Search PubMed⌕ Search

Biomedical subjects

K M Greven

Publications and source records attributed to K M Greven.

At least 37 records · Page 2Linked to original sources
PubMed1997

FDG PET in head and neck cancer.

In our extensive experience with FDG PET imaging in head and neck cancer, we have found the technique to be of high accuracy but of limited usefulness. This seeming paradox arises from several causes. Competing techniques such as CT, MR imaging, and even clinical examination already have good accuracy. In addition, high-resolution studies such as CT and MR imaging provide information required for treatment planning that is unavailable from FDG PET images. The high cost of FDG PET militates against its use in this setting, in which only a small marginal gain can be expected. In the special problem areas in which FDG PET might be expected to offer unique advantages, such as screening for second primary lesions, searching for unknown primary lesions, or differentiating benign salivary rumors from malignant lesions, the results of FDG PET have been disappointedly poor. Of these special problem areas, only the question of accuracy in finding occult primary lesions appears unresolved and in need of further study. The single application in which FDG PET appears to be advantageous is the posttherapy setting. In this setting, the technique is definitely superior to alternative methods of determining tumor recurrence and differentiating posttherapy sequelae such as radiation necrosis from tumor recurrence. We believe that considerable opportunity remains for further research on the use of FDG PET in head and neck cancer. Other agents such as 11C-methionine for example, might improve the diagnostic accuracy of FDG PET in some of the problem areas that we have identified, such as the early postirradiation period. We currently have such a study under way. Also, because FDG PET offers a unique way to measure tumor metabolism, further investigation of the use of FDG PET tracers to evaluate various biologic parameters such as proliferation rates or tumor hypoxia are needed. Such studies could provide a noninvasive technique to identify which fractionation schemes or combinations of therapy might be useful for individual patients. A final caveat is in order. Although our findings of the usefulness (and lack thereof) of FDG PET in head and neck cancer may be disappointing to many, these results should not be generalized to other applications of FDG PET in oncology. Each tumor type and setting presents its own specific problems, and in some instances FDG PET offers unique advantages over other imaging techniques. A good example is the setting of primary lung cancer, in which FDG PET appears clearly superior to all other methods of pretherapy screening [19-20].

Adult↗
PubMed1997

Definitive radiation management for carcinoma of the glottic larynx.

Radiation therapy offers excellent cure rates and preservation of the larynx in the majority of early-stage glottic cancers. Outcome may vary because of patient-, tumor-, and treatment-related variables. Carefully selected advanced lesions may also be successfully managed with irradiation. Hyperfractionation and combined chemotherapy-radiotherapy protocols seem to be promising strategies for the improvement of the therapeutic ratio in treatment of patients with more advanced lesions.

Carcinoma↗
PubMed1995

The efficacy of cranial irradiation in ovarian cancer metastatic to the brain: analysis of 32 cases.

OBJECTIVE: To determine the role of irradiation in the management of brain metastases from epithelial ovarian cancer. METHODS: Tumor registries from five university cancer centers were searched to identify ovarian cancer patients with brain metastases. During a 30-year period (1965-1994), 4027 ovarian cancer patients were evaluated, 32 of whom were found to have cerebral metastases. Each received fractionated whole-brain irradiation (median dose 30 Gy, range 20-52.5). Five patients received concomitant chemotherapy with whole-brain irradiation. RESULTS: The median survival time for the whole population was 4 months. For the entire series, symptomatic response (complete response and partial response) was achieved in 23, 16 of whom were palliated until death. Patients with higher Karnofsky performance status (70 or above versus below 70) were more likely to derive a palliative response and attained a statistically significant survival advantage. No other factor predicted the likelihood of deriving a palliative response or a survival advantage after treatment. CONCLUSIONS: In this large review of patients with cerebral metastases from ovarian cancer, we found that most of those treated with whole-brain irradiation achieved palliation until death. Nearly all women with high performance status derived durable palliation from cerebral irradiation. Whole-brain irradiation was an effective means of palliating ovarian cancer metastatic to the brain and provided a favorable alternative to other means of management.

Adult↗
PubMed1995

Control of advanced chemodectomas of the head and neck with irradiation.

Long-term follow-up of 15 patients treated with definitive radiotherapy for advanced glomus tumors of the head and neck is presented. Disease was locally controlled in all patients. A prescribed dose above 4,500 cGY did not improve treatment results. Radiation therapy remains the treatment of choice for advanced glomus tumors.

Adult↗
PubMed1995

Positron emission tomography in the evaluation of laryngeal carcinoma.

