Biomedical subjects

K Engin

Publications and source records attributed to K Engin.

27 records · Page 2Linked to original sources

PubMedDate not supplied

Optimization of hyperthermia with CT scanning.

In a prospective study CT scanning was used to evaluate the precision of thermometry catheter placement in tumours in the head and neck or on the chest wall in 30 consecutive patients prior to hyperthermia treatment. Patients had variable-sized tumours from several primary sites. Thermometry catheter placement was guided by palpation with or without a prior CT scan. Catheter placement was confirmed by CT. All lesions were less than 8 x 8 x 6 cm (L x W x D) in size. A mean of 4.2 +/- 0.2 (+/- 1 SEM, range 2-7) closed-end polyurethane catheters were inserted orthogonally by the same experienced radiation oncologist. Horizontal thermometry catheters were intended to traverse the centre and base of the tumour mass, and a vertical catheter was often inserted to intersect a horizontal catheter. After catheter placement, wire cables with 1 cm spacings were inserted into the catheters and positions determined using orthogonal films and CT scans. The success of catheter placement was judged on the following criteria: (1) catheter distribution factor (CDF = proportion of tumour CT slices transected by at least one catheter); (2) catheter hit ratio (CHR = average number of catheters in tumour per CT slice); (3) catheter miss factor (CMF = average number of catheters out of tumour per CT slice); (4) catheter placement index, CPI = [(CHR)(CDF)]-CMF; and (5) distance of nearest catheter from the visually estimated centre of tumour in the most central tumour CT scan. In the first seven lesions with 3-6 cm depth catheter insertion was guided by palpation only. In the next 23 lesions catheter insertion was guided by a prior CT scan. In the latter group, 15 lesions had depth 3-6 cm while eight lesions had depth < or = 3 cm. Catheter placement by palpation only, without the benefit of CT scan, was much less accurate in terms of the nearest catheter to the centre of the tumour (p = .001), the proportion of CT slices with catheter in tumour (CDF, p = 0.04) and the probability of a catheter being outside the tumour (CMF, p = 0.01). The catheter placement index (CPI) was a good measure of the accuracy and adequacy of catheter placement in large tumours (p = 0.04). Displacement of normal tissue structures by tumour precluded accurate catheter placement and led to a low CPI. It was difficult to accurately instrument lesions < or = 3 cm depth even with the benefit of a prior CT scan.(ABSTRACT TRUNCATED AT 400 WORDS)

Catheterization↗

PubMedDate not supplied

Randomized trial of one versus two adjuvant hyperthermia treatments per week in patients with superficial tumours.

One test for thermotolerance development in a clinical situation is to evaluate the effects of altering the hyperthermia fractionation interval on tumour response to thermoradiotherapy. Between 1983 and 1990 44 evaluable advanced superficial tumours of miscellaneous origin in 41 patients were randomized to receive either once-weekly or twice-weekly external microwave hyperthermia treatments combined with radiation therapy. The mean age of patients was 62 years, and 85% had failed previous therapy. All lesions were less than 8 x 8 x 4 cm (L x W x D) and were heated by external 915 MHz microwaves. The mean radiation dose was 44 +/- 3 Gy (mean +/- SE) in the once-weekly group and 46 +/- 3 Gy in the twice-weekly group (p = 0.64). The mean volume of the lesions heated once weekly was 17 +/- 6 versus 23 +/- 5 cm3 for those heated twice weekly (p = 0.45). Hyperthermia was administered once weekly for 4.6 +/- 0.2 sessions (range 3-7) or twice weekly for 8.1 +/- 0.3 sessions (range 4-10). Thermometry was performed using 3.4 +/- 0.2 catheters and 5.1 +/- 0.6 thermal sensors per tumour in the once-weekly group, and 2.7 +/- 0.2 catheters and 5.8 +/- 0.3 thermal sensors per tumour in the twice-weekly group. Of the 44 evaluable randomized lesions a complete response (CR) at 2 months post-treatment was observed in 59% (13/22) heated once weekly and 55% (12/22) in those heated twice weekly. The prognostic factors predictive of tumour complete response were found by logistic regression analysis to be radiation dose and tumour volume, while the prognostic factors predictive of duration of response (Cox proportional hazards analysis) were median minimum tumour temperature (Tmin), minimum tumour temperature during the first heat treatment (Tmin1) and tumour volume. The duration of local control in lesions with Tmin < or = 39.5 degrees C was 11.7 +/- 1.9 months while for lesions with Tmin > 39.5 degrees C it was 23.0 +/- 4.2 months (p = 0.01). The ED50 was calculated by logistic regression to be 40 Gy (95% CI = 22-54 Gy) for once- and twice-weekly heated lesions. There was not a significant difference in tumour response or duration of response between populations randomized to receive once- versus twice-weekly hyperthermia treatments. There was also no difference in skin reaction rates between once- and twice-weekly hyperthermia treatments, nor could a correlation be found between any thermal parameter and skin reactions.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMedDate not supplied

