Is Maximum Intensity Projection an Optimal Approach for Internal Target Volume Delineation in Lung Cancer?

PURPOSE: Respiratory-induced tumor motion is a major challenge in lung cancer (LC) radiotherapy. Four-dimensional computed tomography (4D-CT) using a maximum intensity projection (MIP) dataset is a commonly used and time-efficient method to generate internal target volume (ITV). This study compared ITV delineation using MIP or tumor delineation on all phases of the respiratory cycle. MATERIALS AND METHODS: Thirty consecutive patients of LC who underwent 4D-CT from January 2014 to March 2017 were included. ITV delineation was done using MIP (ITVMIP) and all ten phases of the respiratory cycle (ITV10Phases). Both volumes were analyzed using matching index (MI). It is the ratio of the intersection of two volumes to the union of two volumes. A paired sample t-test was used for statistical analysis, and P < 0.05 was considered statistically significant. RESULTS: The mean ± standard deviation volume of ITV10Phases was significantly larger compared to ITVMIP (134 cc ± 39.1 vs. 113 cc ± 124.2, P = 0.000). The mean MI was 0.75 (range 0.57-0.88). The mean volume of ITV10Phases not covered by ITVMIP was 26.33 cc (23.5%) and vice versa was 5.51 cc (6.1%). The mean MI was 0.73 for tumors close to the mediastinum, chest wall, and diaphragm. MI was not different between tumors ≤5 cm and >5 cm. The average time required for delineation was 9 and 96 min, respectively. The center of mass of two ITVs differed by 0.01 cm. CONCLUSION: ITV using MIP is significantly smaller and may miss a tumor compared to ITV delineation in 10 phases of 4D-CT. However, the time required is significantly less with MIP. Caution should be exercised in tumors proximity to the mediastinum, chest wall, and diaphragm.

Outcome of patients following neo-adjuvant chemotherapy for unresectable cervical nodes in head and neck squamous cell carcinomas.

BACKGROUND: This study was undertaken to assess the effects of neo-adjuvant chemotherapy (NACT) on patients with head and neck squamous cell carcinoma (HNSCC) having advanced unresectable cervical nodal metastasis. METHODOLOGY: A retrospective cohort study was conducted to assess the response of unresectable nodes to NACT in a pragmatic manner. Patients were grouped according to the response noted and the treatment offered after chemotherapy. The median survival amongst the patients in these groups was compared. RESULTS: The study included 51 patients. Oral cavity was the commonest site (67.2%). Favourable nodal response was seen in 64.7% of the patients. Up to 87.9% of the nodal responders were amenable to curative intent therapy. The overall survival of patients undergoing surgery, definitive chemoradiotherapy, palliative chemotherapy and palliative radiotherapy was 24, 13, 10 and 9 months, respectively. CONCLUSION: NACT may be utilized in HNSCC with advanced inoperable nodal disease to make them amenable to definitive therapy.

Prognostic factors in parotid cancers: Clinicopathological and treatment factors influencing outcomes.

BACKGROUND: Parotid cancers are uncommon and have a relatively long natural history. Determination of prognostic factors affecting the outcome is difficult. MATERIALS AND METHODS: The primary objective was to determine the demographic, clinical, histopathology and treatment-related factors affecting overall survival (OS) in parotid cancers. The secondary objective was to study the impact of these factors on disease-free survival (DFS) and patterns of failure. Data of consecutive patients who underwent parotidectomy for primary parotid malignancy between July 2006 and April 2015 with at least 6 months of posttreatment follow-up were retrospectively retrieved. Patients whose follow-up status was known at the time of analysis were included. One hundred and sixty-five patients met the inclusion criteria. RESULTS: The median follow-up was 38 months. The mean OS and DFS were 141.03 and 124.38 months, respectively. Age > 45 years affected both OS and DFS (P = 0.00 and 0.002 respectively) adversely. Advanced T stage affected adversely OS in univariate (P = 0.00) but not in multivariate analysis (P = 0.91) and DFS in both univariate (P = 0.00) and multivariate analysis (P = 0.005). Nodal positivity adversely affected survival adversely in univariate (P = 0.00 for OS and DFS) and multivariate analysis (P = 0.022 for OS and P = 0.001 for DFS). Resection margin of < 5mm affected OS as compared to a margin of ≥5mm (P = 0.03). CONCLUSIONS: Nodal positivity is the single most important factor affecting survival in parotid cancers. A histopathological resection margin of at least 5 mm is desirable. Advanced age along with high grade, advanced T and N stages need to be considered for adjuvant treatment.

Organ preservation vs primary surgery in the management of T3 laryngeal and hypopharyngeal cancers.

OBJECTIVE: The main objective is to compare the oncologic outcomes of patients with T3 laryngeal cancers who underwent total laryngectomy or organ preservation protocol (OPP) as the initial plan of management. MATERIALS AND METHODS: This is a retrospective study on 120 patients treated for T3 laryngeal and hypopharyngeal cancers. Patients with functional larynx underwent OPP and dysfunctional larynx underwent upfront laryngectomy. Median follow-up of the patients was 4.6 years. RESULTS: There was a significant difference in 3 year disease-free survival (DFS) between upfront laryngectomy and OPP (73.2 vs. 55.7%; P = 0.028) group but not in 3 year overall survival (73.2 vs. 68.7%, P = 0.8). The rate laryngeal preservation was 65% in CCRT and 44% in only radiotherapy group. At 3 years, the laryngectomy-free survival was 57.2% and the laryngo-esophageal dysfunction-free survival (LEDS) was 53.0%. CONCLUSION: T3 laryngeal cancers treated with upfront laryngectomy have an improved DFS when compared to those treated with non-surgical modalities. Primary surgery should be offered as an option for selected patients especially when CCRT is not feasible.

Hypothyroidism after 3-dimensional conformal radiotherapy and intensity-modulated radiotherapy for head and neck cancers: prospective data from 2 randomized controlled trials.

BACKGROUND: The purpose of this study was to determine the incidence of hypothyroidism after chemoradiation in head and neck squamous cell cancer (HNSCC). METHODS: One hundred twenty-two patients treated with 3-dimensional conformal radiotherapy (3DCRT; 70 Gy/35#) or intensity-modulated radiation therapy (IMRT; 66 Gy/30#) in 2 identical simultaneous randomized trials were studied. Thyroid function was assessed at baseline and every 3 to 6 monthly thereafter. Development of subclinical (thyroid-stimulating hormone [TSH] >4.67 µIU/mL) or biochemical (T4 <4.5 µg/dL) hypothyroidism was noted. Multivariate analyses were done to determine the factors associated with hypothyroidism. RESULTS: At a median of 41 months, 55.1% of the patients developed hypothyroidism (39.3% subclinical, 15.7% biochemical). The IMRT arm had higher subclinical hypothyroidism (51.1% vs 27.3%; p = .021) peaking around 1 year postradiotherapy in both arms. Younger age, hypopharynx/larynx primary, node positivity, higher dose/fraction (IMRT arm), and D100 were statistically significant factors for developing hypothyroidism. CONCLUSION: Postradiotherapy hypothyroidism peaks at 1 year. Higher dose per fraction possibly led to greater incidence of hypothyroidism in the IMRT cohort.