Toxicity and Long-Term Outcomes of Dose-Escalated Intensity Modulated Radiation Therapy to 74Gy for Localised Prostate Cancer in a Single Australian Centre

Long term genitourinary toxicity following curative intent intensity-modulated radiotherapy for prostate cancer: a systematic review and meta-analysis

BACKGROUND

Recent studies have shown that radiation-induced pelvic toxicity often requires urological consultation. However, the 10-year incidence of genitourinary toxicity following intensity-modulated radiotherapy (IMRT) amongst patients with localised prostate cancer remains unclear. Hence, we conducted a systematic review and meta-analysis to determine the incidence of late genitourinary toxicity relying on Radiation Therapy Oncology Group (RTOG) and Common Terminology Criteria for Adverse Events (CTCAE) grade as well as the incidence of specific genitourinary toxicity. Secondary objectives involved quantifing the number of studies reporting 120-month follow-up endpoints, time to event analysis, predictive factors or economic evaluation.

METHODS

Articles published from January 2008 to December 2021 describing prospective studies were systematically searched in MEDLINE, EMBASE and Cochrane (PROSPERO protocol CRD42019133320). Quality assessment was performed by use of the Cochrane Risk of Bias 2 Tool for RCTs and the Newcastle Ottowa Scale for non-RCTs. Meta-analysis was performed on the 60-month incidence of RTOG and CTCAE Grade ≥2 genitourinary toxicity, haematuria, urinary retention and urinary incontinence.

RESULTS

We screened 4721 studies and six studies met our inclusion criteria. All included studies involved normofractionation, three included a hypofractionation comparator arm and none involved nodal irradiation. The pooled 60-month cumulative incidence of RTOG and CTCAE Grade ≥2 genitourinary toxicity were 17% (95% CI: 5-20%, n = 678) and 33% (95% CI: 27-38%, n = 153), respectively. The pooled 60-month cumulative incidence of Haematuria was 5% (95% CI: -4-14%, n = 48), Urinary incontinence 12% (95% CI: 6-18%, n = 194), Urinary retention 24% (95% CI: 9-40%, n = 10). One study reported time to event analyses, one reported predictive factors, no studies reported economic analysis or 120-month toxicity. There was considerable heterogeneity amongst the studies.

CONCLUSION

There are few high-quality studies reporting 60-month toxicity rates after IMRT. Conservative estimates of 60-month toxicity rates are high and there is need for longer follow-up and consistent toxicity reporting standards.

Novel purine thioglycoside analogs: synthesis, nanoformulation and biological evaluation in in vitro human liver and breast cancer models

Background: A series of novel pyrazolopyrimidine and pyrazololpyridine thioglycosides were synthesized and confirmed via their spectral analyses. Purpose: To evaluate the effect of these anti-metabolic compounds against proliferation of Huh-7 and Mcf-7 as in vitro models of human liver and breast cancers, respectively. Vero cells were used as an example of normal green monkey kidney cells. Methods: The most promising compound was subjected to a nanoformulation by its encapsulation into chitosan nanoparticles to increase its anti-cancerous activity. Nanoformulation was confirmed by TEM and FT-IR to ensure encapsulation and screened for their cytotoxicity against Huh-7 and Mcf-7 cells using MTT colorimetric assay and morphological examination. Genotoxic effect was performed by cellular DNA fragmentation assay. Simulated CompuSyn software (linear interaction effect) was conducted to predict the possible synergistic effect of nanocomposite as anticancerous activity. Apoptotic effect was further analyzed by detection of apoptotic proteins using ELISA assay. Results: The nano preparation was successfully prepared by encapsulation of compound 14 into chitosan nanoparticles, controlled to a size at 105 nm and zeta charges at 40.2 mV. Treatment of Huh-7 and Mcf-7 showed that compound 14 was the most cytotoxic compound on both cancer cell lines where IC50 was 24.59 (9.836 μg/mL) and 12.203 (4.8812 μg/mL) on Huh-7 and Mcf-7 respectively. But IC50 of the nano preparation was 37.19 and 30.68 μg/mL on Huh-7 and Mcf-7, respectively, indicating its aggressiveness on human breast cancer cells as confirmed by DNA fragmentation assay and theoretically by CompuSyn tool. Conclusion: A novel series of pyrazolopyrimidine thioglycosides and pyrazolopyridine thioglycosides were synthesized. Nanoformulation of compound 14 into chitosan nanoparticles demonstrated anticancer activity and can be used as a drug delivery system, but further studies are still required.

