve palsy and re-treatment dose affect the prognosis, with a dose of >/=50 Gy significantly improving survival. Radiosurgery boost may also improve survival. Our preliminary data indicates that conformal radiotherapy may decrease the severity of radiation-induced complications. However; longer follow-up and larger sample size is necessary to document the findings.

Results of hypofractionated stereotactic re-irradiation on 13 locally recurrent nasopharyngeal carcinomas

Thirteen patients with locally recurrent, previously-irradiated nasopharyngeal carcinoma were treated with linac-based hypofractionated stereotactic radiotherapy (24 Gy in two or four fractions). One- and 3-year overall survival were 54 and 31%. Three patients were free of disease at 30, 34 and 65 months. No severe acute or late complications were seen.

Stereotactic radiosurgery as a salvage treatment for locally persistent and recurrent nasopharyngeal carcinoma

BACKGROUND

The purpose of this work was to study the efficacy of stereotactic radiosurgery as a salvage treatment in patients with locally persistent and recurrent nasopharyngeal carcinoma (NPC).

METHODS

Between March 1996 and August 1997, 10 patients with locally persistent or recurrent NPC were treated by linac-based stereotactic radiosurgery. Four patients had radiosurgery for persistent disease after a first course of radiotherapy, 3 had radiosurgery as a boost after reirradiation for local recurrence, and 3 had radiosurgery for disease that recurred after reirradiation. The tumor volume ranged from 1.3 to 23.7 cc (median: 5.2). Treatment was prescribed at 80% isodose line and ranged from 12 to 18 Gy (median: 13.4), with a mean tumor surface dose ranged from 10-21 Gy (median: 14). The median clinical follow-up was 10.5 months (range 8-27), and the median imaging follow-up was 9.5 months (range 6-26).

RESULTS

One patient had complete regression of tumor after radiosurgery, five had reduction in tumor size, three had no change, and one had progression of tumor. The overall response rate to radiosurgery was 60% (6/10), with 10% (1/10) developing in-field progression. Excluding patients receiving radiosurgery as a boost treatment after reirradiation, the response rate was 57% (4/7) and none developed in-field progression. Only one patient developed a new cranial neuropathy in the absence of disease progression.

CONCLUSION

In selected patients with locally persistent or recurrent NPC, stereotactic radiosurgery can be considered as a salvage treatment with good short-term local control. The complications appear to be minimal except for treating recurrence in the cavernous sinus. Early results are encouraging although more experience and longer follow-up are still needed to better define the role of radiosurgery in the management of persistent and recurrent NPC.

Re-irradiation of head and neck tumors. Benefits and toxicities

Most patients with head and neck cancer that recurs after irradiation should be treated with curative surgery. In patients whose tumors are nonresectable, or if surgery would cause unacceptable morbidity, a trial of curative re-irradiation may be considered. Taking into account the overall poor prognosis of these patients and the high rate of late tissue toxicity, especially soft tissue necrosis, fistula formation, and potential nerve damage, patients should be carefully selected. Several sites, notably the larynx and nasopharynx, can be re-irradiated with a relatively high rate of locoregional tumor control. In other sites, several criteria may be used to select patients for curative re-irradiation: limited tumor size, a relatively long period since previous irradiation (a suitable, though arbitrary, minimal time period may be 1 year), good performance status, and lack of evidence of skin or soft tissue damage (skin fibrosis, atrophy or telangiectasis) by the previous irradiation course. Even when these selection criteria are used, the prognosis is poor, and long-term survival rates are low even if locoregional tumor control is achieved. Innovative strategies and techniques, including aggressive combined chemoradiation, hyperfractionation, and limiting the extent of irradiated tissues by using conformal irradiation, may improve locoregional control rates. It should be emphasized, however, that the only chance for achieving locoregional control and cure is through the delivery of a full dose of radiation, similar to the dose required for primary tumors. The delivery of a low radiation dose, commonly practiced to avoid complications, is expected to achieve palliation only.

