A Rare Case of Colon Cancer Metastasis to the Brain anda Brief Review of its Treatment and Prognosis.

Metastatic brain tumors are the most common brain masses in adults however it is rare for them to arise from colon cancer. We present a case of a metastatic colon cancer to the brain in a 68 year old male who presented with facial trauma after a fall he sustained secondary to neurological symptoms. He underwent computed tomography and magnetic resonance imaging of the head which revealed a brain mass. The mass was subsequently surgically resected and the diagnosis was confirmed. He went on to receive radiation therapy afterwards. In patients with a history of colon cancer, it is important for clinicians to be aware of the known risk factors for the development of brain metastases in order to best screen for these patients and optimize their prognosis. When brain metastases are discovered, multimodal therapy with surgery, radiation therapy, and chemotherapy provides patients with the most optimal survival.

Impact of the Coronavirus Disease of 2019 Pandemic on Radiation Oncology Clinical Decision Making in a High-Prevalence Environment.

PURPOSE: This study aimed to define how the coronavirus disease of 2019 (COVID-19) pandemic affected the role, timing, and delivery of radiation therapy (RT) in a high-prevalence region at the height of the initial U.S. outbreak. METHODS AND MATERIALS: We performed a retrospective review of all patients seen at 3 radiation oncology departments within the Rutgers Robert Wood Johnson Barnabas Health system in New Jersey during the initial COVID-19 surge. The primary endpoints were to define and quantify COVID-related, radiation-specific care changes, and identify predictive factors of experiencing COVID-related care changes. RESULTS: A total of 545 patients with cancer were seen during the study period, 99 of whom (18.1%) experienced ≥1 COVID-related care change. RT delays were the most common, accounting for 51.5% of all care changes. Physician-directed delays accounted for 41.2% of RT delays, and patient fears, COVID testing, and access barriers were responsible for 27.5%, 17.6%, and 13.7%, respectively. Patient age (P = .040), intent of treatment (P = .047), and cancer type (P < .001) were significantly associated with experiencing a COVID-related care change, as we found that older, curative intent and patients with rectal cancer were more likely to experience care changes. On multivariate analysis, patient age remained significant when controlling for treatment intent and cancer type. CONCLUSIONS: Our study provides a perspective on how care was adapted to protect patients with cancer during a pandemic while maximizing disease control. The positive correlation between age and likelihood of care changes may reflect extra precaution taken with older patients given their vulnerability to severe COVID illness. The lower observed likelihood of COVID-related care changes among patients undergoing palliative RT may reflect either the more urgent needs addressed by palliative RT or simply be logistical, because palliative radiation is often delivered in short courses with less exposure risk. Assessing adaptations others have implemented and monitoring how they affect patient outcomes will be crucial.

The Impact of COVID-19 on Brachytherapy During the Pandemic: A Rutgers-Robert Wood Johnson Barnabas Health Multisite Experience.

PURPOSE: This study aimed to evaluate whether the coronavirus disease of 2019 (COVID-19) pandemic resulted in treatment delays in patients scheduled for or undergoing brachytherapy. METHODS AND MATERIALS: A retrospective cohort study was conducted across 4 affiliated sites after local institutional review board approval. The eligibility criteria were defined as all patients with cancer whose treatment plan included brachytherapy during the COVID-19 pandemic from February 24, 2020 to June 30, 2020. Treatment delays, cancellations, alterations of fractionation regimens, and treatment paradigm changes were evaluated. RESULTS: A total of 47 patients were eligible for the analysis. Median patient age at the time of treatment was 62 years (interquartile range, 56-70 years). Endometrial, cervical, and prostate cancers were the most common sites included in this analysis. Three patients (6.4%) with cervical cancer were diagnosed with COVID-19 during the course of their treatment. Interruptions of external beam radiation therapy (EBRT), cancellations of EBRT, cancellations of brachytherapy, and treatment delays due to COVID occurred in 5 (10.6%), 3 (6.4%), 8 (17%), and 9 (19%) patients, respectively. The mean and median number of days delayed for patients who experienced treatment interruptions were 16.3 days (standard deviation: 13.9 days) and 14 days (interquartile range, 5.75-23.75 days), respectively. For patients with cervical cancer, the mean and median overall treatment times defined as the time from the start of EBRT to the end of brachytherapy were 56 and 49 days, respectively. CONCLUSIONS: Despite the challenges the health care system faced during the pandemic, most patients with cancer were safely treated with minor treatment delays and interruptions. Long-term follow up is needed to assess the impact of COVID-19 and treatment interruptions on oncologic outcomes.