Thermoradiotherapy with combined interstitial and external hyperthermia in advanced tumours in the head and neck with depth > or = 3 cm.

Advanced tumours in the head and neck 3-6 cm depth are too deep to be completely heated by external 915 MHz microwaves. A preliminary study was performed using interstitial plus external hyperthermia combined with external beam radiation therapy to heat tumours to depths > or = 3 cm. Nine advanced metastatic lesions of squamous cell carcinoma located in the head and neck were treated between 1987 and 1990 with the combined hyperthermia technique and radiation doses of 38-60 Gy (mean of 49 +/- 3 Gy). The mean tumour volume was 58 +/- 9 (SE) cm3 (range 24-94 cm3) with a mean tumour depth of 3.9 +/- 0.3 cm (range 3-5.5 cm). The deeper aspects of the tumour were heated by interstitial 915 MHz microwave antennas and the superficial aspects heated by external 915 MHz applicators. A single plane of polyurethane closed-end catheters, 16 Ga, were inserted under local anaesthesia approximately 1.5-2 cm apart in parallel arrays at the base of a lesion behind the sternomastoid muscle, or an equivalent site in a dissected neck, extending forward and angled deeply no more than 15 degrees. Hyperthermia was administered twice weekly immediately after radiation therapy in a mean of 5.3 +/- 0.7 external heat sessions (range 3-7) and a mean of 3.5 +/- 0.6 interstitial heat sessions (range of 1-6). Interstitial hyperthermia was usually administered in alternating sessions with external hyperthermia, but in some patients all of the sessions of one modality were administered followed by all of the sessions of the other modality. In no case were both interstitial and external heatings performed on the same day. Surface thermometers were used to monitor skin temperature during external hyperthermia sessions. Results showed that by 8 weeks after completion of treatment, six lesions exhibited a complete response (67%) and three a partial response (33%). One of the partial responses continued to regress and became a complete response (78% complete response). The recurrence rate in complete responders was 14% (1/7) with time to recurrence of 7.7 months. Six lesions were recurrence-free at last follow-up of 21.3 +/- 8.8 months. Skin reactions were absent in four fields (44%), erythema was noted in five (56%) and thermal blistering in one (11%). Ulceration occurred only in association with tumour breakdown when the skin was infiltrated by tumour (three patients, 33%).(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗

PubMedDate not supplied

Thermoradiotherapy for superficial tumour deposits in the head and neck.

