Low-dose and conventional-dose high resolution CT of pulmonary changes in breast cancer patients treated by tangential field radiotherapy

Twenty-seven consecutive breast cancer patients receiving tangential field radiation therapy were followed by high resolution CT (HRCT) in order to compare the accuracy of reduced-dose HRCT and conventional-dose HRCT in the evaluation of subtle pulmonary changes. Thin section 1-mm HRCT images were obtained at identical levels at 120 kVp, with 320 mAs, 200 mAs, 160 mAs, 120 mAs and 60 mAs settings. HRCT was performed during the planning of radiotherapy and 4, 8 and 24 weeks after the completion of radiotherapy. Radiation was administered according to an individual CT-based plan by tangential fields with 4 or 6 MV photons to the whole breast given with 5 fractions of 1.9 Gy weekly to a total dose of 50 Gy. The tumor bed was boosted by electrons to 60 Gy. Pathological changes were detected in 21 examinations of 10 patients: 9 patients out of 27 (33%) showed radiation induced changes; 1 patient developed metastases within the irradiated volume. Septal thickening appeared in 5 patients at 4 weeks and in another 5 patients at 8 weeks. Parenchymal consolidation was detected in 1 patient at 4 weeks and in 5 patients at 8 weeks. HRCT using 160 mAs yield good quality images of subtle radiation induced injuries. The diagnostic validity of HRCT using lower than 160 mAs depends on the detail analyzed.

The intrinsic radiosensitivity and sublethal damage repair capacity of five cervical carcinoma cell lines tested with the 96-well-plate assay

We have tested the intrinsic radiosensitivity and capacity for sublethal damage repair (SLDR) in split-dose experiments with the 96-well plate clonogenic assay. Four out of five cell lines were squamous-cell carcinoma (SCC) lines (CaSki, ME-180, HX151c, HX156c) and one cell line was established from glassy-cell carcinoma (UM-GCC-1). Comparison of radiosensitivities was by with D value, the mean inactivation dose. D for these cell lines varied from 1.7 Gy to 2.5 Gy. As a group, cervical carcinoma cell lines were more radioresistant than endometrial adenocarcinoma cell lines tested with the same assay, but more radiosensitive than vulvar SCC lines. Three cell lines showed clear SLDR, but two cell lines were unable to carry out this function. Furthermore, cell lines capable of SLDR also showed significant increase in survival when D values were compared after the radiation dose was split into three instead of two fractions. These results indicate the importance of adding another radiobiological parameter to the intrinsic radiosensitivity when predictive tests are planned.

Squamous cell carcinoma is highly sensitive to taxol, a possible new radiation sensitizer

We studied the sensitivity of seven cell lines established from laryngeal carcinoma to the cytotoxic drug paclitaxel (Taxol) in vitro. In all four cell lines tested for growth inhibition, paclitaxel reduced growth at low concentrations, and in two cell lines growth was completely inhibited at a paclitaxel concentration of only 1 x 10(-8) M. Flow cytometric data showed a G2/M block in all seven cell lines after exposure to paclitaxel for 24 h at a concentration of 1 x 10(-8) M. This concentration is about one-one hundredth fold smaller than those measured in serum after a single intravenous dose of about 200 mg/m2. The high in vitro sensitivity of laryngeal cancer cell lines to paclitaxel,and the G2/M block suggest that the drug may potentially be used in conjunction with radiotherapy.

Simultaneous cisplatin and radiation in endometrial adenocarcinoma cell lines

The effects of concomitantly administered cisplatin and radiation were evaluated in four recently established endometrial adenocarcinoma cell lines. We used the 96-well clonogenic assay to obtain survival data which were fitted to the linear quadratic model. The area under the survival curve (AUC) was obtained by numerical integration. It turned out that there was only a systematic additive cytotoxic effect and no supra-additive, true radiosensitising effect could be found. The results were not affected by the cisplatin dose used, the intrinsic radiosensitivity of the cell lines or the sensitivity of the cells to cisplatin.

