Minimally invasive treatment for localized adenocarcinoma of the prostate: review of 1048 patients treated with ultrasound-guided palladium-103 brachytherapy

Sexual function and male cancer

Quality of life in general and sexual functioning in particular have become very important in cancer patients. Biological factors such as anatomic alterations, physiological changes and secondary effect of medical interventions may preclude normal sexual functioning even when sexual desire is intact. In spite of modern surgical techniques, improved chemotherapeutical drugs and sophisticated radiation techniques, still many patients complain of impaired sexual function after cancer treatment. A large number of instruments already exist to assess quality of life in cancer patients. It is important to standardize procedures and to use validated questionnaires. Collecting data on an ongoing basis before and long after treatment is mandatory, and control groups must be used. Patients should be offered sexual counselling and informed about the availability of therapies for sexual dysfunctions. In this paper we review the topic of sexual functioning after treatment (predominantly after radiotherapy) of the most common malignancies in men and give suggestions for treatment.

Prediction of lung cancer using volatile biomarkers in breath

BACKGROUND

Normal metabolism generates several volatile organic compounds (VOCs) that are excreted in the breath (e.g. alkanes). In patients with lung cancer, induction of high-risk cytochrome p450 genotypes may accelerate catabolism of these VOCs, so that their altered abundance in breath may provide biomarkers of lung cancer.

METHODS

VOCs in 1.0 L alveolar breath were analyzed in 193 subjects with primary lung cancer and 211 controls with a negative chest CT. Subjects were randomly assigned to a training set or to a prediction set in a 2:1 split. A fuzzy logic model of breath biomarkers of lung cancer was constructed in the training set and then tested in subjects in the prediction set by generating their typicality scores for lung cancer.

RESULTS

Mean typicality scores employing a 16 VOC model were significantly higher in lung cancer patients than in the control group (p<0.0001 in all TNM stages). The model predicted primary lung cancer with 84.6% sensitivity, 80.0% specificity, and 0.88 area under curve (AUC) of the receiver operating characteristic (ROC) curve. Predictive accuracy was similar in TNM stages 1 through 4, and was not affected by current or former tobacco smoking. The predictive model achieved near-maximal performance with six breath VOCs, and was progressively degraded by random classifiers. Predictions with fuzzy logic were consistently superior to multilinear analysis. If applied to a population with 2% prevalence of lung cancer, a screening breath test would have a negative predictive value of 0.985 and a positive predictive value of 0.163 (true positive rate =0.277, false positive rate =0.029).

CONCLUSIONS

A two-minute breath test predicted lung cancer with accuracy comparable to screening CT of chest. The accuracy of the test was not affected by TNM stage of disease or tobacco smoking. Alterations in breath VOCs in lung cancer were consistent with a non-linear pathophysiologic process, such as an off-on switch controlling high-risk cytochrome p450 activity. Further research is needed to determine if detection of lung cancer with this test will reduce mortality.

Long-term results of interstitial brachytherapy (LDR-Brachytherapy) in the treatment of patients with prostate cancer

Permanent interstitial brachytherapy represents the most conformal form of radiation therapy of the prostate and the number of patients with prostate cancers treated with permanent radioactive implants is increasing world wide. In the meanwhile long-term data on tumor control and treatment morbidity become available. Biochemical and clinical tumor control appears to be as effective as after radical prostatectomy or external beam radiation therapy in early prostate cancer. The risk of postreatment urinary incontinence and bowel dysfunction is low and erectile function can be preserved in the majority of patients. However, prostate brachytherapy requires a careful selection of patients as pretreatment factors predict for long-term outcome. The need for combined modality approaches in intermediate and high-risk patients remains controversely discussed. The continous refinement of intraoperative planning techniques and the elucidation of the etiology of urinary, sexual, and bowel dysfunction should result in further improvements in biochemical outcomes and decreased morbidity. Improved and standardized postimplantation evaluation will make outcome data more reliable and comparable.

