SBRT in 3 Fractions for T1 Glottic Cancer

PURPOSE/OBJECTIVE(S)

The purpose of this study was to report the results of a mature phase II study.

MATERIALS/METHODS

This was a prospective study at a single institution that were enrolling patients with T1 glottic cancer. The true vocal cords (TVCs) were divided into thirds and the third(s) containing disease prescribed 36 Gy in 3 fractions. The portions of the TVCs next to the involved one were planned to receive 30 Gy in 3 fxs. The remaining parts of the TVCs as well the rest of the larynx was tentatively spared. SBRT was delivered by a LINAC-based approach using multiple arcs (VMAT). Toxicity was scored by CTCAE and late events were considered those occurring 3 months after SBRT. Voice quality was investigated by the voice handicap index (VHI) at regular intervals. A generalized linear mixed model was used to analyze longitudinal functional data and the actuarial approach was used to report late toxicity prevalence rates. The planned sample size, 75 patients, was calculated to reject the hypothesis of a 2-yr local control (LC) of 85% against the alternative hypothesis of 95%. The median follow-up time is 40 months (IQR: 31.5-47.3 months).

RESULTS

Accrual was discontinued after 33 patients due to concerns on late toxicity rates on both the mucosa and the cartilages. Median age was 66 yrs (IQR: 60-71 yrs). T stage was as follows: T1a: 23 pts (69.7%); T1b: 10 pts (30.3%). Only two patients never smoked, while of the remaining ones, 13 (41.9%) kept smoking after SBRT despite appropriate counseling. At last, follow up, all patients are alive and without evidence of disease but one patient who died 21.3 months after SBRT for intercurrent causes. The observed local control rate of 100% allows to reject the null hypothesis because, according to the binomial distribution, the probability of not observing at least one recurrence out of the accrued 33 patients is <0.5% if a 2-yr LR ≤85% would be true. All but 5 patients developed transient confluent mucositis of the treated volume with a prevalence peak at 19 days after SBRT. Six patients (18.2%) developed soft tissue necrosis (N = 4) or cartilage necrosis (N = 2) after a median time of 14.9 months from SBRT (range: 9.1-24.5 months). The actuarial prevalence of any necrosis is 3.0%, 1.3% and 0.8% at 12, 24 and 36 months after SBRT, respectively, with a peak at 6.1% between 9.9 and 11.9 months. All 4 soft tissue events healed with conservative therapy after a median time of 2.5 months (range: 1-12.2 months). One patient with chondronecrosis refused total laryngectomy and is alive with persistent toxicity 22.9 months after its onset; the other patient underwent endoscopic removal of the necrotic arytenoid and he is alive without evidence of disease or further complications more than 2 years afterwards. Patient reported outcomes (VHI) will be presented as well.

CONCLUSION

SBRT to 36/30 Gy in 3 fractions is highly effective in controlling T1 true vocal cord carcinoma, but necrosis, though mostly transient, is a concern. Based on the present results, a reduction in total doses is justified and a novel phase II study is ongoing.

DCE-MRI-Based Atlas for Prostate Bed Recurrence after Radical Prostatectomy: Consistency of CTV Delineation with the Available Contouring Guidelines

PURPOSE/OBJECTIVE(S)

To create a magnetic resonance image (MRI)-based atlas of prostate bed recurrence for prostate cancer patients undergoing salvage radiotherapy (sRT) after radical prostatectomy and to evaluate the consistency of contouring guidelines for the prostatic fossa clinical target volume (PF-CTV) delineation.

MATERIALS/METHODS

Patients with biochemical recurrence and prostate bed lesions at MRI before sRT were included. A reference patient was identified and the lesion(s) of each patient was mapped by a deformable co-registration among T2 weighted (T2w) images. The structure sets were combined to create a 3D recurrence incidence map, overlapped on T2w reference set, then transferred to the planning CT. The volume and the location of the lesions were extracted. On the reference CT, 5 PF-CTV contouring strategies were implemented: Radiation Therapy Oncology Group (RTOG); European Organization for Research and Treatment of Cancer (EORTC); Francophone Group of Urological Radiotherapy (GFRU); Faculty of Radiation Oncology Genito-urinary Group (FROGG) and Princess Margaret Hospital (PMH). Coverage was assessed after identifying the centroid of each lesion: if the centroid was included in the PF-CTV, the coverage was considered complete (fully covered-FC), otherwise uncovered (UC). The coverage was evaluated for each contouring strategy and compared with the chi-squared test; the strength of the correlation was assessed with the phi coefficient.

