Impact of obesity on outcomes after definitive dose-escalated intensity-modulated radiotherapy for localized prostate cancer.

BACKGROUND: Previous publications have demonstrated conflicting results regarding body mass index (BMI) and prostate cancer (CaP) outcomes after definitive radiotherapy (RT) before the dose escalation era. The goal of the current study was to determine whether increasing BMI was associated with outcomes in men with localized CaP who were treated with dose-escalated RT. METHODS: The authors identified patients with localized (T1b-T4N0M0) CaP who were treated with definitive intensity-modulated RT and image-guided RT from 2001 through 2010. BMI was analyzed as a continuous variable. Adjusting for confounders, multivariable competing risk and Cox proportional hazards regression models were used to assess the association between BMI and the risk of biochemical failure (BF), distant metastases (DM), cause-specific mortality (CSM), and overall mortality. RESULTS: Of the 1442 patients identified, approximately 20% had a BMI <25 kg/m(2) , 48% had a BMI of 25 to 29.9 kg/m(2) , 23% had a BMI of 30 to 34.9 kg/m(2) , 6% had a BMI of 35 to 39.9 kg/m(2) , and 4% had a BMI of ≥40 kg/m(2) . The median follow-up was 47.6 months (range, 1-145 months), with a median age of 68 years (range, 36-89 years). The median dose was 78 grays (range, 76-80 grays) and 30% of patients received androgen deprivation therapy. Increasing BMI was found to be inversely associated with age (P<.001) and pretreatment prostate-specific antigen level (P = .018). On multivariable analysis, increasing BMI was associated with an increased risk of BF (hazard ratio [HR], 1.03; 95% confidence interval [95% CI], 1.00-1.07 [P = .042]), DM (HR, 1.07; 95% CI, 1.02-1.11 [P = .004]), CSM (HR, 1.15; 95% CI, 1.07-1.23 [P<.001]), and overall mortality (HR, 1.05; 95% CI, 1.02-1.08 [P = .004]). CONCLUSIONS: For patients with CaP receiving dose-escalated intensity-modulated RT with daily image-guidance, increasing BMI appears to be associated with an increased risk of BF, DM, CSM, and overall mortality.

Low-level shRNA cytotoxicity can contribute to MYC-induced hepatocellular carcinoma in adult mice.

Short hairpin RNAs (shRNAs) have emerged as a novel therapeutic modality, but there is increasing concern over nonspecific effects in vivo. Here, we used viral vectors to express shRNAs against endogenous p53 in livers of conditional MYC-transgenic mice. As expected, the shRNAs silenced hepatic p53 and accelerated liver tumorigenesis when MYC was concurrently expressed. Surprisingly, various irrelevant control shRNAs similarly induced a rapid onset of tumorigenesis, comparable to carbon tetrachloride (CCl4), a potent carcinogen. We found that even marginal shRNA doses can already trigger histologically detectable hepatoxicity and increased hepatocyte apoptosis. Moreover, we noted that shRNA expression globally dysregulated hepatic microRNA (miRNA) expression, and that shRNA levels and activity further increased in the presence of MYC. In MYC-expressing transgenic mice, the marginal shRNA-induced liver injury sufficed to further stimulate hepatocellular division that was in turn associated with markedly increased expression of the mitotic cyclin B1. Hence, even at low doses, shRNAs can cause low-level hepatoxicity that can facilitate the ability of the MYC oncogene to induce liver tumorigenesis. Our data warrant caution regarding the possible carcinogenic potential of shRNAs when used as clinical agent, particularly in circumstances where tissues are genetically predisposed to cellular transformation and proliferation.

Predictors of Hematologic Toxicity and Chemotherapy Dose Intensity in Patients Undergoing Chemoradiation for Pancreatic Cancer.

