Intraoperative radiotherapy for breast cancer: its perceived simplicity.

Over one-quarter of a million cases of breast cancer are diagnosed in the United States each year, many of which are early stage.The radiotherapeutic options after breast-conserving surgery in early-stage breast cancer are evolving quickly, with a focus on minimizing treatment volume, toxicity, and treatment duration. One such emerging option is intraoperative radiotherapy (IORT), administered either as a single fraction or as a boost.With many centers seeking to adopt such technology, there are licensing, proctoring, staffing, technical support, and reimbursement issues that need to be considered. We have reviewed the current international experience and describe one community cancer center's experience with initiating an IORT breast cancer program.

Recurrence rates for patients with early-stage breast cancer treated with IOERT at a community hospital per the ASTRO consensus statement for APBI.

PURPOSE: To report the recurrence rates after single-fraction intraoperative electron radiotherapy (IOERT) in patients with early-stage breast cancer treated on a single institution prospective Phase I/II protocol at a community hospital. Results were retrospectively analyzed according to suitability criteria from the updated American Society for Radiation Oncology (ASTRO) consensus statement for accelerated partial breast irradiation (APBI). METHODS AND MATERIALS: Patients over 40 years with early-stage invasive or in situ breast cancer (<2.5 cm and node negative) were enrolled. IOERT 2100 cGy was delivered during breast conservation surgery, and patients were followed up for a median of 3 years (0.8-6.5 years) to determine toxicity and recurrence rates. RESULTS: Single-fraction IOERT was performed in 215 cases (6 bilateral treatments, 196 patients) with 13 patients receiving whole-breast radiation (WBR) after IOERT for adverse pathologic features. Of 202 cases of IOERT without WBR, 89 patients experienced an ipsilateral breast tumor recurrence (IBTR) giving a cumulative incidence of 3.96%. When the ASTRO APBI suitability criteria were applied, the IBTR rate was significantly lower for suitable patients vs. cautionary or unsuitable patients (1.6% vs. 3.4% vs. 21.0%, p = 0.0002). 3-year progression-free survival after IOERT alone was 93.4%. For patients who received standard WBR (4500-5040 cGy) after IOERT, no Grade 3 or 4 toxicities (acute or late) occurred and all patients are disease-free. CONCLUSIONS: Single-fraction IOERT results in a low rate of IBTR when strictly adhering to ASTRO criteria for APBI suitability. Standard dose WBR for unfavorable pathologic results after 2100 cGy IOERT is well tolerated.

Small cell (neuroendocrine) carcinoma of the prostate: etiology, diagnosis, prognosis, and therapeutic implications--a retrospective study of 30 patients from the rare cancer network.

Within the framework of the Rare Cancer Network Study, we examined 30 patients suffering from small cell neuroendocrine prostate cancer, either in an early/localized or an advanced/metastatic stage. Patients were treated with cisplatin-based chemotherapy, with or without pelvic radiotherapy. Two patients with early disease achieved complete remission for a duration of 19 and 22 months. Three patients with advanced disease achieved complete remission for 6, 7, and 54 months, respectively. Twenty-five patients succumbed to massive local and/or distant failure. No patient presented with brain metastases as the initial site of relapse. Small cell neuroendocrine prostate carcinoma is a very aggressive disease with a poor prognosis, even in its localized form. Despite initial response, the common cisplatin-based chemotherapy plus radiotherapy failed to improve outcome markedly. Improvement will come from understanding the biology of the disease and integrating new targeted therapies into the treatment of this rare and aggressive tumor.

The Utility of Penile Bulb Contouring to Localise the Prostate Apex as Compared to Urethrography.