Positron emission tomography (PET) is a relatively new radiologic imaging technique based on glucose analog uptake and metabolism in tumor tissue. In this study, PET was used in evaluating 38 patients with laryngeal cancer. Twenty-five patients were examined with PET prior to treatment to study the reliability of PET in identifying the primary tumor and assessing regional nodal status; 13 patients who had previously received irradiation with curative intent and who represented differential diagnostic problems were imaged to differentiate between irradiation effects and recurrent or residual cancer. Findings for both groups were compared to results of clinical evaluation and those of computed tomography (CT) and magnetic resonance imaging (MRI). The PET results were essentially identical to those of CT, MRI, and clinical evaluation in identifying metastatic lesions (82% correct), and were as reliable as CT and MRI for correctly identifying primary tumors (88%). Positron emission tomography was most helpful in differentiating recurrent tumor from postirradiation tissue sequelae. However, its lack of anatomic detail made PET less valuable for primary staging and therapeutic planning. It may enhance the diagnostic accuracy of CT and MRI where anatomic distortions occur or where diagnostic criteria for CT and MRI are ambiguous.

Carcinoma↗
PubMed1995

A comparative diagnostic study of head and neck nodal metastases using positron emission tomography.

A prospective study was conducted to compare the accuracy of clinical examination, computed tomography (CT), and positron emission tomography (PET) in identifying head and neck squamous cell carcinoma metastatic to cervical lymph nodes. The findings in the necks of 49 patients evaluated by clinical examination and CT were compared to the findings in the same necks by PET, a newly available metabolic imaging modality. Pathology specimens were available for 45 of the necks. The findings of PET and CT correlated in 84% of cases. In the cases that did not correlate, CT proved correct in four of five cases. PET (82%) and CT (84%) were comparable and were both better than clinical examination (71%) in correctly identifying the presence or absence of metastatic disease.

Carcinoma, Squamous Cell↗
PubMed1995

Preoperative identification of benign versus malignant parotid masses: a comparative study including positron emission tomography.

Various diagnostic tools were used in 26 patients with parotid masses to determine their value in preoperative malignant or benign categorization. These tools were positron emission tomography (PET), clinical examination, fine-needle aspiration biopsy (FNAB), computed tomography (CT), and magnetic resonance imaging (MRI). PET identified all 26 lesions and all 12 malignant lesions, but made the correct categorization in only 69% of cases. Thus, it was not as good as the more conventional diagnostic methods, their correct categorizations being 85% (clinical), 87% (CT/MRI), and 78% (FNAB) in the same patients.

Biopsy, Needle↗
PubMed1995

Brachytherapy: criteria for case selection.

Brachytherapy has an established role in the management of a number of malignancies. Contributing to successful application of brachytherapy techniques are proper planning, technical sophistication, and meticulous execution. Equally important, presumably, is proper case selection although conditions favoring brachytherapy utilization are not well described. To facilitate discussion of this topic, a semiquantitative system of brachytherapy case selection is proposed. Variables considered include the natural history of the malignancy, risks involved in the procedure, accessibility of implant site, and results obtainable with other treatment modalities. Brachytherapy Case Selection Scores (0-8) were generated for a number of malignancies. Higher scores were found for sites in which the use of brachytherapy is generally accepted and practiced, implying that the clinical factors considered in this system are clinically relevant, and that such a system could be useful when considering the use of brachytherapy in individual cases. Additional critical analysis regarding brachytherapy case selection is desirable.

Brachytherapy↗
PubMed1994

Prognostic factors and treatment outcome for patients with locally recurrent endometrial cancer.

BACKGROUND: Women who do not receive adjuvant irradiation after hysterectomy for endometrial carcinoma (EC) are at risk for developing a pelvic recurrence. Disease- and treatment-related factors were examined for their impact on disease-specific survival (DSS) and pelvic control (PC) in patients with locoregional recurrences to whom salvage radiotherapy was administered. METHODS: Forty-five patients with pelvic/vaginal recurrences of EC were treated at a single institution between 1973 and 1991. The median follow-up period was 89 months. Multiple patient-, disease-, and treatment-related factors were examined with univariate and multivariate analysis for their impact on DSS and PC. Kaplan-Meier methods were used to estimate outcomes. RESULTS: Overall DSS and PC was 51 and 54% at 5 years, respectively. Univariate analysis revealed the following factors to impact on outcome (P < or = 0.05): age (DSS, PC), vaginal stage of recurrence (DSS, PC), size of recurrence (DSS, PC), time interval from hysterectomy (DSS, PC), initial grade (DSS), location of recurrence (PC), and radiation boost technique (PC). CONCLUSION: Women in whom endometrial cancer recurrences develop can be salvaged with aggressive radiotherapy consisting of external beam therapy followed by a radiation boost. Close follow-up after the initial hysterectomy is important because patients with low-volume recurrence limited to the vagina have the best outcome.

