A randomized trial of standard versus partially hyperfractionated radiation with or without concurrent 5-fluorouracil in locally advanced cervical cancer

The objective of this study was to determine whether the addition of concurrent 5-fluorouracil (5-FU) and/or a change in radiation fractionation improves pelvic control and survival or decreases complications in advanced cervical cancer, FIGO stages IB/IIA (>=5 cm) to IVA inclusive. After stratification by pelvic disease extent, 234 of a planned 292 patients were randomized to receive one of four possible treatments: (a) standard external beam pelvic irradiation (RT) 5000 cGy in 25 fractions versus (b) RT as in arm (a) with infusional IV 5-FU 1g/m2 daily in the first and last 4 days of RT, (c) partially hyperfractionated RT, 5280 cGy in 33 fractions, two fractions per day on the first and last 4 days of RT, or (d) arm (c) with the same FU. All were followed with a linear source of intracavitary RT to deliver 40 Gy. The median duration of follow-up for the 221 evaluable patients was 59 months. The 5-year Kaplan-Meier disease-free survival (DFS) in arm (a), (c), (d), and (b), respectively, were 45, 53, 58, and 61%. The differences in survival and pelvic control were not statistically significant. An exploratory subset analysis was performed within stratum 1 and stratum 2 to generate hypotheses for future studies. Only for the 99 patients in stratum 1 (IB/IIA or medial parametrial IIB disease) was the 5-year DFS significantly better (long rank P = 0.05) for standard RT and 5-FU. The DFS was 39% for arm (a), 76% for arm (b), 58% for arm (c), and 65% for arm (d). A multivariate analysis of patient, tumor, and treatment related prognostic factors identified only the use of 5-FU to account for the observed difference. The crude serious late bowel or bladder complication rate was 5.9%. Overall concurrent infusional 5-FU was not beneficial when added to standard RT in this study. The possible benefit for patients in stratum 1 requires exploration in a further randomized trial with appropriate accrual.

X-ray small angle scattering study of chromatin as a function of fiber length

This work investigates the structure of native calf thymus chromatin as a function of fiber length and isolation procedures by using X-ray small angle scattering technique. Two methods of chromatin isolation have been compared in order to better understand the differences reported by various authors in terms of chromatin high order structure. In addition to these experimental results the effects of shearing have also been studied. In order to explain the differences among these chromatin preparations we built several models of chromatin fibers (represented as a chain of spherical subunits) assuming increasing level of condensation at increasing salt concentrations. For all these fiber models the corresponding theoretical X-ray scattering curves have been calculated and these results have been used to explain the influence of fiber length on the scattering profiles of chromatin. The comparison between experimental and theoretical curves confirms that the high molecular weight chromatin-DNA prepared by hypotonic swelling of nuclei (without enzymatic digestion) displays a partially folded structure even at low ionic strength, whereas the low molecular weight chromatin-DNA prepared by a brief nuclease digestion appears very weakly folded at the same ionic conditions.

Endometrial carcinoma--relative effectiveness of adjuvant irradiation vs therapy reserved for relapse

Fifty-four patients with recurrent endometrial carcinoma were identified from a retrospective review of charts of 304 endometrial cancer patients seen between 1983 and 1989 at our center. A review was undertaken to identify the patterns of relapse, to determine the outcome of salvage treatment, to examine the factors predictive of effective salvage, and, if salvage is effective, to assess an alternative strategy to routine adjuvant postoperative pelvic radiotherapy. Forty percent of the entire recurrent population are long-term survivors. Of the 54 relapsing patients, primary therapy had been surgery alone in 32 and surgery and adjuvant radiotherapy (rt) in 22. Isolated pelvic recurrence was the predominate relapse site in those who had not received adjuvant pelvic RT as primary therapy (23 of 32 or 72%). Distant relapse predominated in those who received adjuvant RT (17 or 22 or 77%). Twenty-eight (54%) failed in the pelvis alone, and 26 (46%) had a component of distant failure. Of the 28 with isolated pelvic relapse, 16 had vaginal mucosal disease involvement only and 12 had disease in the parametrium and/or the pelvic sidewall. With a minimum follow-up for the survivors of 5 years, 21 of the 28 with isolated pelvic relapse received radical radiotherapy and 14 or 67% had maintained pelvic control until death or last follow-up. Eleven of 14 (79%) with disease confined to the mucosa had pelvic control, whereas only 3 of 7 (43%) with extramucosal disease were controlled. No patient experienced major treatment-related toxicity. Tumor size, anatomic extent of pelvic recurrence, RT dose, and disease-free interval were examined for prognostic significance for pelvic control and survival by univariate analysis. Only anatomic extent of pelvic recurrence showed a nonstatistically significant trend as a predictor for control with P = 0.08. In conclusion, a significant proportion of patients with disease recurrence confined to the pelvis can be rendered disease-free long-term with maintained pelvic control. A reexamination of the role of routine adjuvant pelvic RT is therefore undertaken in light of these data.