Fractionated stereotactic radiation therapy for locally recurrent nasopharynx cancer: report of three cases

BACKGROUND

This article reports on experience with fractionated stereotactic radiation therapy (FSRT) for locally recurrent nasopharynx cancer.

METHODS

Three patients with locally recurrent nasopharynx cancer were given FSRT as reirradiation between September 1995 and August 1996. Application of FSRT was the third radiation therapy in two patients. Authors used the individually made relocatable Gill-Thomas-Cosman (GTC) stereotactic frame, and the radiation dose planning was performed using XKnife-3. The total doses to the recurrent tumor were 45 Gy/18 fractions in two patients, who were given concurrent chemotherapy as a radiosensitizer, and 50 Gy/20 fractions in the other patient. In all three patients the dose per fraction was 2.5 Gy, and the fraction schedule was to give five daily treatments per week.

RESULTS

Authors observed satisfactory symptomatic improvement and remarkable objective tumor size decrease through the magnetic resonance (MR) images taken one month post-FSRT in all three patients. No neurological side effect was observed. All three patients died with regional and distant seeding outside the FSRT field at seven, nine, and nine months, respectively.

CONCLUSION

FSRT as reirradiation for locally recurrent nasopharynx cancer seemed to be effective and safe.

Stereotactic radiotherapy for locally recurrent nasopharyngeal carcinoma

OBJECTIVE

To determine the efficacy of stereotactic radiotherapy (SRT) in the treatment of recurrent nasopharyngeal carcinoma.

STUDY DESIGN

A retrospective review of the outcome of SRT for patients with recurrent nasopharyngeal carcinomas following definitive conventional radiation therapy.

METHODS

Five patients were treated with daily static multiportal irradiation. Two Gy was administered with eight isocentric portals in a single plane 5 days a week, and the plane was changed for every 20 to 30 Gy. Of these patients, three had poorly differentiated squamous cell carcinoma. Tumor sizes ranged from 1 to 15 cm3, with a median size 3.2 cm3. Median follow-up time from SRT was 34 months (range, 4-61 mo).

RESULTS

Four of five recurrent tumors responded well and achieved complete regression. Three patients have survived without evidence of local recurrence with a median follow-up time of 34 months. Marginal recurrence was observed at the posterosuperior wall in a patient with adenoid cystic carcinoma at 30 months after SRT. One patient who received SRT after the two complete courses of radiation therapy died 6 months after SRT as a result of rupture of a branch of the left carotid artery, but autopsy revealed no local residual tumor.

CONCLUSIONS

Stereotactic radiotherapy with isocentric multiportals in one plane, which is changed at every 20 to 30 Gy, can provide local control with acceptable toxicity in patients with recurrent nasopharyngeal carcinoma, but increased clinical experience and longer follow-up will be necessary to evaluate the overall role of this technique in nasopharyngeal carcinoma.

The time course of histologic remission after treatment of patients with nasopharyngeal carcinoma

BACKGROUND

The objective of this study was to define the time course of histologic remission and to evaluate the prognostic significance of delayed histologic remission of patients with nasopharyngeal carcinoma (NPC).

METHODS

Between 1986-1994, 803 patients underwent serial postradiotherapy nasopharyngeal biopsies. Patients with positive histology underwent repeated biopsies every 2 weeks until the biopsies were found to be negative or, if remission did not occur by the 12th week after radiotherapy, treatment was initiated for persistent disease. Patients with positive histology found after the fifth week but who achieved spontaneous remission before the twelfth week were considered to have delayed histologic remission. Negative histology by the sixth week was considered early histologic remission. The outcome of patients with delayed histologic remission, early histologic remission, and persistent disease were compared.

RESULTS

Six hundred and seventeen patients (76.8%) had negative histology within 12 weeks of the completion of radiotherapy and 55 (6.9%) had persistent disease at Week 12. In 131 patients (16.3%) spontaneous remission was observed in repeat biopsies after initial positive histology. With increasing time after radiotherapy, the incidence of positive histology decreased but more patients were found to have persistent disease. Patients with early and delayed histologic remission had 5-year NPC control rates of 82.4% and 76.8%, respectively (P = 0.35) versus a 40% NPC control rate among patients with persistent disease (P < 0.001). The 5-year survival rates were 75.3%, 79.4%, and 54.2%, respectively, for the 3 groups (P < 0.001).