Adenocarcinoma↗
PubMed1994

Positron emission tomography of patients with head and neck carcinoma before and after high dose irradiation.

BACKGROUND: Positron emission tomography (PET) with labeled fluorodeoxyglucose (FDG) demonstrates increased tracer uptake in many neoplasms. This study was undertaken to define the patterns of FDG uptake in head and neck neoplasms before and after high dose irradiation. METHODS: Twenty-five patients were evaluated prospectively with PET and standard clinical and radiographic techniques before and after irradiation. RESULTS: Twenty-seven primary sites were confirmed pathologically in 23 patients and included the nasopharynx (four lesions), oropharynx (14 lesions), larynx (five lesions), oral cavity (two lesions), and paranasal sinuses (two lesions). Two patients had unknown primary sites. Twenty-four of 27 primary sites correlated with areas of increased tracer uptake on PET scans. Five patients had increased uptake in cervical lymph nodes that were uninvolved by radiographic or clinical criteria. Positron emission tomography seemed to be able to differentiate tumor activity from fluid-filled sinuses in two patients with paranasal sinus tumors. In two patients with unknown primary sites, increased uptake in the base of tongue after PET suggested occult primary sites. Positron emission tomography scans obtained 1 month after high dose irradiation (RT) indicated decreased levels of FDG uptake in all patients' tumors. However, these scans did not accurately reflect the status of disease in these patients. Scans obtained 4 months after RT were believed to assess more accurately the presence of malignancy. CONCLUSIONS: Positron emission tomography is a new modality that may be useful in defining tumor activity in clinically negative areas. Appropriately timed posttreatment PET may be useful in predicting outcome after definitive RT and in distinguishing viable tumors from normal tissue changes after RT in patients with head and neck carcinomas.

Carcinoma↗
PubMed1994

Distinguishing tumor recurrence from irradiation sequelae with positron emission tomography in patients treated for larynx cancer.

PURPOSE: Distinguishing persistent or recurrent tumor from postradiation edema, or soft tissue/cartilage necrosis in patients treated for carcinoma of the larynx can be difficult. Because recurrent tumor is often submucosal, multiple deep biopsies may be necessary before a diagnosis can be established. Positron emission tomography with 18F-2fluoro-2deoxyglucose (FDG) was studied for its ability to aid in this problem. METHODS AND MATERIALS: Positron emission tomography (18FDG) scans were performed on 11 patients who were suspected of having persistent or recurrent tumor after radiation treatment for carcinoma of the larynx. Patients underwent thorough history and physical examinations, scans with computerized tomography, and pathologic evaluation when indicated. Standard uptake values were used to quantitate the FDG uptake in the larynx. RESULTS: The time between completion of radiation treatment and positron emission tomography examination ranged from 2 to 26 months with a median of 6 months. Ten patients underwent computed tomography (CT) of the larynx, which revealed edema of the larynx (six patients), glottic mass (four patients), and cervical nodes (one patient). Positron emission tomography scans revealed increased FDG uptake in the larynx in five patients and laryngectomy confirmed the presence of carcinoma in these patients. Five patients had positron emission tomography results consistent with normal tissue changes in the larynx, and one patient had increased FDG uptake in neck nodes. This patient underwent laryngectomy, and no cancer was found in the primary site, but nodes were pathologically positive. One patient had slightly elevated FDG uptake and negative biopsy results. The remaining patients have been followed for 11 to 14 months since their positron emission studies and their examinations have remained stable. In patients without tumor, average standard uptake values of the larynx ranged from 2.4 to 4.7, and in patients with tumor, the range was 4.9 to 10.7. CONCLUSION: Positron emission tomography with labeled FDG appears to be useful in distinguishing benign from malignant changes in the larynx after radiation treatment. This noninvasive technique may be preferable to biopsy, which could traumatize radiation-damaged tissues and precipitate necrosis.

Deoxyglucose↗
PubMed1994

Radiation osteitis and insufficiency fractures after pelvic irradiation for gynecologic malignancies.

