Biomedical subjects

Robert J Amdur

Publications and source records attributed to Robert J Amdur.

At least 19 recordsLinked to original sources

PubMed2007

Do pre-irradiation dental extractions reduce the risk of osteoradionecrosis of the mandible?

BACKGROUND: This study was done to determine if pre-radiotherapy (pre-RT) dental extractions reduce the risk of osteoradionecrosis (ORN). METHODS: Between 1987 and 2004, 413 patients with oropharyngeal carcinomas were treated with definitive RT at the University of Florida. Dentate patients underwent pretreatment dental evaluation. Teeth in the RT field were usually extracted if thought to have poor long-term prognosis from dental disease. The endpoint was > or = grade 2 ORN using a modified staging system. Patients were excluded for local recurrence, additional RT above the clavicles, or head and neck surgery besides neck dissection. RESULTS: ORN rates were as follows: edentulous, <1%; teeth in-field with pre-RT extractions, 15%; and teeth in-field without pre-RT extractions, 9%. Patients with poor in-field teeth and pre-RT extractions had a higher 5-year incidence of ORN than those who did not have pre-RT extractions (16% vs 6%, p = .48). Likewise, for those with in-field teeth in good condition and pre-RT extractions, the 5-year ORN incidence was higher than for those who did not undergo extractions (15% vs 2%, p = .42). Multivariate analysis revealed increased ORN risk with doses of >70 Gy, once-daily fractionation, or brachytherapy. CONCLUSION: Pre-RT extractions do not appear to reduce the risk of ORN.

Adult↗

PubMed2006

Definitive radiotherapy for head-and-neck cancer with radiographically positive retropharyngeal nodes: incomplete radiographic response does not necessarily indicate failure.

PURPOSE: Our aim was to report the control rate of radiographically positive retropharyngeal (RP) nodes with radiation therapy (RT) and to correlate posttreatment imaging with clinical outcome. METHODS AND MATERIALS: Sixteen patients treated with definitive RT for head-and-neck cancer had radiographically positive RP nodes (size >1 cm in largest axial dimension, or presence of focal enhancement, lucency, or calcification), and both pre-RT and post-RT image sets available for review. An additional 21 patients with unconfirmed radiographically positive RP nodes had post-RT imaging, which consisted of computed tomography (CT) at a median of 4 weeks after completing RT. Patients with positive post-RT RP nodes underwent observation with serial imaging. RESULTS: Of 16 patients with pre-RT and post-RT images available for review, 9 (56%) had a radiographic complete response, and of 21 patients with unconfirmed positive RP nodes with post-RT images available for review, 14 (67%) had a radiographic complete response. In all, 14 patients with incomplete response on post-RT imaging experienced control of their disease with no further therapy, and no RP node or neck failures were noted during a median follow-up of 2.8 years. Six patients with positive post-RT RP nodes had serial imaging available for review, and none demonstrated radiographic progression of disease. CONCLUSIONS: Radiographic response at 4 weeks may not accurately reflect long-term locoregional control, as RP nodes may continue to resolve over time. The highest index of suspicion should be reserved for patients with progressive changes in size, focal lucency, or focal enhancement on serial imaging after RT.

Adult↗

PubMed2006

Radiotherapy after subtotally resected or recurrent ganglioglioma.

PURPOSE: Gangliogliomas can recur after subtotal resection (STR). The role of postoperative radiation therapy (RT) is undefined. METHODS AND MATERIALS: Eight consecutive patients with low-grade gangliogliomas (n = 7) or anaplastic gangliogliomas (n = 1) were treated with RT between 1987 and 2004. Median age was 17 years. Five patients received adjuvant RT after STR at a median time of 6 weeks after surgery. Three patients received salvage RT at a median time of 17 months after surgery. The median dose of RT was 54 Gy. Control was defined as no progressive disease on serial imaging. Median follow-up was 8.8 years. RESULTS: Of the 7 patients with low-grade gangliogliomas, 3 were controlled after RT and 4 recurred locally. Recurrences were controlled with further surgery (n = 2), chemotherapy (n = 1), or re-irradiation (n = 1) (median follow-up, 9 years after salvage therapy). Patients who received adjuvant RT after STR of their low-grade gangliogliomas had an overall local control rate of 75%. All 3 patients who were treated with salvage RT had recurrences in the treated area alone (n = 2) or in the treated area with leptomeningeal spread (n = 1). The patient with an anaplastic ganglioglioma was treated with adjuvant RT, and had recurrence in the radiation field after 4 months, then died 1 month later. CONCLUSIONS: Adjuvant RT may be indicated to treat select patients with subtotally resected gangliogliomas. Salvage RT for recurrence is probably less effective for long-term control; however, patients who recur may still be candidates for effective salvage therapies in the absence of malignant transformation.

