A method using 4D dose accumulation to quantify the interplay effect in lung stereotactic body radiation therapy

The purpose of this study was to devise and evaluate a method to quantify the dosimetric uncertainty produced by the interplay between the movement of multileaf collimator and respiratory motion in lung stereotactic body radiation therapy. The method calculates the dose distribution for all control points from a dynamic treatment in all respiratory phases. The methodology includes some characteristics of a patient's irregular breathing patterns. It selects, for each control point, the phases with maximum and minimum mean dose over the tumor and their corresponding adjacent phases, whenever necessary. According to this selection, the dose matrices from each control point are summed up to obtain two dose distributions in each phase, which are accumulated in the reference phase subsequently by deformable image registration (DIR). D ₉₅ and [Formula: see text] were calculated over those accumulated dose distributions for Gross Tumor Volume (GTV), Planning Target Volume-based on Internal Target Volume approach-and Evaluation Target Volume (ETV), a novel concept that applies to 4D dose accumulation. With the ETV, DIR and interplay uncertainties are separated. The methodology also evaluated how variations in the breathing rate and field size affects the mean dose received by the GTV. The method was applied retrospectively in five patients treated with intensity modulated radiotherapy-minimum area defined by the leaves configuration at any control point was at least 4 cm². Uncertainties in tumor coverage were small (in most patients, changes on D ₉₅ and [Formula: see text] were below 2% for GTV and ETV) but significant over- and under-dosages near ETV, which can be accentuated by highly irregular breathing. Uncertainties in mean dose for GTV tended to decrease exponentially with increasing field size and were reduced by an increase of breathing rate. The implementation of this method would be helpful to assess treatment quality in patients with irregular breathing. Furthermore, it could be used to study interplay uncertainties when small field sizes are used.

Hypofractionated radiation therapy and temozolomide in patients with glioblastoma and poor prognostic factors. A prospective, single-institution experience

Background

Hypofractionated radiation therapy is a feasible and safe treatment option in elderly and frail patients with glioblastoma. The aim of this study was to evaluate the effectiveness of hypofractionated radiation therapy with concurrent temozolomide in terms of feasibility and disease control in primary glioblastoma patients with poor prognostic factors other than advanced age, such as post-surgical neurological complications, high tumor burden, unresectable or multifocal lesions, and potential low treatment compliance due to social factors or rapidly progressive disease.

Material and methods

GTV included the surgical cavity plus disease visible in T1WI-MRI, FLAIR-MRI and in the MET-uptake. The CTV was defined as the GTV plus 1.5–2 cm margin; the PTV was the CTV+0.3 cm margin. Forty, fourty-five, and fifty grays in 15 fractions were prescribed to 95% of PTV, CTV, and GTV, respectively. Treatment was delivered using IMRT or the VMAT technique. Simultaneously, 75 mg/m²/day of temozolomide were administered.

Results

Between January 2010 and November 2017, we treated a total of 17 patients. The median age at diagnosis was 68-years; median KPS was 50–70%. MGMT-methylation status was negative in 5 patients, and 8 patients were IDH-wildtype. Eight of 18 patients were younger than 65-years. Median tumor volume was 26.95cc; median PTV volume was 322cc. Four lesions were unresectable; 6 patients underwent complete surgical resection. Median residual volume was 1.14cc. Progression-free survival was 60% at 6 months, 33% at 1-year and 13% at 2-years (median OS = 7 months). No acute grade 3–5 toxicities were documented. Symptomatic grade 3 radiation necrosis was observed in one patient.

Conclusions

Patients with poor clinical factors other than advanced age can be selected for hypofractionated radiotherapy. The OS and PFS rates obtained in our series are similar to those in patients treated with standard fractionation, assuring good treatment adherence, low rates of toxicity and probable improved cost-effectiveness.