PURPOSE: High-precision radiotherapy relies on accurate anatomic localisation. Urethrography is often used to localise the prostatic apex. However, urethrography is an invasive localisation procedure and may introduce a systemic error. The penile bulb (PB) is contoured to minimise the risk of erectile dysfunction. The purpose of this study is to assess the value of using the PB, as an alternative to urethrography, to localise the prostate. METHODS AND MATERIALS: The PB was localised on 10 patients treated with simplified intensity-modulated arc radiotherapy at computed tomography simulation during treatment weeks 1 and 7. All patients underwent placement of fiducial markers. Urethrography was used only at simulation. Distances from the superior PB contour to the inferior prostate contour, the apex fiducial marker, and to the inferior prostate contour were obtained as well. The PB was contoured by two observers independently. Agreement coefficients and analysis of variance were used to assess reliability between rates and consistency of measurements over time. RESULTS: The PB-apex distance was greater than or equal to the urethrogram-apex distance in 24/30 (80%) measurements, and the median difference was 3 mm and was consistent between raters. The greatest variation in PB-IM distance between weeks was 6 mm, the median was 3 mm, and the agreements of measurements between weeks for raters 1 and 2 were 0.79 and 0.69, respectively. These differences were not statistically different and were consistent with the computed tomography slice thickness. CONCLUSIONS: The PB can be used to identify the prostate apex and can be reliably contoured between observers. Measurements are consistent between patients and through the duration of treatment. The PB distance measurements support studies indicating that urethrography causes a shift of the prostate superiorly. The distance from the PB to prostate apex remains stable during treatment for individual patients but varies between patients.

Prostate volume contouring: a 3D analysis of segmentation using 3DTRUS, CT, and MR.

PURPOSE: This study evaluated the reproducibility and modality differences of prostate contouring after brachytherapy implant using three-dimensional (3D) transrectal ultrasound (3DTRUS), T2-weighted magnetic resonance (MR), and computed tomography (CT) imaging. METHODS AND MATERIALS: Seven blinded observers contoured 10 patients' prostates, 30 day postimplant, on 3DTRUS, MR, and CT images to assess interobserver variability. Randomized images were contoured twice by each observer. We analyzed length and volume measurements and performed a 3D analysis of intra- and intermodality variation. RESULTS: Average volume ratios were 1.16 for CT/MR, 0.90 for 3DTRUS/MR, and 1.30 for CT/3DTRUS. Overall contouring variability was largest for CT and similar for MR and 3DTRUS. The greatest variability of CT contours occurred at the posterior and anterior portions of the midgland. On MR, overall variability was smaller, with a maximum in the anterior region. On 3DTRUS, high variability occurred in anterior regions of the apex and base, whereas the prostate-rectum interface had the smallest variability. The shape of the prostate on MR was rounder, with the base and apex of similar size, whereas CT contours had broad, flat bases narrowing toward the apex. The average percent of surface area that was significantly different (95% confidence interval) for CT/MR was 4.1%; 3DTRUS/MR, 10.7%; and CT/3DTRUS, 6.3%. The larger variability of CT measurements made significant differences more difficult to detect. CONCLUSIONS: The contouring of prostates on CT, MR, and 3DTRUS results in systematic differences in the locations of and variability in prostate boundary definition between modalities. MR and 3DTRUS display the smallest variability and the closest correspondence.

A prospective evaluation of helical tomotherapy.

PURPOSE: To report results from two clinical trials evaluating helical tomotherapy (HT). METHODS AND MATERIALS: Patients were enrolled in one of two prospective trials of HT (one for palliative and one for radical treatment). Both an HT plan and a companion three-dimensional conformal radiotherapy (3D-CRT) plan were generated. Pretreatment megavoltage computed tomography was used for daily image guidance. RESULTS: From September 2004 to January 2006, a total of 61 sites in 60 patients were treated. In all but one case, a clinically acceptable tomotherapy plan for treatment was generated. Helical tomotherapy plans were subjectively equivalent or superior to 3D-CRT in 95% of plans. Helical tomotherapy was deemed equivalent or superior in two thirds of dose-volume point comparisons. In cases of inferiority, differences were either clinically insignificant and/or reflected deliberate tradeoffs to optimize the HT plan. Overall imaging and treatment time (median) was 27 min (range, 16-91 min). According to a patient questionnaire, 78% of patients were satisfied to very satisfied with the treatment process. CONCLUSIONS: Helical tomotherapy demonstrated clear advantages over conventional 3D-CRT in this diverse patient group. The prospective trials were helpful in deploying this technology in a busy clinical setting.

A prospective phase I comparison of toxicity and cosmesis outcomes of single-fraction IORT and hypofractionated radiotherapy with IORT boost in early-stage breast cancer.