OBJECTIVES: Intensity-modulated radiation therapy (IMRT) has been shown to decrease abdominal toxicity in patients undergoing chemoradiation (CRT) for pancreatic cancer. We evaluated whether IMRT impacts the rates of hematologic toxicity and chemotherapy dose intensity in patients undergoing CRT. METHODS: We retrospectively reviewed patients with borderline resectable or locally advanced pancreatic cancer undergoing CRT between 2006 and 2012. Exclusion criteria included receipt of non-gemcitabine therapy, chemotherapy before CRT, or abnormal baseline hematologic indices. Endpoints included total gemcitabine dose received, dose intensity, unplanned dose reductions, and hematologic toxicity (WBC, ANC, platelet, and hemoglobin). Patient/treatment factors were evaluated for their relationship to the above endpoints during CRT and within the first 3 months post-CRT. Statistical analysis was performed using the Fisher exact test and regression models. Because of the multiple comparisons in the presented analysis, a false discovery rate adjustment was performed at the 5% false discovery rate level. RESULTS: Eighty-five patients met the inclusion criteria. Fifty-eight (68.2%) patients received treatment with IMRT, and 27 (31.8%) patients were treated with 3D-conformal radiation. During CRT, there was no relationship between radiation technique and gemcitabine dose received, dose intensity, or hematologic grade 3+ toxicity. Post-CRT, there was no relationship between radiation technique and total gemcitabine dose received, dose intensity, or dose reduction. Patients receiving IMRT were more likely to have ANC grade 3+ toxicity (P=0.007) post-CRT, although this was no longer statistically significant after correction. There were no other relationships between treatment technique and hematologic toxicity. CONCLUSIONS: IMRT technique may be associated with higher hematologic toxicity in patients undergoing CRT for pancreatic cancer. Given the expanding use of CRT, additional study is needed to identify the impact of IMRT on myelosuppression in these patients.

Surgery and Adjuvant Radiation for High-risk Skin Adnexal Carcinoma of the Head and Neck.

OBJECTIVES: Skin adnexal carcinoma (SAC) is a rare cutaneous malignancy that arises from sebaceous and sweat glands. These carcinomas are believed to behave more aggressively than cutaneous squamous cell carcinomas (SCC) with a propensity for local recurrence. The role of adjuvant radiotherapy in SAC is undefined. METHODS: We retrospectively reviewed all cases of head and neck SAC treated with surgery and adjuvant radiation from 2000 to 2012 at a single institution. RESULTS: Nine cases were identified. Median age was 67 (range, 52 to 88) years. The histologies were: adnexal carcinoma (n=1), adnexal carcinoma with sebaceous differentiation (n=1), adnexal carcinoma with squamous differentiation (n=1), skin appendage carcinoma (n=1), sclerosing sweat duct carcinoma (n=1), mucinous carcinoma (n=1), ductal eccrine adenocarcinoma (n=1), porocarcinoma (n=1), and trichilemmal carcinoma (n=1). All tumors were reviewed by a dermatopathologist to confirm the SAC diagnosis.All patients had undergone surgery. Indications for adjuvant radiation included involved lymph nodes (n=4), perineural invasion (n=2), nodal extracapsular extension (n=2), positive margin (n=1), high-grade histology (n=6), multifocal disease (n=2), and/or recurrent disease (n=5). Radiation was delivered to the primary site alone (n=3), to the draining lymphatics alone (n=2), or to both (n=4). One patient received concurrent cisplatin. Median dose to the primary site was 60 Gy and to the neck was 50 Gy.Median follow-up was 4.0 years (range, 0.6 to 11.4 y). Locoregional control was 100%. Five-year progression-free survival was 89%. There was 1 acute grade 3 toxicity and no greater than or equal to grade 2 late toxicities were recorded. CONCLUSIONS: Surgery and adjuvant radiation for high-risk SAC offers excellent locoregional control with acceptable toxicity.

Lymph-node-positive cutaneous nonmelanoma skin cancer: A poor-prognosis disease in need of treatment intensification.

Locoregionally advanced nonmelanoma skin cancer (NMSC) has an aggressive clinical course characterized by high rates of treatment failure and poor survival compared with localized skin cancers. Our goal was to investigate multimodal therapy for lymph-node-positive NMSC. Data from patients with lymph-node-positive NMSC who underwent surgery and adjuvant therapy at a single tertiary center from 2002 to 2012 were retrospectively reviewed. Median follow-up was 1.8 years (range: 0.5 to 8.5). Overall survival (OS) and progression-free survival (PFS) were calculated using the Kaplan-Meier method. The chi-square test and logistic regression were used to determine the association between locoregional control (LRC) and the following variables: evidence of extracapsular extension, number of lymph nodes positive, largest involved lymph node, presence of a positive margin, and use of concurrent chemoradiation (CRT). Forty-six patients were evaluated, 13 (28%) of whom received adjuvant CRT. CRT patients were younger (p < 0.001) and had a significantly greater number of positive lymph nodes (p = 0.016) than patients who received adjuvant radiation alone. At 5 years, LRC was 76%, PFS was 65%, and OS was 49%. Univariate analysis demonstrated that CRT (p = 0.006), largest lymph node measurement (p = 0.039), and ≥3 involved lymph nodes (p = 0.001) predicted local recurrence. CRT (p = 0.035, odds ratio [OR] 0.20 [95% confidence interval 0.05 to 0.90]) and ≥3 involved lymph nodes (p = 0.017, OR 0.07 [95% confidence interval 0.01 to 0.62]) remained significant on multivariate analysis. CRT was well tolerated. No grade ≥3 toxicities were observed except for 1 asymptomatic grade-4 thrombocytopenia. Patients with lymph-node-positive NMSC do poorly. Patient selection for intensification of adjuvant therapy needs clarification.

