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Biomedical subjects

L J Peters

Publications and source records attributed to L J Peters.

At least 145 records · Page 8Linked to original sources
PubMed1989

Chromosome aberrations in peripheral lymphocytes and radiation dose to active bone marrow in patients treated for cancer of the cervix.

An international study of cervical cancer patients reported a doubling of the risk for leukemia following radiotherapy. To evaluate the extent of residual chromosome damage in circulating T-cell lymphocytes in this population, approximately 200 metaphases were examined from each of 96 irradiated and 26 nonirradiated cervical cancer patients treated more than 17 years ago (average 23 years). Radiation dose averaged over the total red bone marrow was estimated to be 8.1 Gy. The type and frequency of stable and unstable chromosome aberrations were quantified in 24,117 metaphases. Unstable aberrations did not differ significantly between irradiated and nonirradiated patients (P greater than 0.5). Stable aberrations (i.e., translocations, inversions, or chromosomes with deleted segments), however, were significantly higher among irradiated (2.8 per 100 cells) compared to nonirradiated (0.7 per 100 cells) women (P less than 10(4). The frequency of these stable aberrations was found to increase significantly with increasing dose to the bone marrow. These data indicate that a direct relationship between radiation dose and extent of damage to somatic cells persists in populations and can be detected many years after partial-body radiation exposure. The stable aberration rate in irradiated cervical cancer patients was 50 to 75% lower than those observed 25 years or more after radiation exposure in atomic bomb survivors and in ankylosing spondylitis patients treated with radiotherapy. The average marrow dose was only 1 Gy in the examined atomic bomb survivors and 3.5 Gy in the ankylosing spondylitis patients. It appears, then, that a very high dose delivered to the pelvic cavity in fractionated doses resulted in far fewer persistent stable aberrations than lower doses delivered either in acute whole-body exposure or in fractionated doses to the spinal column and sacroiliac joints. The higher radiation dose and the concentration of that dose in a smaller area of the body appear to be responsible for the lower rate of persistent aberrations observed in cervical cancer patients.

Bone Marrow↗
PubMed1989

Response of parotid gland organ culture to radiation.

Organ cultures of rhesus parotid tissue in medium enriched with homologous serum and supplemented with low levels of isoproterenol were irradiated with single photon doses of 2.5, 5.0, 7.5, 10.0, 12.5, or 15.0 Gy. Following irradiation, the tissue was incubated while being agitated for 24 h; then it was fixed in formalin. Microscopically, death of serous acinar cells was seen in areas unaltered by autolysis. Based on the numbers of nuclear aberrations, the dose response did not differ significantly from that observed at 24 h in parotid gland irradiated in vivo. The similar rapid response under the two conditions shows that apoptosis of irradiated parotid serous cells is a direct expression of interphase cell death.

Animals↗
PubMed1988

Effect of radiation-induced injury of tumor bed stroma on metastatic spread of murine sarcomas and carcinomas.

The study was performed to determine whether irradiation of the tumor bed alters the propensity of tumors to metastasize, and if so, whether the effect is dependent on the property of tumors to exhibit the tumor bed effect (TBE). Ten tumors, of which 5 were sarcomas and 5 were carcinomas syngeneic to C3Hf/Kam mice, were used. Tumors were grown s.c. in the right thighs of mice that had or had not been irradiated with 20-Gy gamma-rays 1 day before tumor cell transplantation. All 5 carcinomas and 2 of 5 sarcomas exhibited TBE, as assessed by a significant retardation of growth rate. To test whether irradiation of the tumor bed influenced metastatic spread independently of TBE, tumors of various sizes were surgically removed, and at appropriate times thereafter the lungs were examined for the presence of metastases. All tumors that exhibited TBE, and only 1 of 3 tumors that did not exhibit TBE, metastasized more than tumors of the same size growing in an unirradiated tumor bed. TBE-induced enhancement of metastasis was not seen in tumors less than approximately 7 mm in diameter. All tumors, whether they exhibited TBE or not, were more necrotic if they grew in a preirradiated tumor bed. These observations show that size for size, most tumors growing in irradiated tissues have an increased propensity to metastasize, which is linked to their manifestation of TBE. The evidence presented suggests that TBE-induced retardation of tumor growth is the major factor responsible for the observed enhancement of metastasis. The clinical implication of these findings is that tumors recurrent after radiotherapy should be diagnosed and treated promptly to reduce the risk of metastatic spread.