Recommendations of the American Association of Physicists in Medicine regarding the impact of implementing the 2004 task group 43 report on dose specification for 103Pd and 125I interstitial brachytherapy

In March 2004, the recommendations of the American Association of Physicists in Medicine (AAPM) on the interstitial brachytherapy dosimetry using 125I and 103Pd were reported in Medical Physics [TG-43 Update: Rivard et al., 31, 633-674 (2004)]. These recommendations include some minor changes in the dose-calculation formalism and a major update of the dosimetry parameters for eight widely used interstitial brachytherapy sources. A full implementation of these recommendations could result in unintended changes in delivered dose without corresponding revisions in the prescribed dose. Because most published clinical experience with permanent brachytherapy is based upon two widely used source models, the 125I Model 6711 and 103Pd Model 200 sources, in this report we present an analysis of the dosimetric impact of the 2004 TG-43 dosimetry parameters on the history of dose delivery for these two source models. Our analysis indicates that the currently recommended prescribed dose of 125 Gy for Model 200 103Pd implants planned using previously recommended dosimetry parameters [AAPM 103Pd dose prescription: Williamson et al., Med. Phys. 27, 634-642 (2000)] results in a delivered dose of 120 Gy according to dose calculations based on the 2004 TG-43 update. Further, delivered doses prior to October 1997 varied from 113 to 119 Gy for a prescribed dose of 115 Gy compared to 124 Gy estimated by the AAPM 2000 report. For 125I implants using Model 6711 seeds, there are no significant changes (less than 2%). Practicing physicians should take these results into account when selecting the clinically appropriate prescribed dose for 103Pd interstitial implant patients following implementation of the 2004 TG-43 update dose-calculation recommendations. The AAPM recommends that the radiation oncology community review this report and consider whether the currently recommended dose level (125 Gy) needs to be revised.

103Pd brachytherapy versus radical prostatectomy in patients with clinically localized prostate cancer: A 12-year experience from a single group practice

PURPOSE

In an effort to shed light on the continuing debate over the best treatment options for patients with localized prostate cancer, we present a retrospective review of patients from a single group community urology practice.

METHODS AND MATERIALS

Data from 1707 patients were reviewed. These patients, with T1 or T2 adenocarcinoma of the prostate, were treated from 1992 to 2004 with either brachytherapy or radical retropubic prostatectomy (RRPP); 81% were aged over 65 years. Patients were classified into risk groups based on initial prostate-specific antigen (PSA) and Gleason score. Time to PSA-indicated recurrence was used as the measure of disease control and cure.

RESULTS

Time to PSA-indicated recurrence was used as a measure of efficacy. Brachytherapy with 103Pd exclusively and RRPP were found to provide equivalent control (<0.4 ng/mL for prostatectomy and <3 successive rises in PSA as defined by the American Society for Therapeutic Radiology and Oncology [ASTRO]) in low-risk groups (89% seeds vs. 94% RRPP). In intermediate (89% seeds vs. 58% RRPP) and high-risk (88% seeds vs. 43% RRPP) groups, brachytherapy patients had better control rates. The addition of external radiation, with or without luteinizing hormone-releasing hormone therapy, improved biochemical control rates in intermediate and high-risk brachytherapy groups.

CONCLUSION

The results failed to show any superiority of prostatectomy over brachytherapy with 103Pd (TheraSeed; Theragenics Corp., Buford, GA) regarding time until relapse as indicated by PSA level increase (>0.4 ng/mL for prostatectomy and >3 successive rises in PSA as defined by ASTRO). We recently reviewed our techniques and improved equipment from 1995 to present and found major gains with both brachytherapy and surgery. Low risk brachytherapy resulted in 99% freedom from PSA failure while surgery showed results of 97%. Brachytherapy and prostatectomy should be offered without bias to all men with stage T1 and T2 organ-confined prostate cancer.

Dosimetric consequences of increased seed strength for I-125 prostate implants

Based on the findings of an earlier planning study, we compared post-implant dose distributions for two groups of 20 consecutive patients treated to 145 Gy with 0.414 and 0.526 U I-125 seeds. Dosimetric coverage as measured by the key clinical index D(90) was significantly better for the higher-strength seeds, with no apparent deleterious effects.

Is there a preferred strength for regularly spaced 125I seeds in inverse-planned prostate implants?

PURPOSE

To determine whether a preferred seed strength exists for 125I prostate implants preplanned using a fixed intraneedle seed spacing of 1 cm and an objective needle placement strategy within the planning target volume (PTV), and incorporating explicit dose-volume constraints for the PTV and tissues at risk.

METHODS AND MATERIALS

Prostate, urethra, and rectum contours for 10 patients were obtained from transrectal ultrasound studies. The PTV was defined in accordance with Radiation Therapy Oncology Group (RTOG) 0019 protocol. Inverse planning software was used to optimally arrange seeds of strength 0.3-0.8 U to cover the PTV to D(Rx) = 145 Gy, and limit urethra and rectum doses to 150% and 100% of D(Rx), respectively. Isodose distributions and dosimetric indices were calculated: V(200), V(150), V(100), V(90), D(100), D(90) for PTV; V(150) for urethra; and V(100) for rectum. For seeds of strength 0.414 and 0.6 U and three prostate sizes, the sensitivity of V(90) and D(90) to elementary perturbations of the optimal seed arrangement were examined.

