Biomedical subjects

C Guse

Publications and source records attributed to C Guse.

22 records · Page 2Linked to original sources

PubMed1989

Phase II study of multiple daily fractionations in the palliation of advanced pelvic malignancies: preliminary report of RTOG 8502.

This Phase II protocol was designed around the format of a previously reported study for the palliation of advanced pelvic malignancies (RTOG 7905). The large dose per fraction (1000 cGy) of the first study unexpectedly demonstrated frequent late gastrointestinal toxicity and was replaced in the present study by 2 days of twice daily fractionation (370 cGy/fraction totaling 1480 cGy/course) based on linear quadratic consideration of acute and late toxicities. The interval between courses of 4 weeks was retained and the total dose for three courses was 4440 cGy. A total of 152 patients were entered of which 142 have sufficient follow-up information for analysis. Fifty-nine percent of the patients completed all three courses, 20% completed two courses, and 20% received only one course. The primary sites were: gynecological (39.4%); colorectal (32.4%); genitourinary (24.7%); and other (2.8%). The best overall response was: complete remission (10%); partial remission (22%); no change (24%); progression (10%); and unknown (27%). For the patients completing all three courses, the response was: complete remission (14%); partial remission (31%); no change (40%); progression (7%); and unknown (8%). Median survival was 4.5 months and the actuarial survival at 12 months is 19%. In RTOG 7905, 90% of the late toxicities appeared by 12 months. For RTOG 8502, there were 32 patients alive at 9 months and 19 patients alive at 12 months available for evaluation of late toxicity. There has been one late grade 3 GI toxicity reported and only one acute grade 3 gastrointestinal toxicity. Even if the true rate of late toxicity for 8502 were 20%, the chance of seeing none or one toxicity would be 0.007. This toxicity report represents a marked reduction of the grade 3 and 4 late toxicity seen in RTOG 7905 (37% at 9 months and 45% at 12 months) without lowering the tumor response rate. The interval between courses in both protocols allows for potential tumor proliferation. To test for the effect of tumor proliferation, RTOG 8502 is continuing as a Phase III randomization between 4 weeks and 2 weeks separation.

Adult↗

PubMed1989

194 hepatocellular cancers treated by radiation and chemotherapy combinations: toxicity and response: a Radiation Therapy Oncology Group Study.

Hepatocellular carcinoma is known to have a doubling time of approximately 41 days. This rapid cell division suggested that hyperfractionated radiation and chemotherapy might add an advantage in gaining remission of this malignancy. One hundred and thirty-five patients (70% with metastasis and/or previous treatment) were prospectively treated with single daily fractions to the liver (3.0 Gy external beam radiation, total dose 21.0 Gy), and chemotherapy for hepatocellular carcinoma. The low dose chemotherapy used in conjunction with the radiation was 2 hr before treatment on days 1, 3, 5, and 7 and consisted of Adriamycin, 15 mg IV and 5-FU, 500 mg IV. These patients were compared to a second group of 59 patients (80% with metastases and/or previous treatment) treated using the same chemotherapy regimen but using hyperfractionated whole liver external beam irradiation (1.2 Gy twice daily, 4 hr between treatments, 5 days per week to 24.0 Gy, 10 MV photons). Response was determined by CT scan tumor volumetric analysis. The response rate for the single daily fraction patient group was 22% and for the new hyperfractionated group, 18% (p = 0.68). Toxicity was evaluated by RTOG criteria. The grade 4 hematologic toxicity noted in the daily fraction patient group was 6%. Among 59 patients treated with the hyperfractionated liver irradiation, 2% experienced grade 4 hematologic toxicity. Esophagitis occurred in 1% of patients in the standard fractionation group and 19% in the hyperfractionated group (p = 0.0001). Grade 1-4 thrombocytopenia occurred in 49% of patients in the conventional group and 68% in the hyperfractionated group (p = 0.03). Normal liver volume changes with treatment were measured with CT scan tumor volumetric analysis. The hyperfractionated group experienced a median of 11 cc increase in liver volume and the conventional group a 46 cc decrease, but the difference was not significant. Hyperfractionated radiation did not demonstrate a significant benefit over standard daily radiation, but acute toxicity appeared to be higher.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1988

Tolerance of pelvic normal tissues to hyperfractionated radiation therapy: results of Protocol 83-08 of the Radiation Therapy Oncology Group.

A prospective, centrally randomized Phase I/II trial of hyperfractionation in definitive radiation therapy for locally advanced squamous and transitional cell carcinoma of the bladder was conducted by the Radiation Therapy Oncology Group (RTOG) from April 1983 through June 1986. Patients with T3-4 and T2 N+ (AJC) histologically-confirmed cancer of the bladder received twice daily radiation therapy with 1.2 Gy per fraction and a minimum of 4 hr between fractions. All patients received a whole pelvic total dose of 50.4 Gy: Total doses to reduced volumes were 60.0 Gy, 64.8 Gy, or 69.6 Gy. Of 54 patients entered, 50 were eligible. An unbalanced treatment assignment was used: Nine patients received 60.0 Gy, 15 patients received 64.8 Gy and 26 received 69.6 Gy. Performance status (Karnofsky) was 90-100 in 72% of patients and 92% had transitional carcinoma. Eighty percent of tumors were T3 or T4. Observation of at least 18 months was available for 26 patients. Grade 3 acute reactions (within 90 days) were reported in eight patients (one at 60.0 Gy, three at 64.8 Gy and four at 69.6 Gy). Five patients experienced a total of seven major late effects--four Grade 3 and three Grade 4. The cumulative probability of Grade 3 and 4 late complications of treatment for the 46 patients at risk for late complications was 5% +/- 3% at 6 months, 7% +/- 4% at 12 months, and 10% +/- 5% at 18 and 24 months. The cumulative probability of Grade 3 or 4 late complications for patients who received a total dose of 69.6 Gy was 5% +/- 4% at 6 and 12 months and 11% +/- 8% at 18 and 24 months. Only one patient who experienced major late effects was also reported to have major acute reactions. Comparisons of survival of patients treated in the current study with those who received 60 Gy in 30 fractions in 6 weeks in RTOG Protocol 71-04, did not suggest any deleterious effects from hyperfractionated radiation therapy to the pelvis. The normal pelvic tissues tolerated hyperfractionated radiation therapy sufficiently well to justify exploring it, alone and with brachytherapy, in other pelvic tumors.

Aged↗

PubMedDate not supplied

Use of postoperative information to predict mortality rates for patients who have long stays in the intensive care unit after coronary artery bypass grafting.

OBJECTIVE: To derive and evaluate prediction models for patients who had undergone coronary artery bypass grafting (CABG) and had a difficult postoperative course. DESIGN: Observational. SETTING: Midwestern hospital specializing in high-risk CABG procedures. PATIENTS: One hundred eighty-three patients who stayed at least 10 consecutive days in the intensive care unit after a CABG procedure. OUTCOME MEASURE: Death within 60 days of surgery. INTERVENTION: None. RESULTS: The final logistic regression prediction models included the following findings: pulmonary capillary wedge pressure, cardiac index, heart rate, urine output, positive end-expiratory pressure, blood urea nitrogen levels, and the arterial pressure of carbon dioxide. The model was able to stratify patients into four risk groups with observed 60-day mortality rates of 0.0% (n = 107), 21% (n = 39), 55% (n = 20), and 88% (n = 17). Preoperative patient information was not associated with prognosis for these patients. CONCLUSIONS: The findings suggest that a risk model that is specific for patients who have undergone CABG and is based on postoperative findings may provide useful prognostic information for patients who are having a difficult postoperative course.

Aged↗