Risks of Breast Hypoplasia and Decreased Lactation from Radiation Therapy (RT) in Survivors of Pediatric Malignancy: Results from the Pediatric Normal Tissue Effects in the Clinic (PENTEC) Initiative

Is There an Association Between Breast Hypoplasia and Breastfeeding Outcomes? A Systematic Review

Introduction: Insufficient milk supply is the most common reason for premature breastfeeding cessation. Breast hypoplasia is one reason why women may be inherently unable to make a full milk supply. This review aimed to systematically explore the relationship between breast hypoplasia and breastfeeding duration, milk supply, and lactation onset. Materials and Methods: Medline, CINAHL, ProQuest Central, and the Cochrane Library databases were searched using the keywords "insufficient glandular tissue" or "mammary hypoplasia" or "breast hypoplasia" or "mammary gland hypoplasia" or "droopy breasts" or "snoopy deformity" or "tubular breast*" or "tuberous breast*" AND breastfeeding or "breast feeding" or breast-feeding or lactation. After initially screening 20 records, including reference lists, 9 full texts were assessed for eligibility; 2 were excluded as no breastfeeding outcomes were reported, leaving 7 studies (N = 42 women). Results: The studies in this review drew on results from the oldest included study and plastic surgery literature to define breast hypoplasia. Most women in this review (40/42) ceased exclusive breastfeeding before 1 month postpartum. One case study reported 24-hour milk production, which was 52 mL at 26 weeks postpartum. Conclusion: The relationship between breast hypoplasia and breastfeeding outcomes is underresearched. The co-occurring medical conditions (e.g., polycystic ovary syndrome) of some women provide avenues for future research into the possible pathogenesis of breast hypoplasia resulting in insufficient milk supply. Research is needed to evaluate the reliability of measuring and classifying markers of breast hypoplasia, and prospective studies can help determine the role of breast hypoplasia in milk production. PROSPERO registration number CRD42020191228.

Cardiac-Sparing and Breast-Sparing Whole Lung Irradiation Using Intensity-Modulated Proton Therapy

PURPOSE

Whole lung irradiation (WLI) is indicated for certain pediatric patients with lung metastases. This study investigated whether WLI delivered as intensity-modulated proton therapy (IMPT) could significantly spare the heart and breasts when compared with conventional WLI delivered with anteroposterior/posteroanterior photon fields and with intensity-modulated photon therapy (IMRT) WLI.

MATERIALS AND METHODS

Conventional, IMRT, and IMPT plans were generated for 5 patients (aged 5-22 years). The prescription dose was 16.5 GyRBE in 1.5-GyRBE fractions. Conventional plans used 6-MV photons prescribed to the midline and a field-in-field technique to cover the planning target volume (the internal target volume [ITV] + 1 cm). IMRT plans used 6-MV photons with a 7-beam arrangement with dose prescribed to the planning target volume. IMPT plans used scenario-based optimization with 5% range uncertainty and 5-mm positional uncertainty to cover the ITV robustly. Monte Carlo dose calculation was used for all IMPT plans. Doses were compared with paired Student t test.

RESULTS

The ITV Dmean was similar for the IMPT, conventional, and IMRT plans, but the IMPT plans had a lower Dmin and a higher Dmax at tissue interfaces than conventional plans (Dmean ratio: 0.96, P > .05; Dmin ratio: 0.9, P < .001; Dmax ratio: 1.1, P = .014). Dmeans for breast and heart substructures were lower with IMPT plans than with conventional/IMRT plans (heart ratios, 0.63:0.73; left ventricle ratios, 0.61:0.72; right ventricle ratios, 0.45:0.57; left atrium ratios, 0.79:0.85; right atrium ratios, 0.81:0.86; left breast ratios, 0.40:0.51; right breast ratio, 0.46:0.52; all P < .05).

CONCLUSIONS

IMPT resulted in comparable ITV coverage and lower mean doses to the heart and breasts when compared with other techniques. Whole lung irradiation delivered as IMPT warrants prospective evaluation in pediatric patients.