Adolescent↗

PubMed2006

Adjuvant radiotherapy for cutaneous melanoma: comparing hypofractionation to conventional fractionation.

PURPOSE: To examine locoregional control after adjuvant radiotherapy (RT) for cutaneous melanoma and compare outcomes between conventional fractionation and hypofractionation. METHODS AND MATERIALS: Between January 1980 and June 2004, 56 patients with high-risk disease were treated with adjuvant RT. Indications for RT included: recurrent disease, cervical lymph node involvement, lymph nodes >3 cm, more than three lymph nodes involved, extracapsular extension, gross residual disease, close or positive margins, or satellitosis. Hypofractionation was used in 41 patients (73%) and conventional fractionation was used in 15 patients (27%). RESULTS: The median age was 61 years (21->90). The median follow-up among living patients was 4.4 years (range, 0.6-14.4 years). The primary site was located in the head and neck in 49 patients (87%) and below the clavicles in 7 patients (13%). There were 7 in-field locoregional failures (12%), 3 out-of-field regional failures (5%), and 24 (43%) distant failures. The 5-year in-field locoregional control (ifLRC) and freedom from distant metastases (FFDM) rates were 87% and 43%, respectively. The 5-year cause-specific (CSS) and overall survival (OS) was 57% and 46%, respectively. The only factor associated with ifLRC was satellitosis (p = 0.0002). Nodal involvement was the only factor associated with FFDM (p = 0.0007), CSS (p = 0.0065), and OS (p = 0.016). Two patients (4%) who experienced severe late complications, osteoradionecrosis of the temporal bone and radiation plexopathy, and both received hypofractionation (5%). CONCLUSIONS: Although surgery and adjuvant RT provides excellent locoregional control, distant metastases remain the major cause of mortality. Hypofractionation and conventional fractionation are equally efficacious.

Adult↗

PubMed2006

Intensity-modulated radiotherapy in the standard management of head and neck cancer: promises and pitfalls.

The purpose of this article is to review the role of intensity-modulated radiotherapy (IMRT) in the standard management of patients with head and neck cancer through a critical review of the pertinent literature. IMRT may result in a dose distribution that is more conformal than that achieved with three-dimensional conformal radiotherapy (3D CRT), allowing dose reduction to normal structures and thus decreasing toxicity and possibly enhancing locoregional control through dose escalation. Disadvantages associated with IMRT include increased risk of a marginal miss, decreased dose homogeneity, increased total body dose, and increased labor and expense. Outcomes data after IMRT are limited, and follow-up is relatively short. Locoregional control rates appear to be comparable to those achieved with 3D CRT and, depending on the location and extent of the tumor, late toxicity may be lower. Despite limited data on clinical outcomes, IMRT has been widely adopted as a standard technique in routine practice and clinical trials. The use of IMRT involves a learning curve for the practitioner and will continue to evolve, requiring continuing education and monitoring of outcomes from routine practice. Additional standards pertaining to a variety of issues, including target definitions and dose specification, need to be developed. Phase III trials will better define the role of IMRT in coming years.

Antineoplastic Agents↗

PubMed2006

Postradiotherapy neck dissection for lymph node-positive head and neck cancer: the use of computed tomography to manage the neck.

