Table 2.

Studies excluded with reasons

Study	Reason for exclusion
Christodoulou [21]	Zero out of 30 breast cancer patients developed a scalp metastasis. However, there was no mention of the follow-up time in this patient cohort. Scalp cooling was employed
Campos-Gomez [23]	Sixty-eight patients in scalp cooling were reported as followed up on, but it was unclear as to the timeframe of follow-up. No mention as well of scalp metastasis
Christodoulou [22]	Two out of 227 breast cancer patients developed scalp metastasis. However, there was no mention of the follow-up time in this patient cohort. Scalp cooling was employed
Dean [24]	Fifty-eight breast cancer patients treated with doxorubicin and with scalp cooling were reported on for scalp metastasis, but there was no mention of the follow-up time
Johansen [31]	One patient in scalp cooling group who already had metastatic breast cancer (in the liver) experienced scalp metastasis (n = 61); all patients in group already had metastatic primary or recurrent cancer originating from the breast
Kargar [34]	Unclear as to type of primary cancer patients had
Lemenager [32]	Breast cancer patients treated with chemotherapy (n = 88); all had metastatic disease and were treated with scalp hypothermia. No mention of scalp metastasis
Lookingbill [33]	No mention of how patients with breast cancer were treated; There were 18 patients with scalp metastases out of 707 primary breast cancer patients. (18/707 = 2.5%). There was also no mention of the follow-up time as to when scalp metastases occurred
Massey [25]	Breast cancer patients treated with chemotherapy (n = 94) treated with Paxman cooling system. None of these patients developed scalp metastases during the study period. Unclear as to the length of follow-up on these patients
Middleton et al. [26]	Twenty-four patients with breast cancer receiving adjuvant chemotherapy. No length of follow-up noted. No scalp metastases noted
Nangia et al. [30]	No long-term follow-up on patients in randomized controlled trial
Peck et al. [27]	One patient in scalp cooling group subsequently presented with scalp metastasis. However, patient already had widespread metastatic cancer (n = 10); unclear as to follow-up
Satterwhite [28]	One patient in scalp cooling group already had scalp metastasis (n = 12); no follow-up
van den Hurk [29]	Breast cancer patients treated with chemotherapy in the Dutch scalp cooling registry (n = 1216). No patients developed scalp metastasis during the study period of 2006–2009. However, unclear as to the length of follow-up on these patients