RESULTS

A total of 112 patients with 124 recurrences were identified. The lesions were located at the vesicourethral anastomosis (VUA), around the bladder neck (BN) and beyond the bladder (RV) in 63, 36 and 25 cases. Regardless the contouring strategy, 89.1% of the lesions were FC. Coverage was higher (p<0.001) for BN (95.6%) over RV (83.2%) and VUA (73.7%) lesions. FC/UC rates were 66.1%/33.9%, 83.9%/16.1%, 89.5%/10.5%, 83.1%/16.9%, 87.1%/12.9% for EORTC, FROGG, GFRU, RTOG and PMH, respectively. At pair-wise comparison, the EORTC definition had lower coverage (p<0.001) and was poorly correlated to the other strategies (phi values ranging 0.385-0.540, p <0.001). Conversely, the correlations between the other definitions were >0.700, the highest between PMH-FROG (0.812, p<0.001). After selecting VUA lesions only (N = 63), the probability of FC was 60.3%, 74.6%, 82.5%, 71.4% and 79.4% for EORTC, FROGG, GFRU, RTOG and PMH, respectively. The EORTC definition performed poorly than GFRU (p = 0.006) and PMH (p = 0.020). When considering lesions above the VUA (N = 61), the performance improved (FC: 72.1%, 93.4%, 96.7%, 95.1% and 95.1% for EORTC, FROGG, GFRU, RTOG and PMH, respectively) but the EORTC was significantly less covering and its correlation with the others was ≤ 0.1.

CONCLUSION

According to the criterium of coverage our data do not support the use of the EORTC definition. Here we provide an MRI-based atlas of prostatic bed recurrence that can optimize sRT contours.

Nasopharyngeal cancer: the impact of guidelines and teaching on radiation target volume delineation

Target volume delineation in the radiation treatment of nasopharyngeal cancer is challenging due to several reasons such as the complex anatomy of the site, the need for the elective coverage of definite anatomical regions, the curative intent of treatment and the rarity of the disease, especially in non-endemic areas. We aimed to analyze the impact of educational interactive teaching courses on target volume delineation accuracy between Italian radiation oncology centers. Only one contour dataset per center was admitted. The educational course consisted in three parts: (1) The completely anonymized image dataset of a T4N1 nasopharyngeal cancer patient was shared between centers before the course with the request of target volume and organs at risk delineation; (2) the course was held online with dedicated multidisciplinary sessions on nasopharyngeal anatomy, nasopharyngeal cancer pattern of diffusion and on the description and explanation of international contouring guidelines. At the end of the course, the participating centers were asked to resubmit the contours with appropriate corrections; (3) the pre- and post-course contours were analyzed and quantitatively and qualitatively compared with the benchmark contours delineated by the panel of experts. The analysis of the 19 pre- and post-contours submitted by the participating centers revealed a significant improvement in the Dice similarity index in all the clinical target volumes (CTV1, CTV2 and CTV3) passing from 0.67, 0.51 and 0.48 to 0.69, 0.65 and 0.52, respectively. The organs at risk delineation was also improved. The qualitative analysis consisted in the evaluation of the inclusion of the proper anatomical regions in the target volumes; it was conducted following internationally validated guidelines of contouring for nasopharyngeal radiation treatment. All the sites were properly included in target volume delineation by  >50% of the centers after correction. A significant improvement was registered for the skull base, the sphenoid sinus and the nodal levels. These results demonstrated the important role that educational courses with interactive sessions could have in such a challenging task as target volume delineation in modern radiation oncology.

Hearing Loss After Cisplatin-based Chemoradiotherapy for Locally Advanced Head and Neck Cancer: A Prospective Single-institution Study

BACKGROUND/AIM

A single-institution prospective study was conducted to evaluate hearing loss rate after intensity modulated radiotherapy with concomitant cisplatin-based chemotherapy (CRT) for locally advanced head and neck cancer and identify cochlear dosimetric parameters associated with hearing loss risk.

PATIENTS AND METHODS

Hearing assessment, patients' characteristics, tumor-related variables, and cochlear quantitative dosimetric factors for adults with locally advanced head and neck cancer treated with CRT were prospectively collected. Each patient repeated audiometry at baseline (pre-CRT), 1 month after CRT, and then every 3 to 6 months. For each cochlea minimum dose (D_min), mean dose (D_mean), and maximum dose (D_max) were extracted from treatment plans. Logistic analysis was used for multivariate modeling. The relation between cochlear dosimetric factors and significant hearing loss was also analyzed with receiver operating characteristic (ROC) curves.

