Hypofractionated, Dose Escalation Radiation Therapy for High-Risk Prostate Cancer: The Safety Analysis of the Prostate Cancer Study-5, a Groupe de Radio-Oncologie Génito-Urinaire de Quebec Led Phase 3 Trial

PURPOSE

The low α\β ratio of 1.2 to 2 for prostate cancer (PCa) suggests high radiation-fraction sensitivity and predicts a therapeutic advantage of hypofractionated (HF) radiation therapy (RT). To date, no phase 3 randomized clinical trial has compared moderately HF RT with standard fractionation (SF) exclusively in high-risk PCa patients. We are reporting the safety of moderate HF RT in high-risk PCa in an initially noninferiority-designed phase 3 clinical trial.

METHODS AND MATERIALS

From February 2012 to March 2015, 329 high-risk PCa patients were randomized to receive either SF or HF RT. All patients received neoadjuvant, concurrent, and long-term adjuvant androgen deprivation therapy. Standard fractionation RT consisted of 76 Gy in 2 Gy per fraction to the prostate, where 46 Gy was delivered to the pelvic lymph nodes. Hypofractionated RT included concomitant dose escalation of 68 Gy in 2.72 Gy per fraction to the prostate and 45 Gy in 1.8 Gy per fraction to the pelvic lymph nodes. The coprimary endpoints were acute and delayed toxicity at 6 and 24 months, respectively. The trial was originally designed as a noninferiority with a 5% absolute margin. Given the lower-than-expected toxicities in both arms, the noninferiority analysis was completely dropped.

RESULTS

Of the 329 patients, 164 were randomized to the HF and 165 to the SF arms. In total, there were more grade 1 or worse acute gastrointestinal (GI) events in the HF arm, 102 versus 83 events in the HF and SF arm, respectively (P = .016). This did not remain significant at 8 weeks of follow-up. There were no differences in grade 1 or worse acute GU events in the 2 arms, 105 versus 99 events in the HF and SF arm, respectively (P = .3). At 24 months, 12 patients in the SF arm and 15 patients in the HF arm had grade 2 or worse delayed GI-related adverse events (hazard ratio, 1.32; 95% CI, 0.62-2.83; P = .482). There were 11 patients in the SF arm and 3 patients in the HF arm with grade 2 or higher delayed genitourinary (GU) toxicities (hazard ratio, 0.26; 95% CI, 0.07-0.94; P = .037). There were 3 grade 3 GI and one grade 3 GU delayed toxicities in the HF arm and 3 grade 3 GU and no grade 3 GI toxicities in the SF arm. No grade 4-toxicities were reported.

CONCLUSIONS

This is the first study of moderate HF dose-escalated RT in exclusively high-risk patients with prostate cancer treated with long-term androgen deprivation therapy and pelvic RT. Although our data were not analyzed as a noninferiority, our results demonstrate that moderately HF RT is well-tolerated, similar to SF RT at 2 years, and could be considered an alternative to SF RT.

Conventional vs. Hypo-Fractionated, Radiotherapy for High-Risk Prostate Cancer (PCS5), Randomized, Non-Inferiority, Phase 3 Trial: Posthoc Analysis of IMRT vs. 3D-CRT Radiation Therapy Associated Toxicities

PURPOSE/OBJECTIVE(S)

The Prostate Cancer Study number 5 (PCS5), is a multi-centric non-inferiority, phase 3, randomized controlled trial of high-risk prostate cancer patients of treated with either conventionally fractionated radiotherapy (CFRT) or hypofractionated radiotherapy (HFRT). The 7 years' pre-planned analysis showed that HFRT (68 Gy in 25 fractions) was as effective and well tolerated as CFRT (76 Gy in 38 fractions). In this posthoc analysis we aim to report the genitourinary (GU) and gastrointestinal (GI) toxicities associated with radiation therapy techniques: intensity-modulated radiotherapy (IMRT) and 3D-conformal radiotherapy (3D-CRT).

MATERIALS/METHODS

PCS5 randomized patients in a 1:1 ratio to receive either CFRT or HFRT. All patients received long term neoadjuvant, concurrent and adjuvant androgen suppression, with a median duration of 24 months. The toxicities were reported as per the Common Terminology Criteria for Adverse Events version 4. Acute toxicities were defined as presenting ≤ 180 days post-RT start and delayed > 180 days. The cumulative acute and delayed GI and GU toxicities were classified in grade groups: grade 1 or higher (G1+), G2+, and G3+. For each grade group, acute and delayed, we performed multivariable logistic regression analyses, adjusting for age, CTV volume, diabetes, fractionation (CRFT or HFRT), hypertension, and stage < T3b or ≥ T3b. For efficacy analyses cox-regression was utilized. A p-value < 0.05 was considered significant.