Characterization and radiosensitivity of UT-EC-2A and UT-EC-2B, two new highly radiosensitive endometrial cancer cell lines derived from a primary and metastatic tumor of the same patient

UT-EC-2A was established from a patient with moderately differentiated Stage III endometrial adenocarcinoma with squamous metaplasia. UT-EC-2B was established from the same patient 17 months later from a metastasis in the left supraclavicular fossa. The origin of these cell lines was confirmed by DNA identity testing. Nude mice tumors produced by UT-EC-2A and UT-EC-2B cells recapitulated the histology of the original human tumors. Flow cytometric DNA contents of both primary and metastatic human tumors as well as corresponding nude mice tumors were diploid. The S-phase fractions of both cell lines were > or = 30%. The UT-EC-2A cell line was cytogenetically normal. The UT-EC-2B cell line had quite simple karyotype at low passage with an extra i(18p) and a deletion 21q, but at higher passages an additional three-way translocation 5;14;19 was observed. Radiosensitivity of the cell lines was tested with the 96-well plate clonogenic assay. The areas under the survival curves corresponding to the mean inactivation doses of UT-EC-2A and UT-EC-2B were 0.65 +/- 0.10 and 0.60 +/- 0.06 Gy, respectively. Measured survival at 2.0 Gy (SF2) was 0.042 for UT-EC-2A, 0.044 for UT-EC-2B, and 0.2 for skin fibroblasts. These cell lines are among the most radiosensitive human cancer cell lines described in the literature. Studying the characteristics of primary and metastatic cells derived from the same patient provides an opportunity to evaluate tumor progression.

Dosimetry of irradiation models. The 96-well clonogenic assay for testing radiosensitivity of cell lines

Radiation experiments with cells in single cell suspension in test tubes and on 96-well plates were carried out and compared. The cells originated from cell lines established from carcinomas of the floor of the mouth and from endometrial carcinoma. Two irradiation models were constructed. Both models allowed the absorbed doses to the cells to be administered with a high accuracy in both experimental settings (better than 5.0%). These irradiation models were compared on cancer cell lines with dissimilar inherent radiation sensitivity and histologic type (UM-SCC-1 resistant, UM-SCC-14A sensitive, and UT-EC-2B highly sensitive); various radiation doses were used. The fractions of surviving cells as a function of radiation dose were compared: there was no significant difference between cells irradiated in test tubes and cells irradiated in 96-well plates. Thus, if the absorbed doses in cells suspended in a tube and in a plate were the same, the survival was similar regardless of the type of irradiation model.

Samarium-153-EDTMP in bone metastases

Thirty-five patients with painful bone metastases arising from a variety of tumor types underwent a clinical trial in which 153Sm-EDTMP was injected as a single intravenous dose. The injection ranged in amount from 330 MBq to 1110 MBq of 153Sm-EDTMP. Pain relief usually occurred within one week after administration. The duration of pain relief lasted from 2 to 17 weeks. A detectable degree of pain palliation was experienced by 80% of the treated patients; 54% reported substantial or complete pain relief. Due to the small number of patients, no clear-cut dose-related response was detectable. Moderate myelosuppression was observed in one patient (WHO grade III). The metastatic lesion-to-normal bone ratios remained constant (varying from 1.5 to 4.8) for at least 5 days post-injection. 153Sm cleared very rapidly from the blood. Less than 1% of the injected dose remained in circulation at 4 hours post-injection. No local accumulation of the tracer could be detected outside the skeleton. Urinary excretion was quite complete at 6 hours post-injection. The biodistributions of 153Sm-EDTMP and 99mTc-DPD are very similar in metastatic and normal bone; thus, bone scanning can be used for patient selection and followup. According to our results, it seems that higher doses of 153Sm-EDTMP can be given safely and without any irreversible myelosuppression.

Sublethal damage repair after fractionated irradiation in endometrial cancer cell lines tested with the 96-well plate clonogenic assay

Two long-established and seven newly established endometrial adenocarcinoma cell lines were tested for their capacity to repair sublethal damage after fractionated irradiation. Cell survival was determined with the 96-well plate clonogenic assay based on limiting dilutions. Total radiation doses of 0.75 Gy, 1.25 Gy, 2.50 Gy, 5.00 Gy and 7.50 Gy were used either as a single dose or divided into two or three equal fractions with a 24 h interval. Survival data were fitted to the linear quadratic model, and the area under the survival curve (AUC), equivalent to the mean inactivation dose, was obtained with numerical integration. The amount of sublethal damage repair (SLDR) was expressed as an area-under-the-curve (AUC) ratio comparing survivals from fractionated-dose with those from single-dose experiments. SLDR capacity of the cell lines expressed as an AUC ratio varied between 1.00 and 1.59, and the mean was 1.17. Two highly radiosensitive cell lines were found to be SLDR-deficient, but most of the cell lines studied had some SLDR capacity. We have earlier shown that endometrial cancer cell lines as a group are more radiosensitive than squamous-cell carcinoma (SCC) lines. Data obtained in this study suggest that the capacity for SLDR in these cell lines is rather limited compared with the majority of SCC lines tested. This finding underlines further the high radioresponsiveness of endometrial cancer.