RESULTS

Between January 2016 and December 2018, 35 patients (70 cochleae) were included. Most patients (n=29; 82.9%) had primary cancer in a low-risk region (oral cavity, oropharynx, larynx). All patients completed the programmed CRT. During follow-up, significant hearing loss was recorded in 13 cases (37.1%). The ROC areas for significant hearing loss in relation to D_min, D_mean, and D_max were 0.70, 0.66, and 0.66, respectively. A dose-dependent relationship was noted between cochlear D_min and significant hearing loss.

CONCLUSION

D_min <14.4 Gy is associated with reduced rates of significant hearing loss after concomitant cisplatin-based CRT in patients with locally advanced head and neck cancer.

Stereotactic body radiotherapy for T1 glottic cancer: dosimetric data in 27 consecutive patients

AIM

Because the clinical feasibility of stereotactic body radiotherapy (SBRT) for early glottic cancer (T1) is controversial, we report dosimetric results in 27 consecutive patients from a prospective phase I and II study that started in 2017.

METHODS

In our approach, only the parts of the true vocal cord containing cancer and those immediately adjacent are planned to be treated to 36 Gy and 30 Gy, respectively, in 3 fractions. Several dosimetric metrics for both target volumes and organs at risk were extracted from individual plans and results were compared to those achieved by other authors in a similar setting.

RESULTS

Proper coverage was reached at planning in 2/3 of planning treatment volume 30 Gy, but only 4 planning treatment volume 36 Gy; conversely, the maximum dose objective was met for most of the patients on either arytenoid cartilage, but this was not the case for 51.9% and 96.3% of cricoid and thyroid cartilages, respectively. Our dosimetric results are similar to if not better than those achieved by others.

CONCLUSION

SBRT in 3 fractions for T1 glottic lesions is dosimetrically challenging. Clinical validation is awaited.

Refinement & validation of rectal wall dose volume objectives for prostate hypofractionation in 20 fractions

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LRB was correlated to irradiation technique and several % rectal wall cut points.

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The predictive role of dosimetric variables relates to the irradiation technique.

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Dose volume objectives for patients treated with IMRT/VMAT are reported.

Background and purpose

Dose-volume objectives for the rectum have been proposed to limit long term toxicity after moderately hypofractionated radiotherapy (MHRT) for localized prostate cancer. The purpose of the present study is to validate and possibly refine dose volume objective for the rectal wall after 20-fraction MHRT.

Materials and methods

All patients treated by 20-fraction MHRT at a single Institution were identified and relative rectal wall (%RW) DVH retrieved. The endpoint of the study is the development of grade 2+ late rectal bleeding (LRB) according to a modified RTOG scale. Clinical and dosimetric predictors of LRB were investigated at both uni- and multi-variable analysis.

Results

293 patients were identified and analyzed. Of them, 35 (12%) developed the endpoint. At univariable analysis, antithrombotic drug usage (yes vs no), technique (3DCRT vs IMRT/VMAT) and several %RW DVH cut-points were significantly correlated with LRB. However, within patients treated by 3DCRT (N = 106), a bi-variable model including anti-thrombotic drug usage and selected %RW dose/volume metrics failed to identify independent dosimetric predictors of LRB. Conversely, within patients treated with intensity modulation (N = 187), the same model showed a progressively higher impact of the percent of RW receiving doses above 40 Gy. Based on this model, we were able to confirm (V32), refine (V60) and identify a novel (V50) cut-point for the %RW.

Conclusion

We recommend the following dose volume objectives for the %RW in order to minimize the risk of LRB after 20-fraction MHRT: V32 ≤ 50%; V50 ≤ 25.8% and V60 ≤ 10%.

Successful role of adjuvant radiotherapy in a rare case of tracheal inflammatory myofibroblastic tumor: a case report

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is a rare benign cancer that can express a more aggressive phenotype related to the genetic mutation of the anaplastic lymphoma kinase receptor (ALK). Involvement of trachea is extremely rare and due to the clinical and radiologic nonspecificity, the definitive diagnosis is based on the histologic evaluation of tissue specimens. Total surgical excision is curative and chemotherapy or radiotherapy has been employed in the treatment of unresectable tumors or as adjuvant therapies.

CASE PRESENTATION

The case described here is being reported because of the rare tracheal location and the atypical treatment approach used for an ALK-positive IMT. A 7-week pregnant woman voluntary interrupted pregnancy and underwent total surgical excision that resulted to have close margins. Although ALK-positive expression indicated the use of ALK inhibitors, she refused any type of adjuvant therapy that could affect ovarian function. Thus, 3D conformational external beam radiotherapy was performed with a daily dose of 180 cGy, 5 times per week, up to 45 Gy at the level of trachea. A total of 62 months of follow-up showed and no signs of disease recurrence or late radiation therapy-related toxicity.