The Impact of Formal Mentorship Programs on Mentorship Experience Among Radiation Oncology Residents From the Northeast.

Purpose: Strong mentorship has been shown to improve mentee productivity, clinical skills, medical knowledge, and career preparation. We conducted a survey to evaluate resident satisfaction with mentorship within their radiation oncology residency programs. Methods and Materials: In January 2019, 126 radiation oncology residents training at programs in the northeastern United States were asked to anonymously complete the validated Munich Evaluation of Mentoring Questionnaire (MEMeQ). Results of residents with a formal mentoring program were compared to those without a formal program. Results: Overall response rate was 42%(n = 53). Participants were 25% post-graduate year two (PGY-2), 21% PGY-3, 26% PGY-4, and 28% PGY-5. Only 38% of residents reported participation in a formal mentoring program, while 62% had no formal program, and 13% reported having no mentor at all. Residents participating in a formal mentoring program reported strikingly higher rates of overall satisfaction with mentoring compared to those who were not (90% vs. 9%, p < 0.001). Overall, 38% of residents were either satisfied/very satisfied with their mentoring experience, while 49% of residents were unsatisfied/very unsatisfied. Conclusion: Residents participating in a formal mentorship program are significantly more likely to be satisfied with their mentoring experience than those who are not. Our results suggest that radiation oncology residency programs should strongly consider implementing formal mentorship programs.

Vertebral body irradiation during chemoradiation therapy for esophageal cancer contributes to acute bone marrow toxicity.

BACKGROUND: Hematologic toxicity (HT) commonly occurs during chemoradiation therapy (CRT) for esophageal cancer. We sought to determine radiation doses that correlate with declines in blood counts due to vertebral body (VB) irradiation during CRT. METHODS: We analyzed 53 esophageal cancer patients who were treated with weekly neoadjuvant carboplatin, paclitaxel and RT with weekly complete blood counts (CBC) available during treatment. HTs were graded according to the Common Terminology Criteria for Adverse Events version 4.0 (CTCAE v4.0). Dose volume histogram (DVH) parameters of Vx, defined as percentage of entire bony vertebra (body, pedicles, laminae, processes) receiving at least x Gy of radiation, were collected for VB V5 (VBV5), VBV10-VBV60 in increments of 10, and mean vertebral dose (MVD). Linear and logistic regressions were performed to identify associations between leukopenia nadirs and DVH parameters. Receiver operator curves identified thresholds to avoid grade ≥3 leukopenia. RESULTS: A proportion of 32.1% of patients (n=17) developed grade 3 leukopenia and 5.7% (n=3) developed grade 4 leukopenia. VBV5, VBV10, VBV20, VBV30, and MVD were significantly associated with worsening leukopenia on univariate and multivariate analysis. Associations with leukopenia were not seen with VBV40 and VBV50 DVH values. Thresholds to avoid grade ≥3 leukopenia were VBV10 <49.1%, VBV20 <45.6%, and MVD <17.2 Gy. CONCLUSIONS: VBV5, VBV10, VBV20, VBV30 associate with leukopenia during CRT for esophageal cancer patients. Improved radiation sparing of the VB may decrease HT and may improve tolerability of concurrent chemotherapy and allow for intensification of systemic therapy during RT.

Reduction of organ motion in lung tumors with respiratory gating.