PURPOSE: To determine how to use node response on computed tomography (CT) to indicate the need for neck dissection. PATIENTS AND METHODS: Five hundred fifty patients with lymph node-positive head and neck cancer were treated between 1990 and 2002 with radiotherapy (RT) at a median dose of 74.4 Gy; 24% of these patients (n = 133) were treated with chemotherapy. Three hundred forty-one patients (62%) underwent planned post-RT neck dissection. Physical examination and contrast-enhanced CT were performed 30 days after completion of RT. CT images were reviewed in 211 patients for lymph node size (largest axial dimension) and presence of a focal abnormality (lucency, enhancement, or calcification). By correlating post-RT CT to neck dissection pathology, criteria associated with a low likelihood of residual disease were identified. A subset of patients who fit these criteria of radiographic response who did not undergo post-RT neck dissection was observed for recurrence. RESULTS: Radiographic complete response (rCR) was defined as the absence of any large (> 1.5 cm) or focally abnormal lymph node. Correlation of response with neck dissection pathology indicated a negative predictive value of 77% for complete clinical response and 94% for rCR. In 32 patients (median follow-up time, 3.2 years) with rCR who did not undergo post-RT neck dissection, the 5-year ultimate neck control rate (100%) and cause-specific survival rate (72%) were not significantly different from the rates of patients with a negative post-RT neck dissection. CONCLUSION: Patients with rCR 4 weeks after RT can be spared from a post-RT neck dissection regardless of initial node stage.

Adult↗

PubMed2006

Low-dose prophylactic craniospinal radiotherapy for intracranial germinoma.

PURPOSE: To report outcomes of patients with localized intracranial germinoma treated with low-dose craniospinal irradiation (CSI) followed by a boost to the ventricular system and primary site. METHODS AND MATERIALS: Thirty-one patients had pathologically confirmed intracranial germinoma and no spine metastases. Low-dose CSI was administered in 29 patients: usually 21 Gy of CSI, 9.0 Gy of ventricular boost, and a 19.5-Gy tumor boost, all at 1.5 Gy per fraction. Our neuroradiologist recorded three-dimensional tumor size on magnetic resonance images before, during, and after radiotherapy. RESULTS: With a median follow-up of 7.0 years, 29 of 31 patients (94%) are disease free. One failure had nongerminomatous histology; the initial diagnosis was a sampling error. Of 3 patients who did not receive CSI, 1 died. No patient developed myelopathy, visual deficits, dementia, or skeletal growth problems. In locally controlled patients, tumor response according to magnetic resonance scan was nearly complete within 6 months after radiotherapy. CONCLUSIONS: Radiotherapy alone with low-dose prophylactic CSI cures almost all patients with localized intracranial germinoma. Complications are rare when the daily dose of radiotherapy is limited to 1.5 Gy and the total CSI dose to 21 Gy. Patients without a near-complete response to radiotherapy should undergo resection to rule out a nongerminomatous element.

Adolescent↗

PubMed2006

Definitive radiotherapy for squamous cell carcinoma of the base of tongue.

OBJECTIVE: To evaluate definitive radiotherapy (RT) for treatment of base of tongue cancer. METHODS: There were 333 patients with squamous cell carcinoma of the base of tongue treated with definitive RT and had follow-up from 0.2 to 26.2 years. Follow-up on living patients ranged from 1.2 to 26.2 years (median, 6.6 years). RESULTS: Local control rates at 5 years were: T1, 98%; T2, 92%; T3, 82%; and T4, 53%. The 5-year rates of local-regional control rates were: I-II, 100%; III, 82%; IVA, 87%; and IVB, 58%. The rates of absolute and cause-specific survival at 5 years were as follows: I-II, 67% and 91%; III, 66% and 77%; IVA, 67% and 84%; and IVB, 33% and 45%. Severe complications developed in 52 patients (16%). CONCLUSION: Our data and review of the pertinent literature reveal that the local-regional control rates and survival rates after RT were comparable to those after surgery, and the morbidity associated with RT was less.

Adult↗

PubMed2006

Definitive radiotherapy for juvenile nasopharyngeal angiofibroma.

OBJECTIVES: To update our experience with definitive radiotherapy (RT) for juvenile nasopharyngeal angiofibroma (JNA). METHODS: Twenty-two patients received definitive RT for advanced JNA between June 1975 and March 2003 and were followed from 2.0 to 30.2 years (median, 12.7 years). Total dose ranged from 30 to 36 Gy. RESULTS: Twenty of 22 patients (91%) remained locally controlled after RT; both patients who developed a local recurrence were salvaged so that the ultimate local control rate was 100%. No patient experienced a severe complication. CONCLUSION: Patients with advanced and/or recurrent JNA thought not to be amenable to complete resection with acceptable morbidity have a high likelihood of cure after RT with a low risk of complications.