Animals↗
PubMed1988

Acute radiation injury of ocular adnexa.

Eyelids and lacrimal glands of monkeys examined histologically 24 and 48 hours after receiving 2.5 to 20.0 Gy (250 to 2000 rad) of cobalt 60 radiation contained acute inflammation. Cells of meibomian glands, other sebaceous glands, sweat glands, and goblet cells displayed no significant alterations. Acinar cells of major and accessory lacrimal glands and, to a lesser degree, lacrimal duct epithelium showed degeneration and necrosis that were increased in extent in proportion to the radiation dose. Reduced numbers of serous acini and decreased size of remaining acini indicate that atrophy of lacrimal glands can be recognized within two days after irradiation. The morphologic diagnosis for irradiated lacrimal glands was acute, necrotizing dacryoadenitis.

Acute Disease↗
PubMed1988

Conservation surgery for T2 and T3 carcinomas of the supraglottic larynx.

The treatment of choice for supraglottic carcinomas of intermediate size (stages T2 and T3) remains controversial. Between 1974 and 1983 in our institution, 139 patients with supraglottic carcinoma of intermediate size were judged retrospectively to have been technically amenable to conservation surgery. Primary disease control at three years was achieved in 100% of the patients treated by supraglottic laryngectomy, 91% (34 patients) of those treated by total laryngectomy, and 69% (81 patients) of those treated by radiotherapy. Of the latter group, 62% were salvaged by total laryngectomy yielding a net three-year local control of 85%. Determinate five-year survival rates were 89% for supraglottic laryngectomy, 78% for total laryngectomy, and 70% for radiotherapy. Significant problems with aspiration occurred in four patients (16%) who were treated by conservation surgery, and two patients (8%) required a permanent tracheostomy. The results of this study show that supraglottic laryngectomy with postoperative radiotherapy as indicated is a highly effective method for the local control of supraglottic carcinoma of intermediate size that is amenable to conservation surgery.

Adult↗
PubMed1988

Paragangliomas of the head and neck.

The medical records of 64 patients with paraganglioma of the head and neck seen between 1954 and 1984 at the University of Texas M.D. Anderson Hospital, Houston, were reviewed. Lesions were found in the carotid body (n = 24), jugulotympanic area (n = 37), vagal nerve (n = 4), and larynx (n = 1). A hereditary pattern was identified in six patients (9%). Metastases developed and caused the death of two patients (8%). No functional secreting tumors were identified. Paragangliomas are often misdiagnosed, both clinically and pathologically. Angiography is the definitive clinical study for diagnosis and treatment planning. Computed tomographic scanning further defines extent of the disease. Lesions in the neck are effectively treated by surgery. Jugulotympanic tumors can be successfully managed by surgery, radiation therapy, or a combination of both depending on the size and extent of the tumor. Secondary treatment of residual disease can be as effective as primary treatment.

Adult↗
PubMed1988

Neutron therapy in cervical cancer: results of a phase III RTOG Study.

Between October 1976 and May 1984, 156 patients with locally advanced cervical cancer were entered into a Phase III trial with the participation of five institutions. Patients were randomly assigned to receive photons only (50 Gy in 25 fractions over 5 weeks plus intracavitary applications or external-beam boost) or mixed-beam radiotherapy (2 fractions a week of neutrons, 3 fractions a week of photons to a total RBE-adjusted dose of 50 Gy over 5 weeks plus intracavitary applications or external mixed-beam boost). Only patients with squamous carcinoma of FIGO Stages IIB, III, or IVA with negative para-aortic nodes on lymphangiogram were eligible. Ten patients were excluded from the analysis because of ineligibility or cancellation. Of the 146 patients analyzed, 80 were treated with mixed-beam radiotherapy and 66 with photons. Patients were grouped by stage and institution. The percentage of patients undergoing intracavitary applications was 50% on mixed beam and 75% on photons (p less than 0.01). Tumor clearance was 52% and 72% for mixed beam and photons, respectively (p less than 0.03). Local control at 2 years was 45% for mixed beam and 52% for photons. Median survivals were 1.9 years on mixed beam and 2.3 years on photons. Severe complications occurred in 19% and 11% in mixed beam and photons respectively (p less than 0.13). The inferior outcome with neutron therapy in this study may have resulted from the use of horizontal neutron beams of varying energy and penetration. A new randomized trial using high-energy hospital-based cyclotrons with gantry-mounted beam-delivery systems has recently been activated to evaluate more rigorously the role of fast-neutron therapy for advanced cervical cancer.