Damage to the pelvic bones after radiotherapy for gynecological malignancies is uncommon with megavoltage radiotherapy. It can be misdiagnosed as bony metastases and is a diagnosis of exclusion. We report 12 women, who were treated for endometrial or cervical carcinoma who developed osteitis, femoral head or neck necrosis, or insufficiency fractures of the acetabulum, pubic symphysis or sacroiliac bones after radiotherapy. Many had multiple areas of bone damage. The prescribed external beam dose ranged from 40.0 to 61.2 Gy. All but one patient developed bony discomfort or pain as a symptom. Bony changes of the pelvic girdle appeared between 6 months and 8 years after irradiation. Radiographic studies including plain films, CT or bone scans were performed in these patients and showed correlative changes. Bone scans showed increased radionuclide uptake in affected bones. The subsequent favorable clinical course and outcome with resolution of symptoms confirmed the diagnosis of radiation osteitis. Therapy recommendations are conservative with avoidance of weight-bearing, use of analgesics and physical therapy. Femoral head necrosis/fractures required arthroplasty. Proper shielding, use of multifield technique, treatment of all fields per day, and awareness of tolerance doses are recommended.

Aged↗
PubMed1994

Salivary gland tumors: pretherapy evaluation with PET.

PURPOSE: To determine whether positron emission tomography (PET) can help differentiate benign from malignant lesions of the salivary glands before surgery. MATERIALS AND METHODS: Masses of the salivary glands were examined in 26 patients by means of computed tomography, magnetic resonance imaging, PET, biopsy (n = 18), and surgery. Contiguous PET scans were obtained from the midcranium to the lower chest 45 minutes after administration of 370 MBq (10 mCi) of fluorine-18 fluorodeoxyglucose (FDG). Standard uptake values (SUVs) were determined for all suspect lesions and for normal parotid glands and cerebellum. RESULTS: All lesions were visualized, and all but two showed some increase in FDG uptake. PET findings helped correctly differentiate benign from malignant masses in 18 (69%) but were false-positive for malignancy in eight (31%). SUV analysis, lesion-to-normal SUV ratios, and lesion-to-cerebellar SUV ratios also failed to differentiate the lesions. CONCLUSION: FDG PET is not useful in classifying salivary gland tumors as benign or malignant.

Adult↗
PubMed1994

Impact of improved irradiation technique, age, and lymph node sampling on the severe complication rate of surgically staged endometrial cancer patients: a multivariate analysis.

PURPOSE: Limited information is available regarding factors that predispose to complications following postoperative pelvic radiotherapy (RT) for endometrial cancer. To address this issue, patients with clinically staged I/II endometrial cancer who received postoperative RT following total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH/BSO) with or without lymph node sampling (LNS) were studied. PATIENTS AND METHODS: From 1960 through 1990, 235 patients with adenocarcinoma of the endometrium received postoperative RT after surgical staging. Multiple factors were evaluated to determine associations with severe complications. Pretreatment factors included age, stage, comorbidities. Treatment-related factors consisted of LNS, total RT dose, volume of RT fields, dose per fraction, total number of RT fields, number of RT fields treated per day, machine energy, and addition of vaginal implant. RESULTS: The 5-year actuarial risk of a severe complication was 5.5%. Factors associated with an increased risk of complications in univariate analysis included age more than 65 years (11% v 2%), use of only one portal per day (40% v 3%), use of anteroposterior/posteroanterior fields (23% v 4%), total dose > or = 50 Gy (8% v 2%), and LNS (11% v 3%). In a multivariate analysis, only older age, LNS, and the use of one field per day were significant. Increased risks associated with a total dose > or 50 Gy and the anteroposterior/posteroanterior technique were entirely attributable to the use of one field per day. A subanalysis among patients who had adequate RT techniques (eg, multiple fields treated per day) showed a significant increase in complications (7% v 1%) for those with and without LNS, respectively. CONCLUSIONS: Severe complications associated with adjuvant RT for endometrial cancer were increased among patients who were older or underwent LNS or received suboptimal RT technique. Pelvic RT using proper methods can be delivered with acceptable risks.

Adenocarcinoma↗
PubMed1993

Pathologic stage III endometrial carcinoma. Prognostic factors and patterns of recurrence.

