The development and external validation of an overall survival nomogram in medically inoperable centrally located early-stage non-small cell lung carcinoma.

BACKGROUND AND PURPOSE: Current nomograms predicting survival prognosis after stereotactic body radiation therapy (SBRT) in non-small cell lung cancer (NSCLC) are based on peripherally located tumors. However, patients with a central lung tumor tend to be older, the tumor is often larger and fraction-schedules are risk-adapted. Therefore, we developed and externally validated a nomogram to predict overall survival (OS) in patients having centrally located early-stage NSCLC treated with SBRT. MATERIALS AND METHODS: Patients who underwent SBRT for centrally located NSCLC were identified and baseline characteristics were obtained. A nomogram was built to predict 6-month, 1-, 2- and 3-year OS using Cox proportional hazards model. The model building procedure was validated using bootstrap sampling. To determine generalizability, external validation was performed on a cohort of patients with central NSCLC treated with SBRT from another center. Discriminatory ability was measured with the concordance index (C-index) and calibration plots were used to compare Kaplan-Meier-estimated and nomogram-predicted OS. RESULTS: The nomogram was built on data of 220 patients and consisted of the following variables: PTV, age, WHO performance status, tumor lobe location and ultracentral location. The C-index of the nomogram (corrected for optimism) was moderate at 0.64 (95% confidence interval (CI) 0.59-0.69). Calibration plots showed favorable predictive accuracy. The external validation showed acceptable validity with a C-index of 0.62 (95% CI 0.61-0.64). DISCUSSION: We developed and externally validated the first nomogram to estimate the OS-probability in patients with centrally located NSCLC treated with SBRT. This nomogram is based on 5 patient and tumor characteristics and gives an individualized survival prediction.

Verification measurements and clinical evaluation of the iPlan RT Monte Carlo dose algorithm for 6 MV photon energy.

This study presents data for verification of the iPlan RT Monte Carlo (MC) dose algorithm (BrainLAB, Feldkirchen, Germany). MC calculations were compared with pencil beam (PB) calculations and verification measurements in phantoms with lung-equivalent material, air cavities or bone-equivalent material to mimic head and neck and thorax and in an Alderson anthropomorphic phantom. Dosimetric accuracy of MC for the micro-multileaf collimator (MLC) simulation was tested in a homogeneous phantom. All measurements were performed using an ionization chamber and Kodak EDR2 films with Novalis 6 MV photon beams. Dose distributions measured with film and calculated with MC in the homogeneous phantom are in excellent agreement for oval, C and squiggle-shaped fields and for a clinical IMRT plan. For a field with completely closed MLC, MC is much closer to the experimental result than the PB calculations. For fields larger than the dimensions of the inhomogeneities the MC calculations show excellent agreement (within 3%/1 mm) with the experimental data. MC calculations in the anthropomorphic phantom show good agreement with measurements for conformal beam plans and reasonable agreement for dynamic conformal arc and IMRT plans. For 6 head and neck and 15 lung patients a comparison of the MC plan with the PB plan was performed. Our results demonstrate that MC is able to accurately predict the dose in the presence of inhomogeneities typical for head and neck and thorax regions with reasonable calculation times (5-20 min). Lateral electron transport was well reproduced in MC calculations. We are planning to implement MC calculations for head and neck and lung cancer patients.

Extensive cytoreductive surgery combined with intra-operative intraperitoneal perfusion with cisplatin under hyperthermic conditions (OVHIPEC) in patients with recurrent ovarian cancer: a feasibility pilot.