Long-Term Patient-Reported Outcomes From a Phase 3 Randomized Prospective Trial of Conventional Versus Hypofractionated Radiation Therapy for Localized Prostate Cancer.

PURPOSE: To assess the long-term quality of life (QoL) outcomes from a phase 3 trial comparing 2 modes of intensity modulated radiation therapy (IMRT): conventional IMRT (CIMRT) versus hypofractionated IMRT (HIMRT) in patients with localized prostate cancer. METHODS AND MATERIALS: Between 2002 and 2006, 303 men with low-risk to high-risk prostate cancer were randomized to 76 Gy in 38 fractions (CIMRT) versus 70.2 Gy in 26 fractions (HIMRT). QoL was compared by use of the Expanded Prostate Cancer Index Composite (EPIC), the International Prostate Symptom Score (IPSS), and EuroQoL (EQ5D) questionnaires. The primary outcome of the QoL analysis was a minimum clinically important difference defined as a 0.5 standard deviation change from baseline for each respective QoL parameter. Treatment effects were evaluated with the use of logistic mixed effects regression models. RESULTS: A total of 286, 299, and 218 patients had baseline EPIC, IPSS, or EQ5D data available and were included in the analysis. Overall, there was no statistically significant difference between the 2 treatment arms in terms of EPIC, IPSS, or EQ5D scores over time, although there was a trend toward lower EPIC urinary incontinence scores in the HIMRT arm. More patients in the HIMRT arm had a lower EPIC urinary incontinence score relative to baseline versus patients in the CIMRT arm with long-term follow-up. On multivariable analysis, there was no association between radiation fractionation scheme and any QoL parameter. When other clinical factors were examined, lymph node radiation was associated with worse EPIC hormonal scores versus patients receiving no lymph node radiation. In general, QoL outcomes were generally stable over time, with the exception of EPIC hormonal and EQ5D scores. CONCLUSIONS: In this randomized prospective study, there were stable QoL changes in patients receiving HIMRT or CIMRT. Our results add to the growing body of literature suggesting that HIMRT may be an acceptable treatment modality in clinically localized prostate cancer.

Dosimetric predictors of hematologic toxicity in patients undergoing concurrent gemcitabine-based chemoradiation for localized pancreatic cancer.

PURPOSE: This study was undertaken to identify parameters associated with hematologic toxicity or chemotherapy dose modification in patients undergoing concurrent chemoradiation (CRT) with gemcitabine for localized pancreatic cancer. METHODS AND MATERIALS: We reviewed patients with localized pancreatic cancer undergoing CRT between 2006 and 2012. Exclusion criteria included receipt of nongemcitabine therapy, chemotherapy before CRT, or abnormal baseline hematologic indices. The T11-L3 vertebrae were contoured as bone marrow region at risk. Linear and logistic regression models were used to test associations between dosimetric parameters and gemcitabine dose modification or hematologic toxicity during or within 3 months following CRT. Receiver operator curves were generated to identify threshold doses for hematologic toxicity. RESULTS: Forty-nine patients were included. During CRT, the maximum thoracolumbar dose was associated with grade 2+ neutropenia during CRT (P = .017) and the volume receiving 5 Gy (V5) was associated with grade 2+ leukopenia (P = .041). Post-CRT, thoracolumbar mean dose (P = .015), V5 (P = .01), and V10 (P = .012) were associated with increased grade 2+ neutropenia. On multivariable analysis, the thoracolumbar maximum dose (P = .045) and V5 (P = .045) were associated with grade 2+ neutropenia and grade 2+ leukopenia during CRT, respectively. Post-CRT, the mean dose (P = .046), V5 (P = .019), and V10 (P = .037) were associated with increased grade 2+ neutropenia. A maximum dose of 48.02 Gy and V5 of 57.6% were identified as predictors of toxicity during CRT. A V5 of 56.6%, V10 of 47.05%, and mean dose of 11.67 Gy were identified as predictors of post-CRT hematologic toxicity. Post-CRT, there was a trend toward increased dose modifications with increased V5 (P = .065). CONCLUSIONS: In our dataset, the thoracolumbar mean dose, maximum dose, V5, and V10 correlated with hematologic toxicity during CRT and post-CRT in patients with localized pancreatic cancer. Because of the high rates of distant failure and importance of systemic therapy in these patients, this may be an important consideration during treatment planning.

