Skin toxicity predictive factors in cervical radiotherapy treatement

Head and neck cancer requires a comprehensive multimodal approach involving surgery, chemotherapy, and radiotherapy. As effective as these treatment modalities may be, they are not without drawbacks. In particular, during radiotherapy, skin toxicities are frequently encountered, ranging from mild erythema to severe ulceration, necrosis or hemorrhage. The aims of this study were to assess cumulative skin doses and to identify potential factors that may contribute to skin reactions.

We selected 20 patients treated for head and neck cancer in the Radiotherapy Oncology Department at Salah Azaiez Institute, in Tunisia. Patient data was collected from medical records and dosimetric data from our server (Eclipse). All patients were treated with conformational radiotherapy (RT) and were clinically monitored weekly. Acute radiation dermatitis was recorded based on the Common Terminology Criteria for Adverse Events (CTCAE v5.0) criteria. A 5 mm skin contour was delineated on the treatment plan for each patient.

There were 15 males and 5 females (sex ratio=3). Median age was 58 years old (25 to 79). Seven patients had a smoking habit, while 4 have a past history of immunodepression (Diabetes, autoimmune hepatitis). Tumor localizations were in the nasopharynx (n=11), in the larynx (n=4) in the oral cavity (n=3), in the nasal fossa (n=1) and in the thyroid (n=1). First line treatment was chemotherapy (3 cycles of TPF: docetaxel; cisplatin; fluorouracil) in 63% of nasopharyngeal cancer patients. Only 20% patients (n=4) underwent previous surgery for the primary tumor with neck dissection. Fifty percent of patients recieved concomitant chemotherapy. Volumetric Arctherapy (VMAT) technique was Performed  in 17 cases (85%). On average, radiodermatitis grade 1 (G1) or 2 (G2) appeared after a period of respectively 30 and 37 days, after the first day of RT treatment. Median dose when noticing G1-dermatitis was 34 Gy, correlated with median cumulative mean (Dmean) and maximal (Dmax) doses in the skin, respectively of 17,19 Gy and 32,32 Gy. G2-dermatitis was observed in 6 patients, median dose when noticing G2-dermatitis of 42 Gy, at Dmean of 42 Gy. Median cumulative Dmean and Dmax in the skin were respectively, 23,3 Gy and 43,13 Gy for G2 radiodermatitis. Among the G2-subgroup, median age was 59 years old, there were 3 smokers, 2 cases of immunodepression medical history, 3 underwent previous surgery with neck dissection, 3 had nasopharyngeal cancer with locally advanced tumor. No cases of G3-toxicity were reported in our population study.    

The neck skin should be identified as a sensitive structure for dose optimisation. Skin-sparing techniques should be considered in cervical irradiations for head and neck cancer.