Tumour deposits in the head and neck region were treated with hyperthermia using 915 MHz external microwave applicators and radiation therapy between 1986 and 1990. The mean (+/- SE) radiation dose was 47 +/- 2 Gy (range 21-77 Gy). All but four patients had failed previous therapy. Mean tumour volume was 40 +/- 10 cm3 (range 0.3-276 cm3). Hyperthermia was administered biweekly in 80% of the patients in 6.0 +/- 0.4 sessions (range 1-10); thermometry involved 3.6 +/- 0.4 catheters (range 1-9) and 5.7 +/- 0.4 sensors (range 1-12) per tumour. Of the 50 lesions evaluable for response, 29 had a complete response (58%), and 20 had a partial response (40%). Lesions were stratified by depth. In tumours considered potentially heatable (i.e. depth < or = 3 cm and lateral dimensions at least 2 cm less than boundary of applicator), the complete response rate was 81% (26/32, 47 +/- 2 Gy, 15 +/- 3 cm3); whereas for patients with tumours deeper than 3 cm, the complete response rate was 17% (3/18, 48 +/- 3 Gy, 110 +/- 21 cm3), p = 0.0001. Among lesions < or = 3 cm depth that exhibited a complete response, six recurred (24%, 5.8 +/- 1.8 months) while 20 lesions were recurrence free at last follow-up of 11.9 +/- 1.2 months). The overall survival of patients with lesions < or = 3 cm depth was 11.5 +/- 1.3 months (range 2.4-32.3 months) while for patients with lesions > 3 cm depth survival was 6.7 +/- 0.9 months (range 2.1-18.6 months), p = 0.01. In superficial lesions with depth < or = 3 cm, multivariate logistic regression analysis indicated that the model best correlating with complete response included radiation dose (p = 0.08) and tumour volume (p = 0.08, model p = 0.004). Multivariate proportional hazard analysis indicated that the model best correlating with duration of local control included tumour depth (p = 0.03) and previous radiation therapy (p = 0.08, model p = 0.006). Twenty-two fields were treated without any skin reactions (39%), 23 evidenced erythema (40%) and eight thermal blistering (14%). Ulceration occurred in 11 treatment fields but in all but one of these cases the ulceration may have been due to tumour breakdown as there was direct invasion of the skin by tumour prior to the initiation of treatment. The maximal skin temperature was the best predictor of morbidity although the correlation was not statistically significant (p = 0.19).

Adenocarcinoma↗

PubMedDate not supplied

Multiple field hyperthermia combined with radiotherapy in advanced carcinoma of the breast.

Extensive recurrences on the chest wall of advanced carcinoma of the breast in 20 patients were treated with multiple field patchwork hyperthermia combined with radiation therapy between 1987-1991. The objective of the study was to evaluate the feasibility, tumour response and complications of treating extensive lesions with multiple, overlapping fields of hyperthermia. All lesions were diffuse encompassing up to 2900 cm2 in area with or without multiple nodules < or = 3 cm deep. All lesions had failed previous therapy with all but three failing previous radiotherapy. Hyperthermia consisted of 282 hyperthermia applicator fields and 357 hyperthermia treatments with external 915 MHz microwaves using commercially available applicators. Hyperthermia applicator fields were defined by the surface 50% SAR distribution of a particular applicator, and hyperthermia fields were abutted to cover the entire tumour bearing area. Radiation therapy consisted of 81 fields to a mean dose of 40 +/- 1 Gy (SE), 88% of fields received between 30 and 50 Gy. The equivalent dose was 42 +/- 1 Gy, based on the linear-quadratic model and alpha/beta = 25 (Fowler 1989). Overlapping hyperthermia fields were separated by an interval of at least three days. Up to four heat sessions per week were required to cover the entire tumour in a rotating fashion. The hyperthermia treatment time was 60 min. Hyperthermia treatments were continued for the duration of radiation therapy. Each hyperthermia applicator field was heated at least once. Patients were exposed to a mean of 14 +/- 3 hyperthermia applicator fields (range of 3-46 fields) and a mean of 18 +/- 3 hyperthermia treatments (range of 6-61) delivered over a mean of 7.5 +/- 0.9 weeks (range of 3-17 weeks). Each field was heated an average of 1.3 times. The tumour complete response rate was 95% with a recurrence rate of 5%. Nevertheless, the mean survival of patients with a complete response was only 10.8 +/- 1.7 months (range of 2-28 months) because of the systemic tumour burden existing outside of the treated fields in these patients. Neither complete response, local control nor survival after thermoradiotherapy correlated with the disease free interval between initial mastectomy and recurrence. There was no evidence of increased thermal damage to skin nor evidence of tumour recurrence at junctions of hyperthermia field overlap. It is concluded that recurrent advanced carcinoma of the breast presenting as extensive, diffuse lesions on the chest wall can be treated as effectively with multiple field patchwork thermoradiotherapy as can nodular lesions treated with single hyperthermia fields.