Mucoadhesive Chitosan-Pectinate Nanoparticles for the Delivery of Curcumin to the Colon

In the present study, we report the properties of a mucoadhesive chitosan-pectinate nanoparticulate formulation able to retain its integrity in the milieu of the upper gastrointestinal tract and subsequently, mucoadhere and release curcumin in colon conditions. Using this system, we aimed to deliver curcumin to the colon for the possible management of colorectal cancer. The delivery system comprised of a chitosan-pectinate composite nanopolymeric with a z-average of 206.0 nm (±6.6 nm) and zeta potential of +32.8 mV (±0.5 mV) and encapsulation efficiency of 64%. The nanoparticles mucoadhesiveness was higher at alkaline pH compared to acidic pH. Furthermore, more than 80% release of curcumin was achieved in pectinase-enriched medium (pH 6.4) as opposed to negligible release in acidic and enzyme-restricted media at pH 6.8. SEM images of the nanoparticles after exposure to the various media indicate a retained matrix in acid media as opposed to a distorted/fragmented matrix in pectinase-enriched medium. The data strongly indicates that the system has the potential to be applied as a colon-targeted mucoadhesive curcumin delivery system for the possible treatment of colon cancer.

Synergistic locoregional chemoradiotherapy using a composite liposome-in-gel system as an injectable drug depot

The use of radiosensitizers in clinical radiotherapy is limited by systemic toxicity. The biopolymeric, biodegradable, injectable liposome-in-gel-paclitaxel (LG-PTX) system was developed for regional delivery of the radiosensitizer paclitaxel (PTX), and its efficacy was evaluated with concurrent fractionated radiation. LG-PTX is composed of nano-sized drug-loaded fluidizing liposomes, which are incorporated into a porous biodegradable gellan hydrogel. This allows enhanced drug permeation while maintaining a localization of the drug depot. LG-PTX had an IC₅₀ of 325±117 nM in B16F10 melanoma cells, and cytotoxicity with concurrent doses of fractionated radiation showed significant increase in apoptotic cells (75%) compared to radiation (39%) or LG-PTX (43%) alone. Peri-tumoral injection in tumor-bearing mice showed PTX localization in the tumor 2 hours after administration, with no drug detected in plasma or other organs. LG-PTX administration with doses of focal radiation (5×3 Gy) significantly reduced tumor volumes compared to control (6.4 times) and radiation alone (1.6 times) and improved animal survival. LG-PTX thus efficiently localizes the drug at the tumor site and synergistically enhances the effect of concurrent radiotherapy. This novel liposome-in-gel system can potentially be used as a platform technology for the delivery of radiosensitizing drugs to enhance the efficacy of chemoradiotherapy.

78Gy with Fiducial Marker Image-Guided Radiotherapy in Prostate Cancer: Single Center Analysis of 301 Patients

AIM

In prostate cancer, fiducial marker image-guided radiotherapy (FMIGRT) allows correction of setup errors and interfraction physiological motion resulting in improved accuracy of target and sparing of at risk organs. We aim to report outcomes and toxicities observed in patients treated with dose escalation to 78Gy with FMIGRT in our center.

METHODS AND MATERIALS

Retrospective review of consecutive patients with histologically confirmed T1-4N0M0 localized prostate cancer treated with dose escalation to 78Gy with FMIGRT in our center. All patients had 3-D conformal radiotherapy. Duration of androgen deprivation therapy use was tailored to risk group. Toxicity was scored according to CTCAE.v04. Kaplan-Meier analysis was performed for freedom from biochemical failure (FFBF), prostate cancer-specific survival and overall survival.