We evaluated the ability of a commercial respiratory gating system to assure the reproducibility of internal anatomy in respiration synchronized CT (RS-CT) scans. This passive system uses an infrared sensitive camera to track the motion of reflective markers mounted on the abdomen. Eighteen patients, nine with lung tumors and nine with liver tumors, were selected for evaluation of the Varian Real-Time Position Monitor respiratory gating system. Liver tumors were chosen as surrogate for lower lobe tumors. Each patient underwent at least two identical RS-CT scans, at end-inspiration (EI) or end-expiration (EE), to assess intra-fraction reproducibility. Twelve patients also underwent a free breathing scan and an opposed-respiration phase synchronized scan (EI if the two first were an EE and vice versa). On each CT, a physician contoured the liver, the kidneys, the spleen, and the diaphragms for the liver patients; and similarly, the lungs, the gross tumor volume (GTV), the trachea, the heart and the diaphragms for the lung patients. After registering the different CT images using bony anatomy, the changes of each structure between the respective data sets were quantified in terms of its volume, the displacement of its center of mass (COM), and an "index" coefficient of reproducibility. An analysis of the CT scans obtained at EI and EE phases yielded an average superior-inferior (SI) difference of the diaphragm position of 14.4 mm (range: 45.9-0.9). A similar analysis of CT scans acquired at the same breathing phase yielded 0.7 mm (range: 3.1-0, p=0.0001). Similar conclusions were derived in analysis of COM positions of the following structures: lungs, heart, lung's GTV, liver, spleen and kidneys. Evaluation of volume changes for lungs, liver, and spleen confirmed reproducibility of RS-CT while the "index" coefficient confirmed reproducibility of RS-CT of all organs. A commercial gating system using external markers for RS-CT significantly improves the positional reproducibility of thoracic and upper abdominal structures. This reproducible decrease in organ motion will allow a reduction of the margin of expansion facilitating increase in target dose beyond that allowed by conventional radiation treatments.

Radiation pneumonitis in breast cancer patients treated with taxanes: does sequential radiation therapy lower the risk?

Taxanes are now routinely used in conjunction with radiation therapy (RT) as adjuvant therapy for breast cancer. Recent publications have reported several cases of radiation pneumonitis (RP) in patients receiving RT and taxane chemotherapy, thus raising concern as to the safety of this combination. To decrease the potential risk of RP, we sequenced RT after taxane chemotherapy with a target interval of 3-4 weeks in two consecutive institutional breast protocols. Forty patients were treated on two adjuvant systemic protocols consisting of modified radical mastectomy (n = 9) or breast-conserving surgery (n = 31), followed by adjuvant doxorubicin, cyclophosphamide, and a sequential taxane (ACT), followed by RT. All patients had either node-positive or high-risk node-negative breast cancer and were treated between October 2000 and September 2002. Postmastectomy, a median dose of 5040 cGy was delivered to the chest wall. After breast-conserving surgery, a median dose of 4680 cGy was delivered to the breast plus a 1400 cGy boost to the surgical cavity. Information regarding RP was gathered retrospectively by reviewing patient records. With a median follow-up of 28 months (range 6-42 months), no cases of clinical RP were identified and no local failures had occurred. The median time interval for all patients between the completion of chemotherapy and the initiation of RT was 34 days (range 5-70 days). At the latest follow-up, 2 patients were diagnosed with metastatic disease and 38 patients were without evidence of disease. Sequencing of RT after taxane therapy with a target interval of 3-4 weeks does not appear to result in increased pulmonary toxicity and is associated with good local control.

Interfractional anatomic variation in patients treated with respiration-gated radiotherapy.