AIMS: The feasibility, morbidity and toxicity of an intensified surgical treatment strategy consisting of aggressive cytoreductive surgery, intra-operative intraperitoneal perfusion of cisplatin and hyperthermia were evaluated in women with recurrent ovarian cancer. METHODS: Five heavily pre-treated patients with extensive abdominal tumour bulk entered this pilot study. In all cases aggressive cytoreduction leaving tumour remnants <5 mm in diameter could be performed. This was followed intra-operatively by perfusion of the abdominal cavity with hyperthermic cisplatin 50-70 mg/m(2)for 90 min. During perfusion the intra-abdominal temperature was maintained at 40 degrees C. The median duration of surgery was 10 hours (range 9-11 hours). RESULTS: No major intra- or post-operative complications emerged. Median post-operative ileus (resuming of soft diet) was 11 days (9-13 days). The mean period of hospitalization was 25 days (range 17-42). Toxicity due to i.p. cisplatin was mainly metabolic and of grade 1-2, while no nephrotoxicity was observed. The pharmacokinetics of cisplatin indicated that the maximum concentration of cisplatin measured in the perfusate was 15 times higher than in plasma. CONCLUSIONS: We conclude that aggressive cytoreduction combined with hyperthermic intra-operative intraperitoneal cisplatin was feasible in a small group of heavily pre-treated ovarian cancer patients with extensive tumour bulk with acceptable morbidity and toxicity. Further studies are required in larger groups of patients to further establish the feasibility of this intensified treatment strategy. We stress that OVHIPEC is not a treatment modality on its own for advanced ovarian cancer. The effectiveness of OVHIPEC is likely to be dependent on the effectiveness of post-operative adjuvant chemotherapeutic regimens.

Translational research offers individually tailored treatments for cancer patients.

The measurement of the effect of cisplatin on DNA has become feasible with the development of antibodies against DNA adducts. In a phase II dose escalation trial with concomitant radiotherapy and daily cisplatin in lung cancer, we found that patients with high DNA adduct levels measured in the buccal mucosa had a much higher survival rate than patients with a low or undetectable amount of cisplatin-DNA adducts. The use of this assay may therefore allow the selection of individual patients for concomitant treatment with cisplatin and radiotherapy, as has been shown to be effective in randomized trials in patients with lung, head and neck, and cervix malignancies. To predict the response to radiation treatment, assays have been developed for tumor growth potential by measuring the labeling index after intravenous injection of IdUrd or by estimating cyclin D1 expression. Intrinsic radiation sensitivity of human tumors can be estimated by conventional techniques, which are probably too slow or cumbersome for routine use, or with more rapid assays, such as those for chromosome damage with fluorescent probes. These assays should be able to guide us in the adaptation of the individual radiation doses that should be applied and to select patients for an accelerated or hyperfractionated regimen. Pretreatment levels of apoptosis may also be helpful in predicting treatment outcome, although the data so far show inconsistent results. A better understanding of the signal transduction pathways involved in radiation-induced apoptosis may help in the design of studies aimed at modulating the apoptotic response, thereby increasing cell kill. We have recently shown that alkyllysophospholipids, which inhibit mitogenic signaling, induce apoptosis in a variety of tumor cell lines. In combination with ionizing radiation, these compounds cause an enhancement of apoptotic cell kill. This type of a signaling-based intervention could form the basis for new therapeutic strategies. The role of hormonal therapy in breast cancer patients, both in an adjuvant setting and for the treatment of disseminated disease, is becoming increasingly important. The development of a functional assay for the estrogen receptor (ER-FASAY), based on a yeast growth assay, provides a better way than the classical immunohistochemistry assay of estimating abnormal function of the receptor in tumors. These assays are simply examples, illustrating how clinicians could improve the therapeutic outcome for their patients by implementing knowledge obtained in the laboratory in clinical decision making. With further optimization of these assays, this holds the promise for the future that the treatment for each patient can be tailored rationally to the biology of the individual.

DNA-adduct levels as a predictor of outcome for NSCLC patients receiving daily cisplatin and radiotherapy.

