Definitive Chemoradiotherapy for Locally Advanced, Lymph-node Positive, Nonmetastatic Penile Squamous Cell Carcinoma

INTRODUCTION

Locally advanced penile cancer is rare, with few reported studies on the therapeutic role of chemoradiotherapy. We sought to characterize the efficacy and toxicity of definitive chemoradiotherapy for locally advanced, node-positive, squamous cell carcinoma of the penis.

MATERIALS AND METHODS

Six patients who had refused or were ineligible for surgical resection of clinically staged node-positive squamous cell penile cancer were treated with definitive chemoradiotherapy using either weekly cisplatin or 2 cycles of mitomycin C/5-fluorouracil. The mean radiation dose to the primary sites, involved lymph nodes, involved nodal basins, and uninvolved nodal basins was 57.2, 55.0, 49.7, and 42.3 equivalent dose delivered in 2-Gy fractions.

RESULTS

With a median follow-up of 7.2 years, 4 of the 6 patients were recurrence-free and 2 had developed recurrence. One of the latter died of penile-specific complications after salvage surgery to treat the recurrence. Of the 6 patients, 4 experienced long-term penectomy-free survival. No patient developed distant metastasis after therapy. The 4 patients with durable penectomy-free survival reported excellent urologic, sexual, and bowel function, as assessed by various validated patient-reported outcome surveys and subjective reports. One of the 2 patients with recurrence was successfully salvaged with penectomy. Lymphedema and stricture were not reported by any of the patients.

CONCLUSIONS

Definitive chemoradiotherapy is an effective organ-sparing treatment of node-positive penile cancer, with durable disease control and maintenance of quality of life. This treatment option should be offered to carefully counseled patients within the context of expert multidisciplinary teams and should be incorporated into expert consensus treatment guidelines.

High IDO1 Expression Is Associated with Poor Outcome in Patients with Anal Cancer Treated with Definitive Chemoradiotherapy

Despite increased incidence of anal squamous cell carcinoma (ASCC), treatment recommendations have remained unchanged for the past 35 years. This article profiles the tumor microenvironment of patients with localized ASCC, examining CD8, PD‐1, PD‐L1, IDO1 and HLA class I expression and, specifically, characterizes expression of IDO1 in the context of several key components of the immune microenvironment.

Background.

This study characterizes the tumor‐immune microenvironment in pretreatment, localized anal squamous cell carcinoma (ASCC), including two markers that have not previously been studied in ASCC: indoleamine 2,3 dioxygenase 1 (IDO1) and human leukocyte antigen (HLA) class I.

Materials and Methods.

Retrospective review identified 63 patients with ASCC receiving definitive chemoradiation between 2005 and 2016 with pretreatment tissue available. Immunohistochemistry was used to quantify cluster of differentiation 8 (CD8), programmed cell death protein 1, programmed death‐ligand 1, HLA class I, and IDO1. Cox proportional hazards models evaluated associations between outcomes and immune markers, controlling for clinical characteristics.

Results.

With a median follow‐up of 35 months, 3‐year overall survival was 78%. The only marker found to have a robust association with outcome was tumor IDO1. In general, the percentage of tumor cells expressing IDO1 was low (median 1%, interquartile range 0%–20%); however, patients with >50% of tumor cells expressing IDO1 had significantly worse overall survival (hazard ratio [HR] 4.7, p = .007) as well as higher local recurrence (HR 8.6, p = .0005) and distant metastasis (HR 12.7, p = .0002). Tumors with >50% IDO1 were also more likely to have the lowest quartile of CD8 infiltrate (<40 per high‐power field, p = .024).

Conclusion.

ASCC has a diverse immune milieu. Although patients generally do well with standard therapy, IDO1 may serve as a prognostic indicator of poor outcome and could help identify a patient population that might benefit from IDO‐targeted therapies.

Implications for Practice.

After definitive chemoradiation, patients with locally advanced anal cancer may experience significant treatment morbidity and high risk of recurrence. The goal of the current study is to identify novel prognostic factors in the tumor‐immune microenvironment that predict for poor outcomes after definitive chemoradiation. This study characterizes the tumor‐immune microenvironment in pre‐treatment, localized anal squamous cell carcinoma (ASCC), including two markers which have not previously been studied in ASCC: indoleamine 2,3 dioxygenase 1 (IDO1) and HLA class I. With a median follow‐up of 3 years, this study demonstrated that high IDO1 expression is correlated with significantly worse 3‐year overall survival (88% vs. 25%). Whereas recent studies of IDO1 inhibitors have shown mixed results, this study suggests that patients with anal cancer with high IDO1 expression have dismal prognosis and may represent a patient population primed for response to targeted IDO1 inhibition.

Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT)

INTRODUCTION

Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147-53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue.

METHODS

A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site.

RESULTS

The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose-volume histogram (DVH) doses were consistently lower.

CONCLUSION

The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques.

Anal cancer: are we making progress?

