Predictive indicators for thyroid cartilage involvement in carcinoma of the larynx seen on spiral computed tomography scans

Pretherapeutic Assessment by Multidetector Computed Tomography for Thyroid Cartilage Invasion in Laryngeal Cancer: A Double‑edged Sword

Introduction:Almost one-fourth of head and neck cancers in India are laryngeal cancers. Both conservative and surgical therapeutic approaches are available. According to present tumor-node-metastasis staging protocol, thyroid cartilage invasion is a crucial criterion for diagnosing advanced stages of the disease. A major cartilage invasion depicts T4A stage of disease for which surgical treatment is required. Aims: The present study aims to evaluate the accuracy of multidetector computed tomography (MDCT) in evaluation thyroid cartilage invasion in T3 and T4 stage of laryngeal cancers. Materials and Methods: It is a retrospective analysis done in the Department of Radiology, Pramukhswami Medical College, Anand, Gujarat, on 22 patients of T3 and T4 stage of laryngeal cancer who presented for pretherapeutic MDCT neck evaluation. The MDCT results were retrospectively reviewed and compared with postoperative histopathological results. Statistical analysis was done for each parameter as positive predictive value (PPV) (main statistical parameter), negative predictive value, sensitivity, and specificity. Results: MDCT showed a PPV of 60.00% in detecting any type of thyroid cartilage invasion, 66.66% for major and 33.33% for minor cartilage invasion. Extralaryngeal spread of disease was the most specific marker for cartilage involvement. In total, 31.8% of cases were downgraded in staging by pathology. Conclusion: Overestimation of thyroid cartilage invasion by MDCT is a reality which should be in mind before making final therapeutic decisions. Although crucial, it should not be the sole criteria preventing while making a surgical versus conservative therapeutic call.

[Current diagnostic imaging and treatment planning for laryngeal cancer]

CLINICAL/METHODICAL ISSUE

Laryngeal cancer is the third most common malignancy in the head and neck region. Endoscopic laryngoscopy with assessment of vocal fold function, microlaryngoscopy with biopsy and computed tomography (CT)/magnetic resonance imaging (MRI) remain the cornerstones of diagnostic workup. Thus, in the context of therapy planning, consideration of individual functional and socioeconomic aspects is of major importance.

STANDARD RADIOLOGICAL METHODS

Due to the short acquisition time and the possibility to perform functional maneuvers, CT is the tool of choice. MRI allows better soft tissue differentiation, but is more susceptible to movement artifacts and is complicated by disease-specific symptoms. The choice of examination method therefore depends on the patient's physical resilience.

PERFORMANCE

Depending on the study, the information on the sensitivity of CT with regard to the question of cartilage infiltration varies between 62 and 87% with a specificity between 75 and 98%. For MRI, sensitivity between 64 and 95% and specificity between 56 and 88% are stated.

ACHIEVEMENTS

The synthesis of the findings from endoscopy, biopsy and imaging is prerequisite for initiation of stage-appropriate treatment. For image interpretation, knowledge of the anatomical landmarks is essential. However, the assessment of posttherapeutic changes also poses a challenge for the radiologist.

PRACTICAL RECOMMENDATIONS

Regular interdisciplinary dialogue between radiologists, otorhinolaryngologists and radiotherapists in the context of primary diagnostics, therapy planning and aftercare is essential.

Organ preservation with chemoradiation in advanced laryngeal cancer: The problem of generalizing results from randomized controlled trials

BACKGROUND

The primary goal of treatment in advanced laryngeal cancer is to achieve optimal oncologic outcomes while preserving function and quality of life. Combination of chemotherapy and radiation has been popularized as an alternative to surgery for patients facing total laryngectomy. However, survival analyses from large, population-based databases have not duplicated results reported from randomized trials.

METHODS

A comprehensive literature review was undertaken to try to better understand the reasons why results differ among randomized trials and population cohort studies.

RESULTS

A variety of reasons are discussed, including differences in patient staging, selection bias, complexity bias, inconsistent terminology, patient compliance and treatment expertise.

CONCLUSIONS

Personalized treatment considering all factors is critical for optimal outcomes. In general, evidence supports total laryngectomy for patients with T4 cancers. Definitive chemoradiotherapy strategies are acceptable alternatives for T3 cancers, provided that all resources for the administration of the treatment, follow-up and surgical salvage are available.

Contrast-agent enhancement in ex vivo flat-panel computed tomography of locally advanced laryngeal cancer

CONCLUSION

Visualization of cartilage invasion in ex vivo laryngectomy specimens was improved by flat-panel volumetric computed tomography (fpvCT) after diffusion of contrast agents. A prospective study to assess the specificity and sensitivity of this new method is warranted.

OBJECTIVES

Cartilage invasion is a criterion for staging laryngeal squamous cell carcinoma. Contrast-enhanced CT is routinely used for assessing cartilage invasion. However, the sensitivities and specificities given for this method in the literature vary, and there is a need for improvement of this staging method. The objective of our pilot study was to determine cartilage invasion with fpvCT after contrast agent diffusion.

METHODS

Three patients underwent preoperative CT and total laryngectomy. The excised larynges were immediately scanned with an fpvCT scanner, without contrast enhancement. Additional fpvCT scans were performed after incubation of the larynges in one of three different contrast agents for 24 and 48 h. The results from presurgical conventional scans, fpvCT scans, and histological examination - as the gold standard - were compared.

RESULTS

We demonstrated the feasibility of ex vivo contrast enhancement of laryngeal tissues by diffusion, with a subsequent increase in contrast enhancement and improved visualization of cartilage invasion in fpvCT scans. Histology confirmed the fpvCT results.

Overstaging of cartilage invasion by multidetector CT scan for laryngeal cancer and its potential effect on the use of organ preservation with chemoradiation

OBJECTIVE

The two currently acceptable treatment options for locally advanced laryngeal cancer are total laryngectomy and organ preservation using chemoradiation. To facilitate therapeutic decision making, the accurate pre-treatment evaluation of cartilage invasion is of paramount importance. The purpose of this study was to evaluate the positive predictive value (PPV) and negative predictive value (NPV) of detecting neoplastic cartilage invasion in laryngeal cancer patients using fast-speed multidetector CT (MDCT).

METHODS

61 consecutive patients with clinically staged T3 or T4 squamous cell carcinoma of the larynx or hypopharynx who underwent total laryngectomy were analysed. All patients had MDCT of the neck within 2 weeks prior to surgery. Central radiographic and pathological review was performed in an attempt to correlate findings. MDCT invasion of cartilage was graded based on objective criteria.

RESULTS

MDCT scan was found to have a PPV of 78% and an NPV of 100% for detection of invasion through cartilage, with sensitivity being 100% and specificity 96%. For detection of any cartilage invasion (minor, major or through cartilage invasion), PPV and NPV were 63% and 92%, respectively. The sensitivity was 85% and specificity was 75%. For the detection of tumour invasion through cartilage or major cartilage invasion, MDCT scan had a PPV of 53% and an NPV of 95%. 47% (9/19) patients were down-staged from T4 to T3 after central pathology review.

CONCLUSION

The low PPV for cartilage destruction using MDCT suggests that a significant proportion of patients who were treated by total laryngectomy could have been appropriately offered organ preservation if more accurately staged at initial diagnosis.