Adult↗

PubMedDate not supplied

Extracellular pH distribution in human tumours.

Extracellular pH (pHc) was determined by needle microelectrodes in 67 tumour nodules in 58 patients. The objective was to evaluate the relationship between pHe, tumour histology and tumour volume. The mean age of the patients was 62 years, mean depth of the lesions was 2.7 +/- 0.2 cm, and mean tumour volume was 187 +/- 60 cm3. Lesions were located in readily accessible areas such as on the limbs, neck or chest wall. Tumour histologies included: 48% adenocarcinoma; 34% squamous cell carcinoma; 8% soft tissue sarcoma; and 10% malignant melanoma. The mean tumour pHe for the entire group of tumours was 7.06 +/- 0.05 (range 5.66-7.78). Variation in pHe measurements between tumours was greater than the variation in measurements within tumour (F = 7.11, p < 0.01). In adenocarcinomas pHe was 6.93 +/- 0.08 (range 5.66-7.78), in soft tissue sarcomas 7.01 +/- 0.21 (6.25-7.45), in squamous cell carcinomas 7.16 +/- 0.08 (6.2-7.6), and in malignant melanomas 7.36 +/- 0.1 (6.98-7.77). Tumour pHe was significantly different between the four histological groups (p < 0.001). When adenocarcinoma and soft tissue sarcoma lesions were grouped together, pHe was 6.94 +/- 0.08 compared with 7.20 +/- 0.07 in squamous cell carcinomas and malignant melanomas lesions (p < 0.01). Tumour pHe increased as a function of the logarithm of tumour volume at 0.07 +/- 0.02 pH unit/ln cm3 (p = 0.006, r = 0.34). In conclusion, tumour histology and tumour volume were the most important factors determining the range of pHe's.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMedDate not supplied

Predictive factors for skin reactions in patients treated with thermoradiotherapy.

In this study we performed univariate analyses to analyse the predictive factors for skin reactions, i.e. erythema, thermal blisters and ulceration, that occur during thermoradiotherapy. One hundred and twenty-six fields in 126 patients were treated with thermoradiotherapy using 915 MHz external microwave hyperthermia. Mean age of patients was 62 years. All but 11 lesions received previous therapy. Prior treatment included surgery (75%), chemotherapy (60%) and/or radiation therapy (51%). The mean previous radiation dose was 54 +/- 2 Gy. The concurrent tumour radiation dose was 45 +/- 1 Gy, in 16 fractions, over 35 elapsed days (dose per fraction of 1.6-4.8 Gy). The mean number of heat sessions administered was 5.5 +/- 0.2 (range 1-14). In 83% of cases hyperthermia was administered biweekly. Forty-two patients were treated without any skin reaction (33%), erythema occurred in 59 fields (47%), transient thermal blisters occurred in 25 fields (20%) and ulceration occurred in 23 fields (18%). In 25 cases, two or more skin reactions (20%) were observed concurrently. Concurrent radiation dose correlated with skin reactions (p = 0.02). The incidence of skin reactions was inversely correlated with previous radiation therapy (p = 0.04) and previous radiation therapy dose (p = 0.04) possibly due to fibrosis. None of the tumour or skin thermal parameters correlated with the reaction rate.

Adolescent↗

PubMedDate not supplied

Effect of i.v. glucose versus combined i.v. plus oral glucose on human tumour extracellular pH for potential sensitization to thermoradiotherapy.