CONCLUSIONS

A high proportion of early positive histology remitted spontaneously. Delayed histologic remission in NPC patients is not a poor prognostic factor and additional treatment is not necessary. A confirmatory biopsy at 10 weeks is recommended before the initiation of salvage treatment.

Results and prognostic factors in the retreatment of locally recurrent nasopharyngeal carcinoma

PURPOSE

To review the results and evaluate the prognostic factors in the retreatment of locally recurrent nasopharyngeal carcinoma.

METHODS AND MATERIALS

We reviewed the records of 74 patients with locally recurrent nasopharyngeal carcinoma treated at the University of California, San Francisco between 1957 and 1995. The histologic types included squamous cell carcinoma in 6 (8.1%), nonkeratinizing carcinoma in 48 (64.9%), and undifferentiated carcinoma in 20 (27%) cases. The site of recurrence was in the primary in 46 (62.2%), in the neck nodes in 20 (27%), and in both sites in 8 (10.8%) patients. The recurrent disease was Stage I in 10 (13.5%), Stage II in 16 (21.6%), Stage III in 20 (27%), and Stage IV in 28 (37.9%) patients. Thirty-seven (50%) patients developed recurrence within 2 years and 58 (78.4%) within 5 years after initial treatment. Radiotherapeutic techniques used in the retreatment of primary recurrence consisted of external beam radiotherapy (EBRT), intracavitary brachytherapy, heavy-charged particle beam, and gamma knife, alone or in combination. Reirradiation doses ranged from 18 to 108 Gy, with a median dose of 60 Gy. Treatment of recurrent neck nodes consisted of radical neck dissection (RND) +/- intraoperative radiotherapy (IORT), or EBRT +/- hyperthermia, or chemotherapy +/- hyperthermia. Chemotherapy was used in 22 (30%) patients. Median follow-up was 20 months (range: 2 to 308 months).

RESULTS

The 3-, 5-, and 10-year actuarial overall survival following retreatment were 49, 37, 18%, respectively. Thirty-six patients (49%) were free of further local-regional recurrence after retreatment. The 3-, 5-, and 10-year local-regional progression-free rates were 52, 40, and 38%, respectively. On univariate analysis, histologic type (p < 0.0001), interval to recurrence (p = 0.034), and treatment modality for early-stage disease (p = 0.01) were significant prognostic factors for overall survival, with age being marginally significant (p = 0.053). For local-regional progression-free rate, only histology was significant (p = 0.035). On multivariate analysis, age (p = 0.026), histology (p = 0.015), and interval to recurrence (p = 0.030) were significant for overall survival, and only histology (p = 0.002) and presence of complications (p = 0.016) were significant for local-regional progression-free rate. Of the 64 reirradiated patients, late complications were documented in 29 (45%) patients. The late complications were permanent in 21 (33%) and severe in 15 (23%) patients.

CONCLUSION

Retreatment using radiotherapy alone or in combination with other treatment modalities can achieve long-term local-regional control and survival in a substantial proportion of patients with locally recurrent nasopharyngeal carcinoma. Age, histology, and interval to recurrence were independent prognostic factors for overall survival, but only histology and presence of complications were significant for local-regional progression-free rate.

Locally recurrent nasopharyngeal carcinoma: treatment results for patients with computed tomography assessment

PURPOSE

To study the treatment outcome in patients with locally recurrent nasopharyngeal carcinoma as restaged by computed tomography (CT).

PATIENTS AND METHODS

One hundred forty patients with CT restaged locally recurrent nasopharyngeal carcinoma were reviewed. Patients were restaged at recurrence according to the AJCC stage classification with the following distribution: T1-T2:30%, T3:19%, T4:51%. Ninety-seven patients received reirradiation; among these 62 had external irradiation, 34 had brachytherapy, and 1 had both. Twelve patients received surgery. Thirty-one patients were treated with palliative intent and received either chemotherapy or supportive treatment only. Overall survival (OAS) and performance-adjusted survival (PAS, defined as surviving with a Karnofsky performance score [KPS] > 50) were calculated by Kaplan-Meier method. Multivariate analysis was performed using the Cox model.

