Fractionated stereotactic radiotherapy in the treatment of pituitary macroadenomas

Background

The use of fractionated stereotactic radiotherapy (fsrt) has evolved with technical advances in noninvasive immobilization, radiation delivery, and image guidance. The application of fsrt to pituitary tumours is aimed at reducing toxicity through improved dose conformality and reduced treatment margins. The aim of the present paper is to report our own experience and to review the published data on fsrt for pituitary macroadenomas.

Methods

Between September 2000 and October 2005, 13 patients with pituitary macroadenoma underwent fsrt at our institution. In 12 patients, radiotherapy treatment followed surgical resection (transsphenoidal resection in 8, frontal craniotomy in 3, and multiple transsphenoidal resections followed by craniotomy in 1). In 4 patients, the tumours were functional (2 adrenocorticotropic hormone–secreting, 1 prolactinoma, and 1 growth hormone–secreting); the tumours in the remaining patients were clinically non-secretory. Before radiation, 3 patients had panhypopituitarism, and 6 patients had visual field defects. All patients were treated with fsrt using non-coplanar micro–multileaf collimation portals. A median dose of 50.4 Gy (range: 45–60 Gy) was prescribed to the 76.9%–95.2% isodose surface and delivered in 1.8-Gy fractions. The median planning target volume (gross tumour plus 3 mm) was 33.5 cm3 (range: 3.2–75 cm3).

Results

After a median follow-up of 24 months (range: 6–60 months), local control was 100%. One patient achieved clinical complete response. Treatment was well tolerated acutely for all patients. Neither radiation-induced optic neuropathy nor any radiation-related endocrine dysfunction was observed in our patients.

Conclusions

In accordance with published series, we found fsrt to be safe and effective in the management of large pituitary macroadenomas.

Small cell carcinoma of the endometrium: report of a case and review of the literature

Small cell carcinomas of the endometrium are rare and carry an ominous prognosis. Most patients present with advanced disease. The histopathological diagnosis requires immunohistochemistry confirmation and the tumor should be positive for a neuroendocrine marker. This article reports a new case and reviews the pertinent literature on the subject.

Cognition and quality of life after chemotherapy plus radiotherapy (RT) vs. RT for pure and mixed anaplastic oligodendrogliomas: Radiation therapy oncology group trial 9402

e20519

Background: Radiation Therapy Oncology Group 9402 compared PCV chemotherapy plus radiation therapy (PCV+RT) versus RT alone for anaplastic oligodendroglioma. Here we report 1) longitudinal changes in cognition and quality of life, 2) effects of patient factors and treatments on cognition, quality of life and survival, and 3) prognostic implications of cognition and quality of life. Methods: Cognition was assessed by Mini Mental Status Examination (MMSE) and quality of life by Brain-Quality of Life (B-QOL) by repeat assessments. Scores were analyzed for survivors and within five years of death. Shared parameter models evaluated MMSE/B-QOL with survival. Results: For survivors, MMSE and B-QOL scores were similar longitudinally and between treatments. For those dying within 5 years, MMSE scores were stable initially, while B-QOL scores decreased; both declined rapidly in the last year of life and similarly between arms. In the aggregate, scores decreased over time (P=0.0413 for MMSE; P=0.0016 for B-QOL) and were superior with age < 50 years (P<0.001 for MMSE; P=0.0554 for B-QOL) and KPS 80–100 (P<0.001). Younger age and higher KPS were associated with longer survival. After adjusting for patient factors and drop-out, survival was longer after PCV+RT (HR=0.66, 95% CI=0.49–0.9, P=0.0084; HR=0.74, 95% CI=0.54–1.01, P=0.0592) in models with MMSE and B-QOL. There were no differences in MMSE and B-QOL scores between arms (P=0.4752 and P=0.2767, respectively); higher scores predicted longer survival. Conclusions: MMSE and B-QOL scores held steady in both arms for survivors. For those who died, B-QOL scores declined slowly until the last year of life, then rapidly. Younger, fitter patients had better MMSE and B-QOL scores and longer survival.

No significant financial relationships to disclose.

Short-course irradiation as adjuvant treatment of surgically resected single brain metastases

2067

Background: Surgical resection followed by whole-brain irradiation is a standard treatment approach for patients with a single brain metastasis from solid tumours. As short-course hypofractionated irradiation has proven equivalent to more protracted schedules for the palliative treatment of brain metastasis, it has been commonly applied in the adjuvant setting. Methods: By reviewing our pathology database, we identified patients having undergone complete neurosurgical resection of a single brain metastasis followed by short-course (4–6 fractions) whole-brain irradiation. Irradiation was delivered using standard lateral-opposed megavoltage radiation portals. Local failure and new brain metastases were identified by chart and imaging study reviews. All outcomes were calculated actuarially. Results: Between March 2000 and August 2005, 50 patients received short-course whole-brain irradiation (20 Gy in 5 fractions in 41 of 50 cases) following complete surgical resection of a single brain metastasis. The most common primary malignancies were lung (66%), breast (14%), and cancer of unknown primary origin (10%). Median age was 60 years. Imaging studies were available for all patients and a preoperative MRI was reviewed in 94% of cases. Median follow-up for living patients was 30.0 months. The median overall survival was 10.92 months (29% at 2 years). Following radiation, failure at the surgical site was seen in 51% and 79% of patients at 1 and 2 years. New metastases elsewhere in the brain developed in 26% and 53% of these patients at 1 and 2 years. Conclusions: When calculated actuarially, local failure and new brain metastases were common following surgery and short-course whole-brain radiation therapy. In part, this may represent inefficacy of the short hypofractionated radiation scheme. Further investigation into the local and systemic treatment of these patients is warranted.