Comparative evaluation of cisplatin and carboplatin sensitivity in endometrial adenocarcinoma cell lines

Platinum analogues are frequently used in the treatment of advanced or recurrent endometrial cancer. To study the sensitivity of endometrial cancer to cisplatin and carboplatin, we tested two long-established (RL95-2, KLE) and six new cell lines (UM-EC-1, UM-EC-2, UM-EC-3, UT-EC-2A, UT-EC-2B, UT-EC-3) using the 96-well-plate clonogenic assay. This assay has proven to be suitable for testing chemosensitivity of both adenocarcinoma and squamous cell carcinoma. The chemosensitivity was expressed as an IC50 value, the drug concentration causing 50% inhibition of clonogenic survival. IC50 values were obtained from dose-response curves after fitting the data by the linear quadratic equation, F = exp[-(alpha D + beta D2)]. The IC50 values of the two platinum derivatives varied considerably. The values for cisplatin varied between 0.022 microgram ml-1 and 0.56 microgram ml-1 and the corresponding values for carboplatin were 0.096-1.20 microgram ml-1. The range of the ratios between carboplatin IC50 and cisplatin IC50, from 1.5:1 to 4.4:1, was rather narrow. However, no constant ratio between carboplatin IC50 and cisplatin IC50 could be detected. The equivalent doses with regard to efficacy of these two platinum analogues remain to be determined.

Intercomparison of radiotherapy treatment planning systems for external photon and electron beam dose calculations

Dose distributions calculated by six different treatment planning systems (TPSs), used by the hospitals in Finland or in Russia, were compared with measured dose distributions. Five typical cases of irradiation were selected: regular fields, oblique incidence, irregular field, wedge field and inhomogeneity in a water equivalent phantom. The beam data for each TPS where those pertaining to the beam where the comparative relative measurements were performed. The results indicate that the dose distributions produced by different TPSs can differ from each other as well as from the measured dose distributions up to a level which is not acceptable in terms of the ICRU recommendations. Greatest differences seem to be related to the omission or undue consideration of the scatter components of the beam.

Comparison of effects of 0.5 and 3.0 Gy X-irradiation on lipid peroxidation and antioxidant enzyme function in rat testis and liver

The prooxidant effect of X-irradiation on rat testis and liver tissue was studied with doses of 0.5 and 3.0 Gy; the latter dose kills the proliferating spermatogonia and causes a maturation-depletion process in the germ cells. The level of lipid peroxidation, measured by the formation of diene conjugates and thiobarbituric acid-reactive substances (TBARS) and the activities of the antioxidant enzymes were determined 0.5 hours, 1 day, 7 days, and 31 days after the exposure. In the liver, increased levels of diene conjugation (+36%, P < 0.05) in the group of 3.0 Gy at 0.5 hours indicated increased lipid peroxidation. At the same time, TBARS were increased (+25%, P < 0.05) in the group of 0.5 Gy, but not in the 3.0-Gy group. In the testis, diene conjugation was not determined at 0.5 hours postirradiation, and at day 1 it was at the control level. The level of TBARS in the testis was below control (-11%, P < 0.01) in the 3.0-Gy group at day 1. At day 31 after 3.0 Gy in the testis, an increase in the amount of conjugated dienes (+24%, P < 0.01) was observed in parallel with a decreased level of TBARS (-15%, P < 0.01). The activity of superoxide dismutase (SOD) was decreased in the testis at 0.5 hours postirradiation (-28%, P < 0.05, and -29%, P < 0.05, in the groups of 0.5 and 3.0 Gy), whereafter it returned to normal by day 7. In the liver, such inactivation of SOD was not observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Carboplatin-radiation interaction in squamous cell carcinoma cell lines

Chemoradiotherapy has been considered one of the most promising improvements in the treatment of advanced head and neck cancer. This article describes in vitro chemosensitivity to carboplatin in five squamous cell carcinoma cell lines established from head and neck cancers and in one vulvar squamous cell carcinoma cell line. Sensitivity to carboplatin was found to vary markedly when using the 96-well plate clonogenic assay and continuous drug exposure. The difference in carboplatin response between the most sensitive and the most resistant cell lines was fourfold. No cross-resistance was observed between inherent radiosensitivity and chemosensitivity. Effects of concomitant use of carboplatin and radiation were further investigated in the two cell lines that were found to be most sensitive to carboplatin. The drug was administered 1 hour before acute radiation doses, and an additive effect was observed in both cell lines.