A general weight matrix formulation using optimal control

Classical methods from optimal control theory are used in deriving general forms for neural network weights. The network learning or application task is encoded in a performance index of a general structure. Consequently, different instances of this performance index lead to special cases of weight rules, including some well-known forms. Comparisons are made with the outer product rule, spectral methods, and recurrent back-propagation. Simulation results and comparisons are presented.

Concurrent chemoradiation in advanced cervical cancer

The pelvis is the predominant site of failure following radical radiotherapy (RT) for locally advanced cervical cancer. We report the results of phase I-II studies on 200 patients with bulky (greater than or equal to 5 cm) carcinoma of the cervix. Patients were treated between 1981 and 1988 on sequential protocols of concurrent chemoradiation to establish an acceptable treatment regimen. RT with daily or partially hyperfractionated pelvic (n = 154) or pelvic plus paraaortic (n = 46) fields was given by continuous (n = 154) or split course (n = 46) regimens. Infusional fluorouracil (5-FU) in a dose of 1 g/m2/day was given on the first and last 4 days of a 5-week course of continuous RT, or with both halves of split course RT. Seventy-eight patients received bolus mitomycin C (Mit-C), 6 mg/m2, once or twice with the start of the 5-FU infusion. The median external RT dose was 46 Gy (range 40 to 65 Gy) followed in 90% (n = 181) by a single intracavitary application of 40 Gy using a linear source of cesium-137. Median follow up is 2.5 years (range 0.6 to 6.9 years) and is sufficient to reliably estimate late toxicities. Acute toxicities were transient oral mucositis (13), RT interruption for enteritis (7), febrile neutropenia (3), and thrombocytopenic tumor bleed (1). Serious late toxicities resulted in death in 3 patients and occurred in bladder in 6 and in bowel in 25, including 8 patients with tumor recurrence. The incidence of late bowel toxicity correlated with the specific therapy given and decreased with each successive protocol. On logistic regression the only treatment variable showing a statistically significant effect on complications was the use of Mit-C (P = 0.0053). Pelvic RT and 5-FU alone produced fewer complications, only 4/105, than historically seen with standard pelvic RT alone. Three-year pelvic control and survival rates were 85 and 71% respectively in stage Ib/II (n = 100) and 50 and 42% in stage III/IV (n = 100). Encouraged by these results and decreased toxicity, we have begun a phase III study to determine whether the addition of concurrent 5-FU to continuous partially hyperfractionated pelvic RT improves local control and survival.

Concurrent radiation and chemotherapy in vulvar carcinoma

Between June 1984 and February 1988 the role of radiation with concurrent infusional 5-fluorouracil with or without mitomycin C (CT-RT) was examined in 33 patients with vulvar cancer. The median duration of follow-up is 16 months (range 5 to 45 months). Nine received adjuvant postsurgical CT-RT and none has relapsed in the radiation field. Seven are alive disease free. Two have died of distant metastases. Of the 9 receiving definitive primary CT-RT, 6 had initial complete response with subsequent vulvar relapse developing in 3. Seven of the 9 remain disease free after CT-RT alone (in 3) or with the addition of a local excision of residual or recurrent disease (in 6). One patient did not respond to CT-RT and required a radical vulvectomy and groin node dissection. Fifteen received CT-RT for disease recurrence following primary surgery. Disease was present in the vulva only in 11, vulva and inguinal nodes in 1 and nodes only in 3. Eight of the 15 had a complete response and no relapses occurred in the treated sites. Four of the 8 dying of disease developed pulmonary metastases. Serious late complications developed in 2 patients, 1 avascular hip necrosis and 1 proctitis requiring a defunctioning colostomy. CT-RT appears tolerable and may contribute to enhanced locoregional control in recurrent or advanced disease. As initial therapy it may allow lesser surgery with preservation of normal anatomy in selected primary vulvar cancers.