Adolescent↗

PubMed2006

Definitive radiotherapy for tonsillar squamous cell carcinoma.

PURPOSE: The purpose of this study is to update our experience with definitive radiotherapy (RT) for carcinoma of the tonsillar area. PATIENTS AND METHODS: There were 503 patients treated between October 1964 and May 2003 (potential follow-up for at least 2 years). Of these, 198 patients underwent a planned neck dissection and 57 patients received induction (18 patients) or concomitant (39 patients) chemotherapy. RESULTS: The 5-year local control rates were as follows: T1, 88%; T2, 84%; T3, 78%; and T4, 61%. Multivariate analysis revealed that local control was significantly influenced by T stage, primary site, and fractionation. Local control after RT for early stage cancers was higher for tonsillar fossa/posterior pillar tumors than for those arising from the anterior tonsillar pillar. The 5-year cause-specific survival rates were as follows: I, 100%; II, 86%; III, 84%; IVA, 73%; and IVB, 46%. Multivariate analysis revealed that cause-specific survival was significantly influenced by T stage, overall stage, neck dissection, race, and gender. The incidence of severe late complications was 9%. CONCLUSION: Based on our data and a review of the literature, definitive RT provides cure rates that are as good as those after surgery, and is associated with a lower rate of severe complications. Patients with lateralized tumors may be safely treated with ipsilateral field arrangements. Our limited experience with intensity modulated radiotherapy suggests that it is as efficacious as conventional RT.

Adult↗

PubMed2006

Hypothyroidism when the thyroid is included only in the low neck field during head and neck radiotherapy.

OBJECTIVE: The minimum dose required to electively irradiate all of part of the low neck for squamous cell carcinoma of the oropharynx is 50 Gy in 25 fractions or its radiobiological equivalent. The purpose of our study is to determine the incidence of hypothyroidism when the thyroid is treated only in the low-neck radiotherapy (RT) field to approximately 50 Gy. METHODS AND MATERIALS: 390 patients with oropharyngeal carcinoma received RT between 1990 and 2000, had no prior thyroid disease or surgery, and had RT involving the standard anterior low-neck field including the thyroid with a dose equivalent to 50 Gy at 2Gy/fx with or without a boost to a portion of the field to 60 to 70 Gy. The end point was hypothyroidism defined as thyroid stimulating hormone (TSH) above the upper limit of the normal range. RESULTS: As we did not routinely monitor TSH during this study, it was obtained in 169 of 390 patients. Median follow-up on all 390 patients was 6.1 years. The incidence of hypothyroidism was calculated for 2 groups: 169 patients with TSH data and the total population of 390 patients. For both analyses, patients were censored at last follow-up if the TSH level was normal, or if TSH was not checked. The incidence of hypothyroidism at 5 years was 31% for all 390 patients and 54% for the subset of 169 patients with TSH data. Adjuvant chemotherapy and/or planned neck dissection may be associated with a small increased risk of hypothyroidism. CONCLUSIONS: Including the thyroid in the low-neck field to 50 Gy results in hypothyroidism in 30% to 50% of patients at 5 years, suggesting that the threshold for this complication is <50 Gy.

Carcinoma, Squamous Cell↗

PubMed2006

Surgery and postoperative radiotherapy for squamous cell carcinoma of the larynx and pharynx.

OBJECTIVE: To determine the rates of local-regional control, survival, and complications for patients treated with postoperative radiation for squamous carcinomas of the larynx, hypopharynx, and oropharynx. METHODS: There were 295 patients with previously untreated squamous cell carcinomas of the larynx (n = 199), hypopharynx (n = 80), and oropharynx (n = 16) treated postoperatively with radiotherapy (RT). RESULTS: Five-year local-regional control rates according to site and pathologic American Joint Committee on Cancer (AJCC) stage were: stage III larynx, 89% versus stage IVA larynx, 85% (P = 0.33); stage III oropharynx/hypopharynx, 76% versus stage IVA oropharynx/hypopharynx, 79% (P = 0.72). Local-regional control rates steadily declined as the number of indications for administering postoperative RT increased. Five-year absolute survival rates versus pathologic AJCC stage for the entire group were: stage III 59% and stage IVA 40% (P = 0.40). CONCLUSION: Rates of local-regional control, survival, and complications support the use of postoperative radiation in selected patients. Tumor control and survival will hopefully improve further with the addition of chemotherapy to postoperative radiation.