As quality assurance for respiration-gated treatments using the Varian RPM system, we monitor interfractional diaphragm variation throughout treatment using extra anterior-posterior (AP) portal images. We measure the superior-inferior (SI distance between one or more bony landmarks and the ipsilateral diaphragm dome in each such radiograph and calculate its difference, D, from the corresponding distance in a planning CT scan digitally reconstructed radiograph (DRR). For each patient, the mean of D represents the systematic diaphragm displacement, and the standard deviation of D represents random diaphragm variations and is a measure of interfractional gating reproducibility. We present results for 31 sequential patients (21 lung, 10 liver tumors), each with at least 8 such portal images. For all patients, the gate included end-exhale. The patient-specific duty cycle ranged from 30% to 60%. All patients received customized audio prompting for simulation and treatment, and 14 patients also received visual prompting. Respiration-synchronized fluoroscopic movies taken at a conventional simulator revealed patient-specific diaphragm excursions from 1.0 cm to 5.0 cm and diaphragm excursion within the gate from 0.5 cm to 1.0 cm, demonstrating a significant reduction of intra-fractional diaphragm (and by inference tumor) motion by respiratory gating. One standard deviation of the systematic displacement (the mean of D) was 0.63 cm and 0.48 cm for the lung and liver patient groups, respectively. The average +/-1 SD of the random displacements (i.e., the average of the standard deviations of D) was 0.42 +/- 0.11 cm and 0.50 +/- 0.19 for the two groups, respectively. The similar magnitude of the systematic and random displacements suggests that both derive from a common distribution of interfractional variations. Combining visual with audio prompting did not significantly improve performance, as judged by D. Guided by these portal images, field changes were made during the course of treatment for 6 patients (1 lung, 5 liver).

Postmastectomy CT-based electron beam radiotherapy: dosimetry, efficacy, and toxicity in 118 patients.

PURPOSE: To evaluate the technique, dosimetry, acute and late toxicity, local control (LC), and overall survival (OS) with the use of computed tomography (CT)-based postmastectomy electron beam therapy (PMEBT) in high-risk patients. METHODS AND MATERIALS: From 1990 to 2000, 118 patients with pathologic stage I-IIIB breast cancer underwent PMEBT of the chest wall (CW) (n = 3), CW and supraclavicular fossa (SCV) (n = 63), CW, SCV, and internal mammary lymph nodes (IMN) (n = 51), and SCV+IMN (n = 1). Radiation therapy was delivered with an en face electron beam with a custom cutout. Treatment plans were all CT-based. The plans of 16 patients were retrospectively reviewed to analyze dosimetry data. A retrospective chart review was conducted to assess acute and late complications, LC, and OS. RESULTS: At a median follow-up of 43 months, 5-year LC and OS were 91% and 61%, respectively. Sixty-one patients developed acute grade 3-4 skin toxicity, necessitating treatment breaks in 33 patients. Fifteen patients experienced a worsening of lymphedema, and 2 patients developed cardiac injury thought to be unrelated to radiotherapy. No patients developed symptomatic pneumonitis. Dosimetric analysis revealed heart and lung normal tissue complication probabilities of zero. Analysis of other clinically relevant dosimetric parameters revealed PMEBT to be comparable to previously reported techniques. CONCLUSION: Postmastectomy electron beam therapy is an effective way to deliver radiation to the postmastectomy chest wall and adjacent nodal sites. It offers acceptable acute and late toxicities and a high degree of local control given the high-risk population to which it is offered.

Dosimetric analysis of a simplified intensity modulation technique for prone breast radiotherapy.

PURPOSE: Prone-position breast radiotherapy (RT) has been described as an alternative technique to improve dose homogeneity for women with large, pendulous breasts. We report the feasibility and dosimetric analysis of a simplified intensity-modulated RT (IMRT) technique, previously reported for women in the supine treatment position, to plan prone-position RT to the intact breast. METHODS AND MATERIALS: Twenty patients with clinical Stage TisN0-T1bN1 breast cancer undergoing breast-conserving therapy underwent whole breast RT using a prone position technique. The treatment plans were developed using both conventional tangents and a simplified intensity-modulated tangential beam technique based on optimization of the intensity distributions across the breast. The plans were compared with regard to the dose-volume parameters. RESULTS: Dose heterogeneity within the breast planning target volume was significantly greater for the conventional tangent plans. Of 20 patients, 16 (80%) received maximal doses of > or =110% using the conventional tangents vs. only 1 (5%) using the IMRT plan. The isodose level encompassing 5% of the planning target volume was reduced from an average of 110% with conventional tangents to 105% with IMRT. The maximal dose within the planning target volume was reduced from an average of 114% with conventional tangents to 107% with IMRT. The greatest improvement was seen in the patients with the most pendulous breasts. CONCLUSION: An IMRT planning approach is feasible for prone-position breast RT and improves dose homogeneity, particularly in women with larger, pendulous breasts. Additional follow-up is necessary to determine whether the improvements in dose homogeneity impact acute toxicity and cosmetic outcome in this cohort of women who have historically suffered from poor cosmesis after breast-conserving therapy.