We aimed to investigate whether biological factors related to radiosensitivity and chemosensitivity have prognostic significance in non-small-cell-lung-cancer (NSCLC) patients treated with daily low doses of cisplatin and radiotherapy. We treated 27 NSCLC patients with concomitant daily low-dose cisplatin and radiotherapy between 1993 and 1995. Tumour specimens were analyzed for p53 and bcl-2 expression, and for cell proliferation using antibodies against ki-67. In addition, apoptosis was measured by an end-labeling technique (TUNEL). Finally, cisplatin-induced DNA modification in buccal cells was assessed immunocytochemically using a specific anti-serum. Univariate and multivariate analyses were performed to assess the association between the different variables and survival. The median follow-up was 41 months, and 21 patients (78%) have died. In a univariate analysis, age, tumour stage and cisplatin-DNA-adduct staining were the only factors significantly associated with survival (p < 0.05, log-rank test). p53, bcl-2, Ki-67 and apoptosis showed no relationship with outcome. Multivariate analysis revealed that cisplatin-DNA-adduct staining remained an independent prognostic factor (hazard ratio, 0.10, 95% CI, 0.02-0.49), with shorter survival times for patients with low adduct staining.

Intraperitoneal cisplatin with regional hyperthermia in advanced ovarian cancer: pharmacokinetics and cisplatin-DNA adduct formation in patients and ovarian cancer cell lines.

The purpose of this study was to investigate the influence of hyperthermia on cisplatin pharmacokinetics and DNA adduct formation. The latter was investigated both in tumour cell lines in vitro and in tumour cells and buccal cells from cancer patients. The patients had advanced ovarian carcinoma and were entered into a phase I study for cytoreductive surgery followed by hyperthermia in combination with intraperitoneal cisplatin administration. The cisplatin-DNA modifications in vivo and in vitro were studied by an immunocytochemical method with the polyclonal antiserum NKI-A59. The patient samples for pharmacokinetic determinations were analysed by flameless atomic absorption spectrometry. In vitro, the combination of hyperthermia and cisplatin enhanced cell killing compared with either treatment alone, such that the cisplatin-resistant ovarian cell line A2780/DDP became almost as sensitive as the parent A2780 cell line (resistance factor reduced from 30 to 2 at the IC50). In addition, increased cisplatin-DNA adducts were observed in the resistant cell line after the combined treatment compared with cisplatin alone. A good correlation was found between nuclear staining density and surviving fraction for all groups, indicating that the DNA adducts generated are an important determinant of toxicity and that the mechanism by which hyperthermia enhances kill is by increasing adduct levels. In the patients, the ratio of drug concentration in the peritoneal perfusate compared with that in plasma was found to be approximately 15, indicating a favourable pharmacokinetic ratio. Cisplatin-DNA adduct formation in tumour cells from patients was higher than in buccal cells, reflecting this higher drug exposure, i.e. local plus systemic versus systemic only. In addition, the tumour cells but not buccal cells were exposed to hyperthermia. The higher number of tumour adducts also suggests that a favourable therapeutic ratio could be achieved. Platinum-DNA adduct formation was found to decrease with distance from the surface of the tumour nodules. However, at a distance of 3-5 mm, the nuclear staining density levels were still measurable and higher than in buccal cells. In conclusion, the combined pharmacokinetic and adduct data in patients support the advantages of the intraperitoneal route for drug administration, and the addition of heat.

Hyperthermia enhances the cytotoxicity and platinum-DNA adduct formation of lobaplatin and oxaliplatin in cultured SW 1573 cells.