RESULTS

For our planning scenario, 125I seeds of strength 0.5-0.6 U provided the best possible PTV coverage while maintaining V(200) at approximately 25%. The source arrangement for 0.6-U seeds was only modestly more sensitive to perturbations than that for 0.414-U seeds. These findings may not be applicable to implants planned manually or that involve needle placement outside the PTV.

CONCLUSION

Given a particular source arrangement, inverse planning aimed at maximizing dosimetric coverage of the prostate while limiting doses to the urethra and rectum can be used to search for a preferred seed strength. For regularly spaced sources within the PTV, higher strength seeds can provide better dose coverage and better urethral protection than lower strength seeds.

[Results of external radiotherapy in localized cancer of the prostate]

OBJECTIVE

External radiotherapy is considered to be a modality of treatment with a curative purpose for carcinoma de prostata. We have analysed a series of patients that received radical irradiation as treatment for tumor prostatic. We have the biochemical control results for these patients. We introduce the connection of the PSA nadir value (nPSA) and other prognostic variables with the survival free of biochemical failure.

MATERIAL AND METHODS

Between January 1992 to January 1998, 46 patients with prostate cancer T1-3 NX M0 received external radiotherapy with a curative purpose. A number of 26 of these patients received treatment with androgen blockers. The answer to this treatment was established as a fall in PSA to levels equal/minor than 1.5 ng/ml. The biochemical relapse was established as three rises of PSA over the value of nPSA.

RESULTS

We introduce the connection between nPSA and prognostic variables (clinic stage, gleason, PSA pretreatment y hormonal therapy). Three of these variables--clinic stage, Gleason grade and hormonal therapy--were the ones that showed a significantly connection with obtaining a low level of PSA. The 3-year actuarial BDFS was of 69.5%. The BDFS was of 84.3%, 9% and 6% for a value of nPSA of < or = 1 ng/ml, 1-2 ng/ml and > 2 ng/ml respectively (p < 0.05).

CONCLUSION

Radiotherapy seems to be a good therapeutical option with patients suffering from localised prostate carcinoma. The nPSA value after radiation is a good early determinant of outcome.

Sexual (dys)function after radiotherapy for prostate cancer: a review

PURPOSE

Prostate cancer has become the most common nonskin malignant neoplasm in older men in Western countries. As treatment efficacy has improved, issues related to posttherapy quality of life and sexual functioning have become more important.

METHODS AND MATERIALS

We discuss the various methods used to evaluate erectile and sexual dysfunction and the definition of potency. The etiologies of erectile dysfunction after external beam radiotherapy and brachytherapy for prostate cancer are also reviewed. The literature is summarized, and comparative studies of radiation and surgery are surveyed briefly.

RESULTS

Rates of erectile dysfunction vary from 6 to 84% after external beam radiotherapy and from 0 to 51% after brachytherapy. In most of the studies, the analysis is retrospective, the definition of erectile dysfunction is not clear, only one question about sexual functioning is asked, and nonvalidated instruments are used. The etiology of erectile dysfunction after radiation for prostate cancer is not completely understood.

CONCLUSIONS

Because erectile function is only one component of sexual function, it is necessary to assess sexual desire, satisfaction, frequency of intercourse, and other such factors when evaluating the effects of therapy. Patients should be offered sexual counseling and informed about the availability of effective treatments for erectile dysfunction, such as sildenafil, intracavernosal injection, and vacuum devices.

Brachytherapy for carcinoma of the prostate: techniques, patient selection, and clinical outcomes

Brachytherapy for prostate carcinoma has developed as either low dose rate permanent implants or high dose rate afterloading. Both approaches offer unsurpassed dose escalation and, particularly with permanent implants, the convenience of a single outpatient treatment. These therapies have now entered the mainstream of treatment options and are in the refinement phase of development. Techniques of implantation, treatment planning approaches, innovative fractionation schemes, and appropriate patient selection are the subject of current investigation. Treatment results are available beyond 10 years and appear equivalent or superior to other modalities. Although short term morbidity can be significant with brachytherapy, most current series report low long-term urinary and rectal complications. Meaningful quality of life studies and randomized cooperative group trials are now underway and should help define the role of brachytherapy in the near future.