The risk of axillary relapse after sentinel lymph node biopsy for breast cancer is comparable with that of axillary lymph node dissection: a follow-up study of 4008 procedures.

OBJECTIVE: We sought to identify the rate of axillary recurrence after sentinel lymph node (SLN) biopsy for breast cancer. SUMMARY BACKGROUND DATA: SLN biopsy is a new standard of care for axillary lymph node staging in breast cancer. Nevertheless, most validated series of SLN biopsy confirm that the SLN is falsely negative in 5-10% of node-positive cases, and few studies report the rate of axillary local recurrence (LR) for that subset of patients staged by SLN biopsy alone. METHODS: Through December of 2002, 4008 consecutive SLN biopsy procedures were performed at Memorial Sloan-Kettering Cancer Center for unilateral invasive breast cancer. Patients were categorized in 4 groups: SLN-negative with axillary lymph node dissection (ALND; n = 326), SLN-negative without ALND (n = 2340), SLN-positive with ALND (n = 1132), and SLN-positive without ALND (n = 210). Clinical and pathologic characteristics and follow-up data for each of the 4 cohorts were evaluated with emphasis on patterns of axillary LR. RESULTS: With a median follow-up of 31 months (range, 1-75), axillary LR occurred in 10/4008 (0.25%) patients overall. In 3 cases (0.07%) the axillary LR was the first site of treatment failure, in 4 (0.1%) it was coincident with breast LR, and in 3 (0.07%) it was coincident with distant metastases. Axillary LR was more frequent among the unconventionally treated SLN-positive/no ALND patients than in the other 3 conventionally treated cohorts (1.4% versus 0.18%, P = 0.013). CONCLUSIONS: Axillary LR after SLN biopsy, with or without ALND, is a rare event, and this low relapse rate supports wider use of SLN biopsy for breast cancer staging. There is a low-risk subset of SLN-positive patients in whom completion ALND may not be required.

Gemcitabine-related radiation recall preferentially involves internal tissue and organs.

Radiation recall refers to inflammatory reactions triggered by cytotoxic agents and develops in previously irradiated areas. Most reactions develop cutaneously. The most common chemotherapeutic agents implicated are anthracyclines and taxanes. Gemcitabine, a nucleotide analog, recently was implicated in several cases. The authors performed a literature search using PubMed and the search terms "gemcitabine" and "radiation recall" to find prior cases of radiation recall attributed to gemcitabine. These cases were compared with those attributed to anthracyclines and taxanes. The literature search found 12 cases of radiation recall caused by gemcitabine. The authors also determined that their case of myositis developing in the rectus abdominus muscle of a patient with pancreatic adenocarcinoma was the manifestation of radiation recall, thereby bringing the number of patients who developed radiation recall to gemcitabine and were discussed in the current study to 13. Approximately 70% of the cases manifested as inflammation of internal organs or tissues and 30% manifested as a dermatitis or mucositis. This finding differs from other common agents, in which 63% of the radiation recall events are reported to manifest as a dermatitis. Compared with anthracyclines and taxanes, the interval from the completion of radiation therapy to the initiation of chemotherapy is less for gemcitabine (median time of 56 days for gemcitabine, compared with 218 days for the taxanes and 646 days for doxorubicin). The majority of radiation recall reactions attributed to gemcitabine are reported to affect internal tissue or organs. In contrast, other common agents for the most part trigger cutaneous inflammation. The development of internal tissue inflammation is reportedly correlated with a shorter interval from the time of completion of radiation therapy to the initiation of chemotherapy.

Patterns of initial disease recurrence after resection of gallbladder carcinoma and hilar cholangiocarcinoma: implications for adjuvant therapeutic strategies.

