Comparison of different breast planning techniques and algorithms for radiation therapy treatment

This work aims at investigating the impact of treating breast cancer using different radiation therapy (RT) techniques--forwardly-planned intensity-modulated, f-IMRT, inversely-planned IMRT and dynamic conformal arc (DCART) RT--and their effects on the whole-breast irradiation and in the undesirable irradiation of the surrounding healthy tissues. Two algorithms of iPlan BrainLAB treatment planning system were compared: Pencil Beam Convolution (PBC) and commercial Monte Carlo (iMC). Seven left-sided breast patients submitted to breast-conserving surgery were enrolled in the study. For each patient, four RT techniques--f-IMRT, IMRT using 2-fields and 5-fields (IMRT2 and IMRT5, respectively) and DCART - were applied. The dose distributions in the planned target volume (PTV) and the dose to the organs at risk (OAR) were compared analyzing dose-volume histograms; further statistical analysis was performed using IBM SPSS v20 software. For PBC, all techniques provided adequate coverage of the PTV. However, statistically significant dose differences were observed between the techniques, in the PTV, OAR and also in the pattern of dose distribution spreading into normal tissues. IMRT5 and DCART spread low doses into greater volumes of normal tissue, right breast, right lung and heart than tangential techniques. However, IMRT5 plans improved distributions for the PTV, exhibiting better conformity and homogeneity in target and reduced high dose percentages in ipsilateral OAR. DCART did not present advantages over any of the techniques investigated. Differences were also found comparing the calculation algorithms: PBC estimated higher doses for the PTV, ipsilateral lung and heart than the iMC algorithm predicted.

Nutritional risks and colorectal cancer in a Portuguese population

BACKGROUND

Food and nutrition as major causes of colorectal cancer (CRC) are still debatable.

AIM OF THE STUDY

This cross-sectional study in a Portuguese population aimed to characterize and identify "high-risk" diets/life-styles and explore their associations with colorectal cancer.

METHODS

In 70 colorectal cancer patients and 70 sex, age-matched subjects without cancer history, we evaluated: diet history and detailed nutrient intake (DIET-PLAN5 2002, UK), alcohol (amount, type, years), smoking (number packages/year, years), physical activity, co-morbidities and body mass index. Age-adjusted Relative Risks were calculated, Proportional Hazards models adjusted the analysis for multiple risk factors.

RESULTS

Smoking was a risk factor (1.90). Increased colorectal cancer risk regarding the lowest vs the highest intake quartile emerged for: vitamin B12 (3.41), cholesterol (3.15), total fat (2.87), saturated fat (1.98), animal protein (1.95), energy (1.85), alcohol (1.70), iron (1.49), refined carbohydrates (1.39). Reduced colorectal cancer risk for the highest vs the lowest intake quartile was found for: n-3 fatty acids (0.10), insoluble fiber/folate (0.15), flavonoids/vitamin E (0.25), isoflavones/beta-carotene (0.30), selenium (0.36), copper (0.41), vitamin B6 (0.46).

CONCLUSION

Our results corroborated well-established risk factors and identified emergent nutrients. Prolonged excessive intake of macronutrients and some micronutrients concurrent with marked deficits of fiber and protective compounds were dominant in colorectal cancer and more significant than alcohol and smoking. The interaction diet-colorectal cancer is consistent and the relevance of new nutrients is emerging.

Nutritional Deterioration in Cancer: The Role of Disease and Diet

AIMS

Under-nutrition is a major source of morbidity and mortality in cancer patients. This prospective, cross-sectional study aimed to evaluate the relative contributions of cancer staging, duration and diet on patients' nutritional deterioration.

MATERIALS AND METHODS

We included 205 consecutive patients (133 men and 72 women) with head and neck, gastro-oesophageal, colon and rectum cancer, age 53 +/- 12 (33-86) years, referred for radiotherapy (primary, adjunctive to surgery, combined with chemotherapy or with palliative intent). We registered clinical variables, nutritional status (percentage of weight loss, Patient-Generated Subjective Global Assessment and body mass index), nutritional requirements, usual diet intake (diet history) and current intake (24-h recall).

RESULTS

In stage III and IV, we observed a significant decrease of usual and current energy and protein intake (P=0.002), which were not observed in stage I and II. Reduction in nutritional intake was influenced by disease duration (P=0.04), but when the latter was evaluated in a multivariate analysis, current dietary intake was associated only with staging (P=0.004), thus disclosing a distinct pattern of nutritional intake between stages and diagnosis. Using a general linear model, advanced staging showed the most significant association with nutritional depletion (P=0.0001). We also found significant associations for tumour location (P=0.001), disease duration (P=0.002), nutritional intake (P=0.003) and previous surgery or chemotherapy (P=0.02). Percentage weight loss showed a consistently superior performance with regard to clinical variables and ability to detect mild to extreme nutritional changes. Patient-Generated Subjective Global Assessment had a very high sensitivity and specificity, and a strong capacity for detecting patients at nutritional risk compared with body mass index.

CONCLUSIONS

Nutritional depletion is multifactorial, dependent mainly on the tumour burden of the host. Percentage weight loss is a sensitive and specific tool that can screen and identify malnutrition effectively. Its joint use with Patient-Generated Subjective Global Assessment, which establishes boundaries for nutritional therapy, will optimise the efficacy of nutritional assessment and support in cancer patients.

Postoperative irradiation of primary or recurrent pterygium: results and sequelae

PURPOSE

To evaluate the efficacy of postoperative beta irradiation and to analyze treatment sequelae in patients with primary and recurrent pterygium.

METHODS AND MATERIALS

From June 1986 to June 1998, 94 patients corresponding to 100 eyes received postoperative beta irradiation. Two groups of patients were treated: 37 eyes with primary pterygium (Group I) and 63 eyes with recurrent pterygium (Group II). Terson technique surgery was used in the majority of patients. Time between surgery and beta irradiation ranged from 2 to 48 h. Radiation doses and fractionation consisted of 30 Gy/3 fractions/5 days in 17 cases, 60 Gy/6 fractions/6 weeks in 80 cases, and 20 Gy/1 fraction in 3 patients.

RESULTS

Fourteen of the 100 cases (14%) treated with surgery and adjuvant irradiation recurred. The overall crude local recurrence rates were 5.4% for Group I and 19% for Group II patients. The 5-year probability of local tumor control was 83.5% for the whole group of patients, 94% for Group I, and 76.9% for Group II (p = 0.04). The early sequelae related to surgery or irradiation were self limited and disappeared by 6 months after the end of the treatment: ocular irritation (14 cases), scleral atrophy (5 cases), and neovascularization (7 cases). A greater incidence of sequelae was observed in Group II patients, but the difference between the groups was not statistically significant (p = 0.15). No significant correlation between treatment sequelae and treatment dose was noted: 29% sequelae with 30 Gy vs. 18.7% sequelae with 60 Gy (p = 0.32). No late complications have been observed.

CONCLUSION

Adjuvant beta irradiation provides effective therapy for primary pterygium, is somewhate less effective in patients with recurrent pterygium, and is associated with a moderate rate of early and transient sequelae.