RESULTS

Three hundred twenty of the 329 patients enrolled in the trial were included in this posthoc analyses. The mean age was 71.4 ± 6.1 years, and the mean CTV volume (n = 219) was 47.25 ± 19.9 cc. IMRT was used in 195 (60.6%) patients and 3D-CRT in 125 (39.1%) patients. Multivariable logistic regression showed a significant difference in favor of IMRT for GI G2+ acute toxicity (OR = 0.285 [0.14-0.59]; CI: 95%; p<0.001) and GI G2+ delayed toxicity (OR = 0.202 [0.60-0.69]; CI: 95%; p = 0.01). There were no differences in G3+ GI or GU toxicities and there were no grade 4 toxicities. There were no differences in efficacy at 7 years between the two treatment technics. Outcomes for IMRT vs. 3D-CRT respectively, overall survival (81.5% vs 79.2%; HR: 0.92 [0.55-1.53]; CI: 95%; p-value: 0.74), distant metastasis free survival (90,7% vs 92.8%; HR: 1.4 [0.63-3.1]; CI: 95%; p-value: 0.42), prostate cancer mortality (95.8% vs. 92.2%; HR: 0.93 [0.32-2.67]; CI: 95%; p-value: 0.89), and biochemical failure (85.1% vs 88%; HR: 1.35 [0.72-2.52]; CI: 95%; p-value: 0.35).

CONCLUSION

This is the first phase 3 randomized controlled trial assessing the use of HFRT vs. CFRT, exclusively in high-risk prostate cancer patients. Given that our efficacy data at 7 years follow-up establishes moderate HFRT as a new standard of care and no difference between IMRT and 3D-CRT, we strongly recommend that patients who are treated with EBRT should receive IMRT, given the reduced acute and delayed grade 2 or higher GI toxicities.

Stereotactic radiation therapy for breast cancer in the elderly

The management of breast cancer in elderly women is going to be a major public health issue in a near future. The use of hypofractionated stereotactic radiotherapy is expanding but might be a priori not offered to older patients. We addressed the role of stereotactic radiotherapy (SBRT, 1–10 fractions) in elderly patients with breast cancer, in definitive, adjuvant and metastatic settings. Review of the literature. Of six series using SBRT for partial breast or breast boost irradiation and over 20 oligometastatic (brain, lung, liver, bone) SBRT series including patients aged ≥60 years old, no difference was found in term of efficacy (>80%) and toxicity (<5% G3-4) compared to the younger. Hypofractionation is also well adapted to the elderly, due to limited transportation-related fatigue. SBRT studies by age group are lacking. However, hypofractionated SBRT is particularly adapted to older patients with breast cancer, in term of efficacy and tolerability and should be encouraged rather than more morbid treatments whenever possible.

Hypofractionated, dose escalation radiotherapy for high-risk prostate cancer: The primary endpoint of a group led phase III trial. (PCS5)

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Background: The low α\β ratio of prostate cancer (PCa), 1.5-2, suggests high radiation-fraction sensitivity and predicts a therapeutic advantage of hypofractionated radiation treatment (HFRT). Most available data of moderate HFRT have focused on low, intermediate and/or mixed risk groups. We therefore conducted the first randomized trial of moderately HFRT in high-risk PCa patients and present the primary safety analysis of side effects at 2 years. Methods: We conducted a Canadian multi-centric phase III trial of conventional fractionated radiation therapy (CFRT) vs. intensity-modulated HFRT in men with high-risk PCa as per NCCN definition. From February 2012 to March 2015, 329 patients were randomized in a 1:1 ratio to receive either CFRT or HFRT. All patients received neo-adjuvant, concurrent and adjuvant androgen suppression, with a median duration of 24 months. CFRT consisted of 76 Gy in 2 Gy per fraction to the prostate where 46 Gy was delivered to the pelvic lymph nodes. HFRT consisted of concomitant dose escalation of 68 Gy in 2.72 Gy per fraction to the prostate and 45 Gy, in 1.8Gy per fraction to the pelvic lymph nodes. The primary endpoint was to compare the toxicities at 6 months and at 24 months using the CTCAE v.4. Results: Of the329 patients, 164 were randomized to HFRT and 165 to CFRT. The minimum, median and maximum follow-up were 24, 40 and 60 months respectively. At 24 months, 12 patients in the CFRT arm and 15 patients in the HFRT arm had grade 2 or worse gastrointestinal (GI)-related adverse events (HR:1.32 [0.62.2.83] 95% CI; P=NS). Similarly, 11 patients in the CFRT arm and 3 patients in HFRT arm had grade 2 or higher genitourinary (GU) toxicities (HR:0.26 [0.07-0.94] 95% CI; P=0.037). In the HFRT arm, there were 3 grade 3 GI and one grade 3 GU related toxicities. In the CFRT arm there were 3 grade 3 GU and no grade 3 GI related toxicities. There were no grade 4 toxicities in either arm. Conclusions: This is the first hypofractionated dose escalated radiotherapy study in high-risk PCa patients treated with contemporary radiation and androgen suppression. Our results indicate that moderate HFRT to high risk PCa patients is equally well tolerated as CFRT at 2 years. Clinical trial information: NCT01444820.