BACKGROUND: Current approaches to adjuvant treatment after resection of gallbladder carcinoma (GBCA) and hilar cholangiocarcinoma (HCCA) are based on an incomplete understanding of the recurrence patterns of these diseases. Through an in-depth analysis of the sites of initial recurrence after resection of GBCA and HCCA, the current study aimed to highlight differences in the biology of these tumors and to provide further insight for adjuvant therapeutic strategies. METHODS: Patients with either GBCA or HCCA who underwent a potentially curative resection were identified prospectively from a maintained database. Specific sites of initial disease recurrence were identified retrospectively and categorized as locoregional (resection margin, porta hepatis, or retroperitoneal lymph nodes) or distant (peritoneal, extraabdominal, or discontiguous liver metastases). Differences in disease recurrence patterns, time to disease recurrence, and overall and site-specific survival were analyzed. RESULTS: Between May 1990 and August 2001, 177 patients underwent potentially curative resection, 97 for GBCA and 80 for HCCA. Disease recurrence and follow-up data were available for 156 patients (80 with GBCA and 76 with HCCA). The median time to disease recurrence was shorter for patients with GBCA compared with patients with HCCA (11.5 vs. 20.3 months; P = 0.007). Overall, 52 (68%) patients with HCCA and 53 (66%) patients with GBCA had disease recurrene at a median follow-up of 24 months. Of those who developed disease recurrence, isolated locoregional disease as the first site of failure occurred in 15% of patients with GBCA compared with 59% of patients with HCCA (P < 0.001). By contrast, an initial GBCA recurrence involving a distant site, with or without concomitant locoregional recurrence, occurred in 85% of patients compared with 41% of patients with HCCA (P < 0.001). This pattern of disease recurrence was diagnosis specific and did not change significantly when patients were stratified by several clinicopathologic factors, including disease stage and its component variables. Using multivariate analysis, diagnosis was an independent predictor of the site of disease recurrence. Among patients who experienced disease recurrence, survival was greater among the patients with HCCA compared with patients with GBCA (29 months vs. 20.6 months, respectively; P = 0.037). For both tumors, the site of initial disease recurrence had no apparent impact on survival time. CONCLUSIONS: After resection, recurrent GBCA is much more likely than recurrent HCCA to involve a distant site. GBCA is also associated with a much shorter time to recurrence and a shorter survival period after recurrence. The results demonstrated significant differences in the clinical behavior of these tumors and suggested that an adjuvant therapeutic strategy targeting locoregional disease, such as radiotherapy, is unlikely to have a significant impact in the overall management of GBCA. Conversely, there is at least some rationale for such an approach in patients with HCCA based on the pattern of initial recurrence.

Primary adenocarcinoma of the anus treated with combined modality therapy.

PURPOSE: The purpose of this study was to determine the local control and survival of patients with adenocarcinoma of the anus who received combined modality therapy as a component of their treatment. METHODS: Thirteen patients with primary anal adenocarcinoma (T1: 1, T2: 4, T3: 3, T4: 5; and N0: 9, N1: 2, N2: 2) were treated between 1989 and 2001 in the Department of Radiation Oncology at Memorial Sloan Kettering Cancer Center. Three general treatment approaches were used that were based on physician and patient preference as well as tumor stage. These included preoperative combined modality therapy followed by abdominoperineal resection (n = 5), with four of the five receiving postoperative chemotherapy; local excision followed by postoperative radiation alone or combined modality therapy (n = 5); and abdominoperineal resection followed by postoperative combined modality therapy (n = 3). Two patients received brachytherapy. RESULTS: With a median follow-up of 19 months, the median survival was 26 months, the local failure rate was 37 percent, and the two-year actuarial survival was 62 percent. In the subset of eight patients treated with abdominoperineal resection and preoperative or postoperative radiation or combined modality therapy, local control was 63 percent, and three of eight are without evidence of disease. Of the five patients who underwent a local excision followed by postoperative radiation or combined modality therapy, the local control rate was 60 percent, with one of the local failures salvaged by abdominoperineal resection and one of five patients without evidence of disease. CONCLUSION: Although the experience is limited, our data suggest that the combination of abdominoperineal resection and combined modality therapy is a reasonable approach for this rare tumor.