PURPOSE: Radiation therapy is proven to reduce local recurrence in patients with early-stage breast cancer. To reduce toxicity, treatment time, and improve accuracy, intraoperative radiation therapy was used as definitive treatment or as a boost. The study's objective was to compare the short-term toxicity and cosmesis of single-fraction (SF) IORT and hypofractionated radiotherapy with IORT boost (HfB) given as definitive treatment. METHODS AND MATERIALS: Between March 2011 and December 2013, 57 patients aged 45-91 years and 24 patients aged 43-83 years (total n = 81) with Stage 0-II were treated with SF or HfB (Mobetron, IntraOp Medical, Sunnyvale, CA). For SF treatment, 21 Gy was delivered using 4.5-6 cm applicators with electron energies from 6 to 12 MeV. For HfB, an intraoperative boost of 10 Gy was delivered using 4-7 cm applicators with energies from 4 to 12 MeV followed by whole-breast radiation with 40.5 Gy over 15 fractions. Toxicity was assessed at 2 weeks, 6 months, and 12 months per Radiation Therapy Oncology Group acute skin toxicity criteria and cosmesis. RESULTS: At 12 months, SF and HfB were well tolerated by all patients with no Grade 3+ toxicity. At 1 year, Grade-2 toxicity was resolved. Ninety-eight percent of SF patients and ninety percent of HfB patients had 0-1 grade toxicity. In the SF and HfB groups, 100% of patients had excellent or good cosmesis at 12-month followup interval. The SF exhibited a more favorable cosmesis with a higher percentage of excellent scores compared with HfB (80.4% vs. 45%; p = 0.0033). CONCLUSIONS: After breast conservation surgery, SF or HfB may be an option for patients with early-stage breast cancer compared to conventional external beam radiotherapy.

Prostate contouring uncertainty in megavoltage computed tomography images acquired with a helical tomotherapy unit during image-guided radiation therapy.

PURPOSE: To evaluate the image-guidance capabilities of megavoltage computed tomography (MVCT), this article compares the interobserver and intraobserver contouring uncertainty in kilovoltage computed tomography (KVCT) used for radiotherapy planning with MVCT acquired with helical tomotherapy. METHODS AND MATERIALS: Five prostate-cancer patients were evaluated. Each patient underwent a KVCT and an MVCT study, a total of 10 CT studies. For interobserver variability analysis, four radiation oncologists, one physicist, and two radiation therapists (seven observers in total) contoured the prostate and seminal vesicles (SV) in the 10 studies. The intraobserver variability was assessed by asking all observers to repeat the contouring of 1 patient's KVCT and MVCT studies. Quantitative analysis of contour variations was performed by use of volumes and radial distances. RESULTS: The interobserver and intraobserver contouring uncertainty was larger in MVCT compared with KVCT. Observers consistently segmented larger volumes on MVCT where the ratio of average prostate and SV volumes was 1.1 and 1.2, respectively. On average (interobserver and intraobserver), the local delineation variability, in terms of standard deviations [Deltasigma = radical(sigma2MVCT-sigma2KVCT)], increased by 0.32 cm from KVCT to MVCT. CONCLUSIONS: Although MVCT was inferior to KVCT for prostate delineation, the application of MVCT in prostate radiotherapy remains useful.

Pelvic chemoradiotherapy after chemotherapy for metastatic bladder cancer.

OBJECTIVE: Consolidative radiotherapy has improved local control in other tumors with high local recurrence rates but has not been well studied in urothelial cancer. We hypothesized that pelvic chemoradiotherapy (PCRT) given after systemic chemotherapy for metastatic bladder cancer (MTCC) might alter the pattern of disease recurrence, and reduce the complications and morbidity of intrapelvic disease relapse. A 74% locoregional relapse rate has been observed in MTCC patients with intrapelvic nodal disease after response to chemotherapy. To explore this hypothesis further, we performed a retrospective analysis and report the efficacy, toxicity and pattern of failure with this approach. MATERIALS AND METHODS: Patients treated for MTCC who received consolidative PCRT following at least a partial response to systemic chemotherapy were identified and their charts reviewed for pelvic relapse, disease progression, survival, and toxicity. RESULTS: Twelve patients were identified and median follow-up was 15.6 months. Nine patients developed progressive disease and died, and median survival was 15.6 months. Three patients had pelvic progression (pelvic failure rate 25%). Median time to pelvic failure was 12.8 months. At last follow-up, three patients were alive and disease-free. No life-threatening toxicities were observed. The most common acute non-hematological toxicities were diarrhea and nausea. CONCLUSIONS: These data support a hypothesis that consolidative PCRT following chemotherapy in MTCC patients with systemic disease control may be feasible and efficacious for improving pelvic disease control. This intervention should be considered for further study in prospective controlled clinical trials.

