Search

ObjectivesVitamin supplementation reduces pemetrexed toxicity. Raised plasma homocysteine reflects deficiency in vitamin B12 and folate, and is suppressed by supplementation. This observational study of 112 patients receiving pemetrexed-based chemotherapy assessed homocysteine levels after 3 weeks of vitamin supplementation, hypothesising high levels would correlate with ongoing deficiency, thus increased toxicity.Material and methodsPrimary endpoint was the composite of proportion of patients with treatment delay/ dose reduction/ drug change or hospitalisation during the first six weeks of chemotherapy, comparing those with normal plasma homocysteine (successfully supplemented, SS) and those with high homocysteine (unsuccessfully supplemented, USS). Secondary endpoints included toxicity and analyses for depression. Post-hoc analysis examined correlation between interval of vitamin and folate supplementation and pemetrexed on primary endpoint and grade 3-4 toxicities.ResultsEighty-four patients (84%) were successfully supplemented (SS group). The proportion of patients undergoing a treatment delay/ dose reduction/ drug change or hospitalisation in SS group was 44.0% (95% confidence interval [CI] 33.2%-55.3%) and in USS group was 18.8% (95% CI 4.0%-45.6%) (p = 0.09). Twelve percent of patients gave a past history of depression however 66% of patients had an on study Hospital Anxiety and Depression (HAD) score of >7. Supplementation status was not associated with depression. The median overall survival (OS) was 11.8 months (95% CI 8.6-16.5) in the SS group and 8.8 months (95% CI 6.6-16.2) in the US group (p = 0.5). The number of days (ConclusionOn-treatment homocysteine levels were not a biomarker of toxicity or depression. Standard vitamin supplementation is adequate in the majority of patients receiving pemetrexed. High HAD score were noted in this population giving an opportunity for mental health intervention. The lead-in time for vitamin supplementation can be short.

Introduction To compare nodal response rates following chemoradiotherapy in patients with p16+ and p16− oropharyngeal squamous cell carcinoma (OPSCC). Methods Patients with node-positive OPSCC treated at Peter MacCallum Cancer Centre on the published phase I–III tirapazamine trials were identified. All patients had conventional assessment (clinical examination (CA), CT and/or MRI) and positron emission tomography (PET) at both baseline and 2–4 months post-treatment. Results There were 30 p16+ and 18 p16− patients, the former group having significantly higher stage nodal disease (P = 0.016). The mean overall reduction in nodal size at post-treatment assessment was similar in p16+ and p16− patients (78% vs. 75%), and no statistically significant difference in nodal complete response (CR) rates was detected by either CA (50% vs. 39%, P = 0.35) or PET/PET-CT (93% vs. 83%, P = 0.19). PET was significantly more accurate in determining the true nodal CR rate in both groups, with a negative predictive value of 96%. Conclusion Nodal response rates following chemoradiotherapy appear to be similar in p16+ and p16− patients when assessed by either CA or PET/PET-CT. However, higher nodal CR was seen in PET/PET-CT compared with CA in both groups. Metabolic imaging is more accurate than CA in assessing nodal response post-treatment.

Purpose To assess the correlation of 18F-FDG-PET (PET) response to pathological response after neoadjuvant chemoradiation (CRT) for locally advanced rectal cancer. Methods and materials Twenty patients with locally advanced rectal cancer were identified between 2001 and 2005. The median age was 57 years (range 37–72) with 14 males and 6 females. All patients were staged with endorectal ultrasound and/or MRI, CT, and PET. The clinical staging was T3N0M0 (16), T3N1M0 (2), and T3N0M1 (2). Restaging PET was performed after CRT, and prior to definitive surgery. The response on PET and pathology was assessed and correlated. Patient outcome according to PET response was also assessed. Results Following CRT, a complete PET response occurred in 7 patients, incomplete response in 10, and no response in 3 patients. At surgery, complete pathological response was recorded in 7 patients, incomplete response in 10 and no response in 3. There was a good correlation of PET and pathological responses in complete responders (5/7 cases) and non-responders (3/3 cases). After a median follow-up of 62 months (range 7–73), twelve patients were alive with no evidence of disease. All patients achieving complete metabolic response were alive with no evidence of disease, while as those who had no metabolic response, all died as a result of metastatic disease. Conclusions PET is a promising complementary assessment tool for assessing tumor response after CRT if there is a complete or no response. PET response may also predict for outcome.

Background To analyze interfraction motion of seminal vesicles (SV), and its motion relative to rectal and bladder filling. Methods and Materials SV and prostate were contoured on 771 daily computed tomography “on rails” scans from 24 prostate cancer patients undergoing radiotherapy. Random and systematic errors for SV centroid displacement were measured relative to the prostate centroid. Margins required for complete geometric coverage of SV were determined using isotropic expansion of reference contours. SV motion relative to rectum and bladder was determined. Results Systematic error for the SV was 1.9 mm left-right (LR), 2.9 mm anterior-posterior (AP) and 3.6 mm superior-inferior (SI). Random error was 1.4 mm (LR), 2.7 mm (AP) and 2.1 mm (SI). 10 mm margins covered the entire left SV and right SV on at least 90% of fractions in 50% and 33% of patients and 15 mm margins covered 88% and 79% respectively. SV AP movement correlated with movement of the most posterior point of the bladder (mean R2 = 0.46, SD = 0.24) and rectal area (mean R2 = 0.38, SD = 0.21). Conclusions Considerable interfraction displacement of SV was observed in this cohort of patients. Bladder and rectal parameters correlated with SV movement.