Rectal planning risk volume correlation with acute and late toxicity in 3-dimensional conformal radiation therapy for prostate cancer

The purpose of this study was to evaluate rectum motion during 3-Dimensional conformal radiation therapy (3D-CRT) in prostate cancer patients, to derive a planning volume at risk (PRV) and to correlate the PRV dose-volume histograms (DVH) with treatment complications.This study was conducted in two phases. Initially, the PRV was defined prospectively in 50 consecutive prostate cancer patients (Group 1) who received a radical course of 3-D CRT. Then, the obtained PRV was used in the radiotherapy planning of these same 50 patients plus another 59 prostate cancer patients (Group 2) previously treated between 2004 and 2008. All these patients' data, including the rectum and PRV DVHs, were correlated to acute and late complications, according to the Common Toxicity Criteria (CTC) v4.0.The largest displacement occurred in the anterior axis. Long-term gastrointestinal (GI) complications grade ≥ 2 were seen in 9.2% of the cases. Factors that influenced acute GI reactions were: doses at 25% (p 5 0.011) and 40% (p 5 0.005) of the rectum volume and at 40% of the PRV (p 5 0.012). The dose at 25% of the rectum volume (p 5 0.033) and acute complications ≥ grade 2 (p 5 0.018) were prognostic factors for long-term complications. The PRV DVH did not correlate with late toxicity. The rectum showed a significant inter-fraction motion during 3D-CRT for prostate cancer. PRV dose correlated with acute gastrointestinal complications and may be a useful tool to predict and reduce their occurrence.

Conservative treatment of invasive bladder cancer

The concept of organ-preserving therapies is a trend in modern oncology, and several tumour types are now treated in this fashion. Trimodality therapy consisting of as thorough a transurethral resection of the bladder tumour as is judged safe, followed by concomitant chemoradiation therapy, is emerging as an attractive alternative for bladder preservation in selected patients with muscle-invasive bladder cancer. Long-term data from multiple institutional and cooperative group studies have shown that this approach is safe and effective and that it provides patients with the opportunity to maintain an intact and functional bladder with a survival rate similar to that for modern radical cystectomy.

Single fraction high-dose-rate brachytherapy and hypofractionated external beam radiation therapy in the treatment of intermediate-risk prostate cancer: Long-term results

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Background: We present the long-term results of a cohort of patients with intermediate-risk prostate cancer (PC) treated with single fraction high-dose-rate brachytherapy (HDRB) combined with hypofractionated external beam radiation therapy (HRT).

Methods: Patients with intermediate-risk PC were treated exclusively with HDRB and HRT. HDRB delivered a dose of 10 Gy to the prostate gland and HRT consisted of 50 Gy delivered in 20 daily fractions. The planning target volume was the prostate gland with a 1 cm margin all around. The first 121 consecutive patients with a minimum of 2 years post-treatment follow-up were assessed for acute and chronic toxicity and disease control.

Results: The median follow-up was 62.8 months. No acute grade III or higher toxicities were seen. Grade II late GI toxicity was seen in 9 patients (7.4%) and grade III in 2 (1.6%). Grade 3 GU toxicity was seen in 2 patients (1.6%), both with urinary obstructive symptoms requiring catheterization. A repeat biopsy was offered to the first 58 consecutively treated patients, and 44 patients agreed with the procedure. A negative biopsy was found in 40 patients (91%). The biochemical relapse-free survival rate at 5 and 8 years were 90.7% and 81.4%, with 13 patients presenting biochemical failure. Among them, nine were diagnosed with distant metastasis. Prostate cancer-specific and overall survival rates at 8 years were 100% and 95.5%, respectively.

Conclusions: Our program of HDRB and HRT is well tolerated, with acceptable toxicity rates. Furthermore, results from re-biopsies revealed an elevated rate of local control. These results are encouraging and confirm that the use of conformal RT techniques, adapted to specific biological features, have the potential to improve the therapeutic ratio in intermediate risk PC patients.

No significant financial relationships to disclose.