Adult↗
PubMed1988

Acute and late toxicity associated with sequential bleomycin-containing chemotherapy regimens and radiation therapy in the treatment of carcinoma of the nasopharynx.

Between 1975 and 1984, 33 patients with squamous cell carcinoma of the nasopharynx received adjuvant chemotherapy before and/or after definitive radiotherapy at UT M. D. Anderson Hospital. The favored chemotherapy regimens during this time were BCMF (bleomycin, cyclophosphamide, methotrexate, and 5-FU) and PMB (cisplatinum, methotrexate, and bleomycin). Total radiation doses to the primary site averaged 65 Gy for T1 and T2 lesions and 70 Gy for T3 and T4 lesions. Neck nodes were given boost treatments to a maximum of 70 Gy, depending on the extent of the disease. The outcome of treatment in these patients was compared to that of a stage-matched group of 71 patients treated during the same time period with radiotherapy alone. However, the groups were not matched with regard to histologic subtypes: 45% of the radiation-only group had prognostically unfavorable keratinizing squamous carcinomas (WHO 1) compared with 18% of the combined modality group. Overall disease-free survival at 5 years was 63% in the combined modality group and 44% in the radiation only group (p = 0.15). Both acute reactions and late treatment complications were much more frequent and severe in patients receiving combined modality treatment. In patients treated with chemotherapy prior to radiation therapy, 10/20 (50%) experienced severe acute toxicity (RTOG Grade 3 or 4) versus 9/71 (13%) in the radiotherapy-only group. Severe late normal tissue injury occurred in 15/33 (45%) of the combined modality group versus 5/71 (7.0%) in the control group. The majority of the late complications in the adjuvant chemotherapy group consisted of severe soft tissue and muscle fibrosis. The average total bleomycin dose in the patients with severe late soft tissue and muscle fibrosis was 336 mg. The actuarial risk of developing a severe late complication by 2 years after treatment was 68% in the combined modality group versus 8% in the radiation-therapy-only group (p = .001). The probability of remaining both disease-free and complication-free at 5 years was 40% in the radiation-only group and 22% in the combined-modality group (p = 0.08). Comparison of these results with other published reports emphasizes the importance of late toxicity data in assessing the ultimate value of combined modality therapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

Safety of adjunctive transvaginal beam therapy in the treatment of squamous cell carcinoma of the uterine cervix.

At The University of Texas M. D. Anderson Hospital and Tumor Institute at Houston between 1970 and 1980, 159 patients with bulky cervical cancers of FIGO Stages IB or II were treated with transvaginal orthovoltage radiotherapy (TVR) as an adjunct to standard external beam megavoltage irradiation and brachytherapy. The majority received 10 or 15 Gy air dose in 2-3 fractions using 125-250 kVp X rays. The dose from TVR was ignored in subsequent standard treatment planning. The absolute 5-year local control and survival rates were 82 and 83%, respectively. A total of 9 patients (5.7%) developed serious treatment complications that were significantly related to performance of a staging lymphadenectomy prior to radiotherapy and to an external beam pelvic dose of 50 +/- 0.5 Gy versus 40 +/- 0.5 Gy. The risk complications was not related to the dose of TVR or brachytherapy within the ranges used. Provided patients are properly selected and appropriate technical precautions are exercised, TVR is a safe technique. It is effective in controlling bleeding and shrinking large exophytic tumors, and very likely contributes to improved tumor control by facilitating optimal geometry for intracavitary therapy.

Adult↗
PubMed1988

Hyperfractionated split-course whole abdominal radiotherapy for ovarian carcinoma: tolerance and toxicity.