CONCLUSIONS

This report describes an extremely rare case of a tracheal IMT, underlying the key role of radiotherapy as adjuvant treatment able to definitively cure IMT, limiting systemic chemotherapy-related toxicity.

Regression of a case of Multiple Myeloma with antiviral treatment in a patient with chronic HCV infection

We report a case of a 54 year old patient with Multiple Myeloma (MM) and chronic HCV infection. In 2005 MM was diagnosed and a chemotherapy was prescribed. Before starting treatment a chronic HCV infection was found. When she came to our Institution for a second opinion, chemotherapy treatment was not considered immediately necessary so the patient was treated for the HCV chronic infection (Pegilated alpha-Interferon 180 μg/week and Ribavirin 1000 mg p.o./day). After one month of treatment she presented a reduction of Bence Jones protein (BJ) that further decreased in the following three months. The antiviral treatment was suspended after six months and a re-evaluation showed a complete viral response and a regression of MM. Sixty-eight months after the end of antiviral treatment the patient is asymptomatic and presents a condition compatible with an M-GUS. While the association between HCV infection and non-Hodgkin's lymphoma is consolidated and it is clearly demonstrated that antiviral treatment in these patients can induce a high proportion of partial and complete remission, a similar effect was never described in MM. The response obtained in our patient may suggest a possible a role of HCV in the pathogenesis of MM.

[The optimization of the treatment and timing of the intervention by a nephrologist in pre-dialytic chronic renal insufficiency]

BACKGROUND

Early referral to nephrologists of patients with chronic renal failure (CRF) reduces morbidity and mortality in dialysis. Aim of this work is to evaluate the condition of early and late referral, and whether the two different conditions can affect the treatments.

MATERIALS AND METHODS

This is a prospective study with a 12-month follow-up period. During this time, we verified the prevalence of patients with serum creatinine > 1.5 mg/dL (CRF patients) and the condition of early or late referral, defined as referral to nephrologists for > or < 3 times during follow up, respectively. Diagnosis of diabetes mellitus and/or arterial hypertension, and the use of antihypertensive drugs, insulin, hypoproteic diet and erythropoietin was recorded in each patient.

RESULTS

CRF (mean serum creatinine value = 2.11+/-1.52 mg/dL) was observed in 190 patients aged 72.05+/-11.62 years. The prevalence of CRF was 4718 pmp. Diabetes and hypertension were diagnosed in 107 subjects (56.3%) and 152 subjects (80%), respectively. Only 74.2% (no. 141) of the patients with CRF was habitually followed by the nephrologist and the frequency was directly correlated to the degree of CRF: 100% of the patients with Creatinine Clearance (Cr Cl) < 25 mL/min, 70% with Cr Cl >25 < 50, and 0% with Cr Cl >50 < 80 mL/min. Early referral was coupled with a wider use of a hypoproteic diet, erythropietin, and the association ACE-I + Angiotensin II receptor antagonists.

CONCLUSION

In conclusion, our data show a prevalence of CRF that is at least 5 times greater than that of dialysis patients. The condition of late referral is present in about 30% of the CRF population from the time of the initial phases of renal disease. Referral time affects the modalities of the treatment.

Stereolithographic modelling as an aid to orbital brachytherapy

PURPOSE

This paper describes the technique of stereolithographic biomodelling and its application to a patient who was treated using orbital brachytherapy.

METHODS AND MATERIALS

The process uses a moving laser beam, directed by a computer, to draw cross-sections of the model onto the surface of photo-curable liquid plastic. Using a stereolithographic apparatus (SLA), solid or surface data is sliced by software into very thin cross-sections. A helium cadmium (HeCd) laser then generates a small intense spot of ultraviolet (UV) light that is moved across the top of a vat of liquid photo monomer by a computerised optical scanning system. The laser polymerises the liquid into a solid where it touches, precisely printing each cross-section. A vertical elevator lowers the newly formed layer, and a recoating and levelling system establishes the next layer's thickness. Successive cross-sections (0.25 mm thick), each one adhering to the one below, are built one on top of the other, to form the part from the bottom up. The biomodel allowed the implant to be planned in detail prior to the surgery. The accurate placement of brachytherapy catheters was assured, and the dosimetry could be determined and optimised prior to the definitive procedure.

CONCLUSIONS

Stereolithography is a useful technique in the area of orbital brachytherapy. It allows the implant to to be carried out with greater accuracy and confidence. For the patient, it minimises the risk to the eye and provides them with a greater understanding of the procedure.