Early Prediction of Disease Progression in Small Cell Lung Cancer: Toward Model-Based Personalized Medicine in Oncology

Predictive biomarkers can play a key role in individualized disease monitoring. Unfortunately, the use of biomarkers in clinical settings has thus far been limited. We have previously shown that mechanism-based pharmacokinetic/pharmacodynamic modeling enables integration of nonvalidated biomarker data to provide predictive model-based biomarkers for response classification. The biomarker model we developed incorporates an underlying latent variable (disease) representing (unobserved) tumor size dynamics, which is assumed to drive biomarker production and to be influenced by exposure to treatment. Here, we show that by integrating CT scan data, the population model can be expanded to include patient outcome. Moreover, we show that in conjunction with routine medical monitoring data, the population model can support accurate individual predictions of outcome. Our combined model predicts that a change in disease of 29.2% (relative standard error 20%) between two consecutive CT scans (i.e., 6-8 weeks) gives a probability of disease progression of 50%. We apply this framework to an external dataset containing biomarker data from 22 small cell lung cancer patients (four patients progressing during follow-up). Using only data up until the end of treatment (a total of 137 lactate dehydrogenase and 77 neuron-specific enolase observations), the statistical framework prospectively identified 75% of the individuals as having a predictable outcome in follow-up visits. This included two of the four patients who eventually progressed. In all identified individuals, the model-predicted outcomes matched the observed outcomes. This framework allows at risk patients to be identified early and therapeutic intervention/monitoring to be adjusted individually, which may improve overall patient survival.

Pneumomediastinum as a complication of SABR for lung metastases

BACKGROUND

Stereotactic ablative body radiation (SABR) is a novel and sophisticated radiation modality that involves the irradiation of extracranial tumors through precise and very high doses in patients with oligometastatic lung disease and primary lung tumors.

CASE PRESENTATION

A 52-year-old female with subclinical idiopathic interstitial lung disease (ILD) and oligometastatic lung disease from squamous urethral cancer who was treated with SABR for a metastatic lesion located in the right lower pulmonary lobe. The patient received a hypo-fractionated course of SABR. A 3D-conformal multifield technique was used with six coplanar and one non-coplanar statics beams. A 48 Gy total dose in three fractions over six days was prescribed to the 95% of the PTV. The presence of idiopathic ILD and other identifiable underlying lung conditions were not taken into account as a constraint to prescribe a different than standard total dose or fractionation schedule. Six months after the SABR treatment, a CT-scan showed the presence of a pneumomediastinum with air outside the bronchial tree and within the subcutaneous tissue without co-existing pneumothorax. To our knowledge, this is the first case of pneumomediastinum appearing 6 months after SABR treatment for a lung metastasis located in the perihiliar/central tumors region as defined by the RTOG protocols as the proximal bronchial tree.

CONCLUSION

Radiation oncologist should be aware of the potential risk of severe lung toxicity caused by SABR in patients with ILD, especially when chemotherapy-induced pulmonary toxicity is administered in a short time interval.

A population pharmacodynamic model for lactate dehydrogenase and neuron specific enolase to predict tumor progression in small cell lung cancer patients

The development of individualized therapies poses a major challenge in oncology. Significant hurdles to overcome include better disease monitoring and early prediction of clinical outcome. Current clinical practice consists of using Response Evaluation Criteria in Solid Tumors (RECIST) to categorize response to treatment. However, the utility of RECIST is restricted due to limitations on the frequency of measurement and its categorical rather than continuous nature. We propose a population modeling framework that relates circulating biomarkers in plasma, easily obtained from patients, to tumor progression levels assessed by imaging scans (i.e., RECIST categories). We successfully applied this framework to data regarding lactate dehydrogenase (LDH) and neuron specific enolase (NSE) concentrations in patients diagnosed with small cell lung cancer (SCLC). LDH and NSE have been proposed as independent prognostic factors for SCLC. However, their prognostic and predictive value has not been demonstrated in the context of standard clinical practice. Our model incorporates an underlying latent variable ("disease level") representing (unobserved) tumor size dynamics, which is assumed to drive biomarker production and to be influenced by exposure to treatment; these assumptions are in agreement with the known physiology of SCLC and these biomarkers. Our model predictions of unobserved disease level are strongly correlated with disease progression measured by RECIST criteria. In conclusion, the proposed framework enables prediction of treatment outcome based on circulating biomarkers and therefore can be a powerful tool to help clinicians monitor disease in SCLC.

Predicting esophagitis after chemoradiation therapy for non-small cell lung cancer: an individual patient data meta-analysis

PURPOSE

Concurrent chemoradiation therapy (CCRT) improves survival compared with sequential treatment for locally advanced non-small cell lung cancer, but it increases toxicity, particularly radiation esophagitis (RE). Validated predictors of RE for clinical use are lacking. We performed an individual-patient-data meta-analysis to determine factors predictive of clinically significant RE.

