Ocular surface changes in patients who have undergone head and neck radiation therapy

PURPOSE

Dry eye syndrome (DES) is a familiar sequelae of radiation therapy (RT) for head and neck cancers (HNC). Ocular surface changes such as DES occur due to injury to the conjunctival epithelium, goblet cells, corneal surface, lacrimal glands, and meibomian glands. This study aimed at the evaluation and early detection of changes in ocular surface parameters in patients receiving RT for extraocular HNC.

METHODS

Forty-two eyes of 21 patients undergoing HNC RT were evaluated. Radiation technique and dose of radiation to the lens and eye were recorded. Subjects were evaluated for meibomian gland changes by meiboscore grading, ocular surface disease index (OSDI) questionnaire, Schirmer's test, tear film break-up time (TBUT), and slit-lamp examination before RT, immediately post RT, and 6 weeks post RT. A comparison of the ipsilateral eye on the irradiated side to the contralateral eye was done.

RESULTS

A significant reduction in TBUT was seen immediately post RT and 6 weeks post RT ( P < 0.001 and 0.008, respectively), with an increase in meiboscore at both visits ( P < 0.001). An OSDI score of >13 was seen in 23.80% of patients post RT, with a significant difference from baseline ( P < 0.001). On comparing ipsilateral and contralateral eye groups, a significant difference from baseline was seen in TBUT ( P < 0.001 and 0.033, respectively) and meiboscore ( P < 0.001 for both eyes). A significant change of >1 second in TBUT and >1.7 in meiboscore was seen with a mean dose of around 8 Gy to the lens.

CONCLUSION

All patients undergoing HNC RT should be followed up for ocular surface and meibomian gland changes. The contralateral eye should also be evaluated. Patients receiving lower doses to the ocular structures should also be kept under follow-up.

Extramedullary plasmacytoma of the larynx - Case report

Extramedullary plasmacytoma of the larynx is an extremely rare entity accounting for 0.04-0.45% of malignant tumours of the larynx. The objective of this clinical case report is to highlight the diagnosis and management of a unique case such as this. A 77-year-old gentleman presented with complaints of hoarseness for 1 year. Computed tomography image revealed a soft tissue mass lesion involving the right true vocal cord. Direct laryngoscopic biopsy was performed and subjected to histopathological examination, which showed collection of plasma cells. Immunohistochemistry confirmed the presence of Kappa and Lambda cells. Multiple myeloma (MM) was ruled out. The patient received radical intent radiation therapy using 3DCRT technique with a dose of 50Gy in 25# over 5 weeks. He experienced improvement in hoarseness on subsequent follow-up visits. At 1-year follow up, positron emission tomography computed tomography showed near total resolution of disease with no progression to MM. Radiation therapy alone is known to achieve good local control, recurrence free survival, and organ preservation in such cases.

Primary Neuroendocrine Carcinoma of the Larynx: A Case Report

Neuroendocrine tumours can originate from any part of the body. The most common site in the head and neck is the larynx, accounts for less than 0.6%. The neuroendocrine carcinomas (NECs) of the larynx are rare tumours with high incidence of widespread metastases and poor prognosis. Here we report a 50-year-old male with localised primary moderately differentiated NEC of the larynx. He was treated with surgery followed by adjuvant chemotherapy and concurrent chemoradiation. He is free of his disease and is doing well.

Dosimetric Comparison of Four Different Radiotherapy Planning Techniques for Adjuvant Radiotherapy of Left-Sided Breast, Axilla, and Supraclavicular Fossa

Purpose/Aim:

Forward planned intensity-modulated radiotherapy (forward IMRT) with breath-hold (BH) technique is considered optimal by most practitioners for treating left-sided breast cancer. Regional nodal irradiation including axilla and supraclavicular fossa (SCF) increases can increase dose-to-organs at risk (OAR) especially lung. This study was done to assess the potential of inverse planned IMRT (inverse IMRT) to achieve significant reduction in dose to OAR.

Materials and Methods:

Ten patients with left-sided breast cancer treated with Active Breath Co-ordinator BH technique were included in the study. Forward IMRT plans were generated in both BH and free breathing (FB) scans. Inverse IMRT plans were generated in FB scan using Tomotherapy-Direct and Tomotherapy-Helical techniques. Contouring was done as per the ESTRO consensus contouring guidelines. The dose prescribed was 40 Gy in 15 fractions. Statistical significance was tested using one-way ANOVA for parametric data and Kruskall–Wallis test for nonparametric data. Multiple comparison tests were done by using Bonferroni test. P <0.05 was considered to denote statistical significance.

Results:

Inverse IMRT plans achieved superior homogeneity index compared to forward IMRT with BH. Tomotherapy-Direct reduced dose to ipsilateral lung, compared to the forward IMRT with BH while achieving similar doses to other OAR. Tomotherapy-Helical plans achieved significantly better conformity index and reduced maximum dose to left anterior descending artery compared to forward IMRT plans, but low dose to other OAR was significantly worse.

Conclusion:

For left-sided breast, axilla, and SCF radiotherapy, inverse IMRT with Tomotherapy-Direct plan achieved better homogeneity index and reduced dose to ipsilateral lung compared to forward IMRT with BH.

Capillary flow enhancement in rectangular polymer microchannels with a deformable wall

We report the capillary flow enhancement in rectangular polymer microchannels, when one of the channel walls is a deformable polymer membrane. We provide detailed insight into the physics of elastocapillary interaction between the capillary flow and elastic membrane, which leads to significant improvements in capillary flow performance. As liquid flows by capillary action in such channels, the deformable wall deflects inwards due to the Young-Laplace pressure drop across the liquid meniscus. This, in turn, decreases the radius of curvature of the meniscus and increases the driving capillary pressure. A theoretical model is proposed to predict the resultant increase in filling speed and rise height, respectively, in deformable horizontal and vertical microchannels having large aspect ratios. A non-dimensional parameter J, which represents the ratio of the capillary force to the mechanical restoring force, is identified to quantify the elastocapillary effects in terms of the improvement in filling speed (for J>0.238) and the condition for channel collapse (J>1). The theoretical predictions show good agreement with experimental data obtained using deformable rectangular poly(dimethylsiloxane) microchannels. Both model predictions and experimental data show that over 15% improvement in the Washburn coefficient in horizontal channels, and over 30% improvement in capillary rise height in vertical channels, are possible prior to channel collapse. The proposed technique of using deformable membranes as channel walls is a viable method for capillary flow enhancement in microfluidic devices.