Adult↗

PubMed2006

Definitive radiotherapy for nasopharyngeal carcinoma.

PURPOSE: We sought to report the outcomes after definitive radiotherapy (RT) for nasopharyngeal carcinoma. METHODS: Between March 1983 and November 2003, 82 patients were treated with curative intent and followed from 0.2 to 22 years (median, 5 years). Follow-up on living patients ranged from 2.8 to 22 years (median, 10.8 years). Thirty-two patients (39%) were treated once daily, 45 patients (55%) were treated with hyperfractionation, and 5 patients (6%) were treated with the concomitant boost technique. Eight patients (10%) received intensity-modulated radiotherapy. Thirty-one patients (38%) received induction (17 patients) or concomitant (14 patients) chemotherapy. Fourteen patients (17%) underwent a planned neck dissection. RESULTS: The 5-year outcomes after treatment were: local control, 78%; regional control, 90%; local-regional control, 76%; distant metastasis-free survival, 80%; cause-specific survival, 66%; and survival, 57%. The impact of T-stage, N-stage, overall stage, World Health Organization class, fractionation schedule, and adjuvant chemotherapy were evaluated in a multivariate analysis of various outcomes. Only N-stage and World Health Organization class impacted regional control. CONCLUSIONS: The likelihood of cure after RT is relatively high. Although the likelihood of cure diminished with increasing stage, none of the parameters evaluated significantly influenced outcomes aside from N-stage and WHO class.

Adolescent↗

PubMed2006

Postoperative radiotherapy for squamous cell carcinoma of the head and neck.

This review discusses the role of postoperative radiotherapy (RT) for patients with squamous cell carcinoma of the head and neck. Patients with unfavorable pathologic features have a high-risk of local-regional recurrence and a decreased likelihood of survival after surgery alone. Postoperative RT reduces the risk of local-regional failure and probably improves survival. Patients who are at high risk for recurrence may benefit from more aggressive altered fractionation schedules to decrease the overall time from surgery to the completion of RT. Adjuvant cisplatin-based chemotherapy also appears to improve the probability of cure in high-risk patients.

Carcinoma, Squamous Cell↗

PubMed2005

Radiotherapy alone or combined with carbogen breathing for squamous cell carcinoma of the head and neck: a prospective, randomized trial.

BACKGROUND: The current study was performed to investigate the efficacy of carbogen (95% oxygen [O(2)] and 5% carbon dioxide [CO(2)]) breathing during definitive radiotherapy (RT) to enhance local control. METHODS: Between November 1996 and November 2002, 101 patients with previously untreated T2 to T4 squamous cell carcinomas of the oropharynx, larynx, and hypopharynx were entered onto a prospective trial and randomized to receive definitive hyperfractionated RT alone or combined with carbogen breathing. Patients were stratified according to T classification and primary tumor site. Follow-up ranged from 1-91 months (median, 38 months). All living patients had follow-up for more than 2 years. Outcomes analyses were performed according to intent to treat. RESULTS: Definitive RT alone was completed as planned in 50 of 51 patients (98%); 49 of the 50 patients (98%) who were randomized to receive carbogen breathing were able to complete the RT as planned. Three patients randomized to receive carbogen breathing declined carbogen. The 5-year outcomes after RT alone or combined with carbogen were as follows: local control, 83% versus 88% (P = 0.5155); locoregional control, 81% versus 83% (P = 0.7174); distant metastasis-free survival, 82% versus 86% (P = 0.5184); cause-specific survival, 73% versus 77% (P = 0.5866); and absolute survival, 53% versus 58% (P = 0.4856). CONCLUSIONS: The addition of carbogen breathing to definitive RT did not appear to improve the likelihood of local control significantly. However, because of the limited size of the current study, the authors cannot definitively conclude that carbogen breathing is ineffective.

Carbon Dioxide↗

PubMed2005

Radiotherapy alone or combined with surgery for salivary gland carcinoma.