A relaxation model for memory with high storage density

We present a relaxation model for memory based on a generalized coulomb potential. The model has arbitrarily large storage capacity and, in addition, well-defined basins of attraction about stored memory states. The model is compared with the Hopfield relaxation model.

Role of radiation therapy in localized non-Hodgkin's lymphoma

Relapse occurs in 50% of patients receiving radiation for clinical stage (C.S.) I and II nodal and extranodal non-Hodgkin's lymphoma (N.H.L.). Prior to the introduction of intensive chemotherapy those failing primary control with irradiation and most of those who relapsed died of their disease with a resultant overall mortality of 50%. An analysis of Princess Margaret Hospital results with radiation for C.S. I and II N.H.L. between January 1967 and December 1978 revealed that tumour bulk, age, stage and histology were of independent prognostic significance. It was possible to group patients using combinations of these attributes so that each group encompassed only patients with similar outcomes. Such prognostic groups were identified separately within the low grade and the intermediate plus high grade categories of the Working Formulation. Patients with a high probability of cure with radiation were so defined. Also those patients in whom chemotherapy would be optimal initial therapy were also defined. Such patients were in the intermediate plus high grade histology groups. Thirty percent of all patients with low grade histology lymphoma had an actuarial survival of 83%, and relapse-free rate of 63% at 10 years. By implication, approximately 20% of all patients with these histologies seen at the Princess Margaret Hospital for the same time period achieved prolonged relapse-free survival by localized therapy. This is at variance with the implications of staging from studies where laparotomy and multiple bone marrow biopsies have been used. Such aggressive staging procedures suggest truly localised disease in only 5-6% of patients with low grade lymphoma. A significant relationship between radiation dose and disease control was demonstrated only for patients with intermediate and high grade lymphoma of medium or large bulk. A minimum tumour dose of 30 Gy was required for optimal local control with radiation.

Concurrent radiation, mitomycin C and 5-fluorouracil in poor prognosis carcinoma of cervix: preliminary results of a phase I-II study

Between July 1981 and June 1983, 27 patients with advanced primary squamous cell carcinoma (SCC) of cervix (FIGO Stages IIIB, IVA or extensive nodal involvement) and 8 with recurrent disease were treated using a pilot regimen of combination chemotherapy (CT): Mitomycin C (MIT), 5 Fluorouracil (5 FU), and radiation therapy (RT). CT and RT doses on this Phase I-II Study were escalated to the current regimen. A split course of RT was used, either pelvic RT alone (4560 Gy in 28 fractions) or the same pelvic RT plus para-aortic RT (3600 Gy in 24 fractions). CT was given: MIT 6 mg/M2 IV push day 1, and 5 FU 1.0 g/M2 (maximum daily 1.5 g) by continuous IV infusion days 1 through 4 of each half-course of RT. This was followed by one application of intrauterine 137Cs when possible. Three of the 8 patients with recurrence in the pelvis or para-aortic nodes had a complete response (CR) to CT-RT and are alive without disease at 19, 19 and 22 months after treatment, respectively. Twenty of the 27 (74%) primary patients had a CR. With a median duration of follow-up of 6 months 4/20 have relapsed, 1 in RT field, 2 at distant sites, and 1 in both. Pelvic disease remains controlled in 19/27 (70%) including one patient salvaged with surgery. The acute toxicity of this regimen was tolerable: 2/35 developed transient leukopenia with one febrile episode, 9/35 developed transient thrombocytopenia without bleeding. Symptomatic sigmoid strictures developed in two patients, one requiring surgical intervention. Sigmoid perforation occurred in one patient and contributed to death. Typically, near complete regression of tumor is noted on completion of the external RT, reproducing the dramatic responses that have been observed in SCC of the anal canal, esophagus and head and neck, with this CT-RT regimen. A Phase III Study is required to establish whether the enhanced response rates to CT-RT will result in increased pelvic control and cure rates compared to those after RT alone.