Radiotherapy of prostate cancer: established results and new developments

Accuracy and reproducibility of conformal radiotherapy using data from a randomised controlled trial of conformal radiotherapy in prostate cancer (MRC RT01, ISRCTN47772397)

Aims

The MRC RT01 trial used conformal radiotherapy to the prostate, a method that reduces the volume of normal tissue treated by 40–50%. Because of the risk of geographical miss, the trial used portal imaging to examine whether treatment delivery was within the required accuracy.

Material and methods

In total, 843 patients were randomly assigned to receive 64 Gy in 32 fractions over 6.5 weeks or 74 Gy in 37 fractions over 7.5 weeks. Field displacements and corrections were recorded for all imaged fractions. Displacement trends and their association with time, disease and treatment set-up characteristics were examined using univariate and multivariate analyses. A Radiographer Trial Implementation Group (RTIG) was set up to inform the quality assurance process and to promote the development of best practice.

Results

Treatment isocentre positioning was within 5 mm in every direction on 6238 (83%) of the 7535 fractions imaged. In total, 532 (81%) of 695 included patients had at least one ≥ 3mm displacement and 415 (63%) had at least one ≥ 5mm displacement. Univariate, multivariate and stepwise models of ≥ 5mm displacements showed an increased likelihood of displacement in weeks 1 and 2 with low melting point alloy (LMPA) blocks compared with multileaf collimators, film verification compared with electronic portal imaging (EPI) and increased number of fractions imaged. Except for LMPA, this was also seen for ≥ 5mm displacements in weeks 3–6.

Conclusions

Accurate conformal treatment was delivered. The use of EPI was associated with increased reported accuracy. The RTIG was a crucial part of the quality assurance process.

Update in palliative management of hormone refractory cancer of prostate

Hormone refractory prostate cancer (HRPC) is an incurable disease and as in the pressure sensitive adhesive era the median survival of patients is increasing, these men increasingly develop symptomatic problems as a result of advanced local and or metastatic disease during their progression to death. Recently, it has been shown that it is possible to improve survival in this group of patients with use of chemotherapy which reinforces the need of better options in palliative care. We discus the various clinical problems (Part I) and treatment options of palliative care (Part II) and try to formulate an action plan in this review.

Management of the Spectrum of Hormone Refractory Prostate Cancer

INTRODUCTION

In its advanced stages, hormone refractory prostate cancer (HRPC) is an incurable condition which consists of a spectrum of disease. This requires an integrated multidisciplinary approach by an uro-oncologic team supported by radiologists, skeletal surgeons and palliative care. Aim of this review was to critically evaluate the current and potential approaches to patients affected by HRPC.

MATERIALS AND METHODS

A comprehensive evaluation of available published data included analysis of published full-length papers that were identified with Medline and Cancerlit from January 1981 to January 2006. Official proceedings of internationally known scientific societies held in the same time period were also assessed.

RESULTS

Most men with hormone refractory prostate cancer will die of their disease in the absence of intercurrent illness, and the various conditions arising as a consequence of local and distal cancer progression commonly lead to a spectrum of morbidity requiring treatment. Recent data regarding docetaxel-based chemotherapy have shown small but significant improvements in survival and improvement in quality of life in men receiving treatment. However, this therapy may not be suitable for all patients. New agents used alone or in combination with docetaxel currently are under trial in an attempt to provide much needed improvements in outcome. Bone-targeted treatments, particularly late-generation bisphosphonates, have added to the range of options, reducing the incidence of skeletal complications in some men. Further work is needed to target their use more effectively, to explore their efficacy in combination with existing proven therapies and to develop new approaches to treat bone metastases. Complications arising as a consequence of upper and lower tract dysfunction, haematologic, neurologic and psychologic disorders are common. These complications often are amenable to effective treatment, but interventions may engender difficult clinical and ethical decisions.

CONCLUSIONS

Although HRPC is incurable, it is not untreatable, and that the clinical management embraces not just chemotherapy, but many interventional and supportive therapies. A holistic and supportive approach to patient care is vital for optimal management, and is best provided by a coordinated, multidisciplinary team including urologists and oncologists.

Effects of androgen deprivation on prostatic morphology and vascular permeability evaluated with mr imaging

PURPOSE

To assess magnetic resonance (MR) measures of vascular permeability of prostate cancer treated with androgen deprivation and to correlate these with morphologic appearances and serum prostate-specific antigen (PSA) levels.

MATERIALS AND METHODS

MR examinations in 56 consecutive patients with prostate cancer were performed before and after luteinizing hormone-releasing hormone analog treatment. T2-weighted and contrast medium-enhanced T1-weighted MR images were obtained. Pre- and posttreatment comparisons of morphologic features, glandular volume, and enhancement-related parameters (capillary permeability, leakage space, gadolinium accumulation) were made.

RESULTS

Fifty-five tumors were seen before treatment; 42, after treatment. Signal intensity in the peripheral zone and seminal vesicles decreased on T2-weighted images in 42 (75%) and 25 (45%) patients, respectively. Median volume in tumor decreased by 65% (95% CI: 55%, 76%); in central gland, by 30% (95% CI: 25%, 35%). Reductions in tumor permeability (P <.001) and changes in washout patterns were observed (P <.001). Tumor permeability reductions coincided with a decrease in serum PSA levels in 91% of patients. A weak correlation between tumor permeability and volume change was seen (r = 0.55, P =.04). Reductions in peripheral zone (P <.001) and central gland (P =.009) permeability were noted.

CONCLUSION

Androgen deprivation decreases tumor volume and vascular permeability and impairs detection of prostate cancers. Use of MR estimates of permeability may be an additional way of assessing prostatic tumor response to antiandrogen treatment.

Intensity modulated radiation therapy: a clinical review

Intensity modulated radiotherapy represents a significant advance in conformal radiotherapy. In particular, it allows the delivery of dose distributions with concave isodose profiles such that radiosensitive normal tissue close to, or even within a concavity of, a tumour may be spared from radiation injury. This article reviews the clinical application of this technique to date, and discusses the practical issues of treatment planning and delivery from the clinician's perspective.

An audit of 3D treatment planning facilities and practice in the UK

The availability and use of 3D treatment planning facilities in the UK was investigated by questionnaire. Fifty-eight of the 62 UK radiotherapy centres responded (94%). There was considerable variation in the facilities available and in the manner in which they were used. Although 36 centres (62%) have the facilities to undertake complex, non-coplanar treatment planning, only 12 did so on a regular basis. More surprising was the inconsistent implementation of coplanar CT planning. It is suggested that we need to work towards reaching a consensus on best practice in radiotherapy planning. This will require the creation of systems for guidance and further training of the various staff involved.