Survival Impact of Increasing Time to Treatment Initiation for Patients With Head and Neck Cancer in the United States.

PURPOSE: To estimate the overall survival (OS) impact from increasing time to treatment initiation (TTI) for patients with head and neck squamous cell carcinoma (HNSCC). METHODS: Using the National Cancer Data Base (NCDB), we examined patients who received curative therapy for the following sites: oral tongue, oropharynx, larynx, and hypopharynx. TTI was the number of days from diagnosis to initiation of curative treatment. The effect of TTI on OS was determined by using Cox regression models (MVA). Recursive partitioning analysis (RPA) identified TTI thresholds via conditional inference trees to estimate the greatest differences in OS on the basis of randomly selected training and validation sets, and repeated this 1,000 times to ensure robustness of TTI thresholds. RESULTS: A total of 51,655 patients were included. On MVA, TTI of 61 to 90 days versus less than 30 days (hazard ratio [HR], 1.13; 95% CI, 1.08 to 1.19) independently increased mortality risk. TTI of 67 days appeared as the optimal threshold on the training RPA, statistical significance was confirmed in the validation set (P < .001), and the 67-day TTI was the optimal threshold in 54% of repeated simulations. Overall, 96% of simulations validated two optimal TTI thresholds, with ranges of 46 to 52 days and 62 to 67 days. The median OS for TTI of 46 to 52 days or fewer versus 53 to 67 days versus greater than 67 days was 71.9 months (95% CI, 70.3 to 73.5 months) versus 61 months (95% CI, 57 to 66.1 months) versus 46.6 months (95% CI, 42.8 to 50.7 months), respectively (P < .001). In the most recent year with available data (2011), 25% of patients had TTI of greater than 46 days. CONCLUSION: TTI independently affects survival. One in four patients experienced treatment delay. TTI of greater than 46 to 52 days introduced an increased risk of death that was most consistently detrimental beyond 60 days. Prolonged TTI is currently affecting survival.

Pre-treatment tumor-specific growth rate as a temporal biomarker that predicts treatment failure and improves risk stratification for oropharyngeal cancer.

PURPOSE: To assess the relationship between tumor-specific growth rate (TSGR) and oropharyngeal cancer (OPC) outcomes in the HPV era. METHODS/MATERIALS: Primary tumor volume differences between a diagnostic and secondary scan separated ⩾7days without interval treatment were used to estimate TSGR, defined as percent volume growth/day derived from primary tumor volume doubling time for 85 OPC patients with known p16 status and smoking pack-years managed with (chemo)radiation. Variables were analyzed using Kruskal-Wallis or Fisher's exact test as appropriate. Log-rank tests and Cox proportional models analyzed endpoints. Using concordance probability estimates (CPE), TSGR was incorporated into RTOG 0129 risk grouping (0129RG) to assess whether TSGR could improve prognostic accuracy. RESULTS: Median time between scans was 35days (range 8-314). Median follow up was 26months (range 1-76). The 0129RG classification was: 56% low, 25% intermediate, and 19% high risk. Median TSGR was 0.74%/day (range 0.01-4.25) and increased with 0129RG low (0.41%), intermediate (0.57%) and high (1.23%) risk, respectively (p=0.015). TSGR independently predicted for TF (TSGR: HR (95%CI)=2.79, 1.67-4.65, p<0.001) in the Cox model. On CPE, prognostic accuracy for TF, disease-free survival and overall survival was improved when 0129RG was combined with TSGR. Dichotomizing 0129RG by median TSGR yielded no observed recurrences in low risk patients with TSGR<0.74% and demonstrated significant difference for intermediate risk (8% vs. 50% for TSGR<0.74% vs. ⩾0.74%, respectively, p<0.001). CONCLUSION: Tumor-specific growth rate correlates with increasing 0129RG and predicts treatment failure, potentially improving the prognostic strength and risk stratification of established 0129 risk groups.