Does sex influence the impact that smoking, treatment interruption and impaired pulmonary function have on outcomes in limited stage small cell lung cancer treatment?

PURPOSE: To look for survival differences between men and women with limited stage small cell lung cancer (LS-SCLC) by examining stratified variables that impair treatment efficacy. METHODS: A retrospective review of 215 LS-SCLC patients treated from 1989 to 1999 with concurrent chemotherapy-radiotherapy modelled on the 'early-start' thoracic radiotherapy arm of a National Cancer Institute of Canada randomized trial. RESULTS: Of 215 LS-SCLC patients, 126 (58.6%) were men and 89 (41.4%) were women. Smoking status during treatment for 186 patients (86.5%) was: 107 (58%) nonsmoking (NS) (76 [71%] male [M]; 31 [29%] female [F]) and 79 (42%) smoking (S) (36 M [46%]; 43 F [54%]) (continuing-to-smoke F versus M, P=0.001). Fifty-six patients (26%) had radiotherapy interruptions (RTI) during chemotherapy-radiotherapy because of toxicity. Radiotherapy breaks were not associated with sex (P=0.95). Survival by sex and smoking status at two years was: F + NS = 38.7%; F + S = 21.6%; M + NS = 22.9%; and M + S = 9.1% (P=0.0046). Survival by sex and RTI status at two years was: F + no RTI = 32.4%; F + RTI = 23.6%; M + no RTI = 23.0%; and M + RTI = 3.8% (P=0.0025). Diffusion capacity for carbon monoxide (DLCO) was recorded for 86 patients (40%) and median survival by sex and DLCO was F = 16.7 months and M = 12.1 months for a DLCO less than 60%; and for a DLCO 60% or more, F = 15.1 months and M = 15.3 months. First relapses were recorded in 132 cases (61%), with chest failure in men (45%) greater than for women (35%) and cranial failure rates similar between sexes (48%). Upon multivariable analysis, continued smoking was the strongest negative factor affecting survival. CONCLUSIONS: In LS-SCLC, women overall do better than men, with or without a negative variable. The largest quantifiable improvement in survival for women came from smoking cessation, and for men from avoidance of breaks during treatment.

Is extended volume external beam radiation therapy covering the anastomotic site beneficial in post-esophagectomy high risk patients?

BACKGROUND AND PURPOSE: To assess the impact of extended volume radiation therapy (RT) with anastomotic coverage on local control in high risk post-operative esophageal cancer patients. PATIENTS AND METHODS: This is a retrospective study of high risk (T(3), T(4), nodes positive, with or without margin involvement) post-operative esophageal cancer patients treated at London Regional Cancer Centre from 1989 to 1999. After esophagectomy, all patients received adjuvant combined modality therapy consisting of four cycles of fluorouracil-based chemotherapy, and loco-regional RT with or without coverage of the anastomotic site. RT dose ranged from 45 to 60 Gy at 1.8-2.0 Gy/fraction with treatment fields tailored to the pathologic findings and location of the anastomosis. CT planning was used in all patients to design spinal cord sparing beam arrangements. First relapse rate (first incidence of an event), disease specific survival and overall survival were calculated by Chi-Square, Log-Rank, and Kaplan-Meier (K-M) methods. RESULTS: During the study period, 72 patients had underwent esophagectomy and were considered for adjuvant chemoradiation therapy. Three patients were excluded due to disease progression prior to therapy. The 69 remaining patients formed the study cohort for the present analysis. The median age of the study group was 60 years (range 35-82 years). Pathologic stage distribution (AJCC 1997 staging) was T(2,3) N(1) in 94% patients, 65% of the cases were adenocarcinoma and had undergone transhiatal esophagectomy (86%) with positive/close margins in 34 (49%) patients. Median follow-up was 30.5 months (range 3.4-116.3 months). Two- and 5-year actuarial overall survivals rates were 50 and 31%, respectively. First relapse rate after adjuvant therapy was 63.7% (n = 44) and median time to relapse was 27.2 months. Anastomosis recurrence rates were 29% with small volume and 0% with extended volume RT (P = 0.041). Local and regional relapse occurred in 74.2% of patients treated with small volume RT compared to 15.4% in patients treated with extended volume RT (P < 0.001). After adjusting for resection margin status, the local control benefit of extended volume RT remained significant (P = 0.003). Treatment interruptions and late gastrointestinal toxicity were not significantly increased with the use of extended volume RT. CONCLUSIONS: A significant decrease in local and regional relapse without added late toxicity was achieved with the use of extended volume RT encompassing the anastomotic site post-operatively in high risk esophageal cancer patients.