METHODS AND MATERIALS

After a systematic review of the literature, data were obtained on 1082 patients who underwent CCRT, including patients from Europe, North America, Asia, and Australia. Patients were randomly divided into training and validation sets (2/3 vs 1/3 of patients). Factors predictive of RE (grade≥2 and grade≥3) were assessed using logistic modeling, with the concordance statistic (c statistic) used to evaluate the performance of each model.

RESULTS

The median radiation therapy dose delivered was 65 Gy, and the median follow-up time was 2.1 years. Most patients (91%) received platinum-containing CCRT regimens. The development of RE was common, scored as grade 2 in 348 patients (32.2%), grade 3 in 185 (17.1%), and grade 4 in 10 (0.9%). There were no RE-related deaths. On univariable analysis using the training set, several baseline factors were statistically predictive of RE (P<.05), but only dosimetric factors had good discrimination scores (c>.60). On multivariable analysis, the esophageal volume receiving ≥60 Gy (V60) alone emerged as the best predictor of grade≥2 and grade≥3 RE, with good calibration and discrimination. Recursive partitioning identified 3 risk groups: low (V60<0.07%), intermediate (V60 0.07% to 16.99%), and high (V60≥17%). With use of the validation set, the predictive model performed inferiorly for the grade≥2 endpoint (c=.58) but performed well for the grade≥3 endpoint (c=.66).

CONCLUSIONS

Clinically significant RE is common, but life-threatening complications occur in <1% of patients. Although several factors are statistically predictive of RE, the V60 alone provides the best predictive ability. Efforts to reduce the V60 should be prioritized, with further research needed to identify and validate new predictive factors.

Adrenalectomy for low-tumor-burden metastatic lung cancer: Results of a single institution experience

e19114

Background: Adrenal gland is a common site of metastasis in lung cancer. Adrenal metastasis (AM) can occur at the time of diagnosis (synchronous AM) or later (metachronous AM). When an AM appears as an isolated site of dissemination it is considered a good-prognosis metastatic disease. Nevertheless few data are available about the prognosis and the optimal management of these patients. Methods: Retrospective analysis of the historical series of adrenalectomies in patients treated of lung cancer at our institution. Results: From April 2002 to April 2011, 30 patients (27m/3f) diagnosed of AM of lung cancer (16 non-squamous, 8 squamous, 6 small-cell; 21 metachronous AM, 9 synchronous AM) were treated with adrenalectomy (26 laparoscopic, 4 open surgery). Median age was 55 years old (range: 42-71). Median size of the AM was 35 mm (range: 12-140). There were no severe complications of surgery in any patient. All the patients had received radical treatment for the primary tumour and for other metatatic sites (8 patients brain metastases, 3 patients other sites) before adrenalectomy. Median overall survival (OS) and disease-free survival from adrenalectomy for the entire group were 44 (95% CI: 10-78) and 15 (95%CI: 7,6-22.3) months respectively. We found an statistical trend (p=0.087) of better OS from adrenalectomy for patients with non-squamous histology compared with squamous histology: 57 (95%CI: 38.4-75.6) and 21 (18.3-23.8) months respectively. The percentage of alive patients at 2 and 5 years was 59.1% and 36% respectively. Conclusions: These results add new data about the prognosis of patients with adrenal metastases into the context of low-tumor-burden metastatic lung cancer. Adrenalectomy is a tolerable procedure which plays a role in the management of these patients.

The multimodal management of locally advanced N2 non-small cell lung cancer: is there a role for surgical resection? A single institution's experience

BACKGROUND

The management of operable locally advanced N2 non-small cell lung cancer (NSCLC) is a controversial topic. Concurrent chemoradiation (CT-RT) is considered the standard of care for inoperable or unresectable patients, but the role of trimodality treatment remains controversial. We present our institution's experience with the management of stage III (N2) NSCLC patients, analyzing whether the addition of surgery improves survival when compared with definitive CT-RT alone.