The purpose of this study was to determine whether intravenous or combined intravenous plus oral glucose administration was more effective inducing acute tumour acidification. Seventeen nondiabetic patients at the Henan Tumour Hospital with superficial tumour deposits of various histologies and size were administered, after fasting, either 50 g glucose intravenously (i.v., in 100 ml over 10 min) or 50 g i.v. glucose (in 100 ml over 10 min) combined with 100 g oral glucose (in 200 ml; i.v. + oral). Extracellular tumour pH (pHe) was determined with one or two indwelling needle combination pH microelectrodes. Blood glucose concentration was determined every 15-20 min by finger stick with Chem-Strips and a Glucometer. Ten patients received i.v. glucose, and seven patients received i.v. + oral glucose. Blood glucose rose to 430 +/- 15 mg/dL in both groups. However, the rate of clearance of blood glucose was greater for the i.v. glucose than for the i.v. + oral glucose group (p < 0.00002), and thus the blood glucose levels remained elevated longer after i.v. + oral than after i.v. glucose administration. Relative to the initial fasting blood glucose concentration, blood glucose was -2 +/- 7 mg/dL at 110 min after glucose administration by the i.v. route, whereas, blood glucose relative to initial values was 143 + 23 mg/dL by 110 min after glucose administration by the i.v. + oral route, p = 0.000004. The initial pHe values in the two groups of tumours were similar, 7.34 +/- 0.09 (6.78-7.71) and 7.35 +/- 0.08 (6.99-7.61), respectively. After i.v. glucose, tumour acidification occurred in nine of ten patients (-0.16 + 0.02 pH unit, range -0.24 to -0.05), and after i.v. + oral glucose tumour acidification occurred in six of seven patients (-0.19 +/- 0.07 pH unit, range -0.43 to -0.06). When the initial fasting blood glucose concentration was in excess of 82 mg/dL, all patients (12/12) exhibited tumour acidification during hyperglycaemia, whereas, only 3/5 patients exhibited tumour acidification when the initial blood glucose concentration was less than 82 mg/dL (p = 0.07). The time to maximum decrease in tumour pHe was significantly shorter after i.v. + oral glucose than after i.v. glucose (e.g., 67 +/- 11 versus 102 +/- 8 min, p = 0.02) and correlated with the rate of clearance of blood glucose (p = 0.02, r = 0.55). Larger tumours tended to exhibit a greater decrease in pHe (p = 0.08, r = 0.04). The only side effects of hyperglycaemia were transient nausea and increased urinary output. The effect of hyperglycaemia induced by administration of 200 g oral glucose was similar to i.v. administration in that 83% of tumours exhibited acidification of 0.14 +/- 0.02 pH unit by 91 +/- 7 min. We conclude that i.v. and i.v. + oral glucose administration are equally effective inducing tumour acute acidification, but no more effective than 200 g oral glucose, for investigation of hyperglycemic sensitization to thermoradiotherapy.

Administration, Oral↗

PubMedDate not supplied

Cancers in multiple primary sites.

Seventy-six patients with multiple primary cancers have been found among 9180 cancer patients admitted to the Center of Oncology & Nuclear Medicine, Okmeydani Hospital, Istanbul, Turkey between 1980 and 1984. Overall incidence of multiple primary cancers (MPC) among all cancer patients was 0.83%. The majority of the patients were male in both MPC and all patients, i.e. 64.5% and 63.1%, respectively. In MPC patients, the great majority of the patients was in the 51-70 years age group (57.9%) at the time of initial cancer diagnosis. Combination of larynx cancer and lung cancer was the most commonly seen combination. It was followed by lip cancer-larynx cancer (6.6%), skin cancer-larynx cancer and skin cancer-lung cancer (5.3%), breast cancer-ovary cancer and breast cancer-endometrium cancer (4%) combinations. Larynx cancer was the most commonly seen multiple primary cancer component in all patients (46%) and in male patients (61.2%). It was followed by lung cancer, i.e. 39.5% in all patients and 55.1% in male patients. In female patients, breast cancer was a component in 63% of the cases. In eleven patients, two cancers were diagnosed concurrently. In other cases, the interval between two cancers varied between 1 month and 30 years. The mean interval was 4.1 +/- 0.6 years (median 3.0 years). In 62% of the cases, the interval between two cancers was shorter than 3 years. Smoking rate was 75.5% in male patients whereas it was only 18.5% in females. In larynx cancer-lung cancer patients, smoking rate was 81.2% and reached 83.3% when lip cancers were included.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