Impaired diffusion capacity predicts for decreased treatment tolerance and survival in limited stage small cell lung cancer patients treated with concurrent chemoradiation.

PURPOSE: To determine if stratification of limited stage small cell lung cancer (LSCLC) patients by pre-treatment pulmonary function test (PFT) prognostic indicators predicts for treatment-related toxicity risks and survival following concurrent chemoradiation. MATERIALS AND METHODS: From 1989 to 1999, 215 LSCLC patients received six cycles of alternating cyclophosphamide/doxorubicin/vincristine and etoposide/cisplatin (EP). Thoracic radiation (RT) was initiated only with EP and at cycle 2 or 3. RT dose was: 40 Gy/15 fractions/3 weeks or 50 Gy/25 fractions/5 weeks. RT fields encompassed gross and suspected microscopic disease with a 2 cm margin. Pre-treatment PFT values analyzed included forced expiratory volume in 1s (FEV1) (in liter and as % predicted) and diffusion capacity for carbon monoxide (DLCO) (as % predicted). The "marker" for toxicity during concurrent chemoradiation was the duration of any RT breaks initiated for severe hematologic or locoregional symptomatology. Patient outcomes were analyzed for associations between recognized PFT cut-offs (FEV1 <2l, > or =2l; FEV1 <60%, > or =60% predicted; DLCO <60%, > or =60% predicted), toxicity rates, and survival. RESULTS: For the whole study cohort, median, 2- and 5-year overall survivals were: 14.7 months, 22.7 and 7.2%, respectively. Fifty-six patients (26%) required treatment breaks due to toxicity. FEV1 and DLCO results were available for 96 (45%) and 86 (40%) patients, respectively. Two thirds of FEV1s measured were <2l. On statistical analysis, the incidence of toxicity-related interruptions was significant for DLCO<60% (P=0.043), suggestive for FEV1<2l (P=0.1) and non-significant for FEV1<60%. Patients with simultaneous DLCO<60% and FEV1<2l showed a trend toward increase toxicity risk (P=0.1). For selected PFT measures, median overall survivals were: 12.7 months versus 14.8 months for DLCO<60% versus > or =60%; 13.4 months versus 17.7 months for FEV1<2l versus > or =2l; 15.4 months versus 19.9 months for DLCO<60% + FEV1<2l versus DLCO> or =60% + FEV1> or =2l. Although absolute differences favored all patients with PFT values above the prognostic cut-offs, differences were not statistically significant on this analysis. Patients with both a treatment break and a DLCO<60% had the poorest median survival of all patient subsets, at 11.4 months (P=0.09). CONCLUSIONS: Impaired DLCO (i.e. <60%) is a novel predictor of increased treatment-related toxicity leading to interruptions. The present study suggests a probable role for DLCO and FEV1 (in l) as prognostic factors for predicting survival but larger patient samples are required for confirmation. Patients with impaired DLCOs experiencing treatment interruptions have the poorest survival. Assessment of pre-treatment PFTs contributes to determining optimal management strategies for LSCLC patients receiving definitive chemoradiation.

Intraoperative electron radiotherapy boost as a component of adjuvant radiation for breast cancer in the community setting.

