Prostate morbidity
Late toxicity and biochemical control in 554 prostate cancer patients treated with and without dose escalated image guided radiotherapy

https://doi.org/10.1016/j.radonc.2013.04.007Get rights and content

Abstract

Background and purpose

To compare rates of late gastrointestinal toxicity, late genitourinary toxicity and biochemical failure between patients treated for prostate cancer with implanted fiducial marker image guided radiotherapy (FMIGRT), and those treated without FMIGRT.

Methods and materials

We performed a single institution retrospective study comparing all 311 patients who received 74 Gy without fiducial markers in 2006 versus all 243 patients who received our updated regimen of 78 Gy with FMIGRT in 2008. Patient records were reviewed 27 months after completing radiotherapy. Biochemical failure was defined using the Phoenix definition. Details of late gastrointestinal and genitourinary toxicities were graded according to CTCAEv4. Moderate/severe toxicity was defined as a grade 2 or higher toxicity. Cumulative incidence and prevalence curves for moderate/severe toxicity were constructed and compared using multistate modeling while biochemical failure free survival was compared using the log rank test. A Cox regression model was developed to correct for confounding factors.

Results

Median follow-up time for both groups was 22 months. The hazard ratio for moderate/severe late gastrointestinal toxicity in the non-FMIGRT group was 3.66 [95% CI (1.63–8.23), p = 0.003] compared to patients in the FMIGRT group. There was no difference in the hazard ratio of moderate/severe late genitourinary toxicity between the two groups (0.44 [95% CI (0.19–1.00)]), but patients treated with FMIGRT did have a quicker recovery from their genitourinary toxicities HR = 0.24 [95% CI (0.10–0.59)]. We were unable to detect any differences in biochemical failure free survival between the cohorts HR = 0.60 [95% CI (0.30–1.20), p = 0.143].

Conclusion

Despite dose escalation, the use of FMIGRT in radical radiotherapy for prostate cancer significantly reduces the incidence of gastrointestinal toxicity and the duration of late genitourinary toxicity when compared to conventional non-FMIGRT techniques.

Section snippets

Study design and patient selection

We performed a retrospective study of patients with localized prostate cancer at our institution, comparing all those who received 74 Gy without fiducial markers in 2006 (our standard regimen at this time) versus all those who received our updated regimen of 78 Gy with FMIGRT in 2008. Patients who were treated in 2007 were not considered for this study due to it being a changeover year during which our new FMIGRT regimen was phased in. Patients were excluded from the analysis if they had nodal

Patient characteristics

324 patients were identified who received 74 Gy without FMIGRT in 2006. Twelve patients were excluded due to having no follow up data and a further one patient excluded due to incomplete disease details making a total cohort of 311 patients in the non-FMIGRT group. In 2008, there were 251 patients who received 78 Gy with FMIGRT. Six of these were excluded due to no follow up and two patients had incomplete data resulting in a total of 243 patients in the FMIGRT cohort.

Baseline demographics and

Discussion

This study demonstrates that patients treated with FMIGRT have a significantly reduced likelihood of experiencing moderate/severe late gastrointestinal toxicity and a reduced duration of moderate/severe late genitourinary toxicities. These statistically significant reductions were seen even despite patients in the FMIGRT group being dose escalated to 78 Gy compared to those patients in the non-FMIGRT group receiving 74 Gy. These findings are in keeping with what would be expected from the more

Conflict of interest

None.

References (24)

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