METHODS

From 1996 to 2006, 72 N2 NSCLC patients were treated. Thirty-four patients received cisplatin-based induction chemotherapy, followed by paclitaxel-cisplatin CT-RT, and 38 patients underwent surgery preceded by induction and/or followed by adjuvant therapy. Survival curves were estimated by Kaplan-Meier analysis, and the differences were assessed with the log-rank test.

RESULTS

Most of the patients (87 %) were men. The median age was 59 years. A statistically significant association between T3-T4c and definitive CT-RT as well as between T1-T2c and surgery was noted (p < 0.0001). After a median follow-up period of 35 months, the median overall survival (OS) was 42 months for the surgery group versus 41 months for the CT-RT patients (p = 0.590). The median progression-free survival (PFS) was 14 months after surgery and 25 months after CT-RT (p = 0.933). Responders to radical CT-RT had a better OS than non-responders (43 vs. 17 months, respectively, p = 0.011). No significant differences were found in the OS or PFS between the pN0 [14 (37.8 %) patients] and non-pN0 patients at thoracotomy. Three treatment-related deaths (7.8 %) were observed in the surgical cohort and none in the CT-RT group.

CONCLUSIONS

The addition of surgery did not render a median OS or PFS benefit when compared with CT-RT alone in our series of stage III-N2 NSCLC patients, in accordance with previously published data. However, responses to CT-RT had a greater impact in terms of OS and PFS. Although the patients selected for management including surgery showed a favorable T clinical staging in comparison to patients exclusively treated with definitive CT-RT, similar survival outcomes were found.

Relationship between Day 0 dosimetric parameters and biochemical relapse-free survival in patients treated with transperineal permanent prostate interstitial brachytherapy with (125)I seeds

OBJECTIVES

To determine the relationship between dosimetric parameters obtained on postimplantation Day 0 and biochemical relapse-free survival (bRFS) in patients treated with (125)I transperineal interstitial permanent prostate brachytherapy (TIPPB).

METHODS

Two-hundred twenty men with low-risk (n=155, 70.4%), low-volume intermediate-risk (n=63, 28.7%), or high-risk (n=2, 0.9%) prostate cancer were treated with TIPPB between December 2000 and June 2006. Seventy-four (33.6%) patients received short-term (3-6 months) androgen suppression therapy before TIPPB. The median followup for patients free of biochemical failure was of 37.9 months (range, 24.0-84.5 months).

RESULTS

The receiver operating characteristic (ROC) analysis established a best-fit cutoff value for the quantifiers D(90) and V(100) of 147Gy and 92%, respectively. The Kaplan-Meier analysis of bRFS at the cutoff value of D(90)=147Gy using the ASTRO, nadir+2, and combined (ASTRO and nadir+2) definitions showed a trend toward statistical significance for the ASTRO (p=0.076) and nadir+2 (p=0.064) definitions and a statistically significant correlation for the combined definition (p=0.033). The corresponding 7-year bRFS for the D(90) >147Gy and D(90) </=147Gy subsets using the ASTRO, nadir+2, and combined definitions were 96.5% vs. 89.7% (ASTRO, p=0.076); 93.7% vs. 70.5% (nadir+2, p=0.064); and 94.4 vs. 75.5% (combined, p=0.033). The V(100) (%) cutoff value of 92% predicted by the ROC analysis was not significant. Among other cutoff values, only D(90)=140Gy (p=0.050) and D(90)=160Gy (p=0.098) showed a trend toward statistical significance when the nadir+2 and the ASTRO definitions were used. The rest of dosimetric, tumor, and patient parameters did not show statistical correlation with bRFS in the Kaplan-Meier analysis.

CONCLUSIONS

The cutoff value of D(90)=147Gy obtained on postimplantation Day 0 showed a trend toward significant correlation with bRFS when the standard ASTRO and nadir+2 definitions were used and a weak but statistically significant correlation with bRFS as per the nonstandard combined definition in a series of patients with predominantly low-risk disease (70.4%) treated at high radiation doses (median D(90)=152.9Gy, median V(100)=92.5%).