Sublethal damage repair in squamous cell carcinoma cell lines

Squamous cell carcinoma (SCC) cell lines recently established from head and neck tumors were studied for their capability of repairing sublethal radiation induced damage (SLDR). Total doses of 1.25, 2.50, 5.00, and 7.50 Gy were used either as a single dose or split in two equal fractions with a 24 h interval. Cell survival was determined using a 96-well plate clonogenic assay based on limiting dilution. Survival data was fitted by linear quadratic model, and the area under the survival curve (AUC) was obtained with numerical integration. The amount of SLDR was expressed as AUC-ratio comparing survivals from split dose vs single dose experiments. SLDR capacity was observed to vary markedly between individual cell lines (AUC-ratios 1.0-1.5). The relatively radiation-sensitive cell lines had a tendency toward higher SLDR proficiency (correlation coefficient 0.85). The differences in repair capacity could not be explained by the differences in doubling times of the cell lines. The inverse relationship between SLDR capacity and inherent radiosensitivity could explain the poor radiocurability of the sensitive donor tumors. Two of the most resistant cell lines were found SLDR deficient. This is a novel finding, since SLDR has been previously reported in all studied cells.

Radiation sensitivity of endometrial carcinoma in vitro

The role of radiation therapy is essential in the treatment of endometrial carcinoma. The present knowledge of the radiation sensitivity of endometrial carcinoma is mostly empirical and based on clinical trials. To study the inherent radiation sensitivity of endometrial carcinoma, we tested two long-established cell lines (RL95-2, KLE) and four new, low-passage cell lines (UM-EC-1, UM-EC-2, UM-EC-3, UT-EC-1) by using a 96-well plate clonogenic assay. This method has proved to be suitable for clonogenic studies of both squamous cell carcinomas (SCC) and adenocarcinomas in our recent works. Plating efficiencies of the cell lines tested varied from 0.005 to 0.45. Cells were irradiated in suspension with a 4-MeV linear accelerator at a dose rate of 2.0 Gy/min. Survival data were fitted by the linear quadratic function F = exp (-(alpha D + beta D2)). Radiation sensitivity was expressed as the area under the curve (AUC), equivalent to the mean inactivation dose. UM-EC-1 and UT-EC-1 were the most radiation-resistant cell lines tested (AUC greater than 1.6 Gy), while UM-EC-3 was the most sensitive (AUC = 1.0 Gy). The difference in radiation sensitivity between these cell lines was statistically significant (P less than 0.001). As a group, endometrial carcinoma cell lines were clearly more radiosensitive than most SCC lines of head and neck and vulva earlier tested by us. However, our results showed also great variance in the inherent radiation sensitivity between individual cell lines derived from endometrial carcinomas.

Effects of radiation fractionation on four squamous cell carcinoma lines with dissimilar inherent radiation sensitivity

The effect of radiation fractionation was investigated using a new 96-well-plate clonogenic assay in four squamous cell carcinoma lines. Earlier experiments had shown that two of the cell lines (UT-SCC-1A and UM-SCC-14A) were inherently relatively sensitive to irradiation, and two (UM-SCC-1 and UM-SCV-1A) relatively resistant. All of the four carcinomas from which the cell lines were established had poor clinical outcome. The radiation doses were given as a single exposure, or split into two or three equal fractions with a 24-h interval. The two inherently sensitive cell lines showed enhanced survival after radiation fractionation as compared with a single dose, whereas the resistant cell lines did not. The result suggests that both the inherent resistance of cancer cells to irradiation and the repair of sublethal radiation damage may lead to treatment failure, and that shortening of the total irradiation time may overcome cancer cell recovery between fractions in some, but not in all carcinomas.

DNA-flow cytometry of defined stages of rat seminiferous epithelium: effects of 3 Gy of high-energy X-irradiation

