ESTRO 2024 - Abstract Book

S1418

Clinical - Head & neck

ESTRO 2024

tumour volume on previously irradiated locally recurrent human papilloma virus (HPV) non-mediated oropharyngeal cancer treated with Re-RT.

Material/Methods:

Patients with recurrent HPV negative oropharyngeal cancer who had undergone RT earlier in the past and now underwent radical Re-RT were evaluated. Their tumour volume in 3-dimensions were measured in centimeters while doing target delineation on contouring station. The diagnostic modality used for registration was either PET CT, MRI or both. All patients underwent Re-RT with intensity modulated radiotherapy technique. Early response evaluation was done at 3 months after the completion of Re-RT, and patients were categorized in to either complete responder or having residual disease (less than complete response). Univariate and multivariate analysis was performed to determine the impact of various factors including the type of response achieved.

Results:

Forty one patients were studied. Increasing age, increasing T stage, Re-RT dose more than 60Gy and increasing tumour volume were found to significantly predicting residual disease on univariate analysis. Re-RT dose more than 60Gy and TV were the only factors found significantly affecting residual disease on multivariate analysis (Table 1).

Table 1: Univariate analysis and multivariate analysis for prognostic factors for early tumour response

Factor

Groups

Univariate Analysis

Multivariate Analysis

HR (95 % CI); p value

HR (95 % CI); p value

Age

≤60 years

Reference

Reference

1.778 (1.119 – 4.201);

p =

1.109 (0.653 – 2.554); p = 0.443

>60 years

0.032

Progression type

Second primary

Reference

0.313 (0.176 – 1.304);

p =

Recurrence

0.336

Progression pattern

Second primary

Reference

0.388 (0.133 – 1.769);

p =

Local only

0.544

0.760 (0.052 – 2.772);

p =

Nodal only

0.290

2.109 (0.335 – 7.002);

p =

Local and Nodal

0.760

T Stage

T1

Reference

Reference

2.665 (1.118 – 12.702);

p =

2.660 (0.489 – 6.112); p = 0.873 0.763 (0.390 – 5.228); p = 0.663 1.887 (0.102 – 3.223); p = 0.420

T2

0.034

2.220 (1.103 – 12.662);

p =

T3

0.023

4.023 (0.673 – 9.773);

p =

T4

0.0881