The cytotoxicity of cisplatin and cisplatin-DNA adduct formation in vitro and in vivo is clearly enhanced by hyperthermia. We investigated whether cytotoxicity and platinum-DNA adduct formation of two promising new third-generation platinum derivatives, lobaplatin [1,2-diamminomethylcyclobutane platinum(II) lactate] and oxaliplatin [oxalato-1,2-diaminocyclohexane platinum(II)], are also enhanced by hyperthermia. Cisplatin was used for comparison. SW 1573 cells were incubated with cisplatin, lobaplatin or oxaliplatin at different concentrations for 1 h at 37 degrees, 41 degrees and 43 degrees C. The reproductive capacity of cells was determined by cloning experiments. Immunocytochemical detection of platinum-DNA adducts was performed with the rabbit antiserum NKI-A59. At 37 degrees C, cisplatin was the most cytotoxic, followed by oxaliplatin and lobaplatin. Hyperthermia clearly enhanced the cytotoxicity of cisplatin, lobaplatin and oxaliplatin. There was no further increase in cytotoxicity at 43 degrees C compared to 41 degrees C for cisplatin and oxaliplatin. A further increase in cytotoxicity at 43 degrees C was observed for lobaplatin. At 43 degrees C thermal enhancement was higher for lobaplatin than for oxaliplatin, with the reverse pattern at 41 degrees C. For both drugs, thermal enhancement of cytotoxicity was lower than observed for cisplatin. Immunocytochemical detection of platinum-DNA adducts was feasible for all the drugs. Adduct formation was enhanced at 43 degrees C for cisplatin, lobaplatin and oxaliplatin with a relative increase of 410%, 170% and 180%. These results seem to confirm that an increase in platinum-DNA adduct formation is involved in the in vitro thermal enhancement of cytotoxicity. The observed thermal enhancement of cytotoxicity of lobaplatin and oxaliplatin in vitro warrants further in vivo investigations.

Oral platinum analogue JM216, a radiosensitizer in oxic murine cells.

This study was designed to compare radiosensitization by the oral platinum compound JM216 with cisplatin. RIF1 mouse tumour cells were treated at various doses and at various exposure times with JM216 and irradiated 15 min before the end of drug exposure. The fraction of cells surviving treatment was assessed by colony formation. Results were compared with those for equivalent treatments with cisplatin. JM216 alone showed exponential killing of RIF1 cells, being approximately three times less efficient than cisplatin on a molar basis. For radiosensitization studies, drug doses used gave approximately 50 or 90% cell killing alone. No radiosensitization was seen after 2-h drug exposures, but significant radiosensitization occurred after 1- and 0.5-h exposures (shorter times required proportionally higher drug doses, giving equivalent drug kill). The enhancement ratio and time dependence were similar for the two platinum compounds, reaching 1.5 at the highest concentrations tested. Drug DNA adduct formation was assessed using immunocytochemistry with the NKI-A59 antiserum raised to cisplatin-DNA adducts. The antiserum was shown to recognize JM216-DNA adducts in a dose-dependent manner and maximum nuclear staining was found to be correlated with cell kill for both drugs. However, neither the level of staining at the time of irradiation nor at the time of maximum adducts correlated with radiosensitization, indicating that the number of DNA adducts did not determine radiosensitization. Intracellular glutathione levels were shown to be decreased by the drug, but only by approximately 50%, implying that this was not the cause of the increased radiosensitivity. In summary, JM216 was shown capable of radiosensitizing a platinum-sensitive tumour line to an extent similar to cisplatin. Radiosensitization was exposure-time and drug-concentration dependent, but was not dependent on DNA adduct levels nor glutathione depletion. In contrast, cell kill after drug alone was well correlated with adduct levels. These data suggest that JM216 could replace cisplatin in combined radiotherapy-chemotherapy studies, and also indicate that the NKI-A59 antibody could be used to monitor exposure levels in vivo.

In vitro formation of DNA adducts by cisplatin, lobaplatin and oxaliplatin in calf thymus DNA in solution and in cultured human cells.