Whole abdominal irradiation after chemotherapy and second look laparotomy for advanced ovarian carcinoma is poorly tolerated because of hematologic toxicity that frequently necessitates interruption or abandonment of treatment. A new treatment strategy using a hyperfractionated split course schedule to deliver a total of 30 Gy in 30 fractions over 6 weeks was designed in an attempt to overcome this problem, while not compromising the tolerance of late reacting normal tissues. Of 23 patients treated between August 1984 and June 1986, only one failed to complete therapy as scheduled. Six patients with gross residual disease also received a limited field boost of 15 Gy in 15 fractions after completion of treatment to the whole abdomen. None of these six patients achieved disease control, and five required surgery for intestinal obstruction with pathologic evidence of radiation bowel injury. Of the 17 patients who received no boost, five developed gut obstructions associated with tumor recurrence and not attributable to irradiation. We conclude that whole abdominal irradiation using the hyperfractionated split course schedule without a boost is safe and feasible but its therapeutic efficacy appears confined to subsets of patients with no visible residual disease at the time of second look laparotomy, or in whom all visible residual tumor can be resected.

Adult↗
PubMed1988

Squamous cell carcinoma of the soft palate, uvula, and anterior faucial pillar.

This retrospective study concerns 188 patients with squamous cell carcinoma of the soft palate, uvula, and anterior faucial pillar treated for cure between 1970 and 1983. Men predominated in the group (1.9:1) and 55% of the patients were between 60 and 70 years old. Mean duration of followup was 56.7 months. TNM stage distribution was 29, 67, 37, and 49 patients for stages I, II, III, and IV respectively; six patients were unstaged because of previous excisional biopsy. Treatment to the primary site consisted of radiotherapy for 150 patients, surgery alone for 28 patients, and combined therapy for 10 patients. Primary control for T stages 1 through 4 was: 91% (31 of 34), 77% (71 of 92), 77% (30 of 39), and 35% (6 of 17), respectively. One hundred twenty-eight patients were N0 at presentation, as compared to 60 patients with regional nodal metastasis. Regional control was obtained in 87.5% of patients with N0 necks and in 76.7% of those with nodal involvement. In patients with primary control, these figures were 89% and 81%. Overall determinant survival was 80% at 2 years, but fell to 67% at 5 years. In addition to advanced tumor stage, the survival rate was reduced by regional lymph node metastasis. Tumor extension to the tongue base diminished survival. Survival was poorer among patients with midline tumors or tumors that extended across the palatine arch (37 patients) than for those with unilateral primary tumors (151 patients) (p less than 0.05). Despite similar T-stage distribution, the incidence of regional nodal metastasis was 49% in the former group, compared with 28% in the latter.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Accelerated fractionation in the radiation treatment of head and neck cancer. A critical comparison of different strategies.

There is strong clinical and radiobiological evidence that protraction of overall treatment time has an adverse influence on the radiocurability of certain human tumors. Overall treatment time can be reduced without recourse to large dose fractions by the use of accelerated fractionation, but in patients with head and neck cancer acute mucosal reactions limit the extent to which treatment can be accelerated. Three different prototypical schedules for accelerated fractionation have been devised to avoid exceeding acute mucosal tolerance. Type A consists of an intensive short course in which the overall duration of treatment is markedly decreased with a corresponding substantial reduction of total dose; type B achieves a modest decrease in overall time without reduction of total dose by using a split-course technique; type C also achieves a modest decrease in overall time without reduction of total dose by means of the concomitant boost technique. A hybrid schedule combining features of types B and C allows additional shortening of overall treatment time without reduction of total dose. Available radiobiological and clinical data suggest that schedules of types B or C which do not compromise total dose are generally preferable to those of type A in which there is a trade-off between total dose and overall time. For a given total dose and overall time, a continuous treatment of type C is likely to produce more cell kill than a split-course of type B, although the latter will be better tolerated. Because of the increased acute toxicity associated with all schedules of accelerated fractionation, rational selection of patients for such treatment is important. New techniques to measure the potential doubling time of human tumors in vivo offer this prospect.

Clinical Trials as Topic↗