Respiratory gating for liver tumors: use in dose escalation.

PURPOSE: To determine the clinical impact of the Varian Real-Time Position Monitor (RPM) respiratory gating system for treatment of liver tumors. METHODS AND MATERIALS: Ten patients with liver tumors were selected for evaluation of this passive system, which tracks motion of reflective markers mounted on the abdomen with an infrared-sensitive camera. At simulation, a fluoroscopic movie, breathing trace, and CT scans synchronized at end-expiration (E-E) and end-inspiration were acquired in treatment position using the RPM system. Organs and gross tumor volume were contoured on each CT. Each organ's positional change between two scan sets was quantified by calculation of the center of volume shift and an "index coefficient," defined as the volume common to the two versions of the organ to the volume included in at least one (intersection/union). Treatment dose was determined by use of normal tissue complication probability calculations and dose-volume histograms. Gated portal images were obtained to monitor gating reproducibility with treatment. RESULTS: Eight patients received 177 treatments with RPM gating. Average superior-to-inferior (SI) diaphragm motion on initial fluoroscopy was reduced from 22.7 mm without gating to 5.1 mm with gating. Comparing end-inspiration to E-E CT scans, average SI movement of the right diaphragm was 11.5 mm vs. 2.2 mm for two E-E CT scans. For all organs, average E-I SI organ motion was 12.8 mm vs. 2.0 mm for E-E studies. Index coefficients were closer to 1.0 for E-E than end-inspiration scans, indicating gating reproducibility. The average SI displacement of diaphragm apex on gated portal images compared with DRR was 2.3 mm. Treatment was prolonged less than 10 minutes with gating. The reproducible decrease in organ motion with gating enabled reduction in gross tumor volume-to-planning target volume margin from 2 to 1 cm. This allowed for calculated dose increases of 7%-27% (median: 21.3%) in 6 patients and enabled treatment in 2. CONCLUSION: Gating of radiotherapy for liver tumors enables safe margin reduction on tumor volume, which, in turn, may allow for dose escalation.

Assessing the predictive value of clinical complete response to neoadjuvant therapy for rectal cancer: an analysis of 488 patients.

BACKGROUND: Patients with transmural or node-positive rectal cancer benefit from the addition of chemoradiation to surgical resection. Administration of the chemoradiation (combined modality therapy) preoperatively has gained popularity in recent years. Some patients undergo apparent complete tumor regression after preoperative combined modality therapy, and controversy exists about the proper management of these patients. Some investigators have proposed that such patients should simply be observed and not undergo resection. STUDY DESIGN: The purpose of this study was to determine the significance of clinical complete response to preoperative combined modality therapy. Specifically, we have attempted to determine the frequency with which a clinical complete response (based on the absence of detectable tumor on preoperative digital rectal examination and proctoscopy) correlates with a pathologic complete response (based on the absence of cancer cells in the resected specimen). A retrospective review of the clinical and pathologic characteristics of 488 patients from the Memorial Sloan-Kettering prospective colorectal database who received preoperative chemoradiation followed by resection for primary rectal cancer was performed. The indications for preoperative therapy included clinical or ultrasound T3 or T4 tumors or node-positive disease. RESULTS: The clinical complete response rate to preoperative therapy was 19%. All patients underwent resection subsequent to preoperative therapy regardless of response. The pathologic complete response rate among all patients was 10%. The pathologic complete response rate among clinical complete responders was 25%. Clinical complete response was a significant predictive factor for pathologic complete response, but the majority (75%) of clinical complete responders had persistent foci of tumor that were not detectable on preoperative examination or proctoscopy. CONCLUSIONS: Clinical complete response to preoperative therapy as determined by preoperative digital rectal examination and proctoscopy or EUA is not an accurate predictor of pathologic complete response. A significant percentage of clinical complete responders have persistent deep tumors or nodal involvement. We do not recommend making treatment decisions based solely on the absence of clinically palpable or visible tumor after chemoradiation. Our data suggest that all acceptable-risk patients with a diagnosis of primary rectal cancer should undergo resection, regardless of their response to preoperative therapy.