Anal cancer is an uncommon malignancy. There have been some intriguing developments in the past 3 years, in terms of our understanding of the molecular biology and processes that lead to anal cancer. There have also been some notable successes in prevention, imaging and treatment. Nonsurgical treatment is highly effective. The primary aim of such treatment is to achieve loco-regional control with chemoradiation (CRT), and preserve anal function without a colostomy. Randomised phase III trials presented or published over the past 3 years have explored novel strategies of neoadjuvant chemotherapy, maintenance chemotherapy, radiotherapy dose escalation and replacement of mitomycln C (MMC) with cisplatin in CRT. All have failed to improve on the current standard of care; i.e. MMC/ 5 fluorouracil (5FU) chemoradiation. However, more conformal strategies such as intensity modulated radiotherapy (IMRT) appear feasible to deliver with reduced toxicity, and may offer an opportunity to dose-escalate both to gross tumour and areas of potential nodal spread. Preliminary outcome data suggest no loss of efficacy. We evaluate the relevant recent literature published over the past 2 years, and summarize interesting and important new findings, with the aim of bringing the reader up-to-date on anal cancer.

Normal tissue complication probability modeling of acute hematologic toxicity in patients treated with intensity-modulated radiation therapy for squamous cell carcinoma of the anal canal

PURPOSE

To identify dosimetric parameters that correlate with acute hematologic toxicity (HT) in patients with squamous cell carcinoma of the anal canal treated with definitive chemoradiotherapy (CRT).

METHODS AND MATERIALS

We analyzed 33 patients receiving CRT. Pelvic bone (PBM) was contoured for each patient and divided into subsites: ilium, lower pelvis (LP), and lumbosacral spine (LSS). The volume of each region receiving at least 5, 10, 15, 20, 30, and 40 Gy was calculated. Endpoints included grade ≥3 HT (HT3+) and hematologic event (HE), defined as any grade ≥2 HT with a modification in chemotherapy dose. Normal tissue complication probability (NTCP) was evaluated with the Lyman-Kutcher-Burman (LKB) model. Logistic regression was used to test associations between HT and dosimetric/clinical parameters.

RESULTS

Nine patients experienced HT3+ and 15 patients experienced HE. Constrained optimization of the LKB model for HT3+ yielded the parameters m = 0.175, n = 1, and TD(50) = 32 Gy. With this model, mean PBM doses of 25 Gy, 27.5 Gy, and 31 Gy result in a 10%, 20%, and 40% risk of HT3+, respectively. Compared with patients with mean PBM dose of <30 Gy, patients with mean PBM dose ≥30 Gy had a 14-fold increase in the odds of developing HT3+ (p = 0.005). Several low-dose radiation parameters (i.e., PBM-V10) were associated with the development of HT3+ and HE. No association was found with the ilium, LP, or clinical factors.

CONCLUSIONS

LKB modeling confirms the expectation that PBM acts like a parallel organ, implying that the mean dose to the organ is a useful predictor for toxicity. Low-dose radiation to the PBM was also associated with clinically significant HT. Keeping the mean PBM dose <22.5 Gy and <25 Gy is associated with a 5% and 10% risk of HT, respectively.

[Intensity-modulated radiation therapy for anal carcinoma]

Anal canal carcinoma are highly curable by irradiation, combined with chemotherapy in locally advanced disease, with preservation of sphincter function. The clinical target volume for the nodes is extended, often including the inguinal nodes, which is not usual for other pelvic tumours. Acute and late effects are correlated with the volume and dose delivered to organs at risk, i. e. small bowel, bladder and increased by concomitant chemotherapy. Intensity modulated irradiation (IMRT) makes it possible to optimize the dose distribution in this "complex U shaped" volume, while maintaining the dose distribution for the target volumes. The conversion from conformal irradiation to IMRT necessitates good knowledge of the definition and skills to delineate target volumes and organs at risk, including new volumes needed to optimize the dose distribution. Dosimetric and clinical benefits of IMRT are described, based on early descriptions and evidence-based publication. The growing development of IMRT in anal canal radiotherapy must be encouraged, and long-term benefits should be soon published. Radiation oncologists should precisely learn IMRT recommendations before starting the technique, and evaluate its early and late results for adverse effects, but also for long-term tumour control.

The current landscape of locally advanced rectal cancer

Postoperative adjuvant chemoradiotherapy was recommended as the standard treatment for patients with rectal cancer because it reduces local recurrence. This paradigm shifted with the use of neoadjuvant chemoradiotherapy, which not only reduces local recurrence but also improves sphincter preservation and surgical outcomes. However, the treatment of rectal carcinoma remains complicated. The accuracy of tumor staging can be compromised depending on the imaging modality used. The addition of modern chemotherapeutics and biologics to 5-fluorouracil as radiation sensitizers is questionable. Oxaliplatin as a radiation sensitizer has minimal effects on the pathologic complete response, but improves the radiographical response at the expense of an increased risk of toxicities. The role of biologics in addition to radiation therapy continues to be explored. Attention has focused on improving diagnostic imaging, radiation oncology, and surgical techniques, treatment regimens, and on exploring a role of molecular markers for patients with rectal cancers. We review the pivotal trials that have led to the current treatment paradigm for locally advanced rectal cancer and discuss novel methodologies that are being developed for the treatment of this prevalent malignancy.