No significant financial relationships to disclose.

The impact of varying rectal contours on rectal dose in prostate cancer patients treated with hypofractionated radiation

15598

Background: In curative radiation treatment of prostate cancer,the advent of 3DCRT has made a reduction in the incidence of normal tissue toxicities while optimizing tumor control. To optimize 3DCRT, the ICRU has published standard definitions of target volumes and organs at risk such that the tumor can receive the optimal dose with as little as possible dose to the organs at risk. However, the definition of the rectum as an organ at risk in radiation treatment of the prostate varies widely among institutions and so does the report of toxicities. We studied the effect of varying rectal contouring on rectal dose obtained from DVHs in a homogenous group of prostate cancer patients treated with hypo fractionationed radiation. Methods: 71 patients with favorable risk prostate cancer treated with a total of 66Gy in 3Gy/day fractionation.18 MV photons in a 5-field technique was used. None of the patients received hormonal therapy. Their treatment plans were archived and the rectum was re-contoured by a single investigator. 4 different contours were drawn to compare the rectal dose: i) the whole rectum from the anal verge to the recto sigmoid junction (WR); ii) the rectum from 1cm below the PTV to 1cm above (RPTV); iii) the rectal wall (i.e. the inner and outer rectal wall) from the anal verge to the recto sigmoid junction (RW); iv) the rectal wall from 1cm below the PTV to 1cm above (RWPTV) Results: There were significant differences in the median volume, minimum, mean rectal doses and dose to 50% of the volume, (p=0.0001). The whole rectum (WR) is having the lowest and the rectal wall with 1cm above and below the PTV (RWPTV) having the highest in all the parameters. The only parameter not significantly different among the 4 contours is the maximum rectal dose. Conclusion: the varied rectal contouring across different institutions is a possible reason for the broadly different reports of rectal toxicity after prostate irradiation. Our results suggest significant differences in rectal doses with varied contouring. Contouring the rectal wall only and limiting the volume to 1cm above and below the PTV confers the highest mean rectal dose. Comparison of rectal toxicity between institutions can only be meaningful if a consensual volume definition of the organ at risk is agreed upon.

No significant financial relationships to disclose.

The impact of the duration of adjuvant hormonal therapy in patients with unfavorable prognosis prostate cancer treated with radiotherapy: Secondary analysis of RTOG 85–31

5062

Background: RTOG 85–31 was a Phase III trial of androgen suppression for life as an adjuvant to radiotherapy. However not all patients continued on the protocol-mandated long-term hormonal therapy despite no evidence of recurrent disease. This analysis correlates duration of adjuvant hormonal therapy and outcomes among patients who prematurely discontinued long-term hormonal therapy. Methods: The protocol mandated pelvic radiotherapy (60–66 Gy) followed by goserelin 3.6 mg monthly given indefinitely or until disease progression. To avoid potential bias due to early progression/death, only patients who were alive with no evidence of disease at the time of cessation of hormonal therapy were included. There were 377 analyzable patients. Patients were divided in groups based on the hormonal therapy duration (HTD), as follows: = 1 year (27.3%), 1< and =2 years (11.4%), 2< and =4 years (13.3%), 4< and =6 years (10.6%) and > 6 years (37.4%). End-points were overall survival, disease-free survival, disease-free survival with PSA <1.5 ng/mL, disease-specific survival, local failure and distant failure. Cox-proportional hazards regression model was used to test the outcomes among the 5 groups. Results: The median follow-up time of surviving patients is 11.27 years. Pretreatment characteristics by hormone duration groups were well balanced except for age. The median duration of adjuvant hormonal therapy was 3.59 years. For each outcome, there are statistically significant differences among the 5 HTD groups in all outcomes without adjusting for other covariates. Pairwise comparisons show that HTD > 6 year group is significantly associated with having an improved survival and fewer failure events than all other HTD groups (HR < 1, p-value <0.0001). Adjusted for age and stratification variables, the HTD>6 year group remains the only group significantly associated with having fewer failure events in all outcomes. Conclusions: Prolonged HTD of > 6 years is significantly associated with improvements in all end-points studied. Based on these data, decreasing HTD to < 6 years may have a detrimental effect in patients with unfavorable prostate cancer.

No significant financial relationships to disclose.