BACKGROUND: The authors analyzed the outcomes of patients treated with radiotherapy (RT) alone or combined with surgery for carcinoma of the salivary glands. METHODS: Between October 1964 and June 2003, 224 previously untreated patients were treated with curative intent with RT alone (n = 64) or combined with surgery (n = 160) at the University of Florida College of Medicine (Gainesville, FL). The median follow-up period was 5.0 years (range, 0.4-31.6 years). RESULTS: The 10-year local control rate was 75%. Multivariate analysis of local control revealed that T classification (P < 0.0001) and treatment group (P < 0.0001) impacted this end point. Patients treated with surgery and adjuvant RT had improved local control compared with patients treated with RT alone. The 10-year locoregional control rate was 68%. Multivariate analysis of locoregional control revealed that overall stage (P < 0.0001) and treatment group (P = 0.0002) significantly influenced this end point. The 10-year distant metastasis-free survival rate was 68%. Multivariate analysis of distant metastasis-free survival revealed that overall stage (P < 0.0001) significantly influenced this end point. The 10-year cause-specific and overall survival rates were 57% and 44%, respectively. Multivariate analysis of cause-specific survival revealed that overall stage (P < 0.0001) significantly impacted this end point. Twenty-three patients (10%) experienced severe complications. CONCLUSIONS: A substantial proportion of patients with salivary gland carcinoma were cured with surgery combined with adjuvant RT. RT alone was used for patients with unresectable tumors and cured approximately 20% of those with advanced-stage disease. The probability of cure was influenced by the extent of disease and treatment group.

Adenocarcinoma↗

PubMed2005

Retromolar trigone squamous cell carcinoma treated with radiotherapy alone or combined with surgery.

BACKGROUND: Treatment outcomes were analyzed for retromolar trigone squamous cell carcinoma. METHODS: Between June 1966 and August 2003, 99 patients were treated with radiotherapy alone (35 patients) or radiotherapy combined with surgery (64 patients). Followup ranged from 0.2 to 23.8 years (median, 3.3 yrs). All living patients had followup for at least 1 year. RESULTS: The 5-year local-regional control rates after definitive radiotherapy versus surgery and radiotherapy were as follows: Stages I-III, 51% and 87%; Stage IV, 42% and 62%; and overall, 48% and 71%, respectively. The 5-year cause-specific survival rates after definitive radiotherapy compared with surgery and radiotherapy were as follows: Stages I-III, 56% and 83%; Stage IV, 50% and 61%; and overall, 52% and 69%, respectively. Multivariate analyses revealed that the likelihood of cure was better with surgery and radiotherapy compared with definitive radiotherapy. CONCLUSIONS: The likelihood of cure after treatment for retromolar trigone squamous cell carcinoma was influenced by the extent of disease and treatment. Patients treated with surgery and radiotherapy had a better outcome than those treated with radiotherapy alone.

Carcinoma, Squamous Cell↗

PubMed2005

Impact of radiographic findings on prognosis for skin carcinoma with clinical perineural invasion.

BACKGROUND: The objective of the current study was to correlate pretreatment computed tomography and magnetic resonance imaging studies with outcomes for patients with squamous or basal cell carcinoma of the skin and clinical perineural invasion. METHODS: Between 1986 and 2002, 45 patients were treated with radiotherapy alone (21 patients) or combined with surgery (24 patients), and 4 patients received concomitant chemotherapy. Follow-up ranged from 0.85 years to 17.4 years (median, 3.8 years). Patients were stratified as follows: imaging negative, 10 patients; minimal or moderate peripheral disease, 14 patients; and central and/or macroscopic disease, 21 patients. RESULTS: The 5-year local control rates were as follows: imaging negative, 76%; minimal or moderate peripheral disease, 57%; and central and/or macroscopic disease, 25%. The 5-year absolute and cause-specific survival rates were as follows: imaging negative, 90% and 100%, respectively; minimal or moderate peripheral disease, 50% and 56%, respectively; and central and/or macroscopic disease, 58% and 61%, respectively. CONCLUSIONS: Patients who had symptomatic but imaging-negative perineural invasion had a relatively good prognosis after receiving definitive radiotherapy alone or combined with surgery. Patients who had imaging-positive minimal or moderate peripheral disease had a better local control rate but a similar survival rate compared with patients who had central and/or macroscopic disease.

Adult↗