Testes of adult Sprague-Dawley rats were irradiated locally by 3 Gy of 4 MeV X-rays produced by a linear accelerator. This type and dose of radiation gives an even distribution through the testis and selectively kills the proliferating spermatogonia. The seminiferous tubular cells were quantified by DNA flow cytometry at defined stages of the epithelial cycle at 7, 17, 22, 38, 52, and 80 days after irradiation. The flow cytometric technique was modified by using frozen instead of fresh samples. Freezing did not alter cell numbers when compared with fresh samples. At 7 days post-irradiation no significant changes were observed in any cell population by DNA flow cytometry, whereas histological analysis revealed a reduction in intermediate and type B spermatogonia. At 17 and 22 days post-irradiation, the number of cells at meiotic prophase (4C) was decreased, particularly in stages II-V of the cycle. In stages VII-VIII, cell numbers were 40 and 31%, and in stages IX-XIII, 24 and 43% of that in non-irradiated controls at 17 and 22 days, respectively. At 38 days after irradiation, both 4C and 1C (haploid) cells were decreased in number. The 4C cells were reduced to 24, 17, and 13% of that in non-irradiated controls in stages II-V, VII-VIII, and IX-XIII of the cycle, respectively. The corresponding numbers of 1C cells were 5, 17, and 4%. At 52 days after irradiation, 1C cells had declined to 38 and 19% of control values in stages II-V and IX-XIII, respectively. In stages II-V, 1C' cells (haploid cells with condensed nuclei) declined to 28% of controls at 52 days. The present data provide a quantitative basis for the use of X-ray-irradiated rat testes as a model system in experiments pursuing interactions between Sertoli cells and spermatogenic cells.

Radiation response of vulvar squamous cell carcinoma (UM-SCV-1A, UM-SCV-1B, UM-SCV-2, and A-431) cells in vitro

Standard therapy for squamous cell carcinoma (SCC) of the vulva consists of radical surgery and inguinal node dissection. Radiation therapy has been used for preoperative treatment in advanced cases to reduce the size of the tumor, and also as the only treatment in inoperable or recurrent disease. To study the inherent radiation sensitivity of vulvar carcinoma, we tested three new vulvar carcinoma cell lines and the long-established cell line A-431 by using a 96-well plate clonogenic assay, earlier shown by us to be suitable for survival studies of SCC. SCC and adenocarcinoma cell lines derived from other sites were used as a reference. Cells were irradiated with a 4-MeV linear accelerator at a dose rate of 2.0 Gy/min. The vulvar cell lines were found to be highly resistant to radiation with the average mean inactivation dose of 3.44 +/- 0.34 Gy as calculated from the area under the curve. The results were consistent in repeated experiments and for all cell lines. The average value for area under the curve was 1.79 +/- 0.30 for the other SCC lines tested. The values for area under the curve differed significantly (P less than 0.0001) between the vulvar lines and reference SCC lines. These results indicate that vulvar SCC cells in vitro express exceptional inherent radioresistance, and thus development of other forms of additional treatment would be more advantageous in advanced cases.

Imaging of rats with mammary cancer with two 2-deoxy-2-[18F]fluoro-D-hexoses

Rats with mammary cancer were imaged by scintigraphy: 10 rats with 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) and 10 rats with [18F]F-D-galactose. The uptake of both tracers was similar in the tumors--the tumor-to-normal tissue ratio was 2.7 +/- 1.1 for [18F]FDG and 2.3 +/- 0.9 for [18F]FDGal at 120 min after injection. In addition to the tumors [18F]FDG accumulated in the brain, bladder and heart, [18F]FDGal in the brain, bladder and liver. [18F]FDGal may be useful for tumor imaging in man; further studies should be addressed to elucidate the mechanism of [18F]FDGal uptake into tumors.

Allogeneic bone marrow transplantation in multiple myeloma: a report of four cases

Allogeneic bone marrow transplantation offers a new and promising form for treatment of multiple myeloma incurable with chemotherapy. We present four cases of advanced multiple myeloma given bone marrow transplantation from HLA-identical and MLC-negative sibling donors. One patient had a recurrent plasmacytoma 8 months later and one died 12 days after the transplantation whereas the other two are in good clinical remission 15 and 19 months post-transplantation.

Preliminary biodistribution studies with a hybrid positron scanner

The hybrid positron scanner is a scanning device for imaging with short-lived positron-emitting radioisotopes. It is especially suitable for total body scanning studies. The scanner consists of two moveable parallel detectors, which are NaI(Tl)-crystals 40 cm long and 5 cm in diameter with a photomultiplier at each end. One detector is above and the other below the patient. The coordinate in the direction perpendicular to the crystal axis is determined from mechanical movement of the detectors. The coordinate along the crystal axis is determined from the signals of the photomultipliers. The specifications of the hybrid positron scanner are presented. Biodistribution studies in rabbits on the accumulation of 18F in the skeleton and on the 13NH3 distribution in various organs are described. The regional pharmacokinetics of 11C-ethanol in man after peroral administration of the tracer is presented.