EVALUATION OF SEVERE RADIATION INDUCED SKIN TOXICITY (RIST) IN BLACK WOMEN RECEIVING ADJUVANT RADIOTHERAPY FOR BREAST CANCER IN ZIMBABWE. A PROSPECTIVE COHORT STUDY

Abstract

Purpose:

Radiotherapy is an essential component of breast cancer treatment, but fear of radiation induced skin toxicity (RIST) in Zimbabwe has been suggested to be associated with hesitancy to undergo treatment. This study sought to determine the incidence of severe RIST in Black women and identify modifiable predictive factors to allow development of patient-oriented strategies to mitigate negative perceptions of radiotherapy which potentially reduce compliance to treatment.

Materials and Methods:

A prospective cohort study of Zimbabwean women undergoing adjuvant radiotherapy for breast cancer was conducted. Patient reported and Physician reported skin toxicity assessments were completed using validated skin toxicity scoring tools during radiotherapy. The level of agreement between patient and physician reported incidence of RIST was tested using kappa statistics. Predictive factors for severe RIST were analyzed using a univariate logistics regression.

Results:

Fifty-six patients met eligibility criteria. The most common physician and patient reported skin type was type V at 65% and 85% respectively. A total of 54 (96%) patients had at least 2 patient reported assessments and 46 (82%) had at least 2 physician reported assessments. The incidence of physician reported severe RIST was 12.8%, lower than patient reported one (26.8%), p=0.09. There was a low level of agreement between the patient and physician reported severe RIST, kappa= -0.08 (-0.31, 0.14). No patient characteristics were predictive of severe patient reported RIST. More patients with severe RIST had higher median fraction number, 25 (16.0-30.) (p=.05), total dose, 5500 cGy (4250-60000) (p=.016) and maximum dose 6023.5 cGy (5101-6580) (p=.045). Total dose was predictive of severe patient reported RIST, OR 1.12 (1.01-1.25) p=0.038. More patients using a cream had severe patient reported toxicity when compared to patients who did not report severe RIST, 93% compared to 34% (p=<0.001).

Conclusions:

The patient’s reported incidence of severe RIST was higher than the physician reported. Radiotherapy prescription, maximum dose and use of a cream were associated with worse patient reported toxicity. Findings support consideration of hypo fractionated treatment regiments in patients receiving adjuvant radiotherapy and exploration of ideal skin care creams/ interventions for use during treatment are needed to improve treatment experience mitigating negative perceptions associated with radiotherapy.