[Radiotherapy for lung cancer. Integration with chemotherapy]

The combination of radiotherapy and chemotherapy in lung cancer (locally advanced non-small and small cell) may offer the benefits of radiotherapy in terms of local control and those of chemotherapy in terms of reducing metastatic dissemination of the disease. Several randomized studies have showed that radical radiotherapy combined with chemotherapy improves the survival of these patients at the expense of an increase in toxicity. The technological development and the improvements in software have allowed the introduction of new linear accelerators and a three-dimensional planning system with the intention of delivering higher irradiation doses in the tumor target, and minimizing the dose in adjacent normal tissues (lung, heart, esophagus and spinal cord). The volume of irradiation, the total dose, the fractionation, the schedule for the combination of radiotherapy and chemotherapy, as well as the influence of the prophylactic cranial irradiation in small cell lung cancer are points for discussion at the moment.

[Anesthesia for the patient with cancer]

Surgery and radiotherapy provide the basis for local and regional control of cancer. The cancer patient has special characteristics that have implications for anesthesia. Tumors may involve the airways and affect ventilation, hemodynamics and intracranial pressure. Remote tumors can occur in endocrine cancer and in paraneoplastic syndromes. Other systemic complications of the cancer patient include hemostatic changes, immunosuppressant anemia and altered metabolism. Radiotherapy causes changes with anesthetic implications when treatment is directed at the head and neck, mediastinum, lung or surgical area. Chemotherapy is associated with non-specific toxic effects such as mucositis, aplasia and immunosuppression, alopecia and vascular injury; in addition, each chemical has other more specific toxic effects. Chemicals that are toxic for the heart and lungs have the greatest implications for anesthesia. Preoperative assessment should ascertain the effects caused by both the tumor and its treatment. Preparation for surgery includes improving nutrition and possibly inserting a venous port. Management during surgery depends on type of intervention and the patient's physical status, as they will determine the need for invasive monitoring and vessel access. The patient can be given antiemetic and antithrombotic prophylaxis. Important issues in postoperative care are the need for adequate analgesia; provision of early nutrition; antibiotic, antithrombotic and antiemetic prophylaxis; and prevention of ulcers caused by pressure.

[Effect of PSA nadir and the time to nadir in the disease-free period in localized prostatic carcinoma treated with radical radiation]

OBJECTIVE

To evaluate the prognostic significance of PSA nadir (nPSA) and the time to nadir in disease free of recurrence (DFR) in localized carcinoma of prostate treated with radical radiotherapy (RTR).

MATERIAL AND METHODS

From October 1984 to December 1998, 86 patients have been treated with prostate carcinoma. It was considered of Low risk those patients with PSA < or = 10 ng/ml, Gleason = 6 or stage T1-T2. Moderate risk: those with one elevated of the three parameters. High risk: two or more parameters. The treatment was carried out in a lineal accelerator using photons of 15 MV, with standard technique and frationation, administering a median dose of 66 Gy (58-75 Gy). It was defined disease free of recurrence (DFR), the time to clinical PSA or biochemical failure. This one was defined as the time starting from the date of nadir PSA to the second consecutive increase of PSA value after three separate serial measurements separated for at least one month.

RESULTS

The median of initial PSA value was of 16 ng/ml (1-270), initial clinical stage T1-T2 (70p), stages T3-T4 (14p), and unknown in 2p. The median of Gleason score was 6 (2-10). According to the group of risk they were classified as: low risk in 16 patients (19%), moderated risk in 22 patients (26%), high risk in 21 patients (24%), and unknown in 27 patients (31%). Median nPSA value was 0.8 ng/ml (limits: 0-139) and the median time elapsed between the initial PSA and nPSA has been of 11 months (limits: 0-72 months). The actuarial DFR projected to five years in those patients with nPSA = 1 ng/ml was of 67% vs. 47% in patient with nPSA figures > 1 ng/ml (p = 0.0018). The PFD in patients with time to nadir (t nadir) < 12 months it was of 20% vs. 80% in patients with t nadir > 12 months (p < 0.0001). Multivariate analysis demonstrated that time to nadir (H.R: 0.11 p = 0.001), group of risk (H.R: 28.72 p = 0.020), and grade of differentiation (HR: 28.72 p = 0.010), were determinant to DFR.

CONCLUSIONS

nPSA is an important factor to determine the objective response to radiotherapy. nPSA and time to nadir are prognostic factors that influences significantly on the DFR. The indication of adjuvant treatment in those patients with unfavorable prognostic factors such us those who do not reach nadir PSA < or = 1 ng/ml and time to nadir < or = 12 months, deserves the realization of a prospective study.