Acinic cell carcinoma of the retromolar trigone region: expanding the tumor phenotype in Cowden syndrome?

Cowden syndrome (CS) is a cancer predisposition syndrome caused by germline mutations in the PTEN tumor suppressor gene. It is associated with an increased risk of thyroid, breast and endometrial cancer but many manifestations can be found in the head and neck region, some of which are pathognomonic. Here we report a 35-year-old male referred by his dentist for evaluation of a lesion located near the retromolar trigone. Comprehensive clinical examination revealed papillomatous skin lesions, macrocephaly and gingival hypertrophy. Histopathological examination of the lesion showed an acinic cell carcinoma (ACC) of minor salivary gland origin. Analysis of the PTEN gene identified a germline R130Q mutation in exon 5, confirming the diagnosis of CS, but no loss of heterozygosity was seen in DNA extracted from tumor tissue. This is to our knowledge the first case describing an association of ACC of the minor salivary gland with a PTEN-gene related disorder. It emphasizes the importance of head and neck examination in these patients.

Toxicity report of once weekly radiation therapy for low-risk prostate adenocarcinoma: preliminary results of a phase I/II trial

Background

Increasing clinical data supports a low α/β ratio for prostate adenocarcinoma, potentially lower than that of surrounding normal tissues. A hypofractionated, weekly radiation therapy (RT) schedule should result in improved tumour control, reduced acute toxicity, and similar or decreased late effects. We report the toxicity profile of such treatment.

Materials and Methods

We conducted a multi-institution phase I/II trial of three-dimensional conformal radiation therapy (3D-CRT) for favourable-risk prostate cancer (T1a-T2a, Gleason ≤ 6 and PSA < 10 ng/ml). RT consisted of 45 Gy in nine 5 Gy fractions, once weekly. Primary end-points were feasibility and late gastrointestinal (GI) toxicity (RTOG scale), while secondary end-points included acute GI toxicity, acute and late genitourinary (GU) toxicity, biochemical control, and survival.

Results

Between 2006 and 2008, 80 patients were treated. No treatment interruptions occurred. The median follow-up is 33 months (range: 20-51). Maximal grade 1, 2, and 3 acute (< 3 months) GU toxicity was 29%, 31% and 5% respectively (no grade 4). Acute GI grade 1 toxicity was reported in 30% while grade 2 occurred in 14% (no grade 3 or 4). Crude late grade ≥ 3 toxicity rates at 31 months were 2% for both GU and GI toxicity. Cumulative late grade ≥ 3 GI toxicity at 3 years was 11%. Two patients had PSA failure according to the Phoenix definition. The three-year actuarial biochemical control rate is 97%.

Conclusions

Weekly RT with 45 Gy in 9 fractions is feasible and results in comparable toxicity. Long term tumour control and survival remain to be assessed.

Cervical lymph node metastases from unknown primary cancer: a single-institution experience with intensity-modulated radiotherapy

PURPOSE

To determine the effectiveness and rate of complications of intensity-modulated radiotherapy (IMRT) in the treatment of cervical lymph node metastases from unknown primary cancer.

METHODS AND MATERIALS

Between February 2005 and November 2008, 25 patients with an unknown primary cancer underwent IMRT, with a median radiation dose of 70 Gy. The bilateral neck and ipsilateral putative pharyngeal mucosa were included in the target volume. All patients had squamous cell carcinoma, except for 1 patient who had adenosquamous differentiation. They were all treated with curative intent. Of the 25 included patients, 20 were men and 5 were women, with a median age of 54 years. Of these patients, 3 had Stage III, 18 had Stage IVa, and 4 had Stage IVb. Of the 25 patients, 18 (72%) received platinum-based chemotherapy in a combined-modality setting. Neck dissection was reserved for residual disease after definitive IMRT. Overall survival, disease-free survival, and locoregional control were calculated using the Kaplan-Meier method.

RESULTS

With a median follow-up of 38 months, the overall survival, disease-free survival, and locoregional control rates were all 100% at 3 years. No occurrence of primary cancer was observed during the follow-up period. The reported rates of xerostomia reduced with the interval from the completion of treatment. Nine patients (36%) reported Grade 2 or greater xerostomia at 6 months, and only 2 (8%) of them reported the same grade of salivary function toxicity after 24 months of follow-up.

CONCLUSION

In our institution, IMRT for unknown primary cancer has provided good overall and disease-free survival in all the patients with an acceptable rate of complications. IMRT allowed us to address the bilateral neck and ipsilateral putative pharyngeal mucosa with minimal late salivary function toxicity. The use of concurrent chemotherapy and IMRT for more advanced disease led to good clinical results with reasonable toxicities.