To reduce toxicity/treatment time and improve accuracy, intraoperative electron radiotherapy (IOERT) was used as an alternative to electron beam radiation therapy boost. Primary objective was to determine feasibility and acute toxicity. From August 2009 to June 2011, 50 patients (age 32 to 76 years) with in situ or invasive breast cancer (Stage 0 to IIIA) were treated. Toxicity assessed according to standard National Cancer Institute scales. Median tumor size was 20 mm (range, 6 to 80 mm) with 43 infiltrating ductal, two infiltrating lobular, and five ductal in situ carcinoma. A single 10-Gy fraction boost was given to the tumor bed after resection followed by whole-breast radiotherapy. After IOERT, three patients required completion axillary lymph node dissection, eight had reexcision resulting from positive margins, and four opted for completion mastectomy. The median follow-up was 10 months (range, 2 to 24 months). Ten patients had Grade 1 and one reported Grade 2 breast pain 2 weeks after IOERT; all resolved at 6 weeks. Two patients had delay in wound healing, but none developed a wound infection. Three patients reported symptomatic fat necrosis. No other toxicities were reported. IOERT resulted in a reduction in treatment time, was not associated with additional toxicity or change in the acute toxicity profile, and is a feasible treatment option in a community hospital setting.

Phase I trial of simultaneous in-field boost with helical tomotherapy for patients with one to three brain metastases.

PURPOSE: Stereotactic radiosurgery is an alternative to surgical resection for selected intracranial lesions. Integrated image-guided intensity-modulated-capable radiotherapy platforms such as helical tomotherapy (HT) could potentially replace traditional radiosurgery apparatus. The present study's objective was to determine the maximally tolerated dose of a simultaneous in-field boost integrated with whole brain radiotherapy for palliative treatment of patients with one to three brain metastases using HT. METHODS AND MATERIALS: The inclusion/exclusion criteria and endpoints were consistent with the Radiation Therapy Oncology Group 9508 radiosurgery trial. The cohorts were constructed with a 3 + 3 design; however, additional patients were enrolled in the lower dose tolerable cohorts during the toxicity assessment periods. Whole brain radiotherapy (30 Gy in 10 fractions) was delivered with a 5-30-Gy (total lesion dose of 35-60 Gy in 10 fractions) simultaneous in-field boost delivered to the brain metastases. The maximally tolerated dose was determined by the frequency of neurologic Grade 3-5 National Cancer Institute Common Toxicity Criteria, version 3.0, dose-limiting toxicity events within each Phase I cohort. RESULTS: A total of 48 patients received treatment in the 35-Gy (n = 3), 40-Gy (n = 16), 50-Gy (n = 15), 55-Gy (n = 8), and 60-Gy (n = 6) cohorts. No patients experienced dose-limiting toxicity events in any of the trial cohorts. The 3-month RECIST assessments available for 32 of the 48 patients demonstrated a complete response in 2, a partial response in 16, stable disease in 6, and progressive disease in 8 patients. CONCLUSION: The delivery of 60 Gy in 10 fractions to one to three brain metastases synchronously with 30 Gy whole brain radiotherapy was achieved without dose-limiting central nervous system toxicity as assessed 3 months after treatment. This approach is being tested in a Phase II efficacy trial.

Analysis of a novel protocol of combined induction chemotherapy and concurrent chemoradiation in unresected non-small-cell lung cancer: a ten-year experience with vinblastine, Cisplatin, and radiation therapy.

BACKGROUND: The London Regional Cancer Program (LRCP) uses a unique schedule of induction plus concurrent chemoradiation, termed VCRT (vinblastine, cisplatin, and radiation therapy), for the treatment of a subset of unresectable stage IIIA and IIIB non-small-cell lung cancer (NSCLC). This analysis was conducted to better understand the outcomes in VCRT-treated patients. PATIENTS AND METHODS: We report a retrospective analysis of a large cohort of patients who underwent VCRT at the LRCP over a 10-year period, from 1996 to 2006. The analysis focused on OS, toxicities, and the outcomes from completion surgery in a small subset of patients. RESULTS: A total of 294 patients were included and 5-year OS, determined using Kaplan-Meier methodology, was 19.8% with a MST of 18.2 months. Reported grade 3-4 toxicities included neutropenia (39%), anemia (10%), pneumonitis (1%), and esophagitis (3%). Significant differences in survival between groups of patients were demonstrated with log-rank tests for completion surgery, use of radiation therapy, and cisplatin dose. Similarly, Univariate Cox regression showed that completion surgery, use of radiation therapy, cisplatin dose, and vinblastine dose were associated with increased survival. CONCLUSION: This retrospective analysis of a large cohort of patients reveals an OS for VCRT comparable to that reported in the literature for other current combined chemoradiation protocols. The success of this protocol seems to be dose dependent and the outcomes in those who underwent completion surgery suggests that pathologic complete remission is possible for IIIA and IIIB NSCLC.