Treating intermediate-risk prostate cancer with hypofractionated external beam radiotherapy alone

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Background: A wide range of therapeutic alternatives is available for the treatment of intermediate-risk prostate cancer (IRPC). The use of hypofractionated external beam radiotherapy (HypoRT) in this group of patients appears to be an attractive option. Non-randomized institutional results have provided similar outcomes to conventional fractionation. For health-systems such as we have in Canada, where many patients live far, it significantly shortens treatment duration and impacts favorably in health costs. We report our results using HypoRT alone in IRPC.

Methods: Between October/2002 and July/2009, 82 men with IRPC (T2b-T2c, or PSA 10–20 ng/dL, or GS=7) were treated with HypoRT, without any androgen deprivation. Ultrasound image guidance was used daily to confirm setup. The dose was 66 Gy in 22 daily fractions of 3 Gy (BED=79.4Gy/44) prescribed at the isocenter. PTV was the prostate (+/− 1cm seminal vesicles) with 7-mm margin in all directions. GI and GU toxicity were prospectively assessed every 4–6 months using the CTCAE v3 scoring system. Biochemical failure was defined as nadir PSA + 2 ng/dL.

Results: 60% of patients had Gleason score 7; 43% had stage T2; median initial PSA=9 ng/ml; median age 71 years. With a median follow-up of 43 months (range: 7–89), only three patients (4%) have developed biochemical failure. All three showed metastatic disease few months after biochemical failure. Actuarial biochemical recurrence free survival (bNED) is 95.4%. There was no death related to prostate cancer. Three patients died from other causes without biochemical failure. The 5-year overall survival was 93%. At the last follow up visit, grade ≥ 2 late GI and GU toxicity rates were 2% and 7%, respectively. No grade 4 or 5 has occurred.

Conclusions: Men with IRPC treated with 66Gy/22 fractions and without androgen deprivation have experienced excellent 5-year biochemical control rate with acceptable late toxicity. This regimen is very convenient because the duration of the treatment is half of the time used with conventional fractionation. Whether the addition of short-term androgen deprivation would further improve outcome remains unclear.

No significant financial relationships to disclose.

Postoperative radiation therapy after hip replacement in high-risk patients for development of heterotopic bone formation

PURPOSE

To report the results of postoperative radiation therapy in preventing the development of heterotopic bone formation after hip replacement surgery in high-risk patients.

PATIENTS AND METHODS

Between 1991 and 2007, 44 patients were preventively treated with postoperative RT after total hip replacement. In total, 47 hips were treated. All patients were considered at high risk for developing heterotopic bone formation. Most patients (63.5%) were treated because of a history of severe osteoarthritis or ankylosing spondylitis. All patients were treated with shaped parallel-opposed fields with a single fraction of 7 Gy using 6 or 18 MV photons. Most patients (94%) received radiation therapy within 72 hours postoperative and in only three patients radiation therapy was delivered after 72 hours post-surgery (5-8 days).

RESULTS

Minimum follow-up was 1 year. There were 18 females and 26 males. Median age was 63 years (range: 18-80). Treatments were well tolerated and no acute toxicity was seen post-radiation therapy. Only one of the 47 hips (2%) developed heterotopic bone formation. This patient received postoperative radiation therapy to both hips but only developed heterotopic bone formation in one of them. None of the three patients treated beyond 72 hours failed. To date no late toxicity has been observed.

CONCLUSION

The use of postoperative radiation therapy was an effective and safe treatment in the prevention of heterotopic bone formation in a high-risk group of patients undergoing total hip replacement.

Combining radiation therapy and androgen deprivation for localized prostate cancer-a critical review

Interest has been increasing in the use of androgen deprivation therapy (ADT) combined with radiation therapy (RT) in the management of localized prostate cancer. Preclinical studies have provided some rationale for the use of this combination. In patients with high-risk disease, the benefit of a combined approach, with the addition of adjuvant hormonal therapy, is supported by results of randomized trials. In contrast, for patients with low-risk disease, there is no obvious therapeutic advantage except for cytoreduction. The usefulness of short-term hormonal therapy in association with rt for intermediate-risk patients is still debatable, particularly in the context of doseescalated RT. The optimal timing and duration of ADT, in the neoadjuvant and adjuvant settings alike, are still under investigation. In view of the potential side effects with ADT, further studies are being performed to better identify subsets of patients who will definitely benefit from this therapy in combination with rt.