Dose escalation with a vessel boost in pancreatic adenocarcinoma treated with neoadjuvant chemoradiation.

PURPOSE: Patients with pancreatic adenocarcinoma (PAC) are often treated with neoadjuvant chemoradiation (NACRT) in hopes of downstaging their disease for potential surgical resection. We hypothesized that increasing the radiation dose to the area of the tumor abutting the vessel(s) of concern would increase the rate of surgical resection in patients with borderline resectable PAC (BRPAC) and locally advanced PAC (LAPAC) treated with NACRT. METHODS AND MATERIALS: We retrospectively reviewed consecutive cases of BRPAC and LAPAC treated with NACRT from January 2006 to December 2013, with or without a vessel boost (VB), at a single institution. The primary endpoints were rate of R0/R1 potentially curative surgical resection and acute toxicity. Univariate analysis with the Fisher exact test was performed to evaluate the effect of each variable. Multiple logistic regression was used to adjust for the following covariates: year of diagnosis, age, sex, carbohydrate antigen 19-9 (CA19-9) level at diagnosis, and BRPAC or LAPAC. RESULTS: Of the 104 patients identified, 22% (n = 23) received a VB (median, 54 Gy; range, 54-64 Gy), and 78% (n = 81) received no boost (median, 50.4 Gy; range, 48.6-52.2 Gy). More patients in the VB group were treated from 2010 to 2013 (P < .001) and with intensity modulated radiation therapy (P = .002). Other baseline characteristics were balanced. After adjustment for covariates, there was a statistical trend toward increased surgical resection in patients who received a VB (odds ratio [OR], 2.77; 95% confidence interval [CI], 0.89-8.57; P = .077). Age (≥70 years; OR, 0.42; 95% CI, 0.16-1.05; P = .064) and LAPAC (OR, 0.32; 95% CI, 0.09-1.09; P = .068) also trended toward significance. CA19-9 ≥47.9 U/mL (OR, 0.24; 95% CI, 0.08-0.71; P = .010) was significant on multivariate analysis. There was no significant difference in acute or late toxicity between groups. CONCLUSIONS: In our retrospective series, dose escalation was associated with an improved surgical resection rate in BRPAC and LAPAC patients treated with NACRT, although this improvement was not statistically significant.

Comparison of Adjuvant Radiation Therapy Alone Versus Radiation Therapy and Endocrine Therapy in Elderly Women With Early-Stage, Hormone Receptor-Positive Breast Cancer Treated With Breast-Conserving Surgery.

BACKGROUND: Randomized data examining adjuvant radiation therapy (RT) alone in elderly women with low-risk, hormone receptor-positive (HR(+)) breast cancer is lacking. We investigated the outcomes for elderly women treated with adjuvant RT alone versus RT plus endocrine therapy (ET) after breast-conserving surgery. PATIENTS AND METHODS: We queried our institutional breast cancer database for the following patients: age > 65 years, stage T1-T2N0, HR(+), and treatment with breast-conserving surgery, including adjuvant RT. The χ(2) analysis identified significant baseline differences between the groups. Cox proportional hazard methods identified predictors of endpoints on multivariate analysis. Kaplan-Meier estimates of survival were compared using the log-rank test. RESULTS: A total of 504 patients were identified, 311 had undergone RT plus ET (62%) and 193, RT alone (38%). The median follow-up time was 88 months. The RT-alone group versus RT plus ET group had different median age (72 vs.71 years, P < .001), different median tumor size (1 vs. 1.3 cm, P < .001), lower grade (40% vs. 29%, P = .05), and fewer close or positive margins (11% vs. 19%, P = .01). The adherence rate to prescribed ET was 70%. Tumor size predicted an increased risk of distant metastasis (DM) (hazard ratio, 1.96; 95% confidence interval [CI], 1.23-3.13) and worse disease-free survival (DFS) (hazard ratio, 1.86; 95% CI, 1.22-2.86). ET nonadherence versus adherence predicted for risk of DM (hazard ratio, 5.03; 95% CI, 1.98-12.66) and DFS (HR, 4.24; 95% CI, 1.9-10.3). Of the women with DM, 83.8% had tumors > 1 cm in size. CONCLUSION: ET nonadherence and tumor size > 1 cm predicted an increased risk of DM and worse DFS, favoring the addition of ET in this group. However, RT alone for women with tumors less than or equal to 1 cm may be appropriate.