RESULTS

Median follow-up was 48.6 months. Median duration of androgen deprivation therapy was 6 and 23 months in the intermediate- and high-risk group, respectively. FFBF at 5 years was 88.8%. FFBFs when stratified to risk groups were 100% for low risk, 88.9% for low-intermediate risk, 89.9% for high-intermediate risk and 85.4% for high risk, respectively. Acute severe toxicity (grade≥3) rate for both genitourinary (GU) and gastrointestinal (GI) was 1%. Late moderate-to-severe toxicity (grade≥2) rates for GU and GI were 15% and 17%, respectively, with severe (grade≥3) toxicity rate for GU and GI at 2% and 3%, respectively.

CONCLUSION

Dose escalation to 78Gy with FMIGRT in our series achieved good FFBF at 5 years with low acute and late toxicity rates. These results provide a good comparator cohort to our current use of image-guided intensity modulated radiotherapy.

Ten-year outcomes of intensity-modulated radiation therapy combined with neoadjuvant hormonal therapy for intermediate- and high-risk patients with T1c-T2N0M0 prostate cancer

BACKGROUND

We aimed to analyze the 10-year outcomes of intensity-modulated radiation therapy (IMRT) combined with neoadjuvant hormonal therapy (HT) for patients with intermediate- and high-risk T1c-T2N0M0 prostate cancer.

METHODS

Fifty patients with T1c-T2N0M0 prostate cancer, who were treated with high-dose IMRT combined with neoadjuvant HT, were evaluated. Of these patients, 19 and 31 were classified into the intermediate- and high-risk groups, respectively. Neoadjuvant HT was administered over a median duration of 6 months; 74 and 78 Gy in 2 Gy per fraction were essentially delivered to the intermediate- and high-risk cases, respectively. Adjuvant HT was not administered to any of the patients after the completion of IMRT.

RESULTS

Over a median follow-up period of 118 months, the 10-year prostate-specific antigen failure-free survival, prostate-specific antigen failure-free, salvage hormonal therapy-free, prostate cancer-specific survival, and overall survival rates were 70.2 %, 78.7 %, 89.2 %, 100 %, and 88.8 %, respectively. No grade 3 or higher acute or late toxicities were observed. The 10-year likelihoods of developing grade 2 late urinary and rectal toxicities were 13.7 % and 4.2 %, respectively. Compared with the outcomes of a cohort of historical controls who were locally irradiated with 70 Gy by three-dimensional conformal radiotherapy, the prostate-specific antigen failure-free rate was significantly better in the IMRT groups (78.7 % vs. 53.4 % at 10 years; p = 0.027).

CONCLUSIONS

High-dose IMRT combined with neoadjuvant HT achieved not only high prostate-specific antigen control, but also excellent survival outcomes with acceptable morbidities, for a Japanese cohort of intermediate- and high-risk T1c-T2N0M0 prostate cancer patients, and these results warrant further investigation.

Radical radiotherapy for high-risk prostate cancer in older men

Historical data for older men with high-risk nonmetastatic prostate cancer treated with radiotherapy alone have demonstrated a 10-year prostate-cancer-specific mortality of around 30%. The development of dose escalation, using techniques such as intensity-modulated radiotherapy, has enabled more targeted delivery of treatment with improved efficacy and a reduction in the risk of toxicity compared with conventional radiotherapy. The combination of radiotherapy and androgen-deprivation therapy (ADT) has been shown to improve overall survival compared with radiotherapy or ADT alone without a significant increase in toxicity in patients with minimal comorbidities. There is evidence that patient age has only a marginal effect on genitourinary and gastrointestinal toxicities following radiotherapy. Further research has shown that although age does have an effect on the likelihood of sexual dysfunction after radiation therapy, there is no significant difference in the proportion of men aged ≥ 75 years who feel that sexual dysfunction is a moderate or serious problem before or 24 months after diagnosis. Radical radiotherapy is effective and well tolerated in senior men with high-risk prostate cancer and should be offered in combination with long-term ADT to patients with minimal comorbidities. In case of significant comorbid conditions, shorter durations of ADT may be considered.