BACKGROUND: This review was done to assess the outcomes and patterns of recurrence in a group of patients with Stage III endometrial carcinoma that might help guide adjuvant therapy. METHODS: A retrospective review was performed of 105 patients treated from 1970-1990 at three institutions. All patients underwent abdominal hysterectomy, with 60 having pathologic node assessment and 45 having cytologic examination of peritoneal washings. A single extrauterine site was involved in 75% of patients; 20% and 5% had two and three sites involved, respectively. All patients received postoperative external beam irradiation to the pelvis or pelvis and paraaortic regions for pathologically positive paraaortic nodes. Actuarial techniques were used to estimate the survival and recurrence rates. RESULTS: The 5-year disease-free survival rate for all patients was 64%. Univariate analysis revealed that the depth of myometrial penetration, the clear cell or papillary serous pathologic type, the histologic grade, and the number of extrauterine sites predicted disease-free survival. Cox regression revealed the grade and pathologic findings to be independent predictors of disease-free survival. The overall 5-year pelvic recurrence rate was 21%, with multivariate analysis revealing the grade to be the strongest prognostic factor. Pathologic findings and the number of involved extrauterine sites were the most important prognostic factors for abdominal recurrence and other sites of distant relapse. CONCLUSIONS: The subgroup of patients with low-grade endometrial tumors or superficial myometrial penetration has a low distant relapse rate. Local control remains the goal of therapy in these patients. Patients with high-grade tumors, deep myometrial penetration, clear cell or papillary serous histologic types, or two or more involved extrauterine sites are at high risk for distant recurrence that may include the abdomen. Investigative strategies delivering aggressive adjuvant therapy are appropriate.

Adenocarcinoma↗
PubMed1993

Interstitial reirradiation for recurrent gynecologic malignancies: results and analysis of prognostic factors.

Thirteen patients with recurrent or new primary gynecologic malignancies after previous radiation therapy (RT) underwent interstitial reirradiation (IRI) from July 1986 through December 1990. Mean and median ages were 63 and 70 years, respectively. Mean and median implanted volumes were 14.3 and 12 cc, respectively. Overall, 9/13 (69%) had complete responses to IRI and 6 (46%) continue to have no evidence of disease (NED) 24-71 months later (median follow-up, 59 months). Of 7 patients with recurrent cervical or new primary vaginal carcinoma, 5 (71%) remain free of disease 27-71 months (median, 58 months) after IRI. Of 6 patients with recurrent endometrial carcinomas, only 1 (16%) continues with NED 24 months after IRI. Patients with NED after IRI had a median disease-free interval prior to IRI of 100 months compared to 6 months in patients failing IRI. Trends toward improved outcomes were observed in squamous vs adenocarcinoma, smaller tumor volumes, higher implant doses, and vaginal wall/suburethra vs vaginal cuff location. One possible complication, a rectovaginal fistula, developed in the presence of recurrent cervical cancer 22 months after IRI. Interstitial reirradiation is an effective treatment for selected patients with recurrent gynecologic malignancies after previous RT. Advantages of IRI over radical surgery include its potential to preserve organ structure and function and its applicability to patients with medical contraindications to salvage surgery. Furthermore, since subsequent exenterative surgery should not be compromised in patients failing IRI, a policy of IRI as initial treatment may be justified for patients in whom the potential for morbidity is limited.

Adult↗
PubMed1993

Impact of bone density corrections on target dose delivered to the prostate with 4 MV, 6 MV, 10 MV, and 18 MV photons.

Doses for definitive prostate irradiation have been derived empirically using low-energy megavoltage equipment without availability of bone density corrections. With their increased availability, higher energy photons are being used more frequently because of their improved depth of penetration. Although inhomogeneity corrections lead to greater accuracy of dose delivery, the clinical utility of corrections in the pelvis is unclear. This study evaluates the effect of bone density on the dose delivered with respect to the photon energy employed. Contours and volumes for 10 patients were taken from computed tomography scans at the center of the prostate gland. Treatment plans for bilateral prostate arc fields were run on the Capintec Treatment Planning System for 4, 6, 10, and 18 MV photon energies. The monitor units needed to deliver 6500 cGy to isocenter without bone correction were used for calculations, both with and without bone correction using the equivalent path length algorithm. The median dose to the isocenter was 6500 cGy for all energies without bone correction. The median doses using the uncorrected monitor units for the 4 MV, 6 MV, 10 MV, and 18 MV photon beams corrected for bone density were 6033, 6062, 6166, and 6228 cGy, respectively. The variance in target doses observed in our patient sample was +/- 2.3%, +/- 2.2%, +/- 1.7%, and +/- 1.4%, respectively, for the 4 MV, 6 MV, 10 MV, and 18 MV beams with bone correction. The increased density of bone in the pelvis does alter the actual dose to the prostate from external beam treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Density↗