RESULTS

The median survival for all patients was 23.8 months. After reirradiation, the 3-yr and 5-yr OAS rates were 46% and 36%, respectively. The corresponding PAS rates were 40% and 28%. The 3-yr OAS rates for recurrent T1-2, T3, and T4 disease after reirradiation were 71%, 42%, and 30%; the corresponding 5-yr OAS rates were 57%, 42%, 17%. The 3-yr and 5-yr OAS rates in patients receiving palliative treatments only were 19% and 0%, respectively. The 3-yr OAS rate after surgery was 42%. In the multivariate analysis, older age, recurrent T3-4 disease, and palliative treatment were unfavorable factors in predicting overall survival, whereas recurrent T3-4 disease, baseline KPS < 70, and palliative treatment were unfavorable factors in predicting PAS. A high complication rate was observed after reirradiation, with 34% of patients developing neurological sequel.

CONCLUSION

Aggressive treatment for locally recurrent nasopharyngeal carcinoma is warranted especially for those with disease confined to the nasopharynx. Survival after retreatment for more extensive disease remains poor but was still superior to supportive treatment only. Early diagnosis of local recurrence allows prompt administration of treatment and is associated with better outcome. Future studies should aim at improving the therapeutic ratio in the retreatment of recurrent disease especially in patients with more extensive local recurrence.

The role of stereotactic radiosurgery in the treatment of malignant skull base tumors

PURPOSE

To determine the efficacy and toxicity of stereotactic radiosurgery in the treatment of malignant skull base tumors.

METHODS AND MATERIALS

Thirty-two patients with 35 newly diagnosed or recurrent malignant skull base tumors < or = 33.5 cm3 were treated using the Leksell Gamma unit. Tumor histologies included: adenoid cystic carcinoma [12], basal cell carcinoma [1], chondrosarcoma [1], chordoma [8], nasopharyngeal carcinoma [3], osteogenic sarcoma [2], and squamous cell carcinoma [8].

RESULTS

After a median follow-up of 2.3 years, 83% +/- 15% (+/-95% confidence interval) of patients experienced a symptomatic response to treatment. Local control at the skull base was 95 +/- 9% at 2 years and 78 +/- 23% at 3 years. Local-regional control above the clavicles was 75 +/- 15% at 1 year and 51 +/- 20% at 2 years. Overall and cause specific survival were identical, 82 +/- 13% at 1 year, 76 +/- 14% at 2 years, and 72 +/- 16% at 3 years. One patient developed a radiation-induced optic neuropathy 12 months after radiosurgery.

CONCLUSION

Stereotactic radiosurgery using the Leksell Gamma Unit can provide durable tumor control and symptomatic relief with acceptable toxicity in the majority of patients with malignant tumors 4 cm or less in size involving the skull base. Further evaluation of more patients with longer follow-up is warranted.

Radiosurgery for skull base malignancies and nasopharyngeal carcinoma

PURPOSE

Patients with skull base lesions present a challenging management problem because of intractable symptoms and limited therapeutic options. In 1989 we began treating selected patients with skull base lesions using linac stereotactic radiosurgery. In this study the efficacy and toxicity of this therapeutic modality is investigated.

METHODS AND MATERIALS

Forty-seven patients with 59 malignant skull base lesions were treated with linac radiosurgery between 1989 and 1995. Eleven patients were treated for primary nasopharyngeal carcinoma using radiosurgery as a boost (7 Gy-16 Gy, median: 12 Gy) to the nasopharynx after a course of fractionated radiotherapy (64.8-70 Gy) without chemotherapy. Another 37 patients were treated for 48 skull base metastases or local recurrences from primary head and neck cancers. Eight of these patients had 12 locally recurrent nasopharyngeal carcinoma lesions occuring 6-96 months after standard radiotherapy, including one patient with nasopharyngeal carcinoma who developed a regional relapse after radiotherapy with a stereotactic boost. Lesion volumes by CT or MRI ranged from 0 to 51 cc (median: 8 cc). Radiation doses of 7.0 Gy-35.0 Gy (median: 20.0 Gy) were delivered to recurrent lesions, usually as a single fraction.