Two interesting representatives of a new generation of platinum-based cytostatic drugs that are currently being tested in clinical trials are lobaplatin [1,2-diaminomethylcyclobutane platinum(II) lactate] and oxaliplatin [1,2-diaminocyclohexane platinum (II) oxalate]. Since little is known about the DNA adduct formation of these compounds, we studied their formation in DNA in vitro in calf thymus DNA and in cells. The major adducts formed in vitro were the Pt-GG and Pt-AG intrastrand crosslinks. The latter adducts could be detected using a recently developed 32P-postlabelling method. Using both this assay and atomic absorption spectroscopy, it was shown that there is a substantially higher rate of the in vitro adduct formation by cisplatin, compared with lobaplatin and oxaliplatin. Platinum concentrations required to obtain 90% cell kill during a 2 h incubation of A2780 cells were 15 microM for cisplatin and oxaliplatin and 22 microM for lobaplatin. Using an antiserum originally raised against cisplatin-treated DNA, we were also able to detect platinum-DNA adducts induced by lobaplatin and oxaliplatin. Maximal nuclear staining for all three compounds was observed after a 4 h post-incubation period. The nuclear staining level induced by cisplatin was about 10-fold higher than after lobaplatin and oxaliplatin treatment. GG and AG adducts, measured by 32P-postlabelling, also showed maximum levels at about 4 h after treatment. Relative GG peak levels were 4:1:3 for cisplatin, lobaplatin and oxaliplatin, respectively. The ratios of GG over AG intrastrand crosslinks in the A2780 cells were not significantly different for the various compounds. In conclusion, the 32P-postlabelling technique has been shown to be appropriate for adduct analysis, not only for the classical Pt compounds cisplatin and carboplatin but also for novel platinum compounds like lobaplatin and oxaliplatin. Results indicated large differences in reactivity of the latter compounds to DNA in vitro, compared with cisplatin. This difference was smaller in cells, suggesting enhancement of adduct formation by certain cellular mechanisms and/or compounds. From these studies, no conclusions can be drawn with respect to the cytotoxicity of the different Pt-GG and Pt-AG intrastrand crosslinks formed by these compounds.

Feasibility of escalating daily doses of cisplatin in combination with accelerated radiotherapy in non-small cell lung cancer.

The aim of this study was to determine whether it is feasible to reduce the overall treatment time from 7 to 4 weeks in patients with non-small cell lung cancer (NSCLC) receiving radiotherapy with cisplatin. This follows an EORTC phase III randomised trial (08844) in which cisplatin given before each radiation dose resulted in improved local control and survival, but which had a relatively long treatment period of 7 weeks [Schaake-Koning et al., N Engl J Med 1992, 326, 524-530]. 38 patients with confirmed NSCLC (2 stage I, 1 stage II, 18 stage IIIA, 17 stage IIIB) received a total tumour dose of 55 Gy/20 fractions/26 days, from January 1992 to March 1994. Daily fractions of 2 Gy (5 times/week) were given to the macroscopic tumour and the non-involved adjacent lymph node areas. During the same session, a dose of 0.75 Gy was given to the macroscopic tumour (simultaneous boost). Cisplatin 6 mg/m2 was administered 1-2 h before each fraction, in an escalating total dose, during week 1 in 3 patients, during weeks 1 and 2 in 6 patients, during weeks 1, 2 and 3 in 5 patients and during the whole treatment in 24 patients. 38 patients were evaluable for acute side-effects (WHO). Maximal therapy-related toxicity (WHO) was grade 3 (nausea/vomiting in 2 patients, oesophagitis in 3 patients, dyspnoea in 3 patients, cough in 1 patient). Late side-effects were evaluated in 34 patients. There was grade 2 oesophagitis in 2 patients; grade 3 toxicity in 8 patients (tiredness in 3 patients, dyspnoea in 3 patients, oesophagitis in 2 patients); grade 4 toxicity in 4 patients (dyspnoea in 3 patients, cough in 1 patient). Pulmonary fibrosis grade 3 occurred in 4 and grade 4 in 6 patients. One patient developed a severe (grade 3) radiation pneumonitis. The low incidence of acute and late side-effects with this treatment, combining daily administration of 6 mg cisplatin with radical radiotherapy using a simultaneous boost technique, indicates that escalation of the radiation dose seems feasible.