RESULTS

All 11 patients who received radiosurgery as a nasopharyngeal boost after standard fractionated radiotherapy remain locally controlled (follow-up: 2-34 months, median: 18). However, one patient required a second radiosurgical treatment for regional relapse outside the initial radiosurgery volume. Thirty-three of 48 (69%) recurrent/metastatic lesions have been locally controlled, including 7 of 12 locally recurrent nasopharyngeal lesions. Follow-up for all patients with recurrent lesions ranged from 1 to 60 months (median: 9 months). Local control did not correlate with lesion size (p = 0.80), histology (p = 0.78), or radiosurgical dose (p = 0.44). Major complications developed after 5 of 59 treatments (8.4%), including three cranial nerve palsies, one CSF leak, and one trismus. Complications were not correlated with radiosurgical volume (p = 0.20), prior skull base irradiation (p = 0.90), or radiosurgery dose > 20 Gy (p = 0.49).

CONCLUSION

Stereotactic radiosurgery is a reasonable treatment modality for patients with skull base malignancies, including patients with primary and recurrent nasopharyngeal carcinoma. The dose distribution obtained with stereotactic radiosurgery provides better homogeneity than an intracavitary implant when used as a boost for nasopharyngeal lesions, especially lesions which involve areas distant to the nasopharyngeal mucosa.

Transcervico-mandibulo-palatal approach for surgical salvage of recurrent nasopharyngeal cancer

BACKGROUND

Local relapse of nasopharyngeal carcinoma is a difficult problem of management that is usually treated by re-irradiation. Surgical salvage is rarely offered, judging by the paucity of reports in the literature.

METHODS

This article reviews the six previously described methods of performing nasopharyngectomy and recounts experience with a series of seven patients using a transcervico-mandibulo-palatal approach, which is described.

RESULTS

The results of this small series show survivorship and morbidity which seem to compare favorably with other published surgical treatment options.

CONCLUSIONS

If retreatment with radiotherapy is not favored, the transcervico-mandibulo-palatal approach may be a suitable method of surgical salvage for small, locally recurrent, nasopharyngeal cancer.

Radiosurgery for recurrent cranial base cancer arising from the head and neck

BACKGROUND

Treatment options for head and neck cancers that recur at the cranial base are limited.

METHODS

Twelve patients with head and neck cancers recurrent after resection and fractionated radiotherapy (n = 11) at the cranial base had stereotactic radiosurgery using the gamma unit. The median dose to the tumor margin was 16 Gy. Imaging follow-up varied from 3 to 17 months; the longest clinical follow-up was at 35 months.

RESULTS

Three of 8 tumors studied by postradiosurgery imaging remained unchanged in size, 3 decreased, and 2 were no longer visible. There was no morbidity or worsening of symptoms after radiosurgery. Four patients died between 4 and 8 months and did not have postradiosurgery imaging performed. Mean survival after radiosurgery was 10.5 months, with 7 patients (58%) still living.

CONCLUSIONS

Radiosurgery proved safe and effective in providing local control for recurrent cranial base cancers arising from the extracranial head and neck. Radiosurgery should be considered for those patients who have failed prior fractionated radiation or surgical resection, those who have tumors in high-risk cranial locations, or those who are poor medical candidates. Although this study shows its potential adjuvant role, longer follow-up and increased clinical experience will be necessary to evaluate the overall role of radiosurgery in head and neck cancer.

Advances in radiotherapy for head and neck cancer

Selected advances in radiotherapy for treatment of head and neck cancer are reviewed. These include the role of postoperative radiotherapy, planned postirradiation neck dissection, altered fractionation, neoadjuvant chemotherapy and radiotherapy for laryngeal preservation, three-dimensional conformal treatment planning, charged particle